Initial linear gradient 4f impl
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1688543002
Review URL: https://codereview.chromium.org/1688543002
diff --git a/src/effects/gradients/Sk4fGradientBase.h b/src/effects/gradients/Sk4fGradientBase.h
new file mode 100644
index 0000000..7870bc3
--- /dev/null
+++ b/src/effects/gradients/Sk4fGradientBase.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef Sk4fGradientBase_DEFINED
+#define Sk4fGradientBase_DEFINED
+
+#include "SkColor.h"
+#include "SkGradientShaderPriv.h"
+#include "SkMatrix.h"
+#include "SkNx.h"
+#include "SkPM4f.h"
+#include "SkShader.h"
+#include "SkTArray.h"
+
+class SkGradientShaderBase::
+GradientShaderBase4fContext : public SkShader::Context {
+public:
+ GradientShaderBase4fContext(const SkGradientShaderBase&,
+ const ContextRec&);
+
+ uint32_t getFlags() const override { return fFlags; }
+
+protected:
+ struct Interval {
+ Interval(SkPMColor c0, SkScalar p0,
+ SkPMColor c1, SkScalar p1,
+ const Sk4f& componentScale);
+ Interval(const Sk4f& c0, const Sk4f& dc,
+ SkScalar p0, SkScalar p1);
+
+ bool isZeroRamp() const { return fZeroRamp; }
+
+ // true when fx is in [p0,p1)
+ bool contains(SkScalar fx) const;
+
+ SkPM4f fC0, fDc;
+ SkScalar fP0, fP1;
+ bool fZeroRamp;
+ };
+
+ const Interval* findInterval(SkScalar fx) const;
+
+ SkSTArray<8, Interval, true> fIntervals;
+ SkMatrix fDstToPos;
+ SkMatrix::MapXYProc fDstToPosProc;
+ uint8_t fDstToPosClass;
+ uint8_t fFlags;
+ bool fDither;
+ bool fColorsArePremul;
+
+private:
+ using INHERITED = SkShader::Context;
+
+ mutable const Interval* fCachedInterval;
+};
+
+#endif // Sk4fGradientBase_DEFINED