[Git][freetype/freetype][master] [sfnt] Implement 'COLR' v1 sweep gradients.

[Werner Lemberg]

Werner Lemberg pushed to branch master at FreeType / FreeType

Commits:

• 54c5ad5c
  by Dominik Röttsches at 2021-02-11T14:20:03+01:00

  [sfnt] Implement 'COLR' v1 sweep gradients.
  
  * freetype.h (FT_PaintSweepGradient): Add `FT_PaintSweepGradient` to
  represent a 'COLR' v1 sweep gradient.
  Update format.
  (FT_PaintFormat): Update shifted paint formats.
  Sync with spec.
  * sfnt/ttcolr.c (read_paint): Logic to parse sweep gradients.
  Fix struct access in radial gradient implementation.
  

3 changed files:

• ChangeLog
• include/freetype/freetype.h
• src/sfnt/ttcolr.c

Changes:

ChangeLog

---

	1	+2021-02-10 Dominik Röttsches <drott@chromium.org>
	2	+
	3	+ [sfnt] Implement 'COLR' v1 sweep gradients.
	4	+
	5	+ * freetype.h (FT_PaintSweepGradient): Add `FT_PaintSweepGradient` to
	6	+ represent a 'COLR' v1 sweep gradient.
	7	+ Update format.
	8	+ (FT_PaintFormat): Update shifted paint formats.
	9	+ Sync with spec.
	10	+ * sfnt/ttcolr.c (read_paint): Logic to parse sweep gradients.
	11	+ Fix struct access in radial gradient implementation.
	12	+
1	13	2021-02-09 Dominik Röttsches <drott@chromium.org>
2	14
3	15	[sfnt] Provide optional root transform for 'COLR' v1 glyph graph.

include/freetype/freetype.h

---

...	...	@@ -4235,14 +4235,15 @@ FT_BEGIN_HEADER
4235	4235	FT_COLR_PAINTFORMAT_SOLID = 2,
4236	4236	FT_COLR_PAINTFORMAT_LINEAR_GRADIENT = 3,
4237	4237	FT_COLR_PAINTFORMAT_RADIAL_GRADIENT = 4,
4238		- FT_COLR_PAINTFORMAT_GLYPH = 5,
4239		- FT_COLR_PAINTFORMAT_COLR_GLYPH = 6,
4240		- FT_COLR_PAINTFORMAT_TRANSFORMED = 7,
4241		- FT_COLR_PAINTFORMAT_TRANSLATE = 8,
4242		- FT_COLR_PAINTFORMAT_ROTATE = 9,
4243		- FT_COLR_PAINTFORMAT_SKEW = 10,
4244		- FT_COLR_PAINTFORMAT_COMPOSITE = 11,
4245		- FT_COLR_PAINT_FORMAT_MAX = 12,
	4238	+ FT_COLR_PAINTFORMAT_SWEEP_GRADIENT = 5,
	4239	+ FT_COLR_PAINTFORMAT_GLYPH = 6,
	4240	+ FT_COLR_PAINTFORMAT_COLR_GLYPH = 7,
	4241	+ FT_COLR_PAINTFORMAT_TRANSFORMED = 8,
	4242	+ FT_COLR_PAINTFORMAT_TRANSLATE = 9,
	4243	+ FT_COLR_PAINTFORMAT_ROTATE = 10,
	4244	+ FT_COLR_PAINTFORMAT_SKEW = 11,
	4245	+ FT_COLR_PAINTFORMAT_COMPOSITE = 12,
	4246	+ FT_COLR_PAINT_FORMAT_MAX = 13,
4246	4247	FT_COLR_PAINTFORMAT_UNSUPPORTED = 255
4247	4248
4248	4249	} FT_PaintFormat;
...	...	@@ -4611,7 +4612,6 @@ FT_BEGIN_HEADER
4611	4612	{
4612	4613	FT_ColorLine colorline;
4613	4614
4614		- /* TODO: Potentially expose those as x0, y0 etc. */
4615	4615	FT_Vector c0;
4616	4616	FT_UShort r0;
4617	4617	FT_Vector c1;
...	...	@@ -4620,6 +4620,48 @@ FT_BEGIN_HEADER
4620	4620	} FT_PaintRadialGradient;
4621	4621
4622	4622
	4623	+ /**************************************************************************
	4624	+ *
	4625	+ * @struct:
	4626	+ * FT_PaintSweepGradient
	4627	+ *
	4628	+ * @description:
	4629	+ * A structure representing a `PaintSweepGradient` value of the 'COLR'
	4630	+ * v1 extensions, see
	4631	+ * 'https://github.com/googlefonts/colr-gradients-spec'. The glyph
	4632	+ * layer filled with this paint is drawn filled with a sweep gradient
	4633	+ * from `start_angle` to `end_angle`.
	4634	+ *
	4635	+ * @fields:
	4636	+ * colorline ::
	4637	+ * The @FT_ColorLine information for this paint, i.e., the list of
	4638	+ * color stops along the gradient.
	4639	+ *
	4640	+ * center ::
	4641	+ * The center of the sweep gradient (in font units).
	4642	+ *
	4643	+ * start_angle ::
	4644	+ * The start angle of the sweep gradient, in 16.16 fixed point format
	4645	+ * specifying degrees. Values are given counter-clockwise, starting
	4646	+ * from the (positive) y~axis.
	4647	+ *
	4648	+ * end_angle ::
	4649	+ * The end angle of the sweep gradient, in 16.16 fixed point format
	4650	+ * specifying degrees. Values are given counter-clockwise, starting
	4651	+ * from the (positive) y~axis.
	4652	+ *
	4653	+ */
	4654	+ typedef struct FT_PaintSweepGradient_
	4655	+ {
	4656	+ FT_ColorLine colorline;
	4657	+
	4658	+ FT_Vector center;
	4659	+ FT_Fixed start_angle;
	4660	+ FT_Fixed end_angle;
	4661	+
	4662	+ } FT_PaintSweepGradient;
	4663	+
	4664	+
4623	4665	/**************************************************************************
4624	4666	*
4625	4667	* @struct:
...	...	@@ -4853,6 +4895,7 @@ FT_BEGIN_HEADER
4853	4895	* * @FT_PaintSolid
4854	4896	* * @FT_PaintLinearGradient
4855	4897	* * @FT_PaintRadialGradient
	4898	+ * * @FT_PaintSweepGradient
4856	4899	* * @FT_PaintTransformed
4857	4900	* * @FT_PaintTranslate
4858	4901	* * @FT_PaintRotate
...	...	@@ -4871,6 +4914,7 @@ FT_BEGIN_HEADER
4871	4914	FT_PaintSolid solid;
4872	4915	FT_PaintLinearGradient linear_gradient;
4873	4916	FT_PaintRadialGradient radial_gradient;
	4917	+ FT_PaintSweepGradient sweep_gradient;
4874	4918	FT_PaintTransformed transformed;
4875	4919	FT_PaintTranslate translate;
4876	4920	FT_PaintRotate rotate;

src/sfnt/ttcolr.c

---

...	...	@@ -441,7 +441,7 @@
441	441
442	442	if ( !read_color_line( paint_base,
443	443	color_line_offset,
444		- &apaint->u.linear_gradient.colorline ) )
	444	+ &apaint->u.radial_gradient.colorline ) )
445	445	return 0;
446	446
447	447	/* skip VarIdx entries */
...	...	@@ -462,6 +462,28 @@
462	462	FT_NEXT_ULONG ( p );
463	463	}
464	464
	465	+ else if ( apaint->format == FT_COLR_PAINTFORMAT_SWEEP_GRADIENT )
	466	+ {
	467	+ FT_ULong color_line_offset = color_line_offset = FT_NEXT_OFF3( p );
	468	+
	469	+
	470	+ if ( !read_color_line( paint_base,
	471	+ color_line_offset,
	472	+ &apaint->u.sweep_gradient.colorline ) )
	473	+ return 0;
	474	+
	475	+ /* skip VarIdx entries */
	476	+ apaint->u.sweep_gradient.center.x = FT_NEXT_SHORT ( p );
	477	+ FT_NEXT_ULONG ( p );
	478	+ apaint->u.sweep_gradient.center.y = FT_NEXT_SHORT ( p );
	479	+ FT_NEXT_ULONG ( p );
	480	+
	481	+ apaint->u.sweep_gradient.start_angle = FT_NEXT_LONG( p );
	482	+ FT_NEXT_ULONG ( p );
	483	+ apaint->u.sweep_gradient.end_angle = FT_NEXT_LONG( p );
	484	+ FT_NEXT_ULONG ( p );
	485	+ }
	486	+
465	487	else if ( apaint->format == FT_COLR_PAINTFORMAT_TRANSFORMED )
466	488	{
467	489	FT_UInt32 paint_offset;
...	...	@@ -842,7 +864,7 @@
842	864
843	865	/* `x_scale` and `y_scale` are in 26.6 format, representing the scale
844	866	* factor to get from font units to requested size. However, expected
845		- * return values are in 16.16, so we shift accordingly with rounding.
	867	+ * return values are in 16.16, so we shift accordingly with rounding.
846	868	*/
847	869	ft_root_scale.xx = ( face->root.size->metrics.x_scale + 32 ) >> 6;
848	870	ft_root_scale.xy = 0;

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