Commit 7b73cb0707586e7988efdd07a1dfe690c3036ca1
2018-05-24T22:38:24
[smooth] Formalize Harmony LCD rendering. This generalizes magic outline shifts that make Harmony LCD rendering work in terms of precise two-dimensional RGB subpixel positions. These coordinates are now set in time of the `smooth' module initialization and later used to shift a glyph outline for rendering. FT_RENDER_MODE_LCD and FT_RENDER_MODE_LCD_V use the same coordinates. The letter, however, rotates them before using. The LCD bitmap padding is also calculated using these coordinates. * include/freetype/internal/ftobjs.h (FT_LibraryRec): New array field `lcd_geometry'. * src/base/ftlcdfil.c (ft_lcd_padding): Reworked. * src/base/ftobjs.c (ft_glyphslot_preset_bitmap): Updated accordingly. * src/smooth/ftsmooth.c [!FT_CONFIG_OPTION_SUBPIXEL_RENDERING] (ft_smooth_init): Initialize `lcd_geometry'. (ft_smooth_render_generic): Formalize outline shifts.
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diff --git a/ChangeLog b/ChangeLog
index 789ac94..7c19448 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,24 @@
+2018-05-24 Alexei Podtelezhnikov <apodtele@gmail.com>
+
+ [smooth] Formalize Harmony LCD rendering.
+
+ This generalizes magic outline shifts that make Harmony LCD
+ rendering work in terms of precise two-dimensional RGB subpixel
+ positions. These coordinates are now set in time of the `smooth'
+ module initialization and later used to shift a glyph outline for
+ rendering. FT_RENDER_MODE_LCD and FT_RENDER_MODE_LCD_V use the same
+ coordinates. The letter, however, rotates them before using.
+ The LCD bitmap padding is also calculated using these coordinates.
+
+ * include/freetype/internal/ftobjs.h (FT_LibraryRec): New array field
+ `lcd_geometry'.
+ * src/base/ftlcdfil.c (ft_lcd_padding): Reworked.
+ * src/base/ftobjs.c (ft_glyphslot_preset_bitmap): Updated accordingly.
+
+ * src/smooth/ftsmooth.c [!FT_CONFIG_OPTION_SUBPIXEL_RENDERING]
+ (ft_smooth_init): Initialize `lcd_geometry'.
+ (ft_smooth_render_generic): Formalize outline shifts.
+
2018-05-22 Werner Lemberg <wl@gnu.org>
[truetype] Reject elements of composites with invalid glyph indices.
diff --git a/include/freetype/internal/ftobjs.h b/include/freetype/internal/ftobjs.h
index a8d987f..77f5dc4 100644
--- a/include/freetype/internal/ftobjs.h
+++ b/include/freetype/internal/ftobjs.h
@@ -270,11 +270,11 @@ FT_BEGIN_HEADER
FT_CMap_Done( FT_CMap cmap );
- /* adds LCD padding to Min and Max boundaries */
+ /* add LCD padding to CBox */
FT_BASE( void )
- ft_lcd_padding( FT_Pos* Min,
- FT_Pos* Max,
- FT_GlyphSlot slot );
+ ft_lcd_padding( FT_BBox* cbox,
+ FT_GlyphSlot slot,
+ FT_Render_Mode mode );
#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
@@ -350,8 +350,8 @@ FT_BEGIN_HEADER
/* */
/* lcd_weights :: */
/* lcd_filter_func :: */
- /* If subpixel rendering is activated, the LCD filtering weights */
- /* and callback function. */
+ /* These fields specify the LCD filtering weights and callback */
+ /* function for ClearType-style subpixel rendering. */
/* */
/* refcount :: */
/* A counter initialized to~1 at the time an @FT_Face structure is */
@@ -868,11 +868,15 @@ FT_BEGIN_HEADER
/* interpreter. Currently, only the TrueType */
/* bytecode debugger uses this. */
/* */
- /* lcd_weights :: If subpixel rendering is activated, the LCD */
- /* filter weights, if any. */
+ /* lcd_weights :: The LCD filter weights for ClearType-style */
+ /* subpixel rendering. */
/* */
- /* lcd_filter_func :: If subpixel rendering is activated, the LCD */
- /* filtering callback function. */
+ /* lcd_filter_func :: The LCD filtering callback function for */
+ /* for ClearType-style subpixel rendering. */
+ /* */
+ /* lcd_geometry :: This array specifies LCD subpixel geometry */
+ /* and controls Harmony LCD rendering technique, */
+ /* alternative to ClearType. */
/* */
/* pic_container :: Contains global structs and tables, instead */
/* of defining them globally. */
@@ -904,6 +908,8 @@ FT_BEGIN_HEADER
#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
FT_LcdFiveTapFilter lcd_weights; /* filter weights, if any */
FT_Bitmap_LcdFilterFunc lcd_filter_func; /* filtering callback */
+#else
+ FT_Vector lcd_geometry[3]; /* RGB subpixel positions */
#endif
FT_Int refcount;
diff --git a/src/base/ftlcdfil.c b/src/base/ftlcdfil.c
index 8d314df..213f3f1 100644
--- a/src/base/ftlcdfil.c
+++ b/src/base/ftlcdfil.c
@@ -34,9 +34,9 @@
/* add padding according to filter weights */
FT_BASE_DEF (void)
- ft_lcd_padding( FT_Pos* Min,
- FT_Pos* Max,
- FT_GlyphSlot slot )
+ ft_lcd_padding( FT_BBox* cbox,
+ FT_GlyphSlot slot,
+ FT_Render_Mode mode )
{
FT_Byte* lcd_weights;
FT_Bitmap_LcdFilterFunc lcd_filter_func;
@@ -56,10 +56,20 @@
if ( lcd_filter_func == ft_lcd_filter_fir )
{
- *Min -= lcd_weights[0] ? 43 :
- lcd_weights[1] ? 22 : 0;
- *Max += lcd_weights[4] ? 43 :
- lcd_weights[3] ? 22 : 0;
+ if ( mode == FT_RENDER_MODE_LCD )
+ {
+ cbox->xMin -= lcd_weights[0] ? 43 :
+ lcd_weights[1] ? 22 : 0;
+ cbox->xMax += lcd_weights[4] ? 43 :
+ lcd_weights[3] ? 22 : 0;
+ }
+ else if ( mode == FT_RENDER_MODE_LCD_V )
+ {
+ cbox->yMin -= lcd_weights[0] ? 43 :
+ lcd_weights[1] ? 22 : 0;
+ cbox->yMax += lcd_weights[4] ? 43 :
+ lcd_weights[3] ? 22 : 0;
+ }
}
}
@@ -343,16 +353,28 @@
#else /* !FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
- /* add padding according to accommodate outline shifts */
+ /* add padding to accommodate outline shifts */
FT_BASE_DEF (void)
- ft_lcd_padding( FT_Pos* Min,
- FT_Pos* Max,
- FT_GlyphSlot slot )
+ ft_lcd_padding( FT_BBox* cbox,
+ FT_GlyphSlot slot,
+ FT_Render_Mode mode )
{
- FT_UNUSED( slot );
+ FT_Vector* sub = slot->library->lcd_geometry;
- *Min -= 21;
- *Max += 21;
+ if ( mode == FT_RENDER_MODE_LCD )
+ {
+ cbox->xMin -= FT_MAX( FT_MAX( sub[0].x, sub[1].x ), sub[2].x );
+ cbox->xMax -= FT_MIN( FT_MIN( sub[0].x, sub[1].x ), sub[2].x );
+ cbox->yMin -= FT_MAX( FT_MAX( sub[0].y, sub[1].y ), sub[2].y );
+ cbox->yMax -= FT_MIN( FT_MIN( sub[0].y, sub[1].y ), sub[2].y );
+ }
+ else if ( mode == FT_RENDER_MODE_LCD_V )
+ {
+ cbox->xMin -= FT_MAX( FT_MAX( sub[0].y, sub[1].y ), sub[2].y );
+ cbox->xMax -= FT_MIN( FT_MIN( sub[0].y, sub[1].y ), sub[2].y );
+ cbox->yMin += FT_MIN( FT_MIN( sub[0].x, sub[1].x ), sub[2].x );
+ cbox->yMax += FT_MAX( FT_MAX( sub[0].x, sub[1].x ), sub[2].x );
+ }
}
diff --git a/src/base/ftobjs.c b/src/base/ftobjs.c
index d7768dd..2cd0c92 100644
--- a/src/base/ftobjs.c
+++ b/src/base/ftobjs.c
@@ -397,12 +397,12 @@
case FT_RENDER_MODE_LCD:
pixel_mode = FT_PIXEL_MODE_LCD;
- ft_lcd_padding( &cbox.xMin, &cbox.xMax, slot );
+ ft_lcd_padding( &cbox, slot, mode );
goto Round;
case FT_RENDER_MODE_LCD_V:
pixel_mode = FT_PIXEL_MODE_LCD_V;
- ft_lcd_padding( &cbox.yMin, &cbox.yMax, slot );
+ ft_lcd_padding( &cbox, slot, mode );
goto Round;
case FT_RENDER_MODE_NORMAL:
diff --git a/src/smooth/ftsmooth.c b/src/smooth/ftsmooth.c
index 497926e..3813251 100644
--- a/src/smooth/ftsmooth.c
+++ b/src/smooth/ftsmooth.c
@@ -30,6 +30,22 @@
static FT_Error
ft_smooth_init( FT_Renderer render )
{
+
+#ifndef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
+
+ FT_Vector* sub = render->root.library->lcd_geometry;
+
+
+ /* set up default subpixel geometry for striped RGB panels. */
+ sub[0].x = -21;
+ sub[0].y = 0;
+ sub[1].x = 0;
+ sub[1].y = 0;
+ sub[2].x = 21;
+ sub[2].y = 0;
+
+#endif
+
render->clazz->raster_class->raster_reset( render->raster, NULL, 0 );
return 0;
@@ -234,33 +250,33 @@
unsigned int width = bitmap->width;
int pitch = bitmap->pitch;
+ FT_Vector* sub = slot->library->lcd_geometry;
- /* Render 3 separate monochrome bitmaps, shifting the outline */
- /* by 1/3 pixel. */
- width /= 3;
- bitmap->buffer += width;
+ /* Render 3 separate monochrome bitmaps, shifting the outline. */
+ width /= 3;
+ FT_Outline_Translate( outline, -sub[0].x, -sub[0].y );
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
- FT_Outline_Translate( outline, -21, 0 );
- x_shift -= 21;
bitmap->buffer += width;
-
+ FT_Outline_Translate( outline, sub[0].x - sub[1].x, sub[0].y - sub[1].y );
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
- FT_Outline_Translate( outline, 42, 0 );
- x_shift += 42;
- bitmap->buffer -= 2 * width;
-
+ bitmap->buffer += width;
+ FT_Outline_Translate( outline, sub[1].x - sub[2].x, sub[1].y - sub[2].y );
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
+ x_shift -= sub[2].x;
+ y_shift -= sub[2].y;
+ bitmap->buffer -= 2 * width;
+
/* XXX: Rearrange the bytes according to FT_PIXEL_MODE_LCD. */
/* XXX: It is more efficient to render every third byte above. */
@@ -285,34 +301,36 @@
{
int pitch = bitmap->pitch;
+ FT_Vector* sub = slot->library->lcd_geometry;
- /* Render 3 separate monochrome bitmaps, shifting the outline */
- /* by 1/3 pixel. Triple the pitch to render on each third row. */
+
+ /* Render 3 separate monochrome bitmaps, shifting the outline. */
+ /* Notice that the subpixel geometry vectors are rotated. */
+ /* Triple the pitch to render on each third row. */
bitmap->pitch *= 3;
bitmap->rows /= 3;
- bitmap->buffer += pitch;
-
+ FT_Outline_Translate( outline, -sub[0].y, sub[0].x );
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
- FT_Outline_Translate( outline, 0, 21 );
- y_shift += 21;
bitmap->buffer += pitch;
-
+ FT_Outline_Translate( outline, sub[0].y - sub[1].y, sub[1].x - sub[0].x );
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
- FT_Outline_Translate( outline, 0, -42 );
- y_shift -= 42;
- bitmap->buffer -= 2 * pitch;
-
+ bitmap->buffer += pitch;
+ FT_Outline_Translate( outline, sub[1].y - sub[2].y, sub[2].x - sub[1].x );
error = render->raster_render( render->raster, ¶ms );
if ( error )
goto Exit;
+ x_shift -= sub[2].y;
+ y_shift += sub[2].x;
+ bitmap->buffer -= 2 * pitch;
+
bitmap->pitch /= 3;
bitmap->rows *= 3;
}