util/helper-cairo-user.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2022  Google, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Google Author(s): Behdad Esfahbod
  */

 #ifndef HELPER_CAIRO_USER_HH
 #define HELPER_CAIRO_USER_HH

 #include "font-options.hh"

 #include <cairo.h>
 #include <hb.h>

 #include "hb-blob.hh"

 static void
 move_to (hb_draw_funcs_t *dfuncs,
 	 cairo_t *cr,
 	 hb_draw_state_t *st,
 	 float to_x, float to_y,
 	 void *)
 {
   cairo_move_to (cr,
 		 (double) to_x, (double) to_y);
 }

 static void
 line_to (hb_draw_funcs_t *dfuncs,
 	 cairo_t *cr,
 	 hb_draw_state_t *st,
 	 float to_x, float to_y,
 	 void *)
 {
   cairo_line_to (cr,
 		 (double) to_x, (double) to_y);
 }

 static void
 cubic_to (hb_draw_funcs_t *dfuncs,
 	  cairo_t *cr,
 	  hb_draw_state_t *st,
 	  float control1_x, float control1_y,
 	  float control2_x, float control2_y,
 	  float to_x, float to_y,
 	  void *)
 {
   cairo_curve_to (cr,
 		  (double) control1_x, (double) control1_y,
 		  (double) control2_x, (double) control2_y,
 		  (double) to_x, (double) to_y);
 }

 static void
 close_path (hb_draw_funcs_t *dfuncs,
 	    cairo_t *cr,
 	    hb_draw_state_t *st,
 	    void *)
 {
   cairo_close_path (cr);
 }


 static hb_draw_funcs_t *
 get_cairo_draw_funcs ()
 {
   static hb_draw_funcs_t *funcs;

   if (!funcs)
   {
     funcs = hb_draw_funcs_create ();
     hb_draw_funcs_set_move_to_func (funcs, (hb_draw_move_to_func_t) move_to, nullptr, nullptr);
     hb_draw_funcs_set_line_to_func (funcs, (hb_draw_line_to_func_t) line_to, nullptr, nullptr);
     hb_draw_funcs_set_cubic_to_func (funcs, (hb_draw_cubic_to_func_t) cubic_to, nullptr, nullptr);
     hb_draw_funcs_set_close_path_func (funcs, (hb_draw_close_path_func_t) close_path, nullptr, nullptr);
   }

   return funcs;
 }

 static const cairo_user_data_key_t _hb_font_cairo_user_data_key = {0};

 static cairo_status_t
 render_glyph (cairo_scaled_font_t  *scaled_font,
 	      unsigned long         glyph,
 	      cairo_t              *cr,
 	      cairo_text_extents_t *extents)
 {
   hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
 								  &_hb_font_cairo_user_data_key));

   hb_position_t x_scale, y_scale;
   hb_font_get_scale (font, &x_scale, &y_scale);
   cairo_scale (cr, +1./x_scale, -1./y_scale);

   hb_font_get_glyph_shape (font, glyph, get_cairo_draw_funcs (), cr);
   cairo_fill (cr);

   return CAIRO_STATUS_SUCCESS;
 }

 #ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC

 #ifdef CAIRO_HAS_PNG_FUNCTIONS
 static inline cairo_status_t
 _hb_bytes_read_func (hb_bytes_t	*src,
 		     char	*data,
 		     unsigned	 length)
 {
   if (unlikely (src->length < length))
     return CAIRO_STATUS_READ_ERROR;

   memcpy (data, src->arrayZ, length);
   *src += length;

   return CAIRO_STATUS_SUCCESS;
 }

 static cairo_status_t
 render_color_glyph_png (cairo_scaled_font_t  *scaled_font,
 			unsigned long         glyph,
 			cairo_t              *cr,
 			cairo_text_extents_t *extents)
 {
   hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
 								  &_hb_font_cairo_user_data_key));

   hb_blob_t *blob = hb_ot_color_glyph_reference_png (font, glyph);
   if (blob == hb_blob_get_empty ())
     return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

   hb_position_t x_scale, y_scale;
   hb_font_get_scale (font, &x_scale, &y_scale);
   cairo_scale (cr, +1./x_scale, -1./y_scale);

   /* Draw PNG. */
   hb_bytes_t bytes = blob->as_bytes ();
   cairo_surface_t *surface = cairo_image_surface_create_from_png_stream ((cairo_read_func_t) _hb_bytes_read_func,
 									 std::addressof (bytes));
   hb_blob_destroy (blob);

   if (unlikely (cairo_surface_status (surface)) != CAIRO_STATUS_SUCCESS)
   {
     cairo_surface_destroy (surface);
     return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
   }

   int width = cairo_image_surface_get_width (surface);
   int height = cairo_image_surface_get_width (surface);

   hb_glyph_extents_t hb_extents;
   if (unlikely (!hb_font_get_glyph_extents (font, glyph, &hb_extents)))
   {
     cairo_surface_destroy (surface);
     return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
   }

   cairo_pattern_t *pattern = cairo_pattern_create_for_surface (surface);
   cairo_pattern_set_extend (pattern, CAIRO_EXTEND_PAD);

   cairo_matrix_t matrix = {(double) width, 0, 0, (double) height, 0, 0};
   cairo_pattern_set_matrix (pattern, &matrix);

   cairo_translate (cr, hb_extents.x_bearing, hb_extents.y_bearing);
   cairo_scale (cr, hb_extents.width, hb_extents.height);
   cairo_set_source (cr, pattern);

   cairo_rectangle (cr, 0, 0, 1, 1);
   cairo_fill (cr);
   cairo_pattern_destroy (pattern);

   cairo_surface_destroy (surface);
   return CAIRO_STATUS_SUCCESS;
 }
 #endif

 static cairo_status_t
 render_color_glyph_layers (cairo_scaled_font_t  *scaled_font,
 			   unsigned long         glyph,
 			   cairo_t              *cr,
 			   cairo_text_extents_t *extents)
 {
   hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
 								  &_hb_font_cairo_user_data_key));
   hb_face_t *face = hb_font_get_face (font);

   unsigned count = hb_ot_color_glyph_get_layers (face, glyph, 0, nullptr, nullptr);
   if (!count)
     return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

   hb_ot_color_layer_t layers[16];
   unsigned offset = 0, len;
   do {
     len = ARRAY_LENGTH (layers);
     hb_ot_color_glyph_get_layers (face, glyph,
 				  offset,
 				  &len,
 				  layers);
     for (unsigned i = 0; i < len; i++)
     {
       hb_color_t color;
       unsigned clen = 1;
       unsigned color_index = layers[i].color_index;
       bool is_foreground = color_index == 65535;

       if (!is_foreground)
       {
 	hb_ot_color_palette_get_colors (face,
 					0/*palette_index*/,
 					color_index/*start_offset*/,
 					&clen/*color_count*/,
 					&color);
 	if (clen < 1)
 	  continue;
       }

       cairo_save (cr);
       {
 	if (!is_foreground)
 	  cairo_set_source_rgba (cr,
 				 hb_color_get_red (color) / 255.,
 				 hb_color_get_green (color) / 255.,
 				 hb_color_get_blue (color) / 255.,
 				 hb_color_get_alpha (color) / 255.);

 	cairo_status_t ret = render_glyph (scaled_font, layers[i].glyph, cr, extents);
 	if (ret != CAIRO_STATUS_SUCCESS)
 	  return ret;
       }
       cairo_restore (cr);
     }
   }
   while (len == ARRAY_LENGTH (layers));
   return CAIRO_STATUS_SUCCESS;
 }

 static cairo_status_t
 render_color_glyph (cairo_scaled_font_t  *scaled_font,
 		    unsigned long         glyph,
 		    cairo_t              *cr,
 		    cairo_text_extents_t *extents)
 {
   cairo_status_t ret = CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

 #ifdef CAIRO_HAS_PNG_FUNCTIONS
   ret = render_color_glyph_png (scaled_font, glyph, cr, extents);
   if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
     return ret;
 #endif

   ret = render_color_glyph_layers (scaled_font, glyph, cr, extents);
   if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
     return ret;

   return render_glyph (scaled_font, glyph, cr, extents);
 }

 #endif

 static inline cairo_font_face_t *
 helper_cairo_create_user_font_face (const font_options_t *font_opts)
 {
   cairo_font_face_t *cairo_face = cairo_user_font_face_create ();

   cairo_font_face_set_user_data (cairo_face,
 				 &_hb_font_cairo_user_data_key,
 				 hb_font_reference (font_opts->font),
 				 (cairo_destroy_func_t) hb_font_destroy);

   cairo_user_font_face_set_render_glyph_func (cairo_face, render_glyph);
 #ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC
   hb_face_t *face = hb_font_get_face (font_opts->font);
   if (hb_ot_color_has_png (face) || hb_ot_color_has_layers (face))
     cairo_user_font_face_set_render_color_glyph_func (cairo_face, render_color_glyph);
 #endif

   return cairo_face;
 }

 static inline bool
 helper_cairo_user_font_face_has_data (cairo_font_face_t *font_face)
 {
   return cairo_font_face_get_user_data (font_face, &_hb_font_cairo_user_data_key);
 }

 static inline bool
 helper_cairo_user_scaled_font_has_color (cairo_scaled_font_t *scaled_font)
 {
   /* Ignoring SVG for now, since we cannot render it. */
   hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
 								  &_hb_font_cairo_user_data_key));
   hb_face_t *face = hb_font_get_face (font);
   return hb_ot_color_has_png (face) || hb_ot_color_has_layers (face);
 }

 #endif
	/*
	* Copyright © 2022 Google, Inc.
	*
	* This is part of HarfBuzz, a text shaping library.
	*
	* Permission is hereby granted, without written agreement and without
	* license or royalty fees, to use, copy, modify, and distribute this
	* software and its documentation for any purpose, provided that the
	* above copyright notice and the following two paragraphs appear in
	* all copies of this software.
	*
	* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
	* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
	* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
	* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
	* DAMAGE.
	*
	* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
	* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
	* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
	* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
	* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
	*
	* Google Author(s): Behdad Esfahbod
	*/

	#ifndef HELPER_CAIRO_USER_HH
	#define HELPER_CAIRO_USER_HH

	#include "font-options.hh"

	#include <cairo.h>
	#include <hb.h>

	#include "hb-blob.hh"

	static void
	move_to (hb_draw_funcs_t *dfuncs,
	cairo_t *cr,
	hb_draw_state_t *st,
	float to_x, float to_y,
	void *)
	{
	cairo_move_to (cr,
	(double) to_x, (double) to_y);
	}

	static void
	line_to (hb_draw_funcs_t *dfuncs,
	cairo_t *cr,
	hb_draw_state_t *st,
	float to_x, float to_y,
	void *)
	{
	cairo_line_to (cr,
	(double) to_x, (double) to_y);
	}

	static void
	cubic_to (hb_draw_funcs_t *dfuncs,
	cairo_t *cr,
	hb_draw_state_t *st,
	float control1_x, float control1_y,
	float control2_x, float control2_y,
	float to_x, float to_y,
	void *)
	{
	cairo_curve_to (cr,
	(double) control1_x, (double) control1_y,
	(double) control2_x, (double) control2_y,
	(double) to_x, (double) to_y);
	}

	static void
	close_path (hb_draw_funcs_t *dfuncs,
	cairo_t *cr,
	hb_draw_state_t *st,
	void *)
	{
	cairo_close_path (cr);
	}


	static hb_draw_funcs_t *
	get_cairo_draw_funcs ()
	{
	static hb_draw_funcs_t *funcs;

	if (!funcs)
	{
	funcs = hb_draw_funcs_create ();
	hb_draw_funcs_set_move_to_func (funcs, (hb_draw_move_to_func_t) move_to, nullptr, nullptr);
	hb_draw_funcs_set_line_to_func (funcs, (hb_draw_line_to_func_t) line_to, nullptr, nullptr);
	hb_draw_funcs_set_cubic_to_func (funcs, (hb_draw_cubic_to_func_t) cubic_to, nullptr, nullptr);
	hb_draw_funcs_set_close_path_func (funcs, (hb_draw_close_path_func_t) close_path, nullptr, nullptr);
	}

	return funcs;
	}

	static const cairo_user_data_key_t _hb_font_cairo_user_data_key = {0};

	static cairo_status_t
	render_glyph (cairo_scaled_font_t *scaled_font,
	unsigned long glyph,
	cairo_t *cr,
	cairo_text_extents_t *extents)
	{
	hb_font_t font = (hb_font_t ) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
	&_hb_font_cairo_user_data_key));

	hb_position_t x_scale, y_scale;
	hb_font_get_scale (font, &x_scale, &y_scale);
	cairo_scale (cr, +1./x_scale, -1./y_scale);

	hb_font_get_glyph_shape (font, glyph, get_cairo_draw_funcs (), cr);
	cairo_fill (cr);

	return CAIRO_STATUS_SUCCESS;
	}

	#ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC

	#ifdef CAIRO_HAS_PNG_FUNCTIONS
	static inline cairo_status_t
	_hb_bytes_read_func (hb_bytes_t *src,
	char *data,
	unsigned length)
	{
	if (unlikely (src->length < length))
	return CAIRO_STATUS_READ_ERROR;

	memcpy (data, src->arrayZ, length);
	*src += length;

	return CAIRO_STATUS_SUCCESS;
	}

	static cairo_status_t
	render_color_glyph_png (cairo_scaled_font_t *scaled_font,
	unsigned long glyph,
	cairo_t *cr,
	cairo_text_extents_t *extents)
	{
	hb_font_t font = (hb_font_t ) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
	&_hb_font_cairo_user_data_key));

	hb_blob_t *blob = hb_ot_color_glyph_reference_png (font, glyph);
	if (blob == hb_blob_get_empty ())
	return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

	hb_position_t x_scale, y_scale;
	hb_font_get_scale (font, &x_scale, &y_scale);
	cairo_scale (cr, +1./x_scale, -1./y_scale);

	/* Draw PNG. */
	hb_bytes_t bytes = blob->as_bytes ();
	cairo_surface_t *surface = cairo_image_surface_create_from_png_stream ((cairo_read_func_t) _hb_bytes_read_func,
	std::addressof (bytes));
	hb_blob_destroy (blob);

	if (unlikely (cairo_surface_status (surface)) != CAIRO_STATUS_SUCCESS)
	{
	cairo_surface_destroy (surface);
	return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
	}

	int width = cairo_image_surface_get_width (surface);
	int height = cairo_image_surface_get_width (surface);

	hb_glyph_extents_t hb_extents;
	if (unlikely (!hb_font_get_glyph_extents (font, glyph, &hb_extents)))
	{
	cairo_surface_destroy (surface);
	return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
	}

	cairo_pattern_t *pattern = cairo_pattern_create_for_surface (surface);
	cairo_pattern_set_extend (pattern, CAIRO_EXTEND_PAD);

	cairo_matrix_t matrix = {(double) width, 0, 0, (double) height, 0, 0};
	cairo_pattern_set_matrix (pattern, &matrix);

	cairo_translate (cr, hb_extents.x_bearing, hb_extents.y_bearing);
	cairo_scale (cr, hb_extents.width, hb_extents.height);
	cairo_set_source (cr, pattern);

	cairo_rectangle (cr, 0, 0, 1, 1);
	cairo_fill (cr);
	cairo_pattern_destroy (pattern);

	cairo_surface_destroy (surface);
	return CAIRO_STATUS_SUCCESS;
	}
	#endif

	static cairo_status_t
	render_color_glyph_layers (cairo_scaled_font_t *scaled_font,
	unsigned long glyph,
	cairo_t *cr,
	cairo_text_extents_t *extents)
	{
	hb_font_t font = (hb_font_t ) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
	&_hb_font_cairo_user_data_key));
	hb_face_t *face = hb_font_get_face (font);

	unsigned count = hb_ot_color_glyph_get_layers (face, glyph, 0, nullptr, nullptr);
	if (!count)
	return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

	hb_ot_color_layer_t layers[16];
	unsigned offset = 0, len;
	do {
	len = ARRAY_LENGTH (layers);
	hb_ot_color_glyph_get_layers (face, glyph,
	offset,
	&len,
	layers);
	for (unsigned i = 0; i < len; i++)
	{
	hb_color_t color;
	unsigned clen = 1;
	unsigned color_index = layers[i].color_index;
	bool is_foreground = color_index == 65535;

	if (!is_foreground)
	{
	hb_ot_color_palette_get_colors (face,
	0/palette_index/,
	color_index/start_offset/,
	&clen/color_count/,
	&color);
	if (clen < 1)
	continue;
	}

	cairo_save (cr);
	{
	if (!is_foreground)
	cairo_set_source_rgba (cr,
	hb_color_get_red (color) / 255.,
	hb_color_get_green (color) / 255.,
	hb_color_get_blue (color) / 255.,
	hb_color_get_alpha (color) / 255.);

	cairo_status_t ret = render_glyph (scaled_font, layers[i].glyph, cr, extents);
	if (ret != CAIRO_STATUS_SUCCESS)
	return ret;
	}
	cairo_restore (cr);
	}
	}
	while (len == ARRAY_LENGTH (layers));
	return CAIRO_STATUS_SUCCESS;
	}

	static cairo_status_t
	render_color_glyph (cairo_scaled_font_t *scaled_font,
	unsigned long glyph,
	cairo_t *cr,
	cairo_text_extents_t *extents)
	{
	cairo_status_t ret = CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

	#ifdef CAIRO_HAS_PNG_FUNCTIONS
	ret = render_color_glyph_png (scaled_font, glyph, cr, extents);
	if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
	return ret;
	#endif

	ret = render_color_glyph_layers (scaled_font, glyph, cr, extents);
	if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
	return ret;

	return render_glyph (scaled_font, glyph, cr, extents);
	}

	#endif

	static inline cairo_font_face_t *
	helper_cairo_create_user_font_face (const font_options_t *font_opts)
	{
	cairo_font_face_t *cairo_face = cairo_user_font_face_create ();

	cairo_font_face_set_user_data (cairo_face,
	&_hb_font_cairo_user_data_key,
	hb_font_reference (font_opts->font),
	(cairo_destroy_func_t) hb_font_destroy);

	cairo_user_font_face_set_render_glyph_func (cairo_face, render_glyph);
	#ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC
	hb_face_t *face = hb_font_get_face (font_opts->font);
	if (hb_ot_color_has_png (face) \|\| hb_ot_color_has_layers (face))
	cairo_user_font_face_set_render_color_glyph_func (cairo_face, render_color_glyph);
	#endif

	return cairo_face;
	}

	static inline bool
	helper_cairo_user_font_face_has_data (cairo_font_face_t *font_face)
	{
	return cairo_font_face_get_user_data (font_face, &_hb_font_cairo_user_data_key);
	}

	static inline bool
	helper_cairo_user_scaled_font_has_color (cairo_scaled_font_t *scaled_font)
	{
	/* Ignoring SVG for now, since we cannot render it. */
	hb_font_t font = (hb_font_t ) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
	&_hb_font_cairo_user_data_key));
	hb_face_t *face = hb_font_get_face (font);
	return hb_ot_color_has_png (face) \|\| hb_ot_color_has_layers (face);
	}

	#endif