| |
| /* pngwutil.c - utilities to write a PNG file |
| * |
| * Copyright (c) 2018 Cosmin Truta |
| * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson |
| * Copyright (c) 1996-1997 Andreas Dilger |
| * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc. |
| * |
| * This code is released under the libpng license. |
| * For conditions of distribution and use, see the disclaimer |
| * and license in png.h |
| */ |
| |
| #include "pngpriv.h" |
| |
| #ifdef PNG_WRITE_SUPPORTED |
| |
| #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED |
| /* Place a 32-bit number into a buffer in PNG byte order. We work |
| * with unsigned numbers for convenience, although one supported |
| * ancillary chunk uses signed (two's complement) numbers. |
| */ |
| void PNGAPI |
| png_save_uint_32(png_bytep buf, png_uint_32 i) |
| { |
| buf[0] = (png_byte)((i >> 24) & 0xffU); |
| buf[1] = (png_byte)((i >> 16) & 0xffU); |
| buf[2] = (png_byte)((i >> 8) & 0xffU); |
| buf[3] = (png_byte)( i & 0xffU); |
| } |
| |
| /* Place a 16-bit number into a buffer in PNG byte order. |
| * The parameter is declared unsigned int, not png_uint_16, |
| * just to avoid potential problems on pre-ANSI C compilers. |
| */ |
| void PNGAPI |
| png_save_uint_16(png_bytep buf, unsigned int i) |
| { |
| buf[0] = (png_byte)((i >> 8) & 0xffU); |
| buf[1] = (png_byte)( i & 0xffU); |
| } |
| #endif |
| |
| /* Simple function to write the signature. If we have already written |
| * the magic bytes of the signature, or more likely, the PNG stream is |
| * being embedded into another stream and doesn't need its own signature, |
| * we should call png_set_sig_bytes() to tell libpng how many of the |
| * bytes have already been written. |
| */ |
| void PNGAPI |
| png_write_sig(png_structrp png_ptr) |
| { |
| png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10}; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that the signature is being written */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE; |
| #endif |
| |
| /* Write the rest of the 8 byte signature */ |
| png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes], |
| (size_t)(8 - png_ptr->sig_bytes)); |
| |
| if (png_ptr->sig_bytes < 3) |
| png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE; |
| } |
| |
| /* Write the start of a PNG chunk. The type is the chunk type. |
| * The total_length is the sum of the lengths of all the data you will be |
| * passing in png_write_chunk_data(). |
| */ |
| static void |
| png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name, |
| png_uint_32 length) |
| { |
| png_byte buf[8]; |
| |
| #if defined(PNG_DEBUG) && (PNG_DEBUG > 0) |
| PNG_CSTRING_FROM_CHUNK(buf, chunk_name); |
| png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length); |
| #endif |
| |
| if (png_ptr == NULL) |
| return; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that the chunk header is being written. |
| * PNG_IO_CHUNK_HDR requires a single I/O call. |
| */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR; |
| #endif |
| |
| /* Write the length and the chunk name */ |
| png_save_uint_32(buf, length); |
| png_save_uint_32(buf + 4, chunk_name); |
| png_write_data(png_ptr, buf, 8); |
| |
| /* Put the chunk name into png_ptr->chunk_name */ |
| png_ptr->chunk_name = chunk_name; |
| |
| /* Reset the crc and run it over the chunk name */ |
| png_reset_crc(png_ptr); |
| |
| png_calculate_crc(png_ptr, buf + 4, 4); |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that chunk data will (possibly) be written. |
| * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls. |
| */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA; |
| #endif |
| } |
| |
| void PNGAPI |
| png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string, |
| png_uint_32 length) |
| { |
| png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length); |
| } |
| |
| /* Write the data of a PNG chunk started with png_write_chunk_header(). |
| * Note that multiple calls to this function are allowed, and that the |
| * sum of the lengths from these calls *must* add up to the total_length |
| * given to png_write_chunk_header(). |
| */ |
| void PNGAPI |
| png_write_chunk_data(png_structrp png_ptr, png_const_bytep data, size_t length) |
| { |
| /* Write the data, and run the CRC over it */ |
| if (png_ptr == NULL) |
| return; |
| |
| if (data != NULL && length > 0) |
| { |
| png_write_data(png_ptr, data, length); |
| |
| /* Update the CRC after writing the data, |
| * in case the user I/O routine alters it. |
| */ |
| png_calculate_crc(png_ptr, data, length); |
| } |
| } |
| |
| /* Finish a chunk started with png_write_chunk_header(). */ |
| void PNGAPI |
| png_write_chunk_end(png_structrp png_ptr) |
| { |
| png_byte buf[4]; |
| |
| if (png_ptr == NULL) return; |
| |
| #ifdef PNG_IO_STATE_SUPPORTED |
| /* Inform the I/O callback that the chunk CRC is being written. |
| * PNG_IO_CHUNK_CRC requires a single I/O function call. |
| */ |
| png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC; |
| #endif |
| |
| /* Write the crc in a single operation */ |
| png_save_uint_32(buf, png_ptr->crc); |
| |
| png_write_data(png_ptr, buf, 4); |
| } |
| |
| /* Write a PNG chunk all at once. The type is an array of ASCII characters |
| * representing the chunk name. The array must be at least 4 bytes in |
| * length, and does not need to be null terminated. To be safe, pass the |
| * pre-defined chunk names here, and if you need a new one, define it |
| * where the others are defined. The length is the length of the data. |
| * All the data must be present. If that is not possible, use the |
| * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end() |
| * functions instead. |
| */ |
| static void |
| png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name, |
| png_const_bytep data, size_t length) |
| { |
| if (png_ptr == NULL) |
| return; |
| |
| /* On 64-bit architectures 'length' may not fit in a png_uint_32. */ |
| if (length > PNG_UINT_31_MAX) |
| png_error(png_ptr, "length exceeds PNG maximum"); |
| |
| png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length); |
| png_write_chunk_data(png_ptr, data, length); |
| png_write_chunk_end(png_ptr); |
| } |
| |
| /* This is the API that calls the internal function above. */ |
| void PNGAPI |
| png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string, |
| png_const_bytep data, size_t length) |
| { |
| png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data, |
| length); |
| } |
| |
| /* This is used below to find the size of an image to pass to png_deflate_claim, |
| * so it only needs to be accurate if the size is less than 16384 bytes (the |
| * point at which a lower LZ window size can be used.) |
| */ |
| static png_alloc_size_t |
| png_image_size(png_structrp png_ptr) |
| { |
| /* Only return sizes up to the maximum of a png_uint_32; do this by limiting |
| * the width and height used to 15 bits. |
| */ |
| png_uint_32 h = png_ptr->height; |
| |
| if (png_ptr->rowbytes < 32768 && h < 32768) |
| { |
| if (png_ptr->interlaced != 0) |
| { |
| /* Interlacing makes the image larger because of the replication of |
| * both the filter byte and the padding to a byte boundary. |
| */ |
| png_uint_32 w = png_ptr->width; |
| unsigned int pd = png_ptr->pixel_depth; |
| png_alloc_size_t cb_base; |
| int pass; |
| |
| for (cb_base=0, pass=0; pass<=6; ++pass) |
| { |
| png_uint_32 pw = PNG_PASS_COLS(w, pass); |
| |
| if (pw > 0) |
| cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass); |
| } |
| |
| return cb_base; |
| } |
| |
| else |
| return (png_ptr->rowbytes+1) * h; |
| } |
| |
| else |
| return 0xffffffffU; |
| } |
| |
| #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
| /* This is the code to hack the first two bytes of the deflate stream (the |
| * deflate header) to correct the windowBits value to match the actual data |
| * size. Note that the second argument is the *uncompressed* size but the |
| * first argument is the *compressed* data (and it must be deflate |
| * compressed.) |
| */ |
| static void |
| optimize_cmf(png_bytep data, png_alloc_size_t data_size) |
| { |
| /* Optimize the CMF field in the zlib stream. The resultant zlib stream is |
| * still compliant to the stream specification. |
| */ |
| if (data_size <= 16384) /* else windowBits must be 15 */ |
| { |
| unsigned int z_cmf = data[0]; /* zlib compression method and flags */ |
| |
| if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70) |
| { |
| unsigned int z_cinfo; |
| unsigned int half_z_window_size; |
| |
| z_cinfo = z_cmf >> 4; |
| half_z_window_size = 1U << (z_cinfo + 7); |
| |
| if (data_size <= half_z_window_size) /* else no change */ |
| { |
| unsigned int tmp; |
| |
| do |
| { |
| half_z_window_size >>= 1; |
| --z_cinfo; |
| } |
| while (z_cinfo > 0 && data_size <= half_z_window_size); |
| |
| z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4); |
| |
| data[0] = (png_byte)z_cmf; |
| tmp = data[1] & 0xe0; |
| tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f; |
| data[1] = (png_byte)tmp; |
| } |
| } |
| } |
| } |
| #endif /* WRITE_OPTIMIZE_CMF */ |
| |
| /* Initialize the compressor for the appropriate type of compression. */ |
| static int |
| png_deflate_claim(png_structrp png_ptr, png_uint_32 owner, |
| png_alloc_size_t data_size) |
| { |
| if (png_ptr->zowner != 0) |
| { |
| #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED) |
| char msg[64]; |
| |
| PNG_STRING_FROM_CHUNK(msg, owner); |
| msg[4] = ':'; |
| msg[5] = ' '; |
| PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner); |
| /* So the message that results is "<chunk> using zstream"; this is an |
| * internal error, but is very useful for debugging. i18n requirements |
| * are minimal. |
| */ |
| (void)png_safecat(msg, (sizeof msg), 10, " using zstream"); |
| #endif |
| #if PNG_RELEASE_BUILD |
| png_warning(png_ptr, msg); |
| |
| /* Attempt sane error recovery */ |
| if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */ |
| { |
| png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT"); |
| return Z_STREAM_ERROR; |
| } |
| |
| png_ptr->zowner = 0; |
| #else |
| png_error(png_ptr, msg); |
| #endif |
| } |
| |
| { |
| int level = png_ptr->zlib_level; |
| int method = png_ptr->zlib_method; |
| int windowBits = png_ptr->zlib_window_bits; |
| int memLevel = png_ptr->zlib_mem_level; |
| int strategy; /* set below */ |
| int ret; /* zlib return code */ |
| |
| if (owner == png_IDAT) |
| { |
| if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0) |
| strategy = png_ptr->zlib_strategy; |
| |
| else if (png_ptr->do_filter != PNG_FILTER_NONE) |
| strategy = PNG_Z_DEFAULT_STRATEGY; |
| |
| else |
| strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY; |
| } |
| |
| else |
| { |
| #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED |
| level = png_ptr->zlib_text_level; |
| method = png_ptr->zlib_text_method; |
| windowBits = png_ptr->zlib_text_window_bits; |
| memLevel = png_ptr->zlib_text_mem_level; |
| strategy = png_ptr->zlib_text_strategy; |
| #else |
| /* If customization is not supported the values all come from the |
| * IDAT values except for the strategy, which is fixed to the |
| * default. (This is the pre-1.6.0 behavior too, although it was |
| * implemented in a very different way.) |
| */ |
| strategy = Z_DEFAULT_STRATEGY; |
| #endif |
| } |
| |
| /* Adjust 'windowBits' down if larger than 'data_size'; to stop this |
| * happening just pass 32768 as the data_size parameter. Notice that zlib |
| * requires an extra 262 bytes in the window in addition to the data to be |
| * able to see the whole of the data, so if data_size+262 takes us to the |
| * next windowBits size we need to fix up the value later. (Because even |
| * though deflate needs the extra window, inflate does not!) |
| */ |
| if (data_size <= 16384) |
| { |
| /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to |
| * work round a Microsoft Visual C misbehavior which, contrary to C-90, |
| * widens the result of the following shift to 64-bits if (and, |
| * apparently, only if) it is used in a test. |
| */ |
| unsigned int half_window_size = 1U << (windowBits-1); |
| |
| while (data_size + 262 <= half_window_size) |
| { |
| half_window_size >>= 1; |
| --windowBits; |
| } |
| } |
| |
| /* Check against the previous initialized values, if any. */ |
| if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 && |
| (png_ptr->zlib_set_level != level || |
| png_ptr->zlib_set_method != method || |
| png_ptr->zlib_set_window_bits != windowBits || |
| png_ptr->zlib_set_mem_level != memLevel || |
| png_ptr->zlib_set_strategy != strategy)) |
| { |
| if (deflateEnd(&png_ptr->zstream) != Z_OK) |
| png_warning(png_ptr, "deflateEnd failed (ignored)"); |
| |
| png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED; |
| } |
| |
| /* For safety clear out the input and output pointers (currently zlib |
| * doesn't use them on Init, but it might in the future). |
| */ |
| png_ptr->zstream.next_in = NULL; |
| png_ptr->zstream.avail_in = 0; |
| png_ptr->zstream.next_out = NULL; |
| png_ptr->zstream.avail_out = 0; |
| |
| /* Now initialize if required, setting the new parameters, otherwise just |
| * do a simple reset to the previous parameters. |
| */ |
| if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0) |
| ret = deflateReset(&png_ptr->zstream); |
| |
| else |
| { |
| ret = deflateInit2(&png_ptr->zstream, level, method, windowBits, |
| memLevel, strategy); |
| |
| if (ret == Z_OK) |
| png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; |
| } |
| |
| /* The return code is from either deflateReset or deflateInit2; they have |
| * pretty much the same set of error codes. |
| */ |
| if (ret == Z_OK) |
| png_ptr->zowner = owner; |
| |
| else |
| png_zstream_error(png_ptr, ret); |
| |
| return ret; |
| } |
| } |
| |
| /* Clean up (or trim) a linked list of compression buffers. */ |
| void /* PRIVATE */ |
| png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp) |
| { |
| png_compression_bufferp list = *listp; |
| |
| if (list != NULL) |
| { |
| *listp = NULL; |
| |
| do |
| { |
| png_compression_bufferp next = list->next; |
| |
| png_free(png_ptr, list); |
| list = next; |
| } |
| while (list != NULL); |
| } |
| } |
| |
| #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED |
| /* This pair of functions encapsulates the operation of (a) compressing a |
| * text string, and (b) issuing it later as a series of chunk data writes. |
| * The compression_state structure is shared context for these functions |
| * set up by the caller to allow access to the relevant local variables. |
| * |
| * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size |
| * temporary buffers. From 1.6.0 it is retained in png_struct so that it will |
| * be correctly freed in the event of a write error (previous implementations |
| * just leaked memory.) |
| */ |
| typedef struct |
| { |
| png_const_bytep input; /* The uncompressed input data */ |
| png_alloc_size_t input_len; /* Its length */ |
| png_uint_32 output_len; /* Final compressed length */ |
| png_byte output[1024]; /* First block of output */ |
| } compression_state; |
| |
| static void |
| png_text_compress_init(compression_state *comp, png_const_bytep input, |
| png_alloc_size_t input_len) |
| { |
| comp->input = input; |
| comp->input_len = input_len; |
| comp->output_len = 0; |
| } |
| |
| /* Compress the data in the compression state input */ |
| static int |
| png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name, |
| compression_state *comp, png_uint_32 prefix_len) |
| { |
| int ret; |
| |
| /* To find the length of the output it is necessary to first compress the |
| * input. The result is buffered rather than using the two-pass algorithm |
| * that is used on the inflate side; deflate is assumed to be slower and a |
| * PNG writer is assumed to have more memory available than a PNG reader. |
| * |
| * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an |
| * upper limit on the output size, but it is always bigger than the input |
| * size so it is likely to be more efficient to use this linked-list |
| * approach. |
| */ |
| ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len); |
| |
| if (ret != Z_OK) |
| return ret; |
| |
| /* Set up the compression buffers, we need a loop here to avoid overflowing a |
| * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited |
| * by the output buffer size, so there is no need to check that. Since this |
| * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits |
| * in size. |
| */ |
| { |
| png_compression_bufferp *end = &png_ptr->zbuffer_list; |
| png_alloc_size_t input_len = comp->input_len; /* may be zero! */ |
| png_uint_32 output_len; |
| |
| /* zlib updates these for us: */ |
| png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input); |
| png_ptr->zstream.avail_in = 0; /* Set below */ |
| png_ptr->zstream.next_out = comp->output; |
| png_ptr->zstream.avail_out = (sizeof comp->output); |
| |
| output_len = png_ptr->zstream.avail_out; |
| |
| do |
| { |
| uInt avail_in = ZLIB_IO_MAX; |
| |
| if (avail_in > input_len) |
| avail_in = (uInt)input_len; |
| |
| input_len -= avail_in; |
| |
| png_ptr->zstream.avail_in = avail_in; |
| |
| if (png_ptr->zstream.avail_out == 0) |
| { |
| png_compression_buffer *next; |
| |
| /* Chunk data is limited to 2^31 bytes in length, so the prefix |
| * length must be counted here. |
| */ |
| if (output_len + prefix_len > PNG_UINT_31_MAX) |
| { |
| ret = Z_MEM_ERROR; |
| break; |
| } |
| |
| /* Need a new (malloc'ed) buffer, but there may be one present |
| * already. |
| */ |
| next = *end; |
| if (next == NULL) |
| { |
| next = png_voidcast(png_compression_bufferp, png_malloc_base |
| (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); |
| |
| if (next == NULL) |
| { |
| ret = Z_MEM_ERROR; |
| break; |
| } |
| |
| /* Link in this buffer (so that it will be freed later) */ |
| next->next = NULL; |
| *end = next; |
| } |
| |
| png_ptr->zstream.next_out = next->output; |
| png_ptr->zstream.avail_out = png_ptr->zbuffer_size; |
| output_len += png_ptr->zstream.avail_out; |
| |
| /* Move 'end' to the next buffer pointer. */ |
| end = &next->next; |
| } |
| |
| /* Compress the data */ |
| ret = deflate(&png_ptr->zstream, |
| input_len > 0 ? Z_NO_FLUSH : Z_FINISH); |
| |
| /* Claw back input data that was not consumed (because avail_in is |
| * reset above every time round the loop). |
| */ |
| input_len += png_ptr->zstream.avail_in; |
| png_ptr->zstream.avail_in = 0; /* safety */ |
| } |
| while (ret == Z_OK); |
| |
| /* There may be some space left in the last output buffer. This needs to |
| * be subtracted from output_len. |
| */ |
| output_len -= png_ptr->zstream.avail_out; |
| png_ptr->zstream.avail_out = 0; /* safety */ |
| comp->output_len = output_len; |
| |
| /* Now double check the output length, put in a custom message if it is |
| * too long. Otherwise ensure the z_stream::msg pointer is set to |
| * something. |
| */ |
| if (output_len + prefix_len >= PNG_UINT_31_MAX) |
| { |
| png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long"); |
| ret = Z_MEM_ERROR; |
| } |
| |
| else |
| png_zstream_error(png_ptr, ret); |
| |
| /* Reset zlib for another zTXt/iTXt or image data */ |
| png_ptr->zowner = 0; |
| |
| /* The only success case is Z_STREAM_END, input_len must be 0; if not this |
| * is an internal error. |
| */ |
| if (ret == Z_STREAM_END && input_len == 0) |
| { |
| #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
| /* Fix up the deflate header, if required */ |
| optimize_cmf(comp->output, comp->input_len); |
| #endif |
| /* But Z_OK is returned, not Z_STREAM_END; this allows the claim |
| * function above to return Z_STREAM_END on an error (though it never |
| * does in the current versions of zlib.) |
| */ |
| return Z_OK; |
| } |
| |
| else |
| return ret; |
| } |
| } |
| |
| /* Ship the compressed text out via chunk writes */ |
| static void |
| png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp) |
| { |
| png_uint_32 output_len = comp->output_len; |
| png_const_bytep output = comp->output; |
| png_uint_32 avail = (sizeof comp->output); |
| png_compression_buffer *next = png_ptr->zbuffer_list; |
| |
| for (;;) |
| { |
| if (avail > output_len) |
| avail = output_len; |
| |
| png_write_chunk_data(png_ptr, output, avail); |
| |
| output_len -= avail; |
| |
| if (output_len == 0 || next == NULL) |
| break; |
| |
| avail = png_ptr->zbuffer_size; |
| output = next->output; |
| next = next->next; |
| } |
| |
| /* This is an internal error; 'next' must have been NULL! */ |
| if (output_len > 0) |
| png_error(png_ptr, "error writing ancillary chunked compressed data"); |
| } |
| #endif /* WRITE_COMPRESSED_TEXT */ |
| |
| /* Write the IHDR chunk, and update the png_struct with the necessary |
| * information. Note that the rest of this code depends upon this |
| * information being correct. |
| */ |
| void /* PRIVATE */ |
| png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height, |
| int bit_depth, int color_type, int compression_type, int filter_type, |
| int interlace_type) |
| { |
| png_byte buf[13]; /* Buffer to store the IHDR info */ |
| int is_invalid_depth; |
| |
| png_debug(1, "in png_write_IHDR"); |
| |
| /* Check that we have valid input data from the application info */ |
| switch (color_type) |
| { |
| case PNG_COLOR_TYPE_GRAY: |
| switch (bit_depth) |
| { |
| case 1: |
| case 2: |
| case 4: |
| case 8: |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| case 16: |
| #endif |
| png_ptr->channels = 1; break; |
| |
| default: |
| png_error(png_ptr, |
| "Invalid bit depth for grayscale image"); |
| } |
| break; |
| |
| case PNG_COLOR_TYPE_RGB: |
| is_invalid_depth = (bit_depth != 8); |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| is_invalid_depth = (is_invalid_depth && bit_depth != 16); |
| #endif |
| if (is_invalid_depth) |
| png_error(png_ptr, "Invalid bit depth for RGB image"); |
| |
| png_ptr->channels = 3; |
| break; |
| |
| case PNG_COLOR_TYPE_PALETTE: |
| switch (bit_depth) |
| { |
| case 1: |
| case 2: |
| case 4: |
| case 8: |
| png_ptr->channels = 1; |
| break; |
| |
| default: |
| png_error(png_ptr, "Invalid bit depth for paletted image"); |
| } |
| break; |
| |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| is_invalid_depth = (bit_depth != 8); |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| is_invalid_depth = (is_invalid_depth && bit_depth != 16); |
| #endif |
| if (is_invalid_depth) |
| png_error(png_ptr, "Invalid bit depth for grayscale+alpha image"); |
| |
| png_ptr->channels = 2; |
| break; |
| |
| case PNG_COLOR_TYPE_RGB_ALPHA: |
| is_invalid_depth = (bit_depth != 8); |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| is_invalid_depth = (is_invalid_depth && bit_depth != 16); |
| #endif |
| if (is_invalid_depth) |
| png_error(png_ptr, "Invalid bit depth for RGBA image"); |
| |
| png_ptr->channels = 4; |
| break; |
| |
| default: |
| png_error(png_ptr, "Invalid image color type specified"); |
| } |
| |
| if (compression_type != PNG_COMPRESSION_TYPE_BASE) |
| { |
| png_warning(png_ptr, "Invalid compression type specified"); |
| compression_type = PNG_COMPRESSION_TYPE_BASE; |
| } |
| |
| /* Write filter_method 64 (intrapixel differencing) only if |
| * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and |
| * 2. Libpng did not write a PNG signature (this filter_method is only |
| * used in PNG datastreams that are embedded in MNG datastreams) and |
| * 3. The application called png_permit_mng_features with a mask that |
| * included PNG_FLAG_MNG_FILTER_64 and |
| * 4. The filter_method is 64 and |
| * 5. The color_type is RGB or RGBA |
| */ |
| if ( |
| #ifdef PNG_MNG_FEATURES_SUPPORTED |
| !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 && |
| ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) && |
| (color_type == PNG_COLOR_TYPE_RGB || |
| color_type == PNG_COLOR_TYPE_RGB_ALPHA) && |
| (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) && |
| #endif |
| filter_type != PNG_FILTER_TYPE_BASE) |
| { |
| png_warning(png_ptr, "Invalid filter type specified"); |
| filter_type = PNG_FILTER_TYPE_BASE; |
| } |
| |
| #ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| if (interlace_type != PNG_INTERLACE_NONE && |
| interlace_type != PNG_INTERLACE_ADAM7) |
| { |
| png_warning(png_ptr, "Invalid interlace type specified"); |
| interlace_type = PNG_INTERLACE_ADAM7; |
| } |
| #else |
| interlace_type=PNG_INTERLACE_NONE; |
| #endif |
| |
| /* Save the relevant information */ |
| png_ptr->bit_depth = (png_byte)bit_depth; |
| png_ptr->color_type = (png_byte)color_type; |
| png_ptr->interlaced = (png_byte)interlace_type; |
| #ifdef PNG_MNG_FEATURES_SUPPORTED |
| png_ptr->filter_type = (png_byte)filter_type; |
| #endif |
| png_ptr->compression_type = (png_byte)compression_type; |
| png_ptr->width = width; |
| png_ptr->height = height; |
| |
| png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels); |
| png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width); |
| /* Set the usr info, so any transformations can modify it */ |
| png_ptr->usr_width = png_ptr->width; |
| png_ptr->usr_bit_depth = png_ptr->bit_depth; |
| png_ptr->usr_channels = png_ptr->channels; |
| |
| /* Pack the header information into the buffer */ |
| png_save_uint_32(buf, width); |
| png_save_uint_32(buf + 4, height); |
| buf[8] = (png_byte)bit_depth; |
| buf[9] = (png_byte)color_type; |
| buf[10] = (png_byte)compression_type; |
| buf[11] = (png_byte)filter_type; |
| buf[12] = (png_byte)interlace_type; |
| |
| /* Write the chunk */ |
| png_write_complete_chunk(png_ptr, png_IHDR, buf, 13); |
| |
| if ((png_ptr->do_filter) == PNG_NO_FILTERS) |
| { |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE || |
| png_ptr->bit_depth < 8) |
| png_ptr->do_filter = PNG_FILTER_NONE; |
| |
| else |
| png_ptr->do_filter = PNG_ALL_FILTERS; |
| } |
| |
| png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */ |
| } |
| |
| /* Write the palette. We are careful not to trust png_color to be in the |
| * correct order for PNG, so people can redefine it to any convenient |
| * structure. |
| */ |
| void /* PRIVATE */ |
| png_write_PLTE(png_structrp png_ptr, png_const_colorp palette, |
| png_uint_32 num_pal) |
| { |
| png_uint_32 max_palette_length, i; |
| png_const_colorp pal_ptr; |
| png_byte buf[3]; |
| |
| png_debug(1, "in png_write_PLTE"); |
| |
| max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ? |
| (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH; |
| |
| if (( |
| #ifdef PNG_MNG_FEATURES_SUPPORTED |
| (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 && |
| #endif |
| num_pal == 0) || num_pal > max_palette_length) |
| { |
| if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| png_error(png_ptr, "Invalid number of colors in palette"); |
| } |
| |
| else |
| { |
| png_warning(png_ptr, "Invalid number of colors in palette"); |
| return; |
| } |
| } |
| |
| if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) |
| { |
| png_warning(png_ptr, |
| "Ignoring request to write a PLTE chunk in grayscale PNG"); |
| |
| return; |
| } |
| |
| png_ptr->num_palette = (png_uint_16)num_pal; |
| png_debug1(3, "num_palette = %d", png_ptr->num_palette); |
| |
| png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3)); |
| #ifdef PNG_POINTER_INDEXING_SUPPORTED |
| |
| for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++) |
| { |
| buf[0] = pal_ptr->red; |
| buf[1] = pal_ptr->green; |
| buf[2] = pal_ptr->blue; |
| png_write_chunk_data(png_ptr, buf, 3); |
| } |
| |
| #else |
| /* This is a little slower but some buggy compilers need to do this |
| * instead |
| */ |
| pal_ptr=palette; |
| |
| for (i = 0; i < num_pal; i++) |
| { |
| buf[0] = pal_ptr[i].red; |
| buf[1] = pal_ptr[i].green; |
| buf[2] = pal_ptr[i].blue; |
| png_write_chunk_data(png_ptr, buf, 3); |
| } |
| |
| #endif |
| png_write_chunk_end(png_ptr); |
| png_ptr->mode |= PNG_HAVE_PLTE; |
| } |
| |
| /* This is similar to png_text_compress, above, except that it does not require |
| * all of the data at once and, instead of buffering the compressed result, |
| * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out |
| * because it calls the write interface. As a result it does its own error |
| * reporting and does not return an error code. In the event of error it will |
| * just call png_error. The input data length may exceed 32-bits. The 'flush' |
| * parameter is exactly the same as that to deflate, with the following |
| * meanings: |
| * |
| * Z_NO_FLUSH: normal incremental output of compressed data |
| * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush |
| * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up |
| * |
| * The routine manages the acquire and release of the png_ptr->zstream by |
| * checking and (at the end) clearing png_ptr->zowner; it does some sanity |
| * checks on the 'mode' flags while doing this. |
| */ |
| void /* PRIVATE */ |
| png_compress_IDAT(png_structrp png_ptr, png_const_bytep input, |
| png_alloc_size_t input_len, int flush) |
| { |
| if (png_ptr->zowner != png_IDAT) |
| { |
| /* First time. Ensure we have a temporary buffer for compression and |
| * trim the buffer list if it has more than one entry to free memory. |
| * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been |
| * created at this point, but the check here is quick and safe. |
| */ |
| if (png_ptr->zbuffer_list == NULL) |
| { |
| png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp, |
| png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr))); |
| png_ptr->zbuffer_list->next = NULL; |
| } |
| |
| else |
| png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next); |
| |
| /* It is a terminal error if we can't claim the zstream. */ |
| if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK) |
| png_error(png_ptr, png_ptr->zstream.msg); |
| |
| /* The output state is maintained in png_ptr->zstream, so it must be |
| * initialized here after the claim. |
| */ |
| png_ptr->zstream.next_out = png_ptr->zbuffer_list->output; |
| png_ptr->zstream.avail_out = png_ptr->zbuffer_size; |
| } |
| |
| /* Now loop reading and writing until all the input is consumed or an error |
| * terminates the operation. The _out values are maintained across calls to |
| * this function, but the input must be reset each time. |
| */ |
| png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); |
| png_ptr->zstream.avail_in = 0; /* set below */ |
| for (;;) |
| { |
| int ret; |
| |
| /* INPUT: from the row data */ |
| uInt avail = ZLIB_IO_MAX; |
| |
| if (avail > input_len) |
| avail = (uInt)input_len; /* safe because of the check */ |
| |
| png_ptr->zstream.avail_in = avail; |
| input_len -= avail; |
| |
| ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush); |
| |
| /* Include as-yet unconsumed input */ |
| input_len += png_ptr->zstream.avail_in; |
| png_ptr->zstream.avail_in = 0; |
| |
| /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note |
| * that these two zstream fields are preserved across the calls, therefore |
| * there is no need to set these up on entry to the loop. |
| */ |
| if (png_ptr->zstream.avail_out == 0) |
| { |
| png_bytep data = png_ptr->zbuffer_list->output; |
| uInt size = png_ptr->zbuffer_size; |
| |
| /* Write an IDAT containing the data then reset the buffer. The |
| * first IDAT may need deflate header optimization. |
| */ |
| #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
| if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 && |
| png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) |
| optimize_cmf(data, png_image_size(png_ptr)); |
| #endif |
| |
| if (size > 0) |
| png_write_complete_chunk(png_ptr, png_IDAT, data, size); |
| png_ptr->mode |= PNG_HAVE_IDAT; |
| |
| png_ptr->zstream.next_out = data; |
| png_ptr->zstream.avail_out = size; |
| |
| /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with |
| * the same flush parameter until it has finished output, for NO_FLUSH |
| * it doesn't matter. |
| */ |
| if (ret == Z_OK && flush != Z_NO_FLUSH) |
| continue; |
| } |
| |
| /* The order of these checks doesn't matter much; it just affects which |
| * possible error might be detected if multiple things go wrong at once. |
| */ |
| if (ret == Z_OK) /* most likely return code! */ |
| { |
| /* If all the input has been consumed then just return. If Z_FINISH |
| * was used as the flush parameter something has gone wrong if we get |
| * here. |
| */ |
| if (input_len == 0) |
| { |
| if (flush == Z_FINISH) |
| png_error(png_ptr, "Z_OK on Z_FINISH with output space"); |
| |
| return; |
| } |
| } |
| |
| else if (ret == Z_STREAM_END && flush == Z_FINISH) |
| { |
| /* This is the end of the IDAT data; any pending output must be |
| * flushed. For small PNG files we may still be at the beginning. |
| */ |
| png_bytep data = png_ptr->zbuffer_list->output; |
| uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out; |
| |
| #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED |
| if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 && |
| png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE) |
| optimize_cmf(data, png_image_size(png_ptr)); |
| #endif |
| |
| if (size > 0) |
| png_write_complete_chunk(png_ptr, png_IDAT, data, size); |
| png_ptr->zstream.avail_out = 0; |
| png_ptr->zstream.next_out = NULL; |
| png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT; |
| |
| png_ptr->zowner = 0; /* Release the stream */ |
| return; |
| } |
| |
| else |
| { |
| /* This is an error condition. */ |
| png_zstream_error(png_ptr, ret); |
| png_error(png_ptr, png_ptr->zstream.msg); |
| } |
| } |
| } |
| |
| /* Write an IEND chunk */ |
| void /* PRIVATE */ |
| png_write_IEND(png_structrp png_ptr) |
| { |
| png_debug(1, "in png_write_IEND"); |
| |
| png_write_complete_chunk(png_ptr, png_IEND, NULL, 0); |
| png_ptr->mode |= PNG_HAVE_IEND; |
| } |
| |
| #ifdef PNG_WRITE_gAMA_SUPPORTED |
| /* Write a gAMA chunk */ |
| void /* PRIVATE */ |
| png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma) |
| { |
| png_byte buf[4]; |
| |
| png_debug(1, "in png_write_gAMA"); |
| |
| /* file_gamma is saved in 1/100,000ths */ |
| png_save_uint_32(buf, (png_uint_32)file_gamma); |
| png_write_complete_chunk(png_ptr, png_gAMA, buf, 4); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_sRGB_SUPPORTED |
| /* Write a sRGB chunk */ |
| void /* PRIVATE */ |
| png_write_sRGB(png_structrp png_ptr, int srgb_intent) |
| { |
| png_byte buf[1]; |
| |
| png_debug(1, "in png_write_sRGB"); |
| |
| if (srgb_intent >= PNG_sRGB_INTENT_LAST) |
| png_warning(png_ptr, |
| "Invalid sRGB rendering intent specified"); |
| |
| buf[0]=(png_byte)srgb_intent; |
| png_write_complete_chunk(png_ptr, png_sRGB, buf, 1); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_iCCP_SUPPORTED |
| /* Write an iCCP chunk */ |
| void /* PRIVATE */ |
| png_write_iCCP(png_structrp png_ptr, png_const_charp name, |
| png_const_bytep profile) |
| { |
| png_uint_32 name_len; |
| png_uint_32 profile_len; |
| png_byte new_name[81]; /* 1 byte for the compression byte */ |
| compression_state comp; |
| png_uint_32 temp; |
| |
| png_debug(1, "in png_write_iCCP"); |
| |
| /* These are all internal problems: the profile should have been checked |
| * before when it was stored. |
| */ |
| if (profile == NULL) |
| png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */ |
| |
| profile_len = png_get_uint_32(profile); |
| |
| if (profile_len < 132) |
| png_error(png_ptr, "ICC profile too short"); |
| |
| temp = (png_uint_32) (*(profile+8)); |
| if (temp > 3 && (profile_len & 0x03)) |
| png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)"); |
| |
| { |
| png_uint_32 embedded_profile_len = png_get_uint_32(profile); |
| |
| if (profile_len != embedded_profile_len) |
| png_error(png_ptr, "Profile length does not match profile"); |
| } |
| |
| name_len = png_check_keyword(png_ptr, name, new_name); |
| |
| if (name_len == 0) |
| png_error(png_ptr, "iCCP: invalid keyword"); |
| |
| new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE; |
| |
| /* Make sure we include the NULL after the name and the compression type */ |
| ++name_len; |
| |
| png_text_compress_init(&comp, profile, profile_len); |
| |
| /* Allow for keyword terminator and compression byte */ |
| if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK) |
| png_error(png_ptr, png_ptr->zstream.msg); |
| |
| png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len); |
| |
| png_write_chunk_data(png_ptr, new_name, name_len); |
| |
| png_write_compressed_data_out(png_ptr, &comp); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_sPLT_SUPPORTED |
| /* Write a sPLT chunk */ |
| void /* PRIVATE */ |
| png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette) |
| { |
| png_uint_32 name_len; |
| png_byte new_name[80]; |
| png_byte entrybuf[10]; |
| size_t entry_size = (spalette->depth == 8 ? 6 : 10); |
| size_t palette_size = entry_size * (size_t)spalette->nentries; |
| png_sPLT_entryp ep; |
| #ifndef PNG_POINTER_INDEXING_SUPPORTED |
| int i; |
| #endif |
| |
| png_debug(1, "in png_write_sPLT"); |
| |
| name_len = png_check_keyword(png_ptr, spalette->name, new_name); |
| |
| if (name_len == 0) |
| png_error(png_ptr, "sPLT: invalid keyword"); |
| |
| /* Make sure we include the NULL after the name */ |
| png_write_chunk_header(png_ptr, png_sPLT, |
| (png_uint_32)(name_len + 2 + palette_size)); |
| |
| png_write_chunk_data(png_ptr, (png_bytep)new_name, (size_t)(name_len + 1)); |
| |
| png_write_chunk_data(png_ptr, &spalette->depth, 1); |
| |
| /* Loop through each palette entry, writing appropriately */ |
| #ifdef PNG_POINTER_INDEXING_SUPPORTED |
| for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++) |
| { |
| if (spalette->depth == 8) |
| { |
| entrybuf[0] = (png_byte)ep->red; |
| entrybuf[1] = (png_byte)ep->green; |
| entrybuf[2] = (png_byte)ep->blue; |
| entrybuf[3] = (png_byte)ep->alpha; |
| png_save_uint_16(entrybuf + 4, ep->frequency); |
| } |
| |
| else |
| { |
| png_save_uint_16(entrybuf + 0, ep->red); |
| png_save_uint_16(entrybuf + 2, ep->green); |
| png_save_uint_16(entrybuf + 4, ep->blue); |
| png_save_uint_16(entrybuf + 6, ep->alpha); |
| png_save_uint_16(entrybuf + 8, ep->frequency); |
| } |
| |
| png_write_chunk_data(png_ptr, entrybuf, entry_size); |
| } |
| #else |
| ep=spalette->entries; |
| for (i = 0; i>spalette->nentries; i++) |
| { |
| if (spalette->depth == 8) |
| { |
| entrybuf[0] = (png_byte)ep[i].red; |
| entrybuf[1] = (png_byte)ep[i].green; |
| entrybuf[2] = (png_byte)ep[i].blue; |
| entrybuf[3] = (png_byte)ep[i].alpha; |
| png_save_uint_16(entrybuf + 4, ep[i].frequency); |
| } |
| |
| else |
| { |
| png_save_uint_16(entrybuf + 0, ep[i].red); |
| png_save_uint_16(entrybuf + 2, ep[i].green); |
| png_save_uint_16(entrybuf + 4, ep[i].blue); |
| png_save_uint_16(entrybuf + 6, ep[i].alpha); |
| png_save_uint_16(entrybuf + 8, ep[i].frequency); |
| } |
| |
| png_write_chunk_data(png_ptr, entrybuf, entry_size); |
| } |
| #endif |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_sBIT_SUPPORTED |
| /* Write the sBIT chunk */ |
| void /* PRIVATE */ |
| png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type) |
| { |
| png_byte buf[4]; |
| size_t size; |
| |
| png_debug(1, "in png_write_sBIT"); |
| |
| /* Make sure we don't depend upon the order of PNG_COLOR_8 */ |
| if ((color_type & PNG_COLOR_MASK_COLOR) != 0) |
| { |
| png_byte maxbits; |
| |
| maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 : |
| png_ptr->usr_bit_depth); |
| |
| if (sbit->red == 0 || sbit->red > maxbits || |
| sbit->green == 0 || sbit->green > maxbits || |
| sbit->blue == 0 || sbit->blue > maxbits) |
| { |
| png_warning(png_ptr, "Invalid sBIT depth specified"); |
| return; |
| } |
| |
| buf[0] = sbit->red; |
| buf[1] = sbit->green; |
| buf[2] = sbit->blue; |
| size = 3; |
| } |
| |
| else |
| { |
| if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth) |
| { |
| png_warning(png_ptr, "Invalid sBIT depth specified"); |
| return; |
| } |
| |
| buf[0] = sbit->gray; |
| size = 1; |
| } |
| |
| if ((color_type & PNG_COLOR_MASK_ALPHA) != 0) |
| { |
| if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth) |
| { |
| png_warning(png_ptr, "Invalid sBIT depth specified"); |
| return; |
| } |
| |
| buf[size++] = sbit->alpha; |
| } |
| |
| png_write_complete_chunk(png_ptr, png_sBIT, buf, size); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_cHRM_SUPPORTED |
| /* Write the cHRM chunk */ |
| void /* PRIVATE */ |
| png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy) |
| { |
| png_byte buf[32]; |
| |
| png_debug(1, "in png_write_cHRM"); |
| |
| /* Each value is saved in 1/100,000ths */ |
| png_save_int_32(buf, xy->whitex); |
| png_save_int_32(buf + 4, xy->whitey); |
| |
| png_save_int_32(buf + 8, xy->redx); |
| png_save_int_32(buf + 12, xy->redy); |
| |
| png_save_int_32(buf + 16, xy->greenx); |
| png_save_int_32(buf + 20, xy->greeny); |
| |
| png_save_int_32(buf + 24, xy->bluex); |
| png_save_int_32(buf + 28, xy->bluey); |
| |
| png_write_complete_chunk(png_ptr, png_cHRM, buf, 32); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_tRNS_SUPPORTED |
| /* Write the tRNS chunk */ |
| void /* PRIVATE */ |
| png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha, |
| png_const_color_16p tran, int num_trans, int color_type) |
| { |
| png_byte buf[6]; |
| |
| png_debug(1, "in png_write_tRNS"); |
| |
| if (color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette) |
| { |
| png_app_warning(png_ptr, |
| "Invalid number of transparent colors specified"); |
| return; |
| } |
| |
| /* Write the chunk out as it is */ |
| png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha, |
| (size_t)num_trans); |
| } |
| |
| else if (color_type == PNG_COLOR_TYPE_GRAY) |
| { |
| /* One 16-bit value */ |
| if (tran->gray >= (1 << png_ptr->bit_depth)) |
| { |
| png_app_warning(png_ptr, |
| "Ignoring attempt to write tRNS chunk out-of-range for bit_depth"); |
| |
| return; |
| } |
| |
| png_save_uint_16(buf, tran->gray); |
| png_write_complete_chunk(png_ptr, png_tRNS, buf, 2); |
| } |
| |
| else if (color_type == PNG_COLOR_TYPE_RGB) |
| { |
| /* Three 16-bit values */ |
| png_save_uint_16(buf, tran->red); |
| png_save_uint_16(buf + 2, tran->green); |
| png_save_uint_16(buf + 4, tran->blue); |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0) |
| #else |
| if ((buf[0] | buf[2] | buf[4]) != 0) |
| #endif |
| { |
| png_app_warning(png_ptr, |
| "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8"); |
| return; |
| } |
| |
| png_write_complete_chunk(png_ptr, png_tRNS, buf, 6); |
| } |
| |
| else |
| { |
| png_app_warning(png_ptr, "Can't write tRNS with an alpha channel"); |
| } |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_bKGD_SUPPORTED |
| /* Write the background chunk */ |
| void /* PRIVATE */ |
| png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type) |
| { |
| png_byte buf[6]; |
| |
| png_debug(1, "in png_write_bKGD"); |
| |
| if (color_type == PNG_COLOR_TYPE_PALETTE) |
| { |
| if ( |
| #ifdef PNG_MNG_FEATURES_SUPPORTED |
| (png_ptr->num_palette != 0 || |
| (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) && |
| #endif |
| back->index >= png_ptr->num_palette) |
| { |
| png_warning(png_ptr, "Invalid background palette index"); |
| return; |
| } |
| |
| buf[0] = back->index; |
| png_write_complete_chunk(png_ptr, png_bKGD, buf, 1); |
| } |
| |
| else if ((color_type & PNG_COLOR_MASK_COLOR) != 0) |
| { |
| png_save_uint_16(buf, back->red); |
| png_save_uint_16(buf + 2, back->green); |
| png_save_uint_16(buf + 4, back->blue); |
| #ifdef PNG_WRITE_16BIT_SUPPORTED |
| if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0) |
| #else |
| if ((buf[0] | buf[2] | buf[4]) != 0) |
| #endif |
| { |
| png_warning(png_ptr, |
| "Ignoring attempt to write 16-bit bKGD chunk " |
| "when bit_depth is 8"); |
| |
| return; |
| } |
| |
| png_write_complete_chunk(png_ptr, png_bKGD, buf, 6); |
| } |
| |
| else |
| { |
| if (back->gray >= (1 << png_ptr->bit_depth)) |
| { |
| png_warning(png_ptr, |
| "Ignoring attempt to write bKGD chunk out-of-range for bit_depth"); |
| |
| return; |
| } |
| |
| png_save_uint_16(buf, back->gray); |
| png_write_complete_chunk(png_ptr, png_bKGD, buf, 2); |
| } |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_eXIf_SUPPORTED |
| /* Write the Exif data */ |
| void /* PRIVATE */ |
| png_write_eXIf(png_structrp png_ptr, png_bytep exif, int num_exif) |
| { |
| int i; |
| png_byte buf[1]; |
| |
| png_debug(1, "in png_write_eXIf"); |
| |
| png_write_chunk_header(png_ptr, png_eXIf, (png_uint_32)(num_exif)); |
| |
| for (i = 0; i < num_exif; i++) |
| { |
| buf[0] = exif[i]; |
| png_write_chunk_data(png_ptr, buf, 1); |
| } |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_hIST_SUPPORTED |
| /* Write the histogram */ |
| void /* PRIVATE */ |
| png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist) |
| { |
| int i; |
| png_byte buf[3]; |
| |
| png_debug(1, "in png_write_hIST"); |
| |
| if (num_hist > (int)png_ptr->num_palette) |
| { |
| png_debug2(3, "num_hist = %d, num_palette = %d", num_hist, |
| png_ptr->num_palette); |
| |
| png_warning(png_ptr, "Invalid number of histogram entries specified"); |
| return; |
| } |
| |
| png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2)); |
| |
| for (i = 0; i < num_hist; i++) |
| { |
| png_save_uint_16(buf, hist[i]); |
| png_write_chunk_data(png_ptr, buf, 2); |
| } |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_tEXt_SUPPORTED |
| /* Write a tEXt chunk */ |
| void /* PRIVATE */ |
| png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, |
| size_t text_len) |
| { |
| png_uint_32 key_len; |
| png_byte new_key[80]; |
| |
| png_debug(1, "in png_write_tEXt"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| png_error(png_ptr, "tEXt: invalid keyword"); |
| |
| if (text == NULL || *text == '\0') |
| text_len = 0; |
| |
| else |
| text_len = strlen(text); |
| |
| if (text_len > PNG_UINT_31_MAX - (key_len+1)) |
| png_error(png_ptr, "tEXt: text too long"); |
| |
| /* Make sure we include the 0 after the key */ |
| png_write_chunk_header(png_ptr, png_tEXt, |
| (png_uint_32)/*checked above*/(key_len + text_len + 1)); |
| /* |
| * We leave it to the application to meet PNG-1.0 requirements on the |
| * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of |
| * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them. |
| * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. |
| */ |
| png_write_chunk_data(png_ptr, new_key, key_len + 1); |
| |
| if (text_len != 0) |
| png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_zTXt_SUPPORTED |
| /* Write a compressed text chunk */ |
| void /* PRIVATE */ |
| png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text, |
| int compression) |
| { |
| png_uint_32 key_len; |
| png_byte new_key[81]; |
| compression_state comp; |
| |
| png_debug(1, "in png_write_zTXt"); |
| |
| if (compression == PNG_TEXT_COMPRESSION_NONE) |
| { |
| png_write_tEXt(png_ptr, key, text, 0); |
| return; |
| } |
| |
| if (compression != PNG_TEXT_COMPRESSION_zTXt) |
| png_error(png_ptr, "zTXt: invalid compression type"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| png_error(png_ptr, "zTXt: invalid keyword"); |
| |
| /* Add the compression method and 1 for the keyword separator. */ |
| new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; |
| ++key_len; |
| |
| /* Compute the compressed data; do it now for the length */ |
| png_text_compress_init(&comp, (png_const_bytep)text, |
| text == NULL ? 0 : strlen(text)); |
| |
| if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK) |
| png_error(png_ptr, png_ptr->zstream.msg); |
| |
| /* Write start of chunk */ |
| png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len); |
| |
| /* Write key */ |
| png_write_chunk_data(png_ptr, new_key, key_len); |
| |
| /* Write the compressed data */ |
| png_write_compressed_data_out(png_ptr, &comp); |
| |
| /* Close the chunk */ |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_iTXt_SUPPORTED |
| /* Write an iTXt chunk */ |
| void /* PRIVATE */ |
| png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key, |
| png_const_charp lang, png_const_charp lang_key, png_const_charp text) |
| { |
| png_uint_32 key_len, prefix_len; |
| size_t lang_len, lang_key_len; |
| png_byte new_key[82]; |
| compression_state comp; |
| |
| png_debug(1, "in png_write_iTXt"); |
| |
| key_len = png_check_keyword(png_ptr, key, new_key); |
| |
| if (key_len == 0) |
| png_error(png_ptr, "iTXt: invalid keyword"); |
| |
| /* Set the compression flag */ |
| switch (compression) |
| { |
| case PNG_ITXT_COMPRESSION_NONE: |
| case PNG_TEXT_COMPRESSION_NONE: |
| compression = new_key[++key_len] = 0; /* no compression */ |
| break; |
| |
| case PNG_TEXT_COMPRESSION_zTXt: |
| case PNG_ITXT_COMPRESSION_zTXt: |
| compression = new_key[++key_len] = 1; /* compressed */ |
| break; |
| |
| default: |
| png_error(png_ptr, "iTXt: invalid compression"); |
| } |
| |
| new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE; |
| ++key_len; /* for the keywod separator */ |
| |
| /* We leave it to the application to meet PNG-1.0 requirements on the |
| * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of |
| * any non-Latin-1 characters except for NEWLINE. ISO PNG, however, |
| * specifies that the text is UTF-8 and this really doesn't require any |
| * checking. |
| * |
| * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG. |
| * |
| * TODO: validate the language tag correctly (see the spec.) |
| */ |
| if (lang == NULL) lang = ""; /* empty language is valid */ |
| lang_len = strlen(lang)+1; |
| if (lang_key == NULL) lang_key = ""; /* may be empty */ |
| lang_key_len = strlen(lang_key)+1; |
| if (text == NULL) text = ""; /* may be empty */ |
| |
| prefix_len = key_len; |
| if (lang_len > PNG_UINT_31_MAX-prefix_len) |
| prefix_len = PNG_UINT_31_MAX; |
| else |
| prefix_len = (png_uint_32)(prefix_len + lang_len); |
| |
| if (lang_key_len > PNG_UINT_31_MAX-prefix_len) |
| prefix_len = PNG_UINT_31_MAX; |
| else |
| prefix_len = (png_uint_32)(prefix_len + lang_key_len); |
| |
| png_text_compress_init(&comp, (png_const_bytep)text, strlen(text)); |
| |
| if (compression != 0) |
| { |
| if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK) |
| png_error(png_ptr, png_ptr->zstream.msg); |
| } |
| |
| else |
| { |
| if (comp.input_len > PNG_UINT_31_MAX-prefix_len) |
| png_error(png_ptr, "iTXt: uncompressed text too long"); |
| |
| /* So the string will fit in a chunk: */ |
| comp.output_len = (png_uint_32)/*SAFE*/comp.input_len; |
| } |
| |
| png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len); |
| |
| png_write_chunk_data(png_ptr, new_key, key_len); |
| |
| png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len); |
| |
| png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len); |
| |
| if (compression != 0) |
| png_write_compressed_data_out(png_ptr, &comp); |
| |
| else |
| png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len); |
| |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_oFFs_SUPPORTED |
| /* Write the oFFs chunk */ |
| void /* PRIVATE */ |
| png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset, |
| int unit_type) |
| { |
| png_byte buf[9]; |
| |
| png_debug(1, "in png_write_oFFs"); |
| |
| if (unit_type >= PNG_OFFSET_LAST) |
| png_warning(png_ptr, "Unrecognized unit type for oFFs chunk"); |
| |
| png_save_int_32(buf, x_offset); |
| png_save_int_32(buf + 4, y_offset); |
| buf[8] = (png_byte)unit_type; |
| |
| png_write_complete_chunk(png_ptr, png_oFFs, buf, 9); |
| } |
| #endif |
| #ifdef PNG_WRITE_pCAL_SUPPORTED |
| /* Write the pCAL chunk (described in the PNG extensions document) */ |
| void /* PRIVATE */ |
| png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0, |
| png_int_32 X1, int type, int nparams, png_const_charp units, |
| png_charpp params) |
| { |
| png_uint_32 purpose_len; |
| size_t units_len, total_len; |
| png_size_tp params_len; |
| png_byte buf[10]; |
| png_byte new_purpose[80]; |
| int i; |
| |
| png_debug1(1, "in png_write_pCAL (%d parameters)", nparams); |
| |
| if (type >= PNG_EQUATION_LAST) |
| png_error(png_ptr, "Unrecognized equation type for pCAL chunk"); |
| |
| purpose_len = png_check_keyword(png_ptr, purpose, new_purpose); |
| |
| if (purpose_len == 0) |
| png_error(png_ptr, "pCAL: invalid keyword"); |
| |
| ++purpose_len; /* terminator */ |
| |
| png_debug1(3, "pCAL purpose length = %d", (int)purpose_len); |
| units_len = strlen(units) + (nparams == 0 ? 0 : 1); |
| png_debug1(3, "pCAL units length = %d", (int)units_len); |
| total_len = purpose_len + units_len + 10; |
| |
| params_len = (png_size_tp)png_malloc(png_ptr, |
| (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (size_t)))); |
| |
| /* Find the length of each parameter, making sure we don't count the |
| * null terminator for the last parameter. |
| */ |
| for (i = 0; i < nparams; i++) |
| { |
| params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1); |
| png_debug2(3, "pCAL parameter %d length = %lu", i, |
| (unsigned long)params_len[i]); |
| total_len += params_len[i]; |
| } |
| |
| png_debug1(3, "pCAL total length = %d", (int)total_len); |
| png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len); |
| png_write_chunk_data(png_ptr, new_purpose, purpose_len); |
| png_save_int_32(buf, X0); |
| png_save_int_32(buf + 4, X1); |
| buf[8] = (png_byte)type; |
| buf[9] = (png_byte)nparams; |
| png_write_chunk_data(png_ptr, buf, 10); |
| png_write_chunk_data(png_ptr, (png_const_bytep)units, (size_t)units_len); |
| |
| for (i = 0; i < nparams; i++) |
| { |
| png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]); |
| } |
| |
| png_free(png_ptr, params_len); |
| png_write_chunk_end(png_ptr); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_sCAL_SUPPORTED |
| /* Write the sCAL chunk */ |
| void /* PRIVATE */ |
| png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width, |
| png_const_charp height) |
| { |
| png_byte buf[64]; |
| size_t wlen, hlen, total_len; |
| |
| png_debug(1, "in png_write_sCAL_s"); |
| |
| wlen = strlen(width); |
| hlen = strlen(height); |
| total_len = wlen + hlen + 2; |
| |
| if (total_len > 64) |
| { |
| png_warning(png_ptr, "Can't write sCAL (buffer too small)"); |
| return; |
| } |
| |
| buf[0] = (png_byte)unit; |
| memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */ |
| memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */ |
| |
| png_debug1(3, "sCAL total length = %u", (unsigned int)total_len); |
| png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_pHYs_SUPPORTED |
| /* Write the pHYs chunk */ |
| void /* PRIVATE */ |
| png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit, |
| png_uint_32 y_pixels_per_unit, |
| int unit_type) |
| { |
| png_byte buf[9]; |
| |
| png_debug(1, "in png_write_pHYs"); |
| |
| if (unit_type >= PNG_RESOLUTION_LAST) |
| png_warning(png_ptr, "Unrecognized unit type for pHYs chunk"); |
| |
| png_save_uint_32(buf, x_pixels_per_unit); |
| png_save_uint_32(buf + 4, y_pixels_per_unit); |
| buf[8] = (png_byte)unit_type; |
| |
| png_write_complete_chunk(png_ptr, png_pHYs, buf, 9); |
| } |
| #endif |
| |
| #ifdef PNG_WRITE_tIME_SUPPORTED |
| /* Write the tIME chunk. Use either png_convert_from_struct_tm() |
| * or png_convert_from_time_t(), or fill in the structure yourself. |
| */ |
| void /* PRIVATE */ |
| png_write_tIME(png_structrp png_ptr, png_const_timep mod_time) |
| { |
| png_byte buf[7]; |
| |
| png_debug(1, "in png_write_tIME"); |
| |
| if (mod_time->month > 12 || mod_time->month < 1 || |
| mod_time->day > 31 || mod_time->day < 1 || |
| mod_time->hour > 23 || mod_time->second > 60) |
| { |
| png_warning(png_ptr, "Invalid time specified for tIME chunk"); |
| return; |
| } |
| |
| png_save_uint_16(buf, mod_time->year); |
| buf[2] = mod_time->month; |
| buf[3] = mod_time->day; |
| buf[4] = mod_time->hour; |
| buf[5] = mod_time->minute; |
| buf[6] = mod_time->second; |
| |
| png_write_complete_chunk(png_ptr, png_tIME, buf, 7); |
| } |
| #endif |
| |
| /* Initializes the row writing capability of libpng */ |
| void /* PRIVATE */ |
| png_write_start_row(png_structrp png_ptr) |
| { |
| #ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
| |
| /* Start of interlace block */ |
| static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; |
| |
| /* Offset to next interlace block */ |
| static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; |
| |
| /* Start of interlace block in the y direction */ |
| static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; |
| |
| /* Offset to next interlace block in the y direction */ |
| static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; |
| #endif |
| |
| png_alloc_size_t buf_size; |
| int usr_pixel_depth; |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| png_byte filters; |
| #endif |
| |
| png_debug(1, "in png_write_start_row"); |
| |
| usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth; |
| buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1; |
| |
| /* 1.5.6: added to allow checking in the row write code. */ |
| png_ptr->transformed_pixel_depth = png_ptr->pixel_depth; |
| png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth; |
| |
| /* Set up row buffer */ |
| png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size)); |
| |
| png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE; |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| filters = png_ptr->do_filter; |
| |
| if (png_ptr->height == 1) |
| filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH); |
| |
| if (png_ptr->width == 1) |
| filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH); |
| |
| if (filters == 0) |
| filters = PNG_FILTER_NONE; |
| |
| png_ptr->do_filter = filters; |
| |
| if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG | |
| PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL) |
| { |
| int num_filters = 0; |
| |
| png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size)); |
| |
| if (filters & PNG_FILTER_SUB) |
| num_filters++; |
| |
| if (filters & PNG_FILTER_UP) |
| num_filters++; |
| |
| if (filters & PNG_FILTER_AVG) |
| num_filters++; |
| |
| if (filters & PNG_FILTER_PAETH) |
| num_filters++; |
| |
| if (num_filters > 1) |
| png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr, |
| buf_size)); |
| } |
| |
| /* We only need to keep the previous row if we are using one of the following |
| * filters. |
| */ |
| if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0) |
| png_ptr->prev_row = png_voidcast(png_bytep, |
| png_calloc(png_ptr, buf_size)); |
| #endif /* WRITE_FILTER */ |
| |
| #ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| /* If interlaced, we need to set up width and height of pass */ |
| if (png_ptr->interlaced != 0) |
| { |
| if ((png_ptr->transformations & PNG_INTERLACE) == 0) |
| { |
| png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 - |
| png_pass_ystart[0]) / png_pass_yinc[0]; |
| |
| png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 - |
| png_pass_start[0]) / png_pass_inc[0]; |
| } |
| |
| else |
| { |
| png_ptr->num_rows = png_ptr->height; |
| png_ptr->usr_width = png_ptr->width; |
| } |
| } |
| |
| else |
| #endif |
| { |
| png_ptr->num_rows = png_ptr->height; |
| png_ptr->usr_width = png_ptr->width; |
| } |
| } |
| |
| /* Internal use only. Called when finished processing a row of data. */ |
| void /* PRIVATE */ |
| png_write_finish_row(png_structrp png_ptr) |
| { |
| #ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
| |
| /* Start of interlace block */ |
| static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; |
| |
| /* Offset to next interlace block */ |
| static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; |
| |
| /* Start of interlace block in the y direction */ |
| static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1}; |
| |
| /* Offset to next interlace block in the y direction */ |
| static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2}; |
| #endif |
| |
| png_debug(1, "in png_write_finish_row"); |
| |
| /* Next row */ |
| png_ptr->row_number++; |
| |
| /* See if we are done */ |
| if (png_ptr->row_number < png_ptr->num_rows) |
| return; |
| |
| #ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| /* If interlaced, go to next pass */ |
| if (png_ptr->interlaced != 0) |
| { |
| png_ptr->row_number = 0; |
| if ((png_ptr->transformations & PNG_INTERLACE) != 0) |
| { |
| png_ptr->pass++; |
| } |
| |
| else |
| { |
| /* Loop until we find a non-zero width or height pass */ |
| do |
| { |
| png_ptr->pass++; |
| |
| if (png_ptr->pass >= 7) |
| break; |
| |
| png_ptr->usr_width = (png_ptr->width + |
| png_pass_inc[png_ptr->pass] - 1 - |
| png_pass_start[png_ptr->pass]) / |
| png_pass_inc[png_ptr->pass]; |
| |
| png_ptr->num_rows = (png_ptr->height + |
| png_pass_yinc[png_ptr->pass] - 1 - |
| png_pass_ystart[png_ptr->pass]) / |
| png_pass_yinc[png_ptr->pass]; |
| |
| if ((png_ptr->transformations & PNG_INTERLACE) != 0) |
| break; |
| |
| } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0); |
| |
| } |
| |
| /* Reset the row above the image for the next pass */ |
| if (png_ptr->pass < 7) |
| { |
| if (png_ptr->prev_row != NULL) |
| memset(png_ptr->prev_row, 0, |
| PNG_ROWBYTES(png_ptr->usr_channels * |
| png_ptr->usr_bit_depth, png_ptr->width) + 1); |
| |
| return; |
| } |
| } |
| #endif |
| |
| /* If we get here, we've just written the last row, so we need |
| to flush the compressor */ |
| png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH); |
| } |
| |
| #ifdef PNG_WRITE_INTERLACING_SUPPORTED |
| /* Pick out the correct pixels for the interlace pass. |
| * The basic idea here is to go through the row with a source |
| * pointer and a destination pointer (sp and dp), and copy the |
| * correct pixels for the pass. As the row gets compacted, |
| * sp will always be >= dp, so we should never overwrite anything. |
| * See the default: case for the easiest code to understand. |
| */ |
| void /* PRIVATE */ |
| png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass) |
| { |
| /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */ |
| |
| /* Start of interlace block */ |
| static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0}; |
| |
| /* Offset to next interlace block */ |
| static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1}; |
| |
| png_debug(1, "in png_do_write_interlace"); |
| |
| /* We don't have to do anything on the last pass (6) */ |
| if (pass < 6) |
| { |
| /* Each pixel depth is handled separately */ |
| switch (row_info->pixel_depth) |
| { |
| case 1: |
| { |
| png_bytep sp; |
| png_bytep dp; |
| unsigned int shift; |
| int d; |
| int value; |
| png_uint_32 i; |
| png_uint_32 row_width = row_info->width; |
| |
| dp = row; |
| d = 0; |
| shift = 7; |
| |
| for (i = png_pass_start[pass]; i < row_width; |
| i += png_pass_inc[pass]) |
| { |
| sp = row + (size_t)(i >> 3); |
| value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01; |
| d |= (value << shift); |
| |
| if (shift == 0) |
| { |
| shift = 7; |
| *dp++ = (png_byte)d; |
| d = 0; |
| } |
| |
| else |
| shift--; |
| |
| } |
| if (shift != 7) |
| *dp = (png_byte)d; |
| |
| break; |
| } |
| |
| case 2: |
| { |
| png_bytep sp; |
| png_bytep dp; |
| unsigned int shift; |
| int d; |
| int value; |
| png_uint_32 i; |
| png_uint_32 row_width = row_info->width; |
| |
| dp = row; |
| shift = 6; |
| d = 0; |
| |
| for (i = png_pass_start[pass]; i < row_width; |
| i += png_pass_inc[pass]) |
| { |
| sp = row + (size_t)(i >> 2); |
| value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03; |
| d |= (value << shift); |
| |
| if (shift == 0) |
| { |
| shift = 6; |
| *dp++ = (png_byte)d; |
| d = 0; |
| } |
| |
| else |
| shift -= 2; |
| } |
| if (shift != 6) |
| *dp = (png_byte)d; |
| |
| break; |
| } |
| |
| case 4: |
| { |
| png_bytep sp; |
| png_bytep dp; |
| unsigned int shift; |
| int d; |
| int value; |
| png_uint_32 i; |
| png_uint_32 row_width = row_info->width; |
| |
| dp = row; |
| shift = 4; |
| d = 0; |
| for (i = png_pass_start[pass]; i < row_width; |
| i += png_pass_inc[pass]) |
| { |
| sp = row + (size_t)(i >> 1); |
| value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f; |
| d |= (value << shift); |
| |
| if (shift == 0) |
| { |
| shift = 4; |
| *dp++ = (png_byte)d; |
| d = 0; |
| } |
| |
| else |
| shift -= 4; |
| } |
| if (shift != 4) |
| *dp = (png_byte)d; |
| |
| break; |
| } |
| |
| default: |
| { |
| png_bytep sp; |
| png_bytep dp; |
| png_uint_32 i; |
| png_uint_32 row_width = row_info->width; |
| size_t pixel_bytes; |
| |
| /* Start at the beginning */ |
| dp = row; |
| |
| /* Find out how many bytes each pixel takes up */ |
| pixel_bytes = (row_info->pixel_depth >> 3); |
| |
| /* Loop through the row, only looking at the pixels that matter */ |
| for (i = png_pass_start[pass]; i < row_width; |
| i += png_pass_inc[pass]) |
| { |
| /* Find out where the original pixel is */ |
| sp = row + (size_t)i * pixel_bytes; |
| |
| /* Move the pixel */ |
| if (dp != sp) |
| memcpy(dp, sp, pixel_bytes); |
| |
| /* Next pixel */ |
| dp += pixel_bytes; |
| } |
| break; |
| } |
| } |
| /* Set new row width */ |
| row_info->width = (row_info->width + |
| png_pass_inc[pass] - 1 - |
| png_pass_start[pass]) / |
| png_pass_inc[pass]; |
| |
| row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, |
| row_info->width); |
| } |
| } |
| #endif |
| |
| |
| /* This filters the row, chooses which filter to use, if it has not already |
| * been specified by the application, and then writes the row out with the |
| * chosen filter. |
| */ |
| static void /* PRIVATE */ |
| png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, |
| size_t row_bytes); |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| static size_t /* PRIVATE */ |
| png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp, |
| size_t row_bytes, size_t lmins) |
| { |
| png_bytep rp, dp, lp; |
| size_t i; |
| size_t sum = 0; |
| unsigned int v; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp; |
| i++, rp++, dp++) |
| { |
| v = *dp = *rp; |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| } |
| |
| for (lp = png_ptr->row_buf + 1; i < row_bytes; |
| i++, rp++, lp++, dp++) |
| { |
| v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| |
| if (sum > lmins) /* We are already worse, don't continue. */ |
| break; |
| } |
| |
| return (sum); |
| } |
| |
| static void /* PRIVATE */ |
| png_setup_sub_row_only(png_structrp png_ptr, const png_uint_32 bpp, |
| size_t row_bytes) |
| { |
| png_bytep rp, dp, lp; |
| size_t i; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp; |
| i++, rp++, dp++) |
| { |
| *dp = *rp; |
| } |
| |
| for (lp = png_ptr->row_buf + 1; i < row_bytes; |
| i++, rp++, lp++, dp++) |
| { |
| *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); |
| } |
| } |
| |
| static size_t /* PRIVATE */ |
| png_setup_up_row(png_structrp png_ptr, size_t row_bytes, size_t lmins) |
| { |
| png_bytep rp, dp, pp; |
| size_t i; |
| size_t sum = 0; |
| unsigned int v; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_UP; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1, |
| pp = png_ptr->prev_row + 1; i < row_bytes; |
| i++, rp++, pp++, dp++) |
| { |
| v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| |
| if (sum > lmins) /* We are already worse, don't continue. */ |
| break; |
| } |
| |
| return (sum); |
| } |
| static void /* PRIVATE */ |
| png_setup_up_row_only(png_structrp png_ptr, size_t row_bytes) |
| { |
| png_bytep rp, dp, pp; |
| size_t i; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_UP; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1, |
| pp = png_ptr->prev_row + 1; i < row_bytes; |
| i++, rp++, pp++, dp++) |
| { |
| *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); |
| } |
| } |
| |
| static size_t /* PRIVATE */ |
| png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp, |
| size_t row_bytes, size_t lmins) |
| { |
| png_bytep rp, dp, pp, lp; |
| png_uint_32 i; |
| size_t sum = 0; |
| unsigned int v; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1, |
| pp = png_ptr->prev_row + 1; i < bpp; i++) |
| { |
| v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); |
| |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| } |
| |
| for (lp = png_ptr->row_buf + 1; i < row_bytes; i++) |
| { |
| v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) |
| & 0xff); |
| |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| |
| if (sum > lmins) /* We are already worse, don't continue. */ |
| break; |
| } |
| |
| return (sum); |
| } |
| static void /* PRIVATE */ |
| png_setup_avg_row_only(png_structrp png_ptr, const png_uint_32 bpp, |
| size_t row_bytes) |
| { |
| png_bytep rp, dp, pp, lp; |
| png_uint_32 i; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1, |
| pp = png_ptr->prev_row + 1; i < bpp; i++) |
| { |
| *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); |
| } |
| |
| for (lp = png_ptr->row_buf + 1; i < row_bytes; i++) |
| { |
| *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) |
| & 0xff); |
| } |
| } |
| |
| static size_t /* PRIVATE */ |
| png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp, |
| size_t row_bytes, size_t lmins) |
| { |
| png_bytep rp, dp, pp, cp, lp; |
| size_t i; |
| size_t sum = 0; |
| unsigned int v; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1, |
| pp = png_ptr->prev_row + 1; i < bpp; i++) |
| { |
| v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); |
| |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| } |
| |
| for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes; |
| i++) |
| { |
| int a, b, c, pa, pb, pc, p; |
| |
| b = *pp++; |
| c = *cp++; |
| a = *lp++; |
| |
| p = b - c; |
| pc = a - c; |
| |
| #ifdef PNG_USE_ABS |
| pa = abs(p); |
| pb = abs(pc); |
| pc = abs(p + pc); |
| #else |
| pa = p < 0 ? -p : p; |
| pb = pc < 0 ? -pc : pc; |
| pc = (p + pc) < 0 ? -(p + pc) : p + pc; |
| #endif |
| |
| p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; |
| |
| v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); |
| |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| |
| if (sum > lmins) /* We are already worse, don't continue. */ |
| break; |
| } |
| |
| return (sum); |
| } |
| static void /* PRIVATE */ |
| png_setup_paeth_row_only(png_structrp png_ptr, const png_uint_32 bpp, |
| size_t row_bytes) |
| { |
| png_bytep rp, dp, pp, cp, lp; |
| size_t i; |
| |
| png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH; |
| |
| for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1, |
| pp = png_ptr->prev_row + 1; i < bpp; i++) |
| { |
| *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); |
| } |
| |
| for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes; |
| i++) |
| { |
| int a, b, c, pa, pb, pc, p; |
| |
| b = *pp++; |
| c = *cp++; |
| a = *lp++; |
| |
| p = b - c; |
| pc = a - c; |
| |
| #ifdef PNG_USE_ABS |
| pa = abs(p); |
| pb = abs(pc); |
| pc = abs(p + pc); |
| #else |
| pa = p < 0 ? -p : p; |
| pb = pc < 0 ? -pc : pc; |
| pc = (p + pc) < 0 ? -(p + pc) : p + pc; |
| #endif |
| |
| p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c; |
| |
| *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); |
| } |
| } |
| #endif /* WRITE_FILTER */ |
| |
| void /* PRIVATE */ |
| png_write_find_filter(png_structrp png_ptr, png_row_infop row_info) |
| { |
| #ifndef PNG_WRITE_FILTER_SUPPORTED |
| png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1); |
| #else |
| unsigned int filter_to_do = png_ptr->do_filter; |
| png_bytep row_buf; |
| png_bytep best_row; |
| png_uint_32 bpp; |
| size_t mins; |
| size_t row_bytes = row_info->rowbytes; |
| |
| png_debug(1, "in png_write_find_filter"); |
| |
| /* Find out how many bytes offset each pixel is */ |
| bpp = (row_info->pixel_depth + 7) >> 3; |
| |
| row_buf = png_ptr->row_buf; |
| mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the |
| running sum */; |
| |
| /* The prediction method we use is to find which method provides the |
| * smallest value when summing the absolute values of the distances |
| * from zero, using anything >= 128 as negative numbers. This is known |
| * as the "minimum sum of absolute differences" heuristic. Other |
| * heuristics are the "weighted minimum sum of absolute differences" |
| * (experimental and can in theory improve compression), and the "zlib |
| * predictive" method (not implemented yet), which does test compressions |
| * of lines using different filter methods, and then chooses the |
| * (series of) filter(s) that give minimum compressed data size (VERY |
| * computationally expensive). |
| * |
| * GRR 980525: consider also |
| * |
| * (1) minimum sum of absolute differences from running average (i.e., |
| * keep running sum of non-absolute differences & count of bytes) |
| * [track dispersion, too? restart average if dispersion too large?] |
| * |
| * (1b) minimum sum of absolute differences from sliding average, probably |
| * with window size <= deflate window (usually 32K) |
| * |
| * (2) minimum sum of squared differences from zero or running average |
| * (i.e., ~ root-mean-square approach) |
| */ |
| |
| |
| /* We don't need to test the 'no filter' case if this is the only filter |
| * that has been chosen, as it doesn't actually do anything to the data. |
| */ |
| best_row = png_ptr->row_buf; |
| |
| if (PNG_SIZE_MAX/128 <= row_bytes) |
| { |
| /* Overflow can occur in the calculation, just select the lowest set |
| * filter. |
| */ |
| filter_to_do &= 0U-filter_to_do; |
| } |
| else if ((filter_to_do & PNG_FILTER_NONE) != 0 && |
| filter_to_do != PNG_FILTER_NONE) |
| { |
| /* Overflow not possible and multiple filters in the list, including the |
| * 'none' filter. |
| */ |
| png_bytep rp; |
| size_t sum = 0; |
| size_t i; |
| unsigned int v; |
| |
| { |
| for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) |
| { |
| v = *rp; |
| #ifdef PNG_USE_ABS |
| sum += 128 - abs((int)v - 128); |
| #else |
| sum += (v < 128) ? v : 256 - v; |
| #endif |
| } |
| } |
| |
| mins = sum; |
| } |
| |
| /* Sub filter */ |
| if (filter_to_do == PNG_FILTER_SUB) |
| /* It's the only filter so no testing is needed */ |
| { |
| png_setup_sub_row_only(png_ptr, bpp, row_bytes); |
| best_row = png_ptr->try_row; |
| } |
| |
| else if ((filter_to_do & PNG_FILTER_SUB) != 0) |
| { |
| size_t sum; |
| size_t lmins = mins; |
| |
| sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins); |
| |
| if (sum < mins) |
| { |
| mins = sum; |
| best_row = png_ptr->try_row; |
| if (png_ptr->tst_row != NULL) |
| { |
| png_ptr->try_row = png_ptr->tst_row; |
| png_ptr->tst_row = best_row; |
| } |
| } |
| } |
| |
| /* Up filter */ |
| if (filter_to_do == PNG_FILTER_UP) |
| { |
| png_setup_up_row_only(png_ptr, row_bytes); |
| best_row = png_ptr->try_row; |
| } |
| |
| else if ((filter_to_do & PNG_FILTER_UP) != 0) |
| { |
| size_t sum; |
| size_t lmins = mins; |
| |
| sum = png_setup_up_row(png_ptr, row_bytes, lmins); |
| |
| if (sum < mins) |
| { |
| mins = sum; |
| best_row = png_ptr->try_row; |
| if (png_ptr->tst_row != NULL) |
| { |
| png_ptr->try_row = png_ptr->tst_row; |
| png_ptr->tst_row = best_row; |
| } |
| } |
| } |
| |
| /* Avg filter */ |
| if (filter_to_do == PNG_FILTER_AVG) |
| { |
| png_setup_avg_row_only(png_ptr, bpp, row_bytes); |
| best_row = png_ptr->try_row; |
| } |
| |
| else if ((filter_to_do & PNG_FILTER_AVG) != 0) |
| { |
| size_t sum; |
| size_t lmins = mins; |
| |
| sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins); |
| |
| if (sum < mins) |
| { |
| mins = sum; |
| best_row = png_ptr->try_row; |
| if (png_ptr->tst_row != NULL) |
| { |
| png_ptr->try_row = png_ptr->tst_row; |
| png_ptr->tst_row = best_row; |
| } |
| } |
| } |
| |
| /* Paeth filter */ |
| if (filter_to_do == PNG_FILTER_PAETH) |
| { |
| png_setup_paeth_row_only(png_ptr, bpp, row_bytes); |
| best_row = png_ptr->try_row; |
| } |
| |
| else if ((filter_to_do & PNG_FILTER_PAETH) != 0) |
| { |
| size_t sum; |
| size_t lmins = mins; |
| |
| sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins); |
| |
| if (sum < mins) |
| { |
| best_row = png_ptr->try_row; |
| if (png_ptr->tst_row != NULL) |
| { |
| png_ptr->try_row = png_ptr->tst_row; |
| png_ptr->tst_row = best_row; |
| } |
| } |
| } |
| |
| /* Do the actual writing of the filtered row data from the chosen filter. */ |
| png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1); |
| |
| #endif /* WRITE_FILTER */ |
| } |
| |
| |
| /* Do the actual writing of a previously filtered row. */ |
| static void |
| png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row, |
| size_t full_row_length/*includes filter byte*/) |
| { |
| png_debug(1, "in png_write_filtered_row"); |
| |
| png_debug1(2, "filter = %d", filtered_row[0]); |
| |
| png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH); |
| |
| #ifdef PNG_WRITE_FILTER_SUPPORTED |
| /* Swap the current and previous rows */ |
| if (png_ptr->prev_row != NULL) |
| { |
| png_bytep tptr; |
| |
| tptr = png_ptr->prev_row; |
| png_ptr->prev_row = png_ptr->row_buf; |
| png_ptr->row_buf = tptr; |
| } |
| #endif /* WRITE_FILTER */ |
| |
| /* Finish row - updates counters and flushes zlib if last row */ |
| png_write_finish_row(png_ptr); |
| |
| #ifdef PNG_WRITE_FLUSH_SUPPORTED |
| png_ptr->flush_rows++; |
| |
| if (png_ptr->flush_dist > 0 && |
| png_ptr->flush_rows >= png_ptr->flush_dist) |
| { |
| png_write_flush(png_ptr); |
| } |
| #endif /* WRITE_FLUSH */ |
| } |
| #endif /* WRITE */ |