ref: 2e9519885b8e7e5fdc9d75b35992ef7bbf15e53a
parent: 64cdee73480587352fb45402b771077be05c1715
author: Nikolaus Waxweiler <[email protected]>
date: Thu Feb 16 15:45:45 EST 2017
Add face property for LCD filter weights. * include/freetype/ftlcdfil.h (FT_PARAM_TAG_LCD_FILTER_WEIGHTS, FT_LCD_FILTER_FIVE_TAPS): New macros. (FT_LcdFiveTapFilter): New typedef. * include/freetype/ftobjs.h (FT_Face_InternalRec) [FT_CONFIG_OPTION_SUBPIXEL_RENDERING]: Add `lcd_weights' field. (FT_Bitmap_LcdFilterFunc): Change third argument to weights array. (ft_lcd_filter_fir): New prototype. (FT_LibraryRec): Updated. * src/base/ftlcdfil.c (_ft_lcd_filter_fir): Renamed to... (ft_lcd_filter_dir): ... this base function. Updated. (_ft_lcd_filter_legacy): Updated. (FT_Library_SetLcdFilterWeights, FT_Library_SetLcdFilter): Updated. * src/base/ftobjs.c (ft_open_face_internal): Updated. (FT_Face_Properties): Handle FT_PARAM_TAG_LCD_FILTER_WEIGHTS. * src/smooth/ftsmooth.c (ft_smooth_render_generic) [FT_CONFIG_OPTION_SUBPIXEL_RENDERING: Handle LCD weights from `FT_Face_Internal'.
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,31 @@
+2017-02-16 Nikolaus Waxweiler <[email protected]>
+ Werner Lemberg <[email protected]>
+
+ Add face property for LCD filter weights.
+
+ * include/freetype/ftlcdfil.h (FT_PARAM_TAG_LCD_FILTER_WEIGHTS,
+ FT_LCD_FILTER_FIVE_TAPS): New macros.
+ (FT_LcdFiveTapFilter): New typedef.
+
+ * include/freetype/ftobjs.h (FT_Face_InternalRec)
+ [FT_CONFIG_OPTION_SUBPIXEL_RENDERING]: Add `lcd_weights' field.
+ (FT_Bitmap_LcdFilterFunc): Change third argument to weights array.
+ (ft_lcd_filter_fir): New prototype.
+ (FT_LibraryRec): Updated.
+
+ * src/base/ftlcdfil.c (_ft_lcd_filter_fir): Renamed to...
+ (ft_lcd_filter_dir): ... this base function.
+ Updated.
+ (_ft_lcd_filter_legacy): Updated.
+ (FT_Library_SetLcdFilterWeights, FT_Library_SetLcdFilter): Updated.
+
+ * src/base/ftobjs.c (ft_open_face_internal): Updated.
+ (FT_Face_Properties): Handle FT_PARAM_TAG_LCD_FILTER_WEIGHTS.
+
+ * src/smooth/ftsmooth.c (ft_smooth_render_generic)
+ [FT_CONFIG_OPTION_SUBPIXEL_RENDERING: Handle LCD weights from
+ `FT_Face_Internal'.
+
2017-02-14 Nikolaus Waxweiler <[email protected]>
Werner Lemberg <[email protected]>
--- a/include/freetype/freetype.h
+++ b/include/freetype/freetype.h
@@ -3629,6 +3629,12 @@
* Note that only a subset of the available properties can be
* controlled.
*
+ * * LCD filter weights (@FT_PARAM_TAG_LCD_FILTER_WEIGHTS, corresponding
+ * to function @FT_Library_SetLcdFilterWeights).
+ *
+ * Pass NULL as `data' in @FT_Parameter for a given tag to reset the
+ * option and use the library or module default again.
+ *
* @input:
* face ::
* A handle to the source face object.
--- a/include/freetype/ftlcdfil.h
+++ b/include/freetype/ftlcdfil.h
@@ -275,6 +275,37 @@
FT_Library_SetLcdFilterWeights( FT_Library library,
unsigned char *weights );
+
+ /*
+ * @constant:
+ * FT_PARAM_TAG_LCD_FILTER_WEIGHTS
+ *
+ * @description:
+ * An @FT_Parameter tag to be used with @FT_Face_Properties. The
+ * corresponding argument specifies the five LCD filter weights for a
+ * given face (if using @FT_LOAD_TARGET_LCD, for example), overriding
+ * the global default values or the values set up with
+ * @FT_Library_Set_LcdFilterWeights.
+ *
+ */
+#define FT_PARAM_TAG_LCD_FILTER_WEIGHTS \
+ FT_MAKE_TAG( 'l', 'c', 'd', 'f' )
+
+
+ /*
+ * @type:
+ * FT_LcdFiveTapFilter
+ *
+ * @description:
+ * A typedef for passing the five LCD filter weights to
+ * @FT_Face_Properties within an @FT_Parameter structure.
+ *
+ */
+#define FT_LCD_FILTER_FIVE_TAPS 5
+
+ typedef FT_Byte FT_LcdFiveTapFilter[FT_LCD_FILTER_FIVE_TAPS];
+
+
/* */
--- a/include/freetype/internal/ftobjs.h
+++ b/include/freetype/internal/ftobjs.h
@@ -348,6 +348,10 @@
/* @FT_Done_Face only destroys a face if the counter is~1, */
/* otherwise it simply decrements it. */
/* */
+ /* lcd_weights :: */
+ /* Overrides the library default with custom weights for the 5-tap */
+ /* FIR filter. `{0, 0, 0, 0, 0}' means to use the library default. */+ /* */
typedef struct FT_Face_InternalRec_
{FT_Matrix transform_matrix;
@@ -362,6 +366,10 @@
FT_Int refcount;
+#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
+ FT_LcdFiveTapFilter lcd_weights; /* preset or custom filter weights */
+#endif
+
} FT_Face_InternalRec;
@@ -775,14 +783,21 @@
/* This hook is used by the TrueType debugger. It must be set to an */
/* alternate truetype bytecode interpreter function. */
-#define FT_DEBUG_HOOK_TRUETYPE 0
+#define FT_DEBUG_HOOK_TRUETYPE 0
typedef void (*FT_Bitmap_LcdFilterFunc)( FT_Bitmap* bitmap,
FT_Render_Mode render_mode,
- FT_Library library );
+ FT_Byte* weights );
+ /* This is the default LCD filter, an in-place, 5-tap FIR filter. */
+ FT_BASE( void )
+ ft_lcd_filter_fir( FT_Bitmap* bitmap,
+ FT_Render_Mode mode,
+ FT_LcdFiveTapFilter weights );
+
+
/*************************************************************************/
/* */
/* <Struct> */
@@ -876,7 +891,7 @@
#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
FT_LcdFilter lcd_filter;
FT_Int lcd_extra; /* number of extra pixels */
- FT_Byte lcd_weights[5]; /* filter weights, if any */
+ FT_LcdFiveTapFilter lcd_weights; /* filter weights, if any */
FT_Bitmap_LcdFilterFunc lcd_filter_func; /* filtering callback */
#endif
--- a/src/base/ftlcdfil.c
+++ b/src/base/ftlcdfil.c
@@ -30,14 +30,13 @@
#define USE_LEGACY
/* FIR filter used by the default and light filters */
- static void
- _ft_lcd_filter_fir( FT_Bitmap* bitmap,
- FT_Render_Mode mode,
- FT_Library library )
+ FT_BASE( void )
+ ft_lcd_filter_fir( FT_Bitmap* bitmap,
+ FT_Render_Mode mode,
+ FT_LcdFiveTapFilter weights )
{- FT_Byte* weights = library->lcd_weights;
- FT_UInt width = (FT_UInt)bitmap->width;
- FT_UInt height = (FT_UInt)bitmap->rows;
+ FT_UInt width = (FT_UInt)bitmap->width;
+ FT_UInt height = (FT_UInt)bitmap->rows;
/* horizontal in-place FIR filter */
@@ -176,7 +175,7 @@
static void
_ft_lcd_filter_legacy( FT_Bitmap* bitmap,
FT_Render_Mode mode,
- FT_Library library )
+ FT_Byte* weights )
{FT_UInt width = (FT_UInt)bitmap->width;
FT_UInt height = (FT_UInt)bitmap->rows;
@@ -189,7 +188,7 @@
{ 65538 * 1/13, 65538 * 1/6, 65538 * 9/13 }};
- FT_UNUSED( library );
+ FT_UNUSED( weights );
/* horizontal in-place intra-pixel filter */
@@ -295,8 +294,8 @@
if ( !weights )
return FT_THROW( Invalid_Argument );
- ft_memcpy( library->lcd_weights, weights, 5 );
- library->lcd_filter_func = _ft_lcd_filter_fir;
+ ft_memcpy( library->lcd_weights, weights, FT_LCD_FILTER_FIVE_TAPS );
+ library->lcd_filter_func = ft_lcd_filter_fir;
library->lcd_extra = 2;
return FT_Err_Ok;
@@ -307,10 +306,10 @@
FT_Library_SetLcdFilter( FT_Library library,
FT_LcdFilter filter )
{- static const FT_Byte default_filter[5] =
- { 0x08, 0x4d, 0x56, 0x4d, 0x08 };- static const FT_Byte light_filter[5] =
- { 0x00, 0x55, 0x56, 0x55, 0x00 };+ static const FT_LcdFiveTapFilter default_weights =
+ { 0x08, 0x4d, 0x56, 0x4d, 0x08 };+ static const FT_LcdFiveTapFilter light_weights =
+ { 0x00, 0x55, 0x56, 0x55, 0x00 };if ( !library )
@@ -324,14 +323,18 @@
break;
case FT_LCD_FILTER_DEFAULT:
- ft_memcpy( library->lcd_weights, default_filter, 5 );
- library->lcd_filter_func = _ft_lcd_filter_fir;
+ ft_memcpy( library->lcd_weights,
+ default_weights,
+ FT_LCD_FILTER_FIVE_TAPS );
+ library->lcd_filter_func = ft_lcd_filter_fir;
library->lcd_extra = 2;
break;
case FT_LCD_FILTER_LIGHT:
- ft_memcpy( library->lcd_weights, light_filter, 5 );
- library->lcd_filter_func = _ft_lcd_filter_fir;
+ ft_memcpy( library->lcd_weights,
+ light_weights,
+ FT_LCD_FILTER_FIVE_TAPS );
+ library->lcd_filter_func = ft_lcd_filter_fir;
library->lcd_extra = 2;
break;
@@ -355,6 +358,17 @@
}
#else /* !FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
+
+ FT_BASE( void )
+ ft_lcd_filter_fir( FT_Bitmap* bitmap,
+ FT_Render_Mode mode,
+ FT_LcdFiveTapFilter weights )
+ {+ FT_UNUSED( bitmap );
+ FT_UNUSED( mode );
+ FT_UNUSED( weights );
+ }
+
FT_EXPORT_DEF( FT_Error )
FT_Library_SetLcdFilterWeights( FT_Library library,
--- a/src/base/ftobjs.c
+++ b/src/base/ftobjs.c
@@ -2424,6 +2424,10 @@
internal->transform_delta.y = 0;
internal->refcount = 1;
+
+#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
+ ft_memset( internal->lcd_weights, 0, FT_LCD_FILTER_FIVE_TAPS );
+#endif
}
if ( aface )
@@ -3607,8 +3611,31 @@
for ( ; num_properties > 0; num_properties-- )
{- error = FT_THROW( Invalid_Argument );
- goto Exit;
+ if ( properties->tag == FT_PARAM_TAG_LCD_FILTER_WEIGHTS )
+ {+#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
+ if ( properties->data )
+ ft_memcpy( face->internal->lcd_weights,
+ properties->data,
+ FT_LCD_FILTER_FIVE_TAPS );
+ else
+ {+ /* Value NULL indicates `no custom weights, use library */
+ /* defaults', signaled by filling the weight field with zeros. */
+ ft_memset( face->internal->lcd_weights,
+ 0,
+ FT_LCD_FILTER_FIVE_TAPS );
+ }
+#else
+ error = FT_THROW( Unimplemented_Feature );
+ goto Exit;
+#endif
+ }
+ else
+ {+ error = FT_THROW( Invalid_Argument );
+ goto Exit;
+ }
if ( error )
break;
--- a/src/smooth/ftsmooth.c
+++ b/src/smooth/ftsmooth.c
@@ -122,7 +122,61 @@
FT_Bool have_outline_shifted = FALSE;
FT_Bool have_buffer = FALSE;
+#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
+ FT_Int lcd_extra = 0;
+ FT_LcdFiveTapFilter lcd_weights = { 0 };+ FT_Bool have_custom_weight = FALSE;
+ FT_Bitmap_LcdFilterFunc lcd_filter_func = NULL;
+
+
+ if ( slot->face )
+ {+ FT_Char i;
+
+
+ for ( i = 0; i < FT_LCD_FILTER_FIVE_TAPS; i++ )
+ if ( slot->face->internal->lcd_weights[i] != 0 )
+ {+ have_custom_weight = TRUE;
+ break;
+ }
+ }
+
+ /*
+ * The LCD filter can be set library-wide and per-face. Face overrides
+ * library. If the face filter weights are all zero (the default), it
+ * means that the library default should be used.
+ */
+ if ( have_custom_weight )
+ {+ /*
+ * A per-font filter is set. It always uses the default 5-tap
+ * in-place FIR filter that needs 2 extra pixels.
+ */
+ ft_memcpy( lcd_weights,
+ slot->face->internal->lcd_weights,
+ FT_LCD_FILTER_FIVE_TAPS );
+ lcd_filter_func = ft_lcd_filter_fir;
+ lcd_extra = 2;
+ }
+ else
+ {+ /*
+ * The face's lcd_weights is {0, 0, 0, 0, 0}, meaning `use library+ * default'. If the library is set to use no LCD filtering
+ * (lcd_filter_func == NULL), `lcd_filter_func' here is also set to
+ * NULL and the tests further below pass over the filtering process.
+ */
+ ft_memcpy( lcd_weights,
+ slot->library->lcd_weights,
+ FT_LCD_FILTER_FIVE_TAPS );
+ lcd_filter_func = slot->library->lcd_filter_func;
+ lcd_extra = slot->library->lcd_extra;
+ }
+
+#endif /*FT_CONFIG_OPTION_SUBPIXEL_RENDERING */
+
/* check glyph image format */
if ( slot->format != render->glyph_format )
{@@ -177,28 +231,23 @@
height *= 3;
#ifdef FT_CONFIG_OPTION_SUBPIXEL_RENDERING
-
- if ( slot->library->lcd_filter_func )
+ if ( lcd_filter_func )
{- FT_Int extra = slot->library->lcd_extra;
-
-
if ( hmul )
{- x_shift += 64 * ( extra >> 1 );
- x_left -= extra >> 1;
- width += 3 * extra;
+ x_shift += 64 * ( lcd_extra >> 1 );
+ x_left -= lcd_extra >> 1;
+ width += 3 * lcd_extra;
pitch = FT_PAD_CEIL( width, 4 );
}
if ( vmul )
{- y_shift += 64 * ( extra >> 1 );
- y_top += extra >> 1;
- height += 3 * extra;
+ y_shift += 64 * ( lcd_extra >> 1 );
+ y_top += lcd_extra >> 1;
+ height += 3 * lcd_extra;
}
}
-
#endif
/*
@@ -299,8 +348,8 @@
if ( error )
goto Exit;
- if ( slot->library->lcd_filter_func )
- slot->library->lcd_filter_func( bitmap, mode, slot->library );
+ if ( lcd_filter_func )
+ lcd_filter_func( bitmap, mode, lcd_weights );
#else /* !FT_CONFIG_OPTION_SUBPIXEL_RENDERING */