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Code Issues 4 Releases Wiki Activity

Add data types required for the forthcoming 'sdf' module. 

* include/freetype/freetype.h (FT_Render_Mode): Add new render mode
`FT_RENDER_MODE_SDF`, which will be used to generate SDF.

* include/freetype/ftimage.h (FT_Pixel_Mode): Add new pixel mode
`FT_PIXEL_MODE_GRAY16`, which will be the output of the 'sdf'
module.
(FT_RASTER_FLAG_SDF): New raster flag to be used internally by the
'sdf' module.

* include/freetype/fttypes.h (FT_F6Dot10): New data type.
This commit is contained in:
Anuj Verma 2020-08-16 10:47:41 +05:30 committed by Werner Lemberg
parent 3b9196c467
commit ec9b6c314d
4 changed files with 60 additions and 5 deletions
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15
ChangeLog
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@ -1,3 +1,18 @@
2020-08-16 Anuj Verma <anujv@iitbhilai.ac.in>
Add data types required for the forthcoming 'sdf' module.
* include/freetype/freetype.h (FT_Render_Mode): Add new render mode
`FT_RENDER_MODE_SDF`, which will be used to generate SDF.
* include/freetype/ftimage.h (FT_Pixel_Mode): Add new pixel mode
`FT_PIXEL_MODE_GRAY16`, which will be the output of the 'sdf'
module.
(FT_RASTER_FLAG_SDF): New raster flag to be used internally by the
'sdf' module.
* include/freetype/fttypes.h (FT_F6Dot10): New data type.
2020-08-16 Anuj Verma <anujv@iitbhilai.ac.in>
[base] Allow renderers of different formats.

24
include/freetype/freetype.h
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@ -3204,7 +3204,7 @@ FT_BEGIN_HEADER
*
* @note:
* This function is provided as a convenience, but keep in mind that
* @FT_Matrix coefficients are only 16.16 fixed point values, which can
* @FT_Matrix coefficients are only 16.16 fixed-point values, which can
* limit the accuracy of the results. Using floating-point computations
* to perform the transform directly in client code instead will always
* yield better numbers.
@ -3236,10 +3236,14 @@ FT_BEGIN_HEADER
* in the @FT_GlyphSlotRec structure gives the format of the returned
* bitmap.
*
* All modes except @FT_RENDER_MODE_MONO use 256 levels of opacity,
* indicating pixel coverage. Use linear alpha blending and gamma
* correction to correctly render non-monochrome glyph bitmaps onto a
* surface; see @FT_Render_Glyph.
* All modes except @FT_RENDER_MODE_MONO and @FT_RENDER_MODE_SDF use 256
* levels of opacity, indicating pixel coverage. Use linear alpha
* blending and gamma correction to correctly render non-monochrome
* glyph bitmaps onto a surface; see @FT_Render_Glyph.
*
* The @FT_RENDER_MODE_SDF is a special render mode that uses up to
* 65536 distance values, indicating the signed distance from the grid
* position to the nearest outline.
*
* @values:
* FT_RENDER_MODE_NORMAL ::
@ -3266,6 +3270,15 @@ FT_BEGIN_HEADER
* bitmaps that are 3~times the height of the original glyph outline in
* pixels and use the @FT_PIXEL_MODE_LCD_V mode.
*
* FT_RENDER_MODE_SDF ::
* This mode corresponds to 16-bit signed distance fields (SDF)
* bitmaps. Each pixel in a SDF bitmap contains information about the
* nearest edge of the glyph outline. The distances are calculated
* from the center of the pixel and are positive if they are filled by
* the outline (i.e., inside the outline) and negative otherwise. The
* output bitmap buffer is represented as 6.10 fixed-point values; use
* @FT_6Dot10 and convert accordingly.
*
* @note:
* The selected render mode only affects vector glyphs of a font.
* Embedded bitmaps often have a different pixel mode like
@ -3279,6 +3292,7 @@ FT_BEGIN_HEADER
FT_RENDER_MODE_MONO,
FT_RENDER_MODE_LCD,
FT_RENDER_MODE_LCD_V,
FT_RENDER_MODE_SDF,
FT_RENDER_MODE_MAX

14
include/freetype/ftimage.h
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@ -157,6 +157,13 @@ FT_BEGIN_HEADER
* in font files according to the OpenType specification. We haven't
* found a single font using this format, however.
*
* FT_PIXEL_MODE_GRAY16 ::
* A 16-bit per pixel bitmap used to represent signed distances in a
* signed distance field bitmap as needed by @FT_RENDER_MODE_SDF.
* Values are represented in a 6.10 fixed-point format; this means
* that you have to divide by 1024 to get the actual data generated by
* the SDF rasterizers.
*
* FT_PIXEL_MODE_LCD ::
* An 8-bit bitmap, representing RGB or BGR decimated glyph images used
* for display on LCD displays; the bitmap is three times wider than
@ -184,6 +191,7 @@ FT_BEGIN_HEADER
FT_PIXEL_MODE_GRAY,
FT_PIXEL_MODE_GRAY2,
FT_PIXEL_MODE_GRAY4,
FT_PIXEL_MODE_GRAY16,
FT_PIXEL_MODE_LCD,
FT_PIXEL_MODE_LCD_V,
FT_PIXEL_MODE_BGRA,
@ -959,11 +967,17 @@ FT_BEGIN_HEADER
* will be clipped to a box specified in the `clip_box` field of the
* @FT_Raster_Params structure. Otherwise, the `clip_box` is
* effectively set to the bounding box and all spans are generated.
*
* FT_RASTER_FLAG_SDF ::
* This flag is set to indicate that a signed distance field glyph
* image should be generated. This is only used while rendering with
* the @FT_RENDER_MODE_SDF render mode.
*/
#define FT_RASTER_FLAG_DEFAULT 0x0
#define FT_RASTER_FLAG_AA 0x1
#define FT_RASTER_FLAG_DIRECT 0x2
#define FT_RASTER_FLAG_CLIP 0x4
#define FT_RASTER_FLAG_SDF 0x8
/* these constants are deprecated; use the corresponding */
/* `FT_RASTER_FLAG_XXX` values instead */

12
include/freetype/fttypes.h
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@ -78,6 +78,7 @@ FT_BEGIN_HEADER
* FT_FWord
* FT_UFWord
* FT_F2Dot14
* FT_F6Dot10
* FT_UnitVector
* FT_F26Dot6
* FT_Data
@ -264,6 +265,17 @@ FT_BEGIN_HEADER
typedef signed short FT_F2Dot14;
/**************************************************************************
*
* @type:
* FT_F6Dot10
*
* @description:
* A signed 6.10 fixed-point type used for signed distance values.
*/
typedef signed short FT_F6Dot10;
/**************************************************************************
*
* @type: