Switch gradients to as-encoded blending
Stops are now always transformed all the way to destination color space,
using a new helper struct. Even textured gradients on GPU pre-transform
the stops, for simplicity and consistency. We plumb the destination
config in to drive the choice of texture format - this is simpler and
more correct.
Bug: skia:
Change-Id: Ie3aea9d29a8a5973a72551d9efeaf247ce29606b
Reviewed-on: https://skia-review.googlesource.com/139173
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/src/shaders/gradients/Sk4fGradientBase.cpp b/src/shaders/gradients/Sk4fGradientBase.cpp
index 19eabcf..0f6da52 100644
--- a/src/shaders/gradients/Sk4fGradientBase.cpp
+++ b/src/shaders/gradients/Sk4fGradientBase.cpp
@@ -21,19 +21,19 @@
class IntervalIterator {
public:
- IntervalIterator(const SkGradientShaderBase& shader, SkColorSpace* dstCS, bool reverse)
+ IntervalIterator(const SkGradientShaderBase& shader, bool reverse)
: fShader(shader)
- , fDstCS(dstCS)
, fFirstPos(reverse ? SK_Scalar1 : 0)
, fBegin(reverse ? shader.fColorCount - 1 : 0)
, fAdvance(reverse ? -1 : 1) {
SkASSERT(shader.fColorCount > 0);
}
- void iterate(std::function<void(const SkColor4f&, const SkColor4f&,
+ void iterate(const SkColor4f* colors,
+ std::function<void(const SkColor4f&, const SkColor4f&,
SkScalar, SkScalar)> func) const {
if (!fShader.fOrigPos) {
- this->iterateImplicitPos(func);
+ this->iterateImplicitPos(colors, func);
return;
}
@@ -48,8 +48,7 @@
const SkScalar currPos = fShader.fOrigPos[curr];
if (currPos != prevPos) {
SkASSERT((currPos - prevPos > 0) == (fAdvance > 0));
- func(fShader.getXformedColor(prev, fDstCS), fShader.getXformedColor(curr, fDstCS),
- prevPos, currPos);
+ func(colors[prev], colors[curr], prevPos, currPos);
}
prev = curr;
@@ -58,7 +57,8 @@
}
private:
- void iterateImplicitPos(std::function<void(const SkColor4f&, const SkColor4f&,
+ void iterateImplicitPos(const SkColor4f* colors,
+ std::function<void(const SkColor4f&, const SkColor4f&,
SkScalar, SkScalar)> func) const {
// When clients don't provide explicit color stop positions (fPos == nullptr),
// the color stops are distributed evenly across the unit interval
@@ -73,33 +73,28 @@
SkASSERT(curr >= 0 && curr < fShader.fColorCount);
const SkScalar currPos = prevPos + dt;
- func(fShader.getXformedColor(prev, fDstCS),
- fShader.getXformedColor(curr, fDstCS),
- prevPos, currPos);
+ func(colors[prev], colors[curr], prevPos, currPos);
prev = curr;
prevPos = currPos;
}
// emit the last interval with a pinned end position, to avoid precision issues
- func(fShader.getXformedColor(prev, fDstCS),
- fShader.getXformedColor(prev + fAdvance, fDstCS),
- prevPos, 1 - fFirstPos);
+ func(colors[prev], colors[prev + fAdvance], prevPos, 1 - fFirstPos);
}
const SkGradientShaderBase& fShader;
- SkColorSpace* fDstCS;
const SkScalar fFirstPos;
const int fBegin;
const int fAdvance;
};
void addMirrorIntervals(const SkGradientShaderBase& shader,
- SkColorSpace* dstCS,
+ const SkColor4f* colors,
const Sk4f& componentScale,
bool premulColors, bool reverse,
Sk4fGradientIntervalBuffer::BufferType* buffer) {
- const IntervalIterator iter(shader, dstCS, reverse);
- iter.iterate([&] (const SkColor4f& c0, const SkColor4f& c1, SkScalar t0, SkScalar t1) {
+ const IntervalIterator iter(shader, reverse);
+ iter.iterate(colors, [&] (const SkColor4f& c0, const SkColor4f& c1, SkScalar t0, SkScalar t1) {
SkASSERT(buffer->empty() || buffer->back().fT1 == 2 - t0);
const auto mirror_t0 = 2 - t0;
@@ -193,20 +188,25 @@
const SkScalar first_pos = reverse ? SK_Scalar1 : 0;
const SkScalar last_pos = SK_Scalar1 - first_pos;
+ // Transform all of the colors to destination color space
+ SkColor4fXformer xformedColors(shader.fOrigColors4f, count, shader.fColorSpace.get(), dstCS);
+
if (tileMode == SkShader::kClamp_TileMode) {
// synthetic edge interval: -/+inf .. P0
- const Sk4f clamp_color = pack_color(shader.getXformedColor(first_index, dstCS),
+ const Sk4f clamp_color = pack_color(xformedColors.fColors[first_index],
premulColors, componentScale);
const SkScalar clamp_pos = reverse ? SK_ScalarInfinity : SK_ScalarNegativeInfinity;
fIntervals.emplace_back(clamp_color, clamp_pos,
clamp_color, first_pos);
} else if (tileMode == SkShader::kMirror_TileMode && reverse) {
// synthetic mirror intervals injected before main intervals: (2 .. 1]
- addMirrorIntervals(shader, dstCS, componentScale, premulColors, false, &fIntervals);
+ addMirrorIntervals(shader, xformedColors.fColors, componentScale, premulColors, false,
+ &fIntervals);
}
- const IntervalIterator iter(shader, dstCS, reverse);
- iter.iterate([&] (const SkColor4f& c0, const SkColor4f& c1, SkScalar t0, SkScalar t1) {
+ const IntervalIterator iter(shader, reverse);
+ iter.iterate(xformedColors.fColors,
+ [&] (const SkColor4f& c0, const SkColor4f& c1, SkScalar t0, SkScalar t1) {
SkASSERT(fIntervals.empty() || fIntervals.back().fT1 == t0);
fIntervals.emplace_back(pack_color(c0, premulColors, componentScale), t0,
@@ -215,14 +215,15 @@
if (tileMode == SkShader::kClamp_TileMode) {
// synthetic edge interval: Pn .. +/-inf
- const Sk4f clamp_color = pack_color(shader.getXformedColor(last_index, dstCS),
+ const Sk4f clamp_color = pack_color(xformedColors.fColors[last_index],
premulColors, componentScale);
const SkScalar clamp_pos = reverse ? SK_ScalarNegativeInfinity : SK_ScalarInfinity;
fIntervals.emplace_back(clamp_color, last_pos,
clamp_color, clamp_pos);
} else if (tileMode == SkShader::kMirror_TileMode && !reverse) {
// synthetic mirror intervals injected after main intervals: [1 .. 2)
- addMirrorIntervals(shader, dstCS, componentScale, premulColors, true, &fIntervals);
+ addMirrorIntervals(shader, xformedColors.fColors, componentScale, premulColors, true,
+ &fIntervals);
}
}