New gamut GM, to test gamut conversion in various code-paths

gm/gamut.cpp

+/*
+ * Copyright 2016 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 "SkSurface.h"
+#include "SkGradientShader.h"
+#include "SkPM4fPriv.h"
+
+static const int gRectSize = 50;
+static const SkScalar gScalarSize = SkIntToScalar(gRectSize);
+static const int gTestWidth = 700;
+static const int gTestHeight = 300;
+
+struct CellRenderer {
+    virtual void draw(SkCanvas* canvas) = 0;
+    virtual const char* label() = 0;
+    virtual ~CellRenderer() {}
+};
+
+struct PaintColorCellRenderer : public CellRenderer {
+    PaintColorCellRenderer(SkColor color) : fColor(color) {}
+    void draw(SkCanvas* canvas) override {
+        canvas->drawColor(fColor);
+    }
+    const char* label() override {
+        return "Paint Color";
+    }
+protected:
+    SkColor fColor;
+};
+
+struct BitmapCellRenderer : public CellRenderer {
+    BitmapCellRenderer(SkColor color, SkFilterQuality quality) : fQuality(quality) {
+        fBitmap.allocPixels(SkImageInfo::MakeS32(gRectSize, gRectSize, kPremul_SkAlphaType));
+        fBitmap.eraseColor(color);
+        const char* qualityNames[] = { "None", "Low", "Medium", "High" };
+        fLabel = SkStringPrintf("Bitmap (%s)", qualityNames[quality]);
+    }
+    void draw(SkCanvas* canvas) override {
+        SkPaint paint;
+        paint.setFilterQuality(fQuality);
+        canvas->drawBitmap(fBitmap, 0, 0, &paint);
+    }
+    const char* label() override {
+        return fLabel.c_str();
+    }
+protected:
+    SkFilterQuality fQuality;
+    SkBitmap        fBitmap;
+    SkString        fLabel;
+};
+
+struct GradientCellRenderer : public CellRenderer {
+    GradientCellRenderer(SkColor colorOne, SkColor colorTwo) {
+        fColors[0] = colorOne;
+        fColors[1] = colorTwo;
+    }
+    void draw(SkCanvas* canvas) override {
+        SkPoint points[2] = {
+            SkPoint::Make(0, 0),
+            SkPoint::Make(0, gScalarSize)
+        };
+        SkPaint paint;
+        paint.setShader(SkGradientShader::MakeLinear(points, fColors, nullptr, 2,
+                                                     SkShader::kClamp_TileMode));
+        canvas->drawPaint(paint);
+    }
+    const char* label() override {
+        return "Linear Gradient";
+    }
+protected:
+    SkColor fColors[2];
+};
+
+struct VerticesCellRenderer : public CellRenderer {
+    VerticesCellRenderer(SkColor colorOne, SkColor colorTwo) {
+        fColors[0] = fColors[1] = colorOne;
+        fColors[2] = fColors[3] = colorTwo;
+    }
+    void draw(SkCanvas* canvas) override {
+        SkPaint paint;
+        SkPoint vertices[4] = {
+            SkPoint::Make(0, 0),
+            SkPoint::Make(gScalarSize, 0),
+            SkPoint::Make(gScalarSize, gScalarSize),
+            SkPoint::Make(0, gScalarSize)
+        };
+        canvas->drawVertices(SkCanvas::kTriangleFan_VertexMode, 4, vertices, nullptr, fColors,
+                             nullptr, nullptr, 0, paint);
+    }
+    const char* label() override {
+        return "Vertices";
+    }
+protected:
+    SkColor fColors[4];
+};
+
+static void draw_gamut_grid(SkCanvas* canvas, SkTArray<CellRenderer*>& renderers) {
+    // We want our colors in our wide gamut to be obviously visibly distorted from sRGB, so we use
+    // Wide Gamut RGB (with sRGB gamma, for HW acceleration) as the working space for this test:
+    const float gWideGamutRGB_toXYZD50[]{
+        0.7161046f, 0.2581874f, 0.0000000f,  // * R
+        0.1009296f, 0.7249378f, 0.0517813f,  // * G
+        0.1471858f, 0.0168748f, 0.7734287f,  // * B
+    };
+
+    SkMatrix44 wideGamutRGB_toXYZD50(SkMatrix44::kUninitialized_Constructor);
+    wideGamutRGB_toXYZD50.set3x3RowMajorf(gWideGamutRGB_toXYZD50);
+
+    // Use the original canvas' color type, but account for gamma requirements
+    SkImageInfo origInfo = canvas->imageInfo();
+    auto srgbCS = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
+    auto wideCS = SkColorSpace::NewRGB(SkColorSpace::kSRGB_GammaNamed, wideGamutRGB_toXYZD50);
+    switch (origInfo.colorType()) {
+        case kRGBA_8888_SkColorType:
+        case kBGRA_8888_SkColorType:
+            break;
+        case kRGBA_F16_SkColorType:
+            srgbCS = srgbCS->makeLinearGamma();
+            wideCS = wideCS->makeLinearGamma();
+            break;
+        default:
+            return;
+    }
+
+    // Make our two working surfaces (one sRGB, one Adobe)
+    SkImageInfo srgbGamutInfo = SkImageInfo::Make(gRectSize, gRectSize, origInfo.colorType(),
+                                                  kPremul_SkAlphaType, srgbCS);
+    SkImageInfo wideGamutInfo = SkImageInfo::Make(gRectSize, gRectSize, origInfo.colorType(),
+                                                  kPremul_SkAlphaType, wideCS);
+    // readPixels doesn't do color conversion (yet), so we can use it to see the raw (wide) data

[msarett, 2016/09/06 20:07:54]

This is fine, but is there another hack to access the pixels?

I've run into trouble before in test code, where I assume something doesn't do
color conversion, then I fix it, then the test doesn't work anymore.

----------------------

Edit: Won't this work fine forever?  You're setting the SkColorSpace on dstInfo
to nullptr.

[Brian Osman, 2016/09/07 13:26:02]

I don't think we have another way to get at this data. I agree that nullptr
color space will always suppress conversion, so this code is probably going to
keep
working. I just wanted to be clear about current vs. (potential) future changes.

+    SkImageInfo dstInfo = srgbGamutInfo.makeColorSpace(nullptr);
+    sk_sp<SkSurface> srgbGamutSurface = canvas->makeSurface(srgbGamutInfo);
+    sk_sp<SkSurface> wideGamutSurface = canvas->makeSurface(wideGamutInfo);
+    if (!srgbGamutSurface || !wideGamutSurface) {
+        return;
+    }
+    SkCanvas* srgbGamutCanvas = srgbGamutSurface->getCanvas();
+    SkCanvas* wideGamutCanvas = wideGamutSurface->getCanvas();
+
+    SkPaint textPaint;
+    textPaint.setAntiAlias(true);
+    textPaint.setColor(SK_ColorWHITE);
+    sk_tool_utils::set_portable_typeface(&textPaint);
+
+    SkScalar x = 0, y = 0;
+    SkScalar textHeight = textPaint.getFontSpacing();
+
+    for (auto renderer : renderers) {
+        srgbGamutCanvas->clear(SK_ColorBLACK);
+        renderer->draw(srgbGamutCanvas);
+        wideGamutCanvas->clear(SK_ColorBLACK);
+        renderer->draw(wideGamutCanvas);
+
+        canvas->drawText(renderer->label(), strlen(renderer->label()), x, y + textHeight,
+                         textPaint);
+
+        SkBitmap srgbBitmap;
+        srgbBitmap.setInfo(dstInfo);
+        srgbGamutCanvas->readPixels(&srgbBitmap, 0, 0);
+        canvas->drawBitmap(srgbBitmap, x, y + textHeight + 5);
+        x += (gScalarSize + 1);
+
+        SkBitmap wideBitmap;
+        wideBitmap.setInfo(dstInfo);
+        wideGamutCanvas->readPixels(&wideBitmap, 0, 0);
+        canvas->drawBitmap(wideBitmap, x, y + textHeight + 5);
+        x += (gScalarSize + 10);
+
+        if (x + (2 * gScalarSize + 1) > gTestWidth) {
+            x = 0;
+            y += (textHeight + gScalarSize + 10);
+        }
+    }
+}
+
+DEF_SIMPLE_GM_BG(gamut, canvas, gTestWidth, gTestHeight, SK_ColorBLACK) {
+    SkTArray<CellRenderer*> renderers;
+
+    // sRGB primaries, rendered as paint color
+    renderers.push_back(new PaintColorCellRenderer(SK_ColorRED));
+    renderers.push_back(new PaintColorCellRenderer(SK_ColorGREEN));
+
+    // sRGB primaries, rendered as bitmaps
+    renderers.push_back(new BitmapCellRenderer(SK_ColorRED, kNone_SkFilterQuality));
+    renderers.push_back(new BitmapCellRenderer(SK_ColorGREEN, kLow_SkFilterQuality));
+    renderers.push_back(new BitmapCellRenderer(SK_ColorRED, kMedium_SkFilterQuality));
+    renderers.push_back(new BitmapCellRenderer(SK_ColorGREEN, kHigh_SkFilterQuality));
+
+    // Various gradients involving sRGB primaries and white/black
+    renderers.push_back(new GradientCellRenderer(SK_ColorRED, SK_ColorGREEN));
+    renderers.push_back(new GradientCellRenderer(SK_ColorGREEN, SK_ColorBLACK));
+    renderers.push_back(new GradientCellRenderer(SK_ColorGREEN, SK_ColorWHITE));
+
+    // Vertex colors
+    renderers.push_back(new VerticesCellRenderer(SK_ColorRED, SK_ColorRED));
+    renderers.push_back(new VerticesCellRenderer(SK_ColorRED, SK_ColorGREEN));
+
+    draw_gamut_grid(canvas, renderers);
+
+    for (auto renderer : renderers) {

[msarett, 2016/09/06 20:07:54]

Can we make these auto deletes or something?

[Brian Osman, 2016/09/07 13:26:02]

Done.

+        delete renderer;
+    }
+}