| /**************************************************************************** |
| * |
| * afloader.c |
| * |
| * Auto-fitter glyph loading routines (body). |
| * |
| * Copyright (C) 2003-2022 by |
| * David Turner, Robert Wilhelm, and Werner Lemberg. |
| * |
| * This file is part of the FreeType project, and may only be used, |
| * modified, and distributed under the terms of the FreeType project |
| * license, LICENSE.TXT. By continuing to use, modify, or distribute |
| * this file you indicate that you have read the license and |
| * understand and accept it fully. |
| * |
| */ |
| |
| |
| #include "afglobal.h" |
| #include "afloader.h" |
| #include "afhints.h" |
| #include "aferrors.h" |
| #include "afmodule.h" |
| |
| #include <freetype/internal/ftcalc.h> |
| |
| |
| /* Initialize glyph loader. */ |
| |
| FT_LOCAL_DEF( void ) |
| af_loader_init( AF_Loader loader, |
| AF_GlyphHints hints ) |
| { |
| FT_ZERO( loader ); |
| |
| loader->hints = hints; |
| } |
| |
| |
| /* Reset glyph loader and compute globals if necessary. */ |
| |
| FT_LOCAL_DEF( FT_Error ) |
| af_loader_reset( AF_Loader loader, |
| AF_Module module, |
| FT_Face face ) |
| { |
| FT_Error error = FT_Err_Ok; |
| |
| |
| loader->face = face; |
| loader->globals = (AF_FaceGlobals)face->autohint.data; |
| |
| if ( !loader->globals ) |
| { |
| error = af_face_globals_new( face, &loader->globals, module ); |
| if ( !error ) |
| { |
| face->autohint.data = |
| (FT_Pointer)loader->globals; |
| face->autohint.finalizer = |
| (FT_Generic_Finalizer)af_face_globals_free; |
| } |
| } |
| |
| return error; |
| } |
| |
| |
| /* Finalize glyph loader. */ |
| |
| FT_LOCAL_DEF( void ) |
| af_loader_done( AF_Loader loader ) |
| { |
| loader->face = NULL; |
| loader->globals = NULL; |
| loader->hints = NULL; |
| } |
| |
| |
| #define af_intToFixed( i ) \ |
| ( (FT_Fixed)( (FT_UInt32)(i) << 16 ) ) |
| #define af_fixedToInt( x ) \ |
| ( (FT_Short)( ( (FT_UInt32)(x) + 0x8000U ) >> 16 ) ) |
| #define af_floatToFixed( f ) \ |
| ( (FT_Fixed)( (f) * 65536.0 + 0.5 ) ) |
| |
| |
| static FT_Error |
| af_loader_embolden_glyph_in_slot( AF_Loader loader, |
| FT_Face face, |
| AF_StyleMetrics style_metrics ) |
| { |
| FT_Error error = FT_Err_Ok; |
| |
| FT_GlyphSlot slot = face->glyph; |
| AF_FaceGlobals globals = loader->globals; |
| AF_WritingSystemClass writing_system_class; |
| |
| FT_Size_Metrics* size_metrics = &face->size->internal->autohint_metrics; |
| |
| FT_Pos stdVW = 0; |
| FT_Pos stdHW = 0; |
| |
| FT_Bool size_changed = size_metrics->x_ppem != |
| globals->stem_darkening_for_ppem; |
| |
| FT_Fixed em_size = af_intToFixed( face->units_per_EM ); |
| |
| FT_Matrix scale_down_matrix = { 0x10000L, 0, 0, 0x10000L }; |
| |
| |
| /* Skip stem darkening for broken fonts. */ |
| if ( !face->units_per_EM ) |
| { |
| error = FT_ERR( Corrupted_Font_Header ); |
| goto Exit; |
| } |
| |
| /* |
| * We depend on the writing system (script analyzers) to supply |
| * standard widths for the script of the glyph we are looking at. If |
| * it can't deliver, stem darkening is disabled. |
| */ |
| writing_system_class = |
| af_writing_system_classes[style_metrics->style_class->writing_system]; |
| |
| if ( writing_system_class->style_metrics_getstdw ) |
| writing_system_class->style_metrics_getstdw( style_metrics, |
| &stdHW, |
| &stdVW ); |
| else |
| { |
| error = FT_ERR( Unimplemented_Feature ); |
| goto Exit; |
| } |
| |
| if ( size_changed || |
| ( stdVW > 0 && stdVW != globals->standard_vertical_width ) ) |
| { |
| FT_Fixed darken_by_font_units_x, darken_x; |
| |
| |
| darken_by_font_units_x = |
| af_loader_compute_darkening( loader, |
| face, |
| stdVW ) ; |
| darken_x = FT_MulFix( darken_by_font_units_x, |
| size_metrics->x_scale ); |
| |
| globals->standard_vertical_width = stdVW; |
| globals->stem_darkening_for_ppem = size_metrics->x_ppem; |
| globals->darken_x = af_fixedToInt( darken_x ); |
| } |
| |
| if ( size_changed || |
| ( stdHW > 0 && stdHW != globals->standard_horizontal_width ) ) |
| { |
| FT_Fixed darken_by_font_units_y, darken_y; |
| |
| |
| darken_by_font_units_y = |
| af_loader_compute_darkening( loader, |
| face, |
| stdHW ) ; |
| darken_y = FT_MulFix( darken_by_font_units_y, |
| size_metrics->y_scale ); |
| |
| globals->standard_horizontal_width = stdHW; |
| globals->stem_darkening_for_ppem = size_metrics->x_ppem; |
| globals->darken_y = af_fixedToInt( darken_y ); |
| |
| /* |
| * Scale outlines down on the Y-axis to keep them inside their blue |
| * zones. The stronger the emboldening, the stronger the downscaling |
| * (plus heuristical padding to prevent outlines still falling out |
| * their zones due to rounding). |
| * |
| * Reason: `FT_Outline_Embolden' works by shifting the rightmost |
| * points of stems farther to the right, and topmost points farther |
| * up. This positions points on the Y-axis outside their |
| * pre-computed blue zones and leads to distortion when applying the |
| * hints in the code further below. Code outside this emboldening |
| * block doesn't know we are presenting it with modified outlines the |
| * analyzer didn't see! |
| * |
| * An unfortunate side effect of downscaling is that the emboldening |
| * effect is slightly decreased. The loss becomes more pronounced |
| * versus the CFF driver at smaller sizes, e.g., at 9ppem and below. |
| */ |
| globals->scale_down_factor = |
| FT_DivFix( em_size - ( darken_by_font_units_y + af_intToFixed( 8 ) ), |
| em_size ); |
| } |
| |
| FT_Outline_EmboldenXY( &slot->outline, |
| globals->darken_x, |
| globals->darken_y ); |
| |
| scale_down_matrix.yy = globals->scale_down_factor; |
| FT_Outline_Transform( &slot->outline, &scale_down_matrix ); |
| |
| Exit: |
| return error; |
| } |
| |
| |
| /* Load the glyph at index into the current slot of a face and hint it. */ |
| |
| FT_LOCAL_DEF( FT_Error ) |
| af_loader_load_glyph( AF_Loader loader, |
| AF_Module module, |
| FT_Face face, |
| FT_UInt glyph_index, |
| FT_Int32 load_flags ) |
| { |
| FT_Error error; |
| |
| FT_Size size = face->size; |
| FT_Size_Internal size_internal = size->internal; |
| FT_GlyphSlot slot = face->glyph; |
| FT_Slot_Internal slot_internal = slot->internal; |
| FT_GlyphLoader gloader = slot_internal->loader; |
| |
| AF_GlyphHints hints = loader->hints; |
| AF_ScalerRec scaler; |
| AF_StyleMetrics style_metrics; |
| FT_UInt style_options = AF_STYLE_NONE_DFLT; |
| AF_StyleClass style_class; |
| AF_WritingSystemClass writing_system_class; |
| |
| |
| if ( !size ) |
| return FT_THROW( Invalid_Size_Handle ); |
| |
| FT_ZERO( &scaler ); |
| |
| if ( !size_internal->autohint_metrics.x_scale || |
| size_internal->autohint_mode != FT_LOAD_TARGET_MODE( load_flags ) ) |
| { |
| /* switching between hinting modes usually means different scaling */ |
| /* values; this later on enforces recomputation of everything */ |
| /* related to the current size */ |
| |
| size_internal->autohint_mode = FT_LOAD_TARGET_MODE( load_flags ); |
| size_internal->autohint_metrics = size->metrics; |
| |
| #ifdef AF_CONFIG_OPTION_TT_SIZE_METRICS |
| { |
| FT_Size_Metrics* size_metrics = &size_internal->autohint_metrics; |
| |
| |
| /* set metrics to integer values and adjust scaling accordingly; */ |
| /* this is the same setup as with TrueType fonts, cf. function */ |
| /* `tt_size_reset' in file `ttobjs.c' */ |
| size_metrics->ascender = FT_PIX_ROUND( |
| FT_MulFix( face->ascender, |
| size_metrics->y_scale ) ); |
| size_metrics->descender = FT_PIX_ROUND( |
| FT_MulFix( face->descender, |
| size_metrics->y_scale ) ); |
| size_metrics->height = FT_PIX_ROUND( |
| FT_MulFix( face->height, |
| size_metrics->y_scale ) ); |
| |
| size_metrics->x_scale = FT_DivFix( size_metrics->x_ppem << 6, |
| face->units_per_EM ); |
| size_metrics->y_scale = FT_DivFix( size_metrics->y_ppem << 6, |
| face->units_per_EM ); |
| size_metrics->max_advance = FT_PIX_ROUND( |
| FT_MulFix( face->max_advance_width, |
| size_metrics->x_scale ) ); |
| } |
| #endif /* AF_CONFIG_OPTION_TT_SIZE_METRICS */ |
| } |
| |
| /* |
| * TODO: This code currently doesn't support fractional advance widths, |
| * i.e., placing hinted glyphs at anything other than integer |
| * x-positions. This is only relevant for the warper code, which |
| * scales and shifts glyphs to optimize blackness of stems (hinting on |
| * the x-axis by nature places things on pixel integers, hinting on the |
| * y-axis only, i.e., LIGHT mode, doesn't touch the x-axis). The delta |
| * values of the scaler would need to be adjusted. |
| */ |
| scaler.face = face; |
| scaler.x_scale = size_internal->autohint_metrics.x_scale; |
| scaler.x_delta = 0; |
| scaler.y_scale = size_internal->autohint_metrics.y_scale; |
| scaler.y_delta = 0; |
| |
| scaler.render_mode = FT_LOAD_TARGET_MODE( load_flags ); |
| scaler.flags = 0; |
| |
| /* note that the fallback style can't be changed anymore */ |
| /* after the first call of `af_loader_load_glyph' */ |
| error = af_loader_reset( loader, module, face ); |
| if ( error ) |
| goto Exit; |
| |
| /* |
| * Glyphs (really code points) are assigned to scripts. Script |
| * analysis is done lazily: For each glyph that passes through here, |
| * the corresponding script analyzer is called, but returns immediately |
| * if it has been run already. |
| */ |
| error = af_face_globals_get_metrics( loader->globals, glyph_index, |
| style_options, &style_metrics ); |
| if ( error ) |
| goto Exit; |
| |
| style_class = style_metrics->style_class; |
| writing_system_class = |
| af_writing_system_classes[style_class->writing_system]; |
| |
| loader->metrics = style_metrics; |
| |
| if ( writing_system_class->style_metrics_scale ) |
| writing_system_class->style_metrics_scale( style_metrics, &scaler ); |
| else |
| style_metrics->scaler = scaler; |
| |
| if ( writing_system_class->style_hints_init ) |
| { |
| error = writing_system_class->style_hints_init( hints, |
| style_metrics ); |
| if ( error ) |
| goto Exit; |
| } |
| |
| /* |
| * Do the main work of `af_loader_load_glyph'. Note that we never have |
| * to deal with composite glyphs as those get loaded into |
| * FT_GLYPH_FORMAT_OUTLINE by the recursed `FT_Load_Glyph' function. |
| * In the rare cases where FT_LOAD_NO_RECURSE is set, it implies |
| * FT_LOAD_NO_SCALE and as such the auto-hinter is never called. |
| */ |
| load_flags |= FT_LOAD_NO_SCALE | |
| FT_LOAD_IGNORE_TRANSFORM | |
| FT_LOAD_LINEAR_DESIGN; |
| load_flags &= ~FT_LOAD_RENDER; |
| |
| error = FT_Load_Glyph( face, glyph_index, load_flags ); |
| if ( error ) |
| goto Exit; |
| |
| /* |
| * Apply stem darkening (emboldening) here before hints are applied to |
| * the outline. Glyphs are scaled down proportionally to the |
| * emboldening so that curve points don't fall outside their |
| * precomputed blue zones. |
| * |
| * Any emboldening done by the font driver (e.g., the CFF driver) |
| * doesn't reach here because the autohinter loads the unprocessed |
| * glyphs in font units for analysis (functions `af_*_metrics_init_*') |
| * and then above to prepare it for the rasterizers by itself, |
| * independently of the font driver. So emboldening must be done here, |
| * within the autohinter. |
| * |
| * All glyphs to be autohinted pass through here one by one. The |
| * standard widths can therefore change from one glyph to the next, |
| * depending on what script a glyph is assigned to (each script has its |
| * own set of standard widths and other metrics). The darkening amount |
| * must therefore be recomputed for each size and |
| * `standard_{vertical,horizontal}_width' change. |
| * |
| * Ignore errors and carry on without emboldening. |
| * |
| */ |
| |
| /* stem darkening only works well in `light' mode */ |
| if ( scaler.render_mode == FT_RENDER_MODE_LIGHT && |
| ( !face->internal->no_stem_darkening || |
| ( face->internal->no_stem_darkening < 0 && |
| !module->no_stem_darkening ) ) ) |
| af_loader_embolden_glyph_in_slot( loader, face, style_metrics ); |
| |
| loader->transformed = slot_internal->glyph_transformed; |
| if ( loader->transformed ) |
| { |
| FT_Matrix inverse; |
| |
| |
| loader->trans_matrix = slot_internal->glyph_matrix; |
| loader->trans_delta = slot_internal->glyph_delta; |
| |
| inverse = loader->trans_matrix; |
| if ( !FT_Matrix_Invert( &inverse ) ) |
| FT_Vector_Transform( &loader->trans_delta, &inverse ); |
| } |
| |
| switch ( slot->format ) |
| { |
| case FT_GLYPH_FORMAT_OUTLINE: |
| /* translate the loaded glyph when an internal transform is needed */ |
| if ( loader->transformed ) |
| FT_Outline_Translate( &slot->outline, |
| loader->trans_delta.x, |
| loader->trans_delta.y ); |
| |
| /* compute original horizontal phantom points */ |
| /* (and ignore vertical ones) */ |
| loader->pp1.x = hints->x_delta; |
| loader->pp1.y = hints->y_delta; |
| loader->pp2.x = FT_MulFix( slot->metrics.horiAdvance, |
| hints->x_scale ) + hints->x_delta; |
| loader->pp2.y = hints->y_delta; |
| |
| /* be sure to check for spacing glyphs */ |
| if ( slot->outline.n_points == 0 ) |
| goto Hint_Metrics; |
| |
| /* now load the slot image into the auto-outline */ |
| /* and run the automatic hinting process */ |
| if ( writing_system_class->style_hints_apply ) |
| { |
| error = writing_system_class->style_hints_apply( |
| glyph_index, |
| hints, |
| &gloader->base.outline, |
| style_metrics ); |
| if ( error ) |
| goto Exit; |
| } |
| |
| /* we now need to adjust the metrics according to the change in */ |
| /* width/positioning that occurred during the hinting process */ |
| if ( scaler.render_mode != FT_RENDER_MODE_LIGHT ) |
| { |
| AF_AxisHints axis = &hints->axis[AF_DIMENSION_HORZ]; |
| |
| |
| if ( axis->num_edges > 1 && AF_HINTS_DO_ADVANCE( hints ) ) |
| { |
| AF_Edge edge1 = axis->edges; /* leftmost edge */ |
| AF_Edge edge2 = edge1 + |
| axis->num_edges - 1; /* rightmost edge */ |
| |
| FT_Pos old_rsb = loader->pp2.x - edge2->opos; |
| /* loader->pp1.x is always zero at this point of time */ |
| FT_Pos old_lsb = edge1->opos; /* - loader->pp1.x */ |
| FT_Pos new_lsb = edge1->pos; |
| |
| /* remember unhinted values to later account */ |
| /* for rounding errors */ |
| FT_Pos pp1x_uh = new_lsb - old_lsb; |
| FT_Pos pp2x_uh = edge2->pos + old_rsb; |
| |
| |
| /* prefer too much space over too little space */ |
| /* for very small sizes */ |
| |
| if ( old_lsb < 24 ) |
| pp1x_uh -= 8; |
| |
| if ( old_rsb < 24 ) |
| pp2x_uh += 8; |
| |
| loader->pp1.x = FT_PIX_ROUND( pp1x_uh ); |
| loader->pp2.x = FT_PIX_ROUND( pp2x_uh ); |
| |
| if ( loader->pp1.x >= new_lsb && old_lsb > 0 ) |
| loader->pp1.x -= 64; |
| |
| if ( loader->pp2.x <= edge2->pos && old_rsb > 0 ) |
| loader->pp2.x += 64; |
| |
| slot->lsb_delta = loader->pp1.x - pp1x_uh; |
| slot->rsb_delta = loader->pp2.x - pp2x_uh; |
| } |
| else |
| { |
| FT_Pos pp1x = loader->pp1.x; |
| FT_Pos pp2x = loader->pp2.x; |
| |
| |
| loader->pp1.x = FT_PIX_ROUND( pp1x ); |
| loader->pp2.x = FT_PIX_ROUND( pp2x ); |
| |
| slot->lsb_delta = loader->pp1.x - pp1x; |
| slot->rsb_delta = loader->pp2.x - pp2x; |
| } |
| } |
| /* `light' mode uses integer advance widths */ |
| /* but sets `lsb_delta' and `rsb_delta' */ |
| else |
| { |
| FT_Pos pp1x = loader->pp1.x; |
| FT_Pos pp2x = loader->pp2.x; |
| |
| |
| loader->pp1.x = FT_PIX_ROUND( pp1x ); |
| loader->pp2.x = FT_PIX_ROUND( pp2x ); |
| |
| slot->lsb_delta = loader->pp1.x - pp1x; |
| slot->rsb_delta = loader->pp2.x - pp2x; |
| } |
| |
| break; |
| |
| default: |
| /* we don't support other formats (yet?) */ |
| error = FT_THROW( Unimplemented_Feature ); |
| } |
| |
| Hint_Metrics: |
| { |
| FT_BBox bbox; |
| FT_Vector vvector; |
| |
| |
| vvector.x = slot->metrics.vertBearingX - slot->metrics.horiBearingX; |
| vvector.y = slot->metrics.vertBearingY - slot->metrics.horiBearingY; |
| vvector.x = FT_MulFix( vvector.x, style_metrics->scaler.x_scale ); |
| vvector.y = FT_MulFix( vvector.y, style_metrics->scaler.y_scale ); |
| |
| /* transform the hinted outline if needed */ |
| if ( loader->transformed ) |
| { |
| FT_Outline_Transform( &gloader->base.outline, &loader->trans_matrix ); |
| FT_Vector_Transform( &vvector, &loader->trans_matrix ); |
| } |
| |
| /* we must translate our final outline by -pp1.x and compute */ |
| /* the new metrics */ |
| if ( loader->pp1.x ) |
| FT_Outline_Translate( &gloader->base.outline, -loader->pp1.x, 0 ); |
| |
| FT_Outline_Get_CBox( &gloader->base.outline, &bbox ); |
| |
| bbox.xMin = FT_PIX_FLOOR( bbox.xMin ); |
| bbox.yMin = FT_PIX_FLOOR( bbox.yMin ); |
| bbox.xMax = FT_PIX_CEIL( bbox.xMax ); |
| bbox.yMax = FT_PIX_CEIL( bbox.yMax ); |
| |
| slot->metrics.width = bbox.xMax - bbox.xMin; |
| slot->metrics.height = bbox.yMax - bbox.yMin; |
| slot->metrics.horiBearingX = bbox.xMin; |
| slot->metrics.horiBearingY = bbox.yMax; |
| |
| slot->metrics.vertBearingX = FT_PIX_FLOOR( bbox.xMin + vvector.x ); |
| slot->metrics.vertBearingY = FT_PIX_FLOOR( bbox.yMax + vvector.y ); |
| |
| /* for mono-width fonts (like Andale, Courier, etc.) we need */ |
| /* to keep the original rounded advance width; ditto for */ |
| /* digits if all have the same advance width */ |
| if ( scaler.render_mode != FT_RENDER_MODE_LIGHT && |
| ( FT_IS_FIXED_WIDTH( slot->face ) || |
| ( af_face_globals_is_digit( loader->globals, glyph_index ) && |
| style_metrics->digits_have_same_width ) ) ) |
| { |
| slot->metrics.horiAdvance = |
| FT_MulFix( slot->metrics.horiAdvance, |
| style_metrics->scaler.x_scale ); |
| |
| /* Set delta values to 0. Otherwise code that uses them is */ |
| /* going to ruin the fixed advance width. */ |
| slot->lsb_delta = 0; |
| slot->rsb_delta = 0; |
| } |
| else |
| { |
| /* non-spacing glyphs must stay as-is */ |
| if ( slot->metrics.horiAdvance ) |
| slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x; |
| } |
| |
| slot->metrics.vertAdvance = FT_MulFix( slot->metrics.vertAdvance, |
| style_metrics->scaler.y_scale ); |
| |
| slot->metrics.horiAdvance = FT_PIX_ROUND( slot->metrics.horiAdvance ); |
| slot->metrics.vertAdvance = FT_PIX_ROUND( slot->metrics.vertAdvance ); |
| |
| slot->format = FT_GLYPH_FORMAT_OUTLINE; |
| } |
| |
| Exit: |
| return error; |
| } |
| |
| |
| /* |
| * Compute amount of font units the face should be emboldened by, in |
| * analogy to the CFF driver's `cf2_computeDarkening' function. See there |
| * for details of the algorithm. |
| * |
| * XXX: Currently a crude adaption of the original algorithm. Do better? |
| */ |
| FT_LOCAL_DEF( FT_Fixed ) |
| af_loader_compute_darkening( AF_Loader loader, |
| FT_Face face, |
| FT_Pos standard_width ) |
| { |
| AF_Module module = loader->globals->module; |
| |
| FT_UShort units_per_EM; |
| FT_Fixed ppem, em_ratio; |
| FT_Fixed stem_width, stem_width_per_1000, scaled_stem, darken_amount; |
| FT_Int log_base_2; |
| FT_Int x1, y1, x2, y2, x3, y3, x4, y4; |
| |
| |
| ppem = FT_MAX( af_intToFixed( 4 ), |
| af_intToFixed( face->size->metrics.x_ppem ) ); |
| units_per_EM = face->units_per_EM; |
| |
| em_ratio = FT_DivFix( af_intToFixed( 1000 ), |
| af_intToFixed ( units_per_EM ) ); |
| if ( em_ratio < af_floatToFixed( .01 ) ) |
| { |
| /* If something goes wrong, don't embolden. */ |
| return 0; |
| } |
| |
| x1 = module->darken_params[0]; |
| y1 = module->darken_params[1]; |
| x2 = module->darken_params[2]; |
| y2 = module->darken_params[3]; |
| x3 = module->darken_params[4]; |
| y3 = module->darken_params[5]; |
| x4 = module->darken_params[6]; |
| y4 = module->darken_params[7]; |
| |
| if ( standard_width <= 0 ) |
| { |
| stem_width = af_intToFixed( 75 ); /* taken from cf2font.c */ |
| stem_width_per_1000 = stem_width; |
| } |
| else |
| { |
| stem_width = af_intToFixed( standard_width ); |
| stem_width_per_1000 = FT_MulFix( stem_width, em_ratio ); |
| } |
| |
| log_base_2 = FT_MSB( (FT_UInt32)stem_width_per_1000 ) + |
| FT_MSB( (FT_UInt32)ppem ); |
| |
| if ( log_base_2 >= 46 ) |
| { |
| /* possible overflow */ |
| scaled_stem = af_intToFixed( x4 ); |
| } |
| else |
| scaled_stem = FT_MulFix( stem_width_per_1000, ppem ); |
| |
| /* now apply the darkening parameters */ |
| if ( scaled_stem < af_intToFixed( x1 ) ) |
| darken_amount = FT_DivFix( af_intToFixed( y1 ), ppem ); |
| |
| else if ( scaled_stem < af_intToFixed( x2 ) ) |
| { |
| FT_Int xdelta = x2 - x1; |
| FT_Int ydelta = y2 - y1; |
| FT_Int x = stem_width_per_1000 - |
| FT_DivFix( af_intToFixed( x1 ), ppem ); |
| |
| |
| if ( !xdelta ) |
| goto Try_x3; |
| |
| darken_amount = FT_MulDiv( x, ydelta, xdelta ) + |
| FT_DivFix( af_intToFixed( y1 ), ppem ); |
| } |
| |
| else if ( scaled_stem < af_intToFixed( x3 ) ) |
| { |
| Try_x3: |
| { |
| FT_Int xdelta = x3 - x2; |
| FT_Int ydelta = y3 - y2; |
| FT_Int x = stem_width_per_1000 - |
| FT_DivFix( af_intToFixed( x2 ), ppem ); |
| |
| |
| if ( !xdelta ) |
| goto Try_x4; |
| |
| darken_amount = FT_MulDiv( x, ydelta, xdelta ) + |
| FT_DivFix( af_intToFixed( y2 ), ppem ); |
| } |
| } |
| |
| else if ( scaled_stem < af_intToFixed( x4 ) ) |
| { |
| Try_x4: |
| { |
| FT_Int xdelta = x4 - x3; |
| FT_Int ydelta = y4 - y3; |
| FT_Int x = stem_width_per_1000 - |
| FT_DivFix( af_intToFixed( x3 ), ppem ); |
| |
| |
| if ( !xdelta ) |
| goto Use_y4; |
| |
| darken_amount = FT_MulDiv( x, ydelta, xdelta ) + |
| FT_DivFix( af_intToFixed( y3 ), ppem ); |
| } |
| } |
| |
| else |
| { |
| Use_y4: |
| darken_amount = FT_DivFix( af_intToFixed( y4 ), ppem ); |
| } |
| |
| /* Convert darken_amount from per 1000 em to true character space. */ |
| return FT_DivFix( darken_amount, em_ratio ); |
| } |
| |
| |
| /* END */ |
