Create an SkColorSpaceXform image generator

This should be immediately useful in the Skia-Android
rendering pipeline.

Possible future uses include creating a "renderable"
SkImage from a bitmap with a funny color space.

Inspired by:
https://skia-review.googlesource.com/c/13981/

Bug: b/62347704
Change-Id: I388c7af1fc43834b8ad22022d0caf3ac90b734c8
Reviewed-on: https://skia-review.googlesource.com/18598
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/gm/xform_image_gen.cpp b/gm/xform_image_gen.cpp
new file mode 100644
index 0000000000..69a1ce173f
--- /dev/null
+++ b/gm/xform_image_gen.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2017 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 "SkColorSpaceXformImageGenerator.h"
+
+class ColorXformImageGenGM : public skiagm::GM {
+public:
+    ColorXformImageGenGM() {}
+
+protected:
+
+    SkString onShortName() override {
+        return SkString("color_xform_image_gen");
+    }
+
+    SkISize onISize() override {
+        return SkISize::Make(100, 100);
+    }
+
+    void onDraw(SkCanvas* canvas) override {
+        SkBitmap bitmap;
+        SkImageInfo info =
+                SkImageInfo::MakeN32(100, 100, kOpaque_SkAlphaType, SkColorSpace::MakeSRGB());
+        bitmap.allocPixels(info);
+        bitmap.eraseColor(SK_ColorRED);
+        bitmap.eraseArea(SkIRect::MakeWH(25, 25), SK_ColorBLUE); // We should not see any blue.
+
+        std::unique_ptr<SkImageGenerator> gen = SkColorSpaceXformImageGenerator::Make(
+                bitmap,
+                SkColorSpace::MakeRGB(SkColorSpace::kSRGB_RenderTargetGamma,
+                                      SkColorSpace::kRec2020_Gamut),
+                kNever_SkCopyPixelsMode);
+
+        SkIRect subset = SkIRect::MakeXYWH(25, 25, 50, 50);
+        sk_sp<SkImage> image = SkImage::MakeFromGenerator(std::move(gen), &subset);
+        canvas->drawImage(image, 25, 25);
+    }
+
+private:
+    typedef GM INHERITED;
+};
+
+DEF_GM( return new ColorXformImageGenGM(); )