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Code Issues 4 Releases Wiki Activity

Improve FT_Outline_Render docs.

This commit is contained in:
Alexei Podtelezhnikov 2020-08-28 22:28:47 -04:00
parent 6730854c39
commit d8228a0070
2 changed files with 22 additions and 22 deletions
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28
include/freetype/ftimage.h
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@ -1011,20 +1011,26 @@ FT_BEGIN_HEADER
* User-supplied data that is passed to each drawing callback.
*
* clip_box ::
* An optional clipping box. It is only used in direct rendering mode.
* Note that coordinates here should be expressed in _integer_ pixels
* (and not in 26.6 fixed-point units).
* An optional span clipping box expressed in _integer_ pixels
* (not in 26.6 fixed-point units).
*
* @note:
* An anti-aliased glyph bitmap is drawn if the @FT_RASTER_FLAG_AA bit
* flag is set in the `flags` field, otherwise a monochrome bitmap is
* generated.
* The @FT_RASTER_FLAG_AA bit flag must be set in the `flags` to
* generate an anti-aliased glyph bitmap, otherwise a monochrome bitmap
* is generated. The `target` should have appropriate pixel mode and its
* dimensions define the clipping region.
*
* If the @FT_RASTER_FLAG_DIRECT bit flag is set in `flags`, the raster
* will call the `gray_spans` callback to draw gray pixel spans. This
* allows direct composition over a pre-existing bitmap through
* user-provided callbacks to perform the span drawing and composition.
* Not supported by the monochrome rasterizer.
* If both `( @FT_RASTER_FLAG_AA | @FT_RASTER_FLAG_DIRECT )` bit flags
* are set in `flags`, the raster will call an @FT_SpanFunc callback
* `gray_spans` with `user` data as an argument ignoring `target`. This
* allows direct composition over a pre-existing user surface to perform
* the span drawing and composition. To optionally clip the spans, set
* the @FT_RASTER_FLAG_CLIP flag and `clip_box`. The monochrome raster
* does not support the direct mode.
*
* The gray-level rasterizer always uses 256 gray levels. If you want
* fewer gray levels, you have to use @FT_RASTER_FLAG_DIRECT and reduce
* the levels in the callback function.
*/
typedef struct FT_Raster_Params_
{

16
include/freetype/ftoutln.h
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@ -482,19 +482,13 @@ FT_BEGIN_HEADER
* FreeType error code. 0~means success.
*
* @note:
* This advanced function uses @FT_Raster_Params as an argument,
* allowing FreeType rasterizer to be used for direct composition,
* translucency, etc. You should know how to set up @FT_Raster_Params
* for this function to work.
*
* This advanced function uses @FT_Raster_Params as an argument.
* The field `params.source` will be set to `outline` before the scan
* converter is called, which means that the value you give to it is
* actually ignored.
*
* The gray-level rasterizer always uses 256 gray levels. If you want
* less gray levels, you have to provide your own span callback. See the
* @FT_RASTER_FLAG_DIRECT value of the `flags` field in the
* @FT_Raster_Params structure for more details.
* actually ignored. Either `params.target` must point to preallocated
* bitmap, or @FT_RASTER_FLAG_DIRECT must be set in `params.flags`
* allowing FreeType rasterizer to be used for direct composition,
* translucency, etc. See @FT_Raster_Params for more details.
*/
FT_EXPORT( FT_Error )
FT_Outline_Render( FT_Library library,