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[sdf] Add 'bsdf' renderer to 'sdf' module. 

* src/sdf/ftsdfrend.c (ft_bsdf_render): New function.

(ft_bitmap_sdf_renderer_class): New structure.
This commit is contained in:
Anuj Verma 2020-08-20 21:57:43 -07:00 committed by Werner Lemberg
parent d27d107f15
commit 6cd6df55c9
3 changed files with 158 additions and 2 deletions
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8
ChangeLog
View File

@ -1,3 +1,11 @@
2020-08-20 Anuj Verma <anujv@iitbhilai.ac.in>
[sdf] Add 'bsdf' renderer to 'sdf' module.
* src/sdf/ftsdfrend.c (ft_bsdf_render): New function.
(ft_bitmap_sdf_renderer_class): New structure.
2020-08-20 Anuj Verma <anujv@iitbhilai.ac.in>
[sdf] Add interface functions for the 'bsdf' rasterizer.

4
src/sdf/ftsdf.h
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@ -19,14 +19,14 @@ FT_BEGIN_HEADER
* @description:
* This struct must be passed to the raster render function
* @FT_Raster_RenderFunc instead of @FT_Raster_Params because the
* rasterizer requires some additional information to render properly.
* rasterizer requires some additional information to render properly.
*
* @fields:
* root ::
* The native raster parameters structure.
*
* spread ::
* This is an essential parameter/property required by the renderer.
* This is an essential parameter/property required by the renderer.
* `spread` defines the maximum unsigned value that is present in the
* final SDF output. For the default value check file
* `ftsdfcommon.h`.

148
src/sdf/ftsdfrend.c
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@ -187,6 +187,14 @@
}
/*************************************************************************/
/*************************************************************************/
/** **/
/** OUTLINE TO SDF CONVERTER **/
/** **/
/*************************************************************************/
/*************************************************************************/
/**************************************************************************
*
* interface functions
@ -421,4 +429,144 @@
(FT_Raster_Funcs*)&ft_sdf_raster /* raster_class */
)
/*************************************************************************/
/*************************************************************************/
/** **/
/** BITMAP TO SDF CONVERTER **/
/** **/
/*************************************************************************/
/*************************************************************************/
/* generate signed distance field from glyph's bitmap */
static FT_Error
ft_bsdf_render( FT_Renderer module,
FT_GlyphSlot slot,
FT_Render_Mode mode,
const FT_Vector* origin )
{
FT_Error error = FT_Err_Ok;
FT_Memory memory = NULL;
FT_Bitmap* bitmap = &slot->bitmap;
FT_Renderer render = NULL;
FT_Bitmap target;
FT_Pos x_pad = 0;
FT_Pos y_pad = 0;
SDF_Raster_Params params;
SDF_Renderer sdf_module = SDF_RENDERER( module );
/* initialize the bitmap in case any error occurs */
FT_Bitmap_Init( &target );
render = &sdf_module->root;
memory = render->root.memory;
/* check whether slot format is correct before rendering */
if ( slot->format != render->glyph_format )
{
FT_ERROR(( "ft_bsdf_render: slot format must be a bitmap\n" ));
error = FT_THROW( Invalid_Glyph_Format );
goto Exit;
}
/* check whether render mode is correct */
if ( mode != FT_RENDER_MODE_SDF )
{
FT_ERROR(( "ft_bsdf_render: need `FT_RENDER_MODE_SDF' mode\n" ));
error = FT_THROW( Cannot_Render_Glyph );
goto Exit;
}
if ( origin )
{
FT_ERROR(( "ft_bsdf_render: can't translate the bitmap\n" ));
error = FT_THROW( Unimplemented_Feature );
goto Exit;
}
if ( !bitmap->rows || !bitmap->pitch )
goto Exit;
FT_Bitmap_New( &target );
/* padding will simply be equal to `spread` */
x_pad = sdf_module->spread;
y_pad = sdf_module->spread;
/* apply padding, which extends to all directions */
target.rows = bitmap->rows + y_pad * 2;
target.width = bitmap->width + x_pad * 2;
/* set up the target bitmap */
target.pixel_mode = FT_PIXEL_MODE_GRAY16;
target.pitch = target.width * 2;
target.num_grays = 65535;
if ( FT_ALLOC_MULT( target.buffer, target.rows, target.pitch ) )
goto Exit;
/* set up parameters */
params.root.target = &target;
params.root.source = bitmap;
params.root.flags = FT_RASTER_FLAG_SDF;
params.spread = sdf_module->spread;
params.flip_sign = sdf_module->flip_sign;
params.flip_y = sdf_module->flip_y;
error = render->raster_render( render->raster,
(const FT_Raster_Params*)&params );
Exit:
if ( !error )
{
/* the glyph is successfully converted to a SDF */
if ( slot->internal->flags & FT_GLYPH_OWN_BITMAP )
{
FT_FREE( bitmap->buffer );
slot->internal->flags &= ~FT_GLYPH_OWN_BITMAP;
}
slot->bitmap = target;
slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
}
else if ( target.buffer )
FT_FREE( target.buffer );
return error;
}
FT_DEFINE_RENDERER(
ft_bitmap_sdf_renderer_class,
FT_MODULE_RENDERER,
sizeof ( SDF_Renderer_Module ),
"bsdf",
0x10000L,
0x20000L,
NULL,
(FT_Module_Constructor)ft_sdf_init,
(FT_Module_Destructor) ft_sdf_done,
(FT_Module_Requester) ft_sdf_requester,
FT_GLYPH_FORMAT_BITMAP,
(FT_Renderer_RenderFunc) ft_bsdf_render, /* render_glyph */
(FT_Renderer_TransformFunc)ft_sdf_transform, /* transform_glyph */
(FT_Renderer_GetCBoxFunc) ft_sdf_get_cbox, /* get_glyph_cbox */
(FT_Renderer_SetModeFunc) ft_sdf_set_mode, /* set_mode */
(FT_Raster_Funcs*)&ft_bitmap_sdf_raster /* raster_class */
)
/* END */