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comparison: gfx/cairo/quartz-first-stop.patch
gfx/cairo/quartz-first-stop.patch
- changeset 0
- 6474c204b198
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| -1:000000000000 | 0:a359dbaf1f0b |
|---|---|
| 1 diff --git a/gfx/cairo/cairo/src/cairo-quartz-surface.c b/gfx/cairo/cairo/src/cairo-quartz-surface.c | |
| 2 --- a/gfx/cairo/cairo/src/cairo-quartz-surface.c | |
| 3 +++ b/gfx/cairo/cairo/src/cairo-quartz-surface.c | |
| 4 @@ -690,31 +690,51 @@ ComputeGradientValue (void *info, const | |
| 5 } | |
| 6 | |
| 7 static const float gradient_output_value_ranges[8] = { | |
| 8 0.f, 1.f, 0.f, 1.f, 0.f, 1.f, 0.f, 1.f | |
| 9 }; | |
| 10 static const CGFunctionCallbacks gradient_callbacks = { | |
| 11 0, ComputeGradientValue, (CGFunctionReleaseInfoCallback) cairo_pattern_destroy | |
| 12 }; | |
| 13 +/* Quartz will clamp input values to the input range. | |
| 14 + | |
| 15 + Our stops are all in the range 0.0 to 1.0. However, the color before the | |
| 16 + beginning of the gradient line is obtained by Quartz computing a negative | |
| 17 + position on the gradient line, clamping it to the input range we specified | |
| 18 + for our color function, and then calling our color function (actually it | |
| 19 + pre-samples the color function into an array, but that doesn't matter just | |
| 20 + here). Therefore if we set the lower bound to 0.0, a negative position | |
| 21 + on the gradient line will pass 0.0 to ComputeGradientValue, which will | |
| 22 + select the last color stop with position 0, although it should select | |
| 23 + the first color stop (this matters when there are multiple color stops with | |
| 24 + position 0). | |
| 25 + | |
| 26 + Therefore we pass a small negative number as the lower bound of the input | |
| 27 + range, so this value gets passed into ComputeGradientValue, which will | |
| 28 + return the color of the first stop. The number should be small because | |
| 29 + as far as I can tell, Quartz pre-samples the entire input range of the color | |
| 30 + function into an array of fixed size, so if the input range is larger | |
| 31 + than needed, the resolution of the gradient will be unnecessarily low. | |
| 32 +*/ | |
| 33 +static const float nonrepeating_gradient_input_value_range[2] = { -0.001f, 1.f }; | |
| 34 | |
| 35 static CGFunctionRef | |
| 36 CreateGradientFunction (const cairo_gradient_pattern_t *gpat) | |
| 37 { | |
| 38 cairo_pattern_t *pat; | |
| 39 - float input_value_range[2] = { 0.f, 1.f }; | |
| 40 | |
| 41 if (_cairo_pattern_create_copy (&pat, &gpat->base)) | |
| 42 /* quartz doesn't deal very well with malloc failing, so there's | |
| 43 * not much point in us trying either */ | |
| 44 return NULL; | |
| 45 | |
| 46 return CGFunctionCreate (pat, | |
| 47 1, | |
| 48 - input_value_range, | |
| 49 + nonrepeating_gradient_input_value_range, | |
| 50 4, | |
| 51 gradient_output_value_ranges, | |
| 52 &gradient_callbacks); | |
| 53 } | |
| 54 | |
| 55 static void | |
| 56 UpdateLinearParametersToIncludePoint(double *min_t, double *max_t, CGPoint *start, | |
| 57 double dx, double dy, |
