Support Float32 output from SkColorSpaceXform

gm/colorspacexform.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "gm.h"
+#include "SkColor.h"
+#include "SkColorSpaceXform.h"
+#include "SkRect.h"
+
+class ColorSpaceXformGM : public skiagm::GM {
+public:
+    ColorSpaceXformGM() {}
+
+protected:
+    void onOnceBeforeDraw() override {
+        SkColor colors[] = {
+            SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorMAGENTA, SK_ColorCYAN, SK_ColorYELLOW,
+            SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorMAGENTA,
+        };
+        static_assert(kNumColors == SK_ARRAY_COUNT(colors), "Fix number of colors.");
+
+        for (int i = 0; i < kNumColors; i++) {
+            fSRGBColors[i] = SkColor4f::FromColor(colors[i]);
+
+            // FIXME (msarett): SkColorSpaceXform does not support BGRA.
+            colors[i] = SkSwizzle_RB(colors[i]);
+        }
+
+        static constexpr float kWideGamutRGB_toXYZD50[]{
+            0.7161046f, 0.1009296f, 0.1471858f,
+            0.2581874f, 0.7249378f, 0.0168748f,
+            0.0000000f, 0.0517813f, 0.7734287f,
+        };
+
+        SkMatrix44 wideGamut(SkMatrix44::kUninitialized_Constructor);
+        wideGamut.set3x3RowMajorf(kWideGamutRGB_toXYZD50);
+        std::unique_ptr<SkColorSpaceXform> xform = SkColorSpaceXform::New(
+                SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named),
+                SkColorSpace::NewRGB(SkColorSpace::kLinear_RenderTargetGamma, wideGamut));
+
+        xform->apply(fWideGamutColors, colors, kNumColors,
+                     SkColorSpaceXform::kRGBA_F32_ColorFormat, kOpaque_SkAlphaType);
+    }
+
+    SkString onShortName() override {
+        return SkString("colorspacexform");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(500, 200);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        auto drawColors = [canvas](SkColor4f* colors) {
+            SkRect r = SkRect::MakeXYWH(0.0f, 0.0f, 50.0f, 100.0f);
+
+            canvas->save();
+            for (int i = 0; i < kNumColors; i++) {
+                sk_sp<SkColorSpace> space =
+                        SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named)->makeLinearGamma();
+                sk_sp<SkShader> s = SkShader::MakeColorShader(colors[i], space);
+                SkPaint paint;
+                paint.setShader(s);
+                canvas->drawRect(r, paint);
+                canvas->translate(50.0f, 0.0f);
+            }
+            canvas->restore();
+        };
+
+        // Wide gamut colors should appear darker - we are simulating a more intense display.
+        drawColors(fSRGBColors);
+        canvas->translate(0.0f, 100.0f);
+        drawColors(fWideGamutColors);
+    }
+
+private:
+    static constexpr int kNumColors = 10;
+
+    SkColor4f fSRGBColors[kNumColors];
+    SkColor4f fWideGamutColors[kNumColors];
+
+    typedef skiagm::GM INHERITED;
+};
+
+DEF_GM(return new ColorSpaceXformGM;)