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* include/freetype/ftlcdfil.h: Documentation tweak.

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This commit is contained in:
Alexei Podtelezhnikov 2016-01-19 22:54:59 -05:00
parent ec776596ce
commit 1409b3e0aa
1 changed files with 14 additions and 17 deletions
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31
include/freetype/ftlcdfil.h
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@ -57,7 +57,8 @@ FT_BEGIN_HEADER
* Note that no filter is active by default, and that this function is
* *not* implemented in default builds of the library. You need to
* #define FT_CONFIG_OPTION_SUBPIXEL_RENDERING in your `ftoption.h' file
* in order to activate it.
* in order to activate it and explicitly call @FT_Library_SetLcdFilter
* to enable it.
*
* A filter should have two properties:
*
@ -102,6 +103,18 @@ FT_BEGIN_HEADER
* - [0x08 0x4D 0x56 0x4D 0x08] is beveled, normalized and, almost
* balanced.
*
* The filter affects glyph bitmaps rendered through @FT_Render_Glyph,
* @FT_Load_Glyph, and @FT_Load_Char. It does _not_ affect the output
* of @FT_Outline_Render and @FT_Outline_Get_Bitmap.
*
* If this feature is activated, the dimensions of LCD glyph bitmaps are
* either larger or taller than the dimensions of the corresponding
* outline with regards to the pixel grid. For example, for
* @FT_RENDER_MODE_LCD, the filter adds 3~subpixels to the left, and
* 3~subpixels to the right. The bitmap offset values are adjusted
* accordingly, so clients shouldn't need to modify their layout and
* glyph positioning code when enabling the filter.
*
* It is important to understand that linear alpha blending and gamma
* correction is critical for correctly rendering glyphs onto surfaces
* without artifacts and even more critical when subpixel rendering is
@ -220,22 +233,6 @@ FT_BEGIN_HEADER
* defined in your build of the library, which should correspond to all
* default builds of FreeType.
*
* The filter affects glyph bitmaps rendered through @FT_Render_Glyph,
* @FT_Outline_Get_Bitmap, @FT_Load_Glyph, and @FT_Load_Char.
*
* It does _not_ affect the output of @FT_Outline_Render and
* @FT_Outline_Get_Bitmap.
*
* If this feature is activated, the dimensions of LCD glyph bitmaps are
* either larger or taller than the dimensions of the corresponding
* outline with regards to the pixel grid. For example, for
* @FT_RENDER_MODE_LCD, the filter adds up to 3~pixels to the left, and
* up to 3~pixels to the right.
*
* The bitmap offset values are adjusted correctly, so clients shouldn't
* need to modify their layout and glyph positioning code when enabling
* the filter.
*
* @since:
* 2.3.0
*/