Here's something.
>From 0d62556870ccd939782141a2ba7aa3150a1b03b8 Mon Sep 17 00:00:00 2001
From: Nikolaus Waxweiler <[email protected]>
Date: Sun, 23 Oct 2016 22:43:25 +0200
Subject: [PATCH] Minor clean-up of af_loader_load_glyph().
Merge af_loader_load_g into af_loader_load_glyph, move emboldening into own
function, minor documentation improvements.
---
src/autofit/afloader.c | 600 ++++++++++++++++++++++++-------------------------
src/autofit/afloader.h | 5 +
2 files changed, 304 insertions(+), 301 deletions(-)
diff --git a/src/autofit/afloader.c b/src/autofit/afloader.c
index 26bba06..e593db8 100644
--- a/src/autofit/afloader.c
+++ b/src/autofit/afloader.c
@@ -86,161 +86,135 @@
( (FT_Fixed)( (f) * 65536.0 + 0.5 ) )
- /* 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. */
-
- static FT_Error
- af_loader_load_g( AF_Loader loader,
- AF_Scaler scaler,
- FT_UInt glyph_index,
- FT_Int32 load_flags )
+ /* 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 )
{
- AF_Module module = loader->globals->module;
+ FT_Error error;
+ FT_Size size = face->size;
+ FT_GlyphSlot slot = face->glyph;
+ FT_Slot_Internal internal = slot->internal;
+ FT_GlyphLoader gloader = 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;
+#ifdef FT_CONFIG_OPTION_PIC
+ AF_FaceGlobals globals = loader->globals;
+#endif
- FT_Error error;
- FT_Face face = loader->face;
- AF_StyleMetrics metrics = loader->metrics;
- AF_GlyphHints hints = loader->hints;
- FT_GlyphSlot slot = face->glyph;
- FT_Slot_Internal internal = slot->internal;
- FT_GlyphLoader gloader = internal->loader;
- FT_Int32 flags;
+ if ( !size )
+ return FT_THROW( Invalid_Size_Handle );
- flags = load_flags | FT_LOAD_LINEAR_DESIGN;
- error = FT_Load_Glyph( face, glyph_index, flags );
- if ( error )
- goto Exit;
+ FT_ZERO( &scaler );
/*
- * 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.
+ * 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.
*/
- if ( !module->no_stem_darkening )
- {
- AF_FaceGlobals globals = loader->globals;
- AF_WritingSystemClass writing_system_class;
-
- FT_Pos stdVW = 0;
- FT_Pos stdHW = 0;
-
- FT_Bool size_changed = face->size->metrics.x_ppem
- != globals->stem_darkening_for_ppem;
+ scaler.face = face;
+ scaler.x_scale = size->metrics.x_scale;
+ scaler.x_delta = 0;
+ scaler.y_scale = size->metrics.y_scale;
+ scaler.y_delta = 0;
- FT_Fixed em_size = af_intToFixed( face->units_per_EM );
- FT_Fixed em_ratio = FT_DivFix( af_intToFixed( 1000 ), em_size );
+ scaler.render_mode = FT_LOAD_TARGET_MODE( load_flags );
+ scaler.flags = 0;
- FT_Matrix scale_down_matrix = { 0x10000L, 0, 0, 0x10000L };
+ error = af_loader_reset( loader, module, face );
+ if ( error )
+ goto Exit;
- /* Skip stem darkening for broken fonts. */
- if ( !face->units_per_EM )
- goto After_Emboldening;
+#ifdef FT_OPTION_AUTOFIT2
+ /* XXX: undocumented hook to activate the latin2 writing system. */
+ if ( load_flags & ( 1UL << 20 ) )
+ style_options = AF_STYLE_LTN2_DFLT;
+#endif
- /*
- * 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 effectively disabled.
- */
- writing_system_class =
- AF_WRITING_SYSTEM_CLASSES_GET[metrics->style_class->writing_system];
+ /*
+ * Glyphs (really code points) are assigned 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;
- if ( writing_system_class->style_metrics_getstdw )
- writing_system_class->style_metrics_getstdw( metrics,
- &stdHW,
- &stdVW );
- else
- goto After_Emboldening;
+ style_class = style_metrics->style_class;
+ writing_system_class =
+ AF_WRITING_SYSTEM_CLASSES_GET[style_class->writing_system];
+ loader->metrics = style_metrics;
- if ( size_changed ||
- ( stdVW > 0 && stdVW != globals->standard_vertical_width ) )
- {
- FT_Fixed darken_by_font_units_x, darken_x;
+ 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;
+ }
- darken_by_font_units_x =
- af_intToFixed( af_loader_compute_darkening( loader,
- face,
- stdVW ) );
- darken_x = FT_DivFix( FT_MulFix( darken_by_font_units_x,
- face->size->metrics.x_scale ),
- em_ratio );
+ /*
+ * 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;
- globals->standard_vertical_width = stdVW;
- globals->stem_darkening_for_ppem = face->size->metrics.x_ppem;
- globals->darken_x = af_fixedToInt( darken_x );
- }
+ error = FT_Load_Glyph( face, glyph_index, load_flags );
- 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_intToFixed( af_loader_compute_darkening( loader,
- face,
- stdHW ) );
- darken_y = FT_DivFix( FT_MulFix( darken_by_font_units_y,
- face->size->metrics.y_scale ),
- em_ratio );
-
- globals->standard_horizontal_width = stdHW;
- globals->stem_darkening_for_ppem = face->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 );
- }
+ if ( error )
+ goto Exit;
- FT_Outline_EmboldenXY( &slot->outline,
- globals->darken_x,
- globals->darken_y );
+ /*
+ * 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.
+ */
+ if ( !module->no_stem_darkening )
+ af_loader_embolden_glyph_in_slot( loader, face, style_metrics );
- scale_down_matrix.yy = globals->scale_down_factor;
- FT_Outline_Transform( &slot->outline, &scale_down_matrix );
- }
- After_Emboldening:
loader->transformed = internal->glyph_transformed;
if ( loader->transformed )
{
@@ -257,87 +231,100 @@
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 */
- {
+ 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 */
+ {
#ifdef FT_CONFIG_OPTION_PIC
- AF_FaceGlobals globals = loader->globals;
+ AF_FaceGlobals globals = loader->globals;
#endif
- AF_StyleClass style_class = metrics->style_class;
- AF_WritingSystemClass writing_system_class =
- AF_WRITING_SYSTEM_CLASSES_GET[style_class->writing_system];
+ AF_StyleClass style_class = style_metrics->style_class;
+ AF_WritingSystemClass writing_system_class =
+ AF_WRITING_SYSTEM_CLASSES_GET[style_class->writing_system];
- if ( writing_system_class->style_hints_apply )
- writing_system_class->style_hints_apply( glyph_index,
- hints,
- &gloader->base.outline,
- metrics );
- }
+ if ( writing_system_class->style_hints_apply )
+ writing_system_class->style_hints_apply( glyph_index,
+ hints,
+ &gloader->base.outline,
+ style_metrics );
+ }
- /* 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 )
- {
- FT_Pos old_rsb, old_lsb, new_lsb;
- FT_Pos pp1x_uh, pp2x_uh;
- AF_AxisHints axis = &hints->axis[AF_DIMENSION_HORZ];
- AF_Edge edge1 = axis->edges; /* leftmost edge */
- AF_Edge edge2 = edge1 +
- axis->num_edges - 1; /* rightmost edge */
+ /* 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 )
+ {
+ FT_Pos old_rsb, old_lsb, new_lsb;
+ FT_Pos pp1x_uh, pp2x_uh;
+ AF_AxisHints axis = &hints->axis[AF_DIMENSION_HORZ];
+ AF_Edge edge1 = axis->edges; /* leftmost edge */
+ AF_Edge edge2 = edge1 +
+ axis->num_edges - 1; /* rightmost edge */
- if ( axis->num_edges > 1 && AF_HINTS_DO_ADVANCE( hints ) )
- {
- old_rsb = loader->pp2.x - edge2->opos;
- old_lsb = edge1->opos;
- new_lsb = edge1->pos;
+ if ( axis->num_edges > 1 && AF_HINTS_DO_ADVANCE( hints ) )
+ {
+ old_rsb = loader->pp2.x - edge2->opos;
+ old_lsb = edge1->opos;
+ new_lsb = edge1->pos;
+
+ /* remember unhinted values to later account */
+ /* for rounding errors */
- /* remember unhinted values to later account */
- /* for rounding errors */
+ pp1x_uh = new_lsb - old_lsb;
+ pp2x_uh = edge2->pos + old_rsb;
- pp1x_uh = new_lsb - old_lsb;
- pp2x_uh = edge2->pos + old_rsb;
+ /* prefer too much space over too little space */
+ /* for very small sizes */
- /* prefer too much space over too little space */
- /* for very small sizes */
+ if ( old_lsb < 24 )
+ pp1x_uh -= 8;
- if ( old_lsb < 24 )
- pp1x_uh -= 8;
+ if ( old_rsb < 24 )
+ pp2x_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 );
- 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->pp1.x >= new_lsb && old_lsb > 0 )
- loader->pp1.x -= 64;
+ if ( loader->pp2.x <= edge2->pos && old_rsb > 0 )
+ loader->pp2.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;
- slot->lsb_delta = loader->pp1.x - pp1x_uh;
- slot->rsb_delta = loader->pp2.x - pp2x_uh;
+
+ 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;
+ }
}
else
{
@@ -345,34 +332,21 @@
FT_Pos pp2x = loader->pp2.x;
- loader->pp1.x = FT_PIX_ROUND( pp1x );
- loader->pp2.x = FT_PIX_ROUND( pp2x );
+ loader->pp1.x = FT_PIX_ROUND( pp1x + hints->xmin_delta );
+ loader->pp2.x = FT_PIX_ROUND( pp2x + hints->xmax_delta );
slot->lsb_delta = loader->pp1.x - pp1x;
slot->rsb_delta = loader->pp2.x - pp2x;
}
- }
- else
- {
- FT_Pos pp1x = loader->pp1.x;
- FT_Pos pp2x = loader->pp2.x;
-
-
- loader->pp1.x = FT_PIX_ROUND( pp1x + hints->xmin_delta );
- loader->pp2.x = FT_PIX_ROUND( pp2x + hints->xmax_delta );
-
- slot->lsb_delta = loader->pp1.x - pp1x;
- slot->rsb_delta = loader->pp2.x - pp2x;
- }
- break;
+ break;
- default:
- /* we don't support other formats (yet?) */
- error = FT_THROW( Unimplemented_Feature );
+ default:
+ /* we don't support other formats (yet?) */
+ error = FT_THROW( Unimplemented_Feature );
}
- Hint_Metrics:
+Hint_Metrics:
{
FT_BBox bbox;
FT_Vector vvector;
@@ -380,8 +354,8 @@
vvector.x = slot->metrics.vertBearingX - slot->metrics.horiBearingX;
vvector.y = slot->metrics.vertBearingY - slot->metrics.horiBearingY;
- vvector.x = FT_MulFix( vvector.x, metrics->scaler.x_scale );
- vvector.y = FT_MulFix( vvector.y, metrics->scaler.y_scale );
+ 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 )
@@ -389,12 +363,12 @@
FT_Outline_Transform( &gloader->base.outline, &loader->trans_matrix );
FT_Vector_Transform( &vvector, &loader->trans_matrix );
}
-#if 1
+
/* 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 );
-#endif
+
FT_Outline_Get_CBox( &gloader->base.outline, &bbox );
bbox.xMin = FT_PIX_FLOOR( bbox.xMin );
@@ -413,20 +387,13 @@
/* 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 0
- if ( !FT_IS_FIXED_WIDTH( slot->face ) )
- slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x;
- else
- slot->metrics.horiAdvance = FT_MulFix( slot->metrics.horiAdvance,
- x_scale );
-#else
- if ( scaler->render_mode != FT_RENDER_MODE_LIGHT &&
+ if ( scaler.render_mode != FT_RENDER_MODE_LIGHT &&
( FT_IS_FIXED_WIDTH( slot->face ) ||
( af_face_globals_is_digit( loader->globals, glyph_index ) &&
- metrics->digits_have_same_width ) ) )
+ style_metrics->digits_have_same_width ) ) )
{
slot->metrics.horiAdvance = FT_MulFix( slot->metrics.horiAdvance,
- metrics->scaler.x_scale );
+ style_metrics->scaler.x_scale );
/* Set delta values to 0. Otherwise code that uses them is */
/* going to ruin the fixed advance width. */
@@ -439,106 +406,137 @@
if ( slot->metrics.horiAdvance )
slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x;
}
-#endif
slot->metrics.vertAdvance = FT_MulFix( slot->metrics.vertAdvance,
- metrics->scaler.y_scale );
+ style_metrics->scaler.y_scale );
slot->metrics.horiAdvance = FT_PIX_ROUND( slot->metrics.horiAdvance );
slot->metrics.vertAdvance = FT_PIX_ROUND( slot->metrics.vertAdvance );
-#if 0
- /* reassign all outline fields except flags to protect them */
- slot->outline.n_contours = internal->loader->base.outline.n_contours;
- slot->outline.n_points = internal->loader->base.outline.n_points;
- slot->outline.points = internal->loader->base.outline.points;
- slot->outline.tags = internal->loader->base.outline.tags;
- slot->outline.contours = internal->loader->base.outline.contours;
-#endif
-
slot->format = FT_GLYPH_FORMAT_OUTLINE;
}
-
- Exit:
+Exit:
return error;
}
- /* Load a glyph. */
-
FT_LOCAL_DEF( FT_Error )
- af_loader_load_glyph( AF_Loader loader,
- AF_Module module,
- FT_Face face,
- FT_UInt gindex,
- FT_Int32 load_flags )
+ af_loader_embolden_glyph_in_slot( AF_Loader loader,
+ FT_Face face,
+ AF_StyleMetrics style_metrics )
{
- FT_Error error;
- FT_Size size = face->size;
- AF_ScalerRec scaler;
+ FT_Error error = FT_Err_Ok;
+ FT_GlyphSlot slot = face->glyph;
+ AF_FaceGlobals globals = loader->globals;
+ AF_WritingSystemClass writing_system_class;
+ FT_Pos stdVW = 0;
+ FT_Pos stdHW = 0;
- if ( !size )
- return FT_THROW( Invalid_Size_Handle );
+ FT_Bool size_changed = face->size->metrics.x_ppem
+ != globals->stem_darkening_for_ppem;
- FT_ZERO( &scaler );
+ FT_Fixed em_size = af_intToFixed( face->units_per_EM );
+ FT_Fixed em_ratio = FT_DivFix( af_intToFixed( 1000 ), em_size );
- scaler.face = face;
- scaler.x_scale = size->metrics.x_scale;
- scaler.x_delta = 0; /* XXX: TODO: add support for sub-pixel hinting */
- scaler.y_scale = size->metrics.y_scale;
- scaler.y_delta = 0; /* XXX: TODO: add support for sub-pixel hinting */
+ FT_Matrix scale_down_matrix = { 0x10000L, 0, 0, 0x10000L };
- scaler.render_mode = FT_LOAD_TARGET_MODE( load_flags );
- scaler.flags = 0; /* XXX: fix this */
- error = af_loader_reset( loader, module, face );
- if ( !error )
+ /* Skip stem darkening for broken fonts. */
+ if ( !face->units_per_EM )
{
- AF_StyleMetrics metrics;
- FT_UInt options = AF_STYLE_NONE_DFLT;
+ 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_GET[style_metrics->style_class->writing_system];
-#ifdef FT_OPTION_AUTOFIT2
- /* XXX: undocumented hook to activate the latin2 writing system */
- if ( load_flags & ( 1UL << 20 ) )
- options = AF_STYLE_LTN2_DFLT;
-#endif
+ 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;
+ }
- error = af_face_globals_get_metrics( loader->globals, gindex,
- options, &metrics );
- if ( !error )
- {
-#ifdef FT_CONFIG_OPTION_PIC
- AF_FaceGlobals globals = loader->globals;
-#endif
- AF_StyleClass style_class = metrics->style_class;
- AF_WritingSystemClass writing_system_class =
- AF_WRITING_SYSTEM_CLASSES_GET[style_class->writing_system];
+ if ( size_changed ||
+ ( stdVW > 0 && stdVW != globals->standard_vertical_width ) )
+ {
+ FT_Fixed darken_by_font_units_x, darken_x;
- loader->metrics = metrics;
- if ( writing_system_class->style_metrics_scale )
- writing_system_class->style_metrics_scale( metrics, &scaler );
- else
- metrics->scaler = scaler;
+ darken_by_font_units_x =
+ af_intToFixed( af_loader_compute_darkening( loader,
+ face,
+ stdVW ) );
+ darken_x = FT_DivFix( FT_MulFix( darken_by_font_units_x,
+ face->size->metrics.x_scale ),
+ em_ratio );
- load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_IGNORE_TRANSFORM;
- load_flags &= ~FT_LOAD_RENDER;
+ globals->standard_vertical_width = stdVW;
+ globals->stem_darkening_for_ppem = face->size->metrics.x_ppem;
+ globals->darken_x = af_fixedToInt( darken_x );
+ }
- if ( writing_system_class->style_hints_init )
- {
- error = writing_system_class->style_hints_init( loader->hints,
- metrics );
- if ( error )
- goto Exit;
- }
+ if ( size_changed ||
+ ( stdHW > 0 && stdHW != globals->standard_horizontal_width ) )
+ {
+ FT_Fixed darken_by_font_units_y, darken_y;
- error = af_loader_load_g( loader, &scaler, gindex, load_flags );
- }
+
+ darken_by_font_units_y =
+ af_intToFixed( af_loader_compute_darkening( loader,
+ face,
+ stdHW ) );
+ darken_y = FT_DivFix( FT_MulFix( darken_by_font_units_y,
+ face->size->metrics.y_scale ),
+ em_ratio );
+
+ globals->standard_horizontal_width = stdHW;
+ globals->stem_darkening_for_ppem = face->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 );
}
- Exit:
+
+ 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;
}
diff --git a/src/autofit/afloader.h b/src/autofit/afloader.h
index 0062eb9..2e6f36b 100644
--- a/src/autofit/afloader.h
+++ b/src/autofit/afloader.h
@@ -75,6 +75,11 @@ FT_BEGIN_HEADER
FT_UInt gindex,
FT_Int32 load_flags );
+ FT_LOCAL_DEF( FT_Error )
+ af_loader_embolden_glyph_in_slot( AF_Loader loader,
+ FT_Face face,
+ AF_StyleMetrics style_metrics );
+
FT_LOCAL_DEF( FT_Int32 )
af_loader_compute_darkening( AF_Loader loader,
FT_Face face,
--
2.7.4
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