skia2/gm/wacky_yuv_formats.cpp

/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "gm/gm.h"
#include "include/core/SkBitmap.h"
#include "include/core/SkBlendMode.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkColorFilter.h"
#include "include/core/SkColorPriv.h"
#include "include/core/SkColorSpace.h"
#include "include/core/SkFilterQuality.h"
#include "include/core/SkFont.h"
#include "include/core/SkFontStyle.h"
#include "include/core/SkFontTypes.h"
#include "include/core/SkImage.h"
#include "include/core/SkImageGenerator.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPath.h"
#include "include/core/SkPixmap.h"
#include "include/core/SkPoint.h"
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/core/SkSize.h"
#include "include/core/SkString.h"
#include "include/core/SkTypeface.h"
#include "include/core/SkTypes.h"
#include "include/core/SkYUVAIndex.h"
#include "include/core/SkYUVASizeInfo.h"
#include "include/gpu/GrBackendSurface.h"
#include "include/gpu/GrConfig.h"
#include "include/gpu/GrContext.h"
#include "include/gpu/GrTypes.h"
#include "include/private/GrTypesPriv.h"
#include "include/private/SkTArray.h"
#include "include/private/SkTDArray.h"
#include "include/private/SkTemplates.h"
#include "include/utils/SkTextUtils.h"
#include "src/gpu/GrContextPriv.h"
#include "src/gpu/GrGpu.h"
#include "tools/ToolUtils.h"

#include <math.h>
#include <string.h>
#include <initializer_list>
#include <memory>
#include <utility>

class GrRenderTargetContext;

static const int kTileWidthHeight = 128;
static const int kLabelWidth = 64;
static const int kLabelHeight = 32;
static const int kDomainPadding = 8;
static const int kPad = 1;

enum YUVFormat {
    // 4:4:4 formats, 32 bpp
    kAYUV_YUVFormat,  // 8-bit YUVA values all interleaved
    kY410_YUVFormat,  // AVYU w/ 10bpp for YUV and 2 for A all interleaved

    // 4:2:0 formats, 12 bpp
    kNV12_YUVFormat, // 8-bit Y plane + 2x2 down sampled interleaved U/V planes
    kNV21_YUVFormat, // same as kNV12 but w/ U/V reversed in the interleaved plane

    kI420_YUVFormat, // 8-bit Y plane + 2x2 down sampled U and V planes
    kYV12_YUVFormat, // 8-bit Y plane + 2x2 down sampled V and U planes

    kLast_YUVFormat = kYV12_YUVFormat
};

// Helper to setup the SkYUVAIndex array correctly
// Skia allows the client to tack an additional alpha plane onto any of the standard opaque
// formats (via the addExtraAlpha) flag. In this case it is assumed to be a stand-alone single-
// channel plane.
static void setup_yuv_indices(YUVFormat yuvFormat, bool addExtraAlpha, SkYUVAIndex yuvaIndices[4]) {
    switch (yuvFormat) {
        case kAYUV_YUVFormat:
            SkASSERT(!addExtraAlpha); // this format already has an alpha channel
            yuvaIndices[0].fIndex = 0;
            yuvaIndices[0].fChannel = SkColorChannel::kR;
            yuvaIndices[1].fIndex = 0;
            yuvaIndices[1].fChannel = SkColorChannel::kG;
            yuvaIndices[2].fIndex = 0;
            yuvaIndices[2].fChannel = SkColorChannel::kB;
            yuvaIndices[3].fIndex = 0;
            yuvaIndices[3].fChannel = SkColorChannel::kA;
            break;
        case kY410_YUVFormat:
            SkASSERT(!addExtraAlpha); // this format already has an alpha channel
            yuvaIndices[0].fIndex = 0;
            yuvaIndices[0].fChannel = SkColorChannel::kG;
            yuvaIndices[1].fIndex = 0;
            yuvaIndices[1].fChannel = SkColorChannel::kB;
            yuvaIndices[2].fIndex = 0;
            yuvaIndices[2].fChannel = SkColorChannel::kR;
            yuvaIndices[3].fIndex = 0;
            yuvaIndices[3].fChannel = SkColorChannel::kA;
            break;
        case kNV12_YUVFormat:
            yuvaIndices[0].fIndex = 0;
            yuvaIndices[0].fChannel = SkColorChannel::kA;
            yuvaIndices[1].fIndex = 1;
            yuvaIndices[1].fChannel = SkColorChannel::kR;
            yuvaIndices[2].fIndex = 1;
            yuvaIndices[2].fChannel = SkColorChannel::kG;
            if (addExtraAlpha) {
                yuvaIndices[3].fIndex = 2;
                yuvaIndices[3].fChannel = SkColorChannel::kA;
            } else {
                yuvaIndices[3].fIndex = -1; // No alpha channel
            }
            break;
        case kNV21_YUVFormat:
            yuvaIndices[0].fIndex = 0;
            yuvaIndices[0].fChannel = SkColorChannel::kA;
            yuvaIndices[1].fIndex = 1;
            yuvaIndices[1].fChannel = SkColorChannel::kG;
            yuvaIndices[2].fIndex = 1;
            yuvaIndices[2].fChannel = SkColorChannel::kR;
            if (addExtraAlpha) {
                yuvaIndices[3].fIndex = 2;
                yuvaIndices[3].fChannel = SkColorChannel::kA;
            } else {
                yuvaIndices[3].fIndex = -1; // No alpha channel
            }
            break;
        case kI420_YUVFormat:
            yuvaIndices[0].fIndex = 0;
            yuvaIndices[0].fChannel = SkColorChannel::kA;
            yuvaIndices[1].fIndex = 1;
            yuvaIndices[1].fChannel = SkColorChannel::kA;
            yuvaIndices[2].fIndex = 2;
            yuvaIndices[2].fChannel = SkColorChannel::kA;
            if (addExtraAlpha) {
                yuvaIndices[3].fIndex = 3;
                yuvaIndices[3].fChannel = SkColorChannel::kA;
            } else {
                yuvaIndices[3].fIndex = -1; // No alpha channel
            }
            break;
        case kYV12_YUVFormat:
            yuvaIndices[0].fIndex = 0;
            yuvaIndices[0].fChannel = SkColorChannel::kA;
            yuvaIndices[1].fIndex = 2;
            yuvaIndices[1].fChannel = SkColorChannel::kA;
            yuvaIndices[2].fIndex = 1;
            yuvaIndices[2].fChannel = SkColorChannel::kA;
            if (addExtraAlpha) {
                yuvaIndices[3].fIndex = 3;
                yuvaIndices[3].fChannel = SkColorChannel::kA;
            } else {
                yuvaIndices[3].fIndex = -1; // No alpha channel
            }
            break;
    }
}

// All the planes we need to construct the various YUV formats
struct PlaneData {
   SkBitmap fYFull;
   SkBitmap fUFull;
   SkBitmap fVFull;
   SkBitmap fAFull;
   SkBitmap fUQuarter; // 2x2 downsampled U channel
   SkBitmap fVQuarter; // 2x2 downsampled V channel
};

// Add a portion of a circle to 'path'. The points 'o1' and 'o2' are on the border of the circle
// and have tangents 'v1' and 'v2'.
static void add_arc(SkPath* path,
                    const SkPoint& o1, const SkVector& v1,
                    const SkPoint& o2, const SkVector& v2,
                    SkTDArray<SkRect>* circles, bool takeLongWayRound) {

    SkVector v3 = { -v1.fY, v1.fX };
    SkVector v4 = { v2.fY, -v2.fX };

    SkScalar t = ((o2.fX - o1.fX) * v4.fY - (o2.fY - o1.fY) * v4.fX) / v3.cross(v4);
    SkPoint center = { o1.fX + t * v3.fX, o1.fY + t * v3.fY };

    SkRect r = { center.fX - t, center.fY - t, center.fX + t, center.fY + t };

    if (circles) {
        circles->push_back(r);
    }

    SkVector startV = o1 - center, endV = o2 - center;
    startV.normalize();
    endV.normalize();

    SkScalar startDeg = SkRadiansToDegrees(SkScalarATan2(startV.fY, startV.fX));
    SkScalar endDeg = SkRadiansToDegrees(SkScalarATan2(endV.fY, endV.fX));

    startDeg += 360.0f;
    startDeg = fmodf(startDeg, 360.0f);

    endDeg += 360.0f;
    endDeg = fmodf(endDeg, 360.0f);

    if (endDeg < startDeg) {
        endDeg += 360.0f;
    }

    SkScalar sweepDeg = SkTAbs(endDeg - startDeg);
    if (!takeLongWayRound) {
        sweepDeg = sweepDeg - 360;
    }

    path->arcTo(r, startDeg, sweepDeg, false);
}

static SkPath create_splat(const SkPoint& o, SkScalar innerRadius, SkScalar outerRadius,
                           SkScalar ratio, int numLobes, SkTDArray<SkRect>* circles) {
    if (numLobes <= 1) {
        return SkPath();
    }

    SkPath p;

    int numDivisions = 2 * numLobes;
    SkScalar fullLobeDegrees = 360.0f / numLobes;
    SkScalar outDegrees = ratio * fullLobeDegrees / (ratio + 1.0f);
    SkScalar innerDegrees = fullLobeDegrees / (ratio + 1.0f);
    SkMatrix outerStep, innerStep;
    outerStep.setRotate(outDegrees);
    innerStep.setRotate(innerDegrees);
    SkVector curV = SkVector::Make(0.0f, 1.0f);

    if (circles) {
        circles->push_back(SkRect::MakeLTRB(o.fX - innerRadius, o.fY - innerRadius,
                                            o.fX + innerRadius, o.fY + innerRadius));
    }

    p.moveTo(o.fX + innerRadius * curV.fX, o.fY + innerRadius * curV.fY);

    for (int i = 0; i < numDivisions; ++i) {

        SkVector nextV;
        if (0 == (i % 2)) {
            nextV = outerStep.mapVector(curV.fX, curV.fY);

            SkPoint top = SkPoint::Make(o.fX + outerRadius * curV.fX,
                                        o.fY + outerRadius * curV.fY);
            SkPoint nextTop = SkPoint::Make(o.fX + outerRadius * nextV.fX,
                                            o.fY + outerRadius * nextV.fY);

            p.lineTo(top);
            add_arc(&p, top, curV, nextTop, nextV, circles, true);
        } else {
            nextV = innerStep.mapVector(curV.fX, curV.fY);

            SkPoint bot = SkPoint::Make(o.fX + innerRadius * curV.fX,
                                        o.fY + innerRadius * curV.fY);
            SkPoint nextBot = SkPoint::Make(o.fX + innerRadius * nextV.fX,
                                            o.fY + innerRadius * nextV.fY);

            p.lineTo(bot);
            add_arc(&p, bot, curV, nextBot, nextV, nullptr, false);
        }

        curV = nextV;
    }

    p.close();

    return p;
}

static SkBitmap make_bitmap(SkColorType colorType, const SkPath& path,
                            const SkTDArray<SkRect>& circles, bool opaque, bool padWithRed) {
    const SkColor kGreen  = ToolUtils::color_to_565(SkColorSetARGB(0xFF, 178, 240, 104));
    const SkColor kBlue   = ToolUtils::color_to_565(SkColorSetARGB(0xFF, 173, 167, 252));
    const SkColor kYellow = ToolUtils::color_to_565(SkColorSetARGB(0xFF, 255, 221, 117));

    int widthHeight = kTileWidthHeight + (padWithRed ? 2 * kDomainPadding : 0);

    SkImageInfo ii = SkImageInfo::Make(widthHeight, widthHeight,
                                       colorType, kPremul_SkAlphaType);

    SkBitmap bm;
    bm.allocPixels(ii);

    std::unique_ptr<SkCanvas> canvas = SkCanvas::MakeRasterDirect(ii,
                                                                  bm.getPixels(),
                                                                  bm.rowBytes());
    if (padWithRed) {
        canvas->clear(SK_ColorRED);
        canvas->translate(kDomainPadding, kDomainPadding);
        canvas->clipRect(SkRect::MakeWH(kTileWidthHeight, kTileWidthHeight));
    }
    canvas->clear(opaque ? kGreen : SK_ColorTRANSPARENT);

    SkPaint paint;
    paint.setAntiAlias(false); // serialize-8888 doesn't seem to work well w/ partial transparency
    paint.setColor(kBlue);

    canvas->drawPath(path, paint);

    paint.setColor(opaque ? kYellow : SK_ColorTRANSPARENT);
    paint.setBlendMode(SkBlendMode::kSrc);
    for (int i = 0; i < circles.count(); ++i) {
        SkRect r = circles[i];
        r.inset(r.width()/4, r.height()/4);
        canvas->drawOval(r, paint);
    }

    return bm;
}

static void convert_rgba_to_yuva_601_shared(SkColor col, uint8_t yuv[4],
                                            uint8_t off, uint8_t range) {
    static const float Kr = 0.299f;
    static const float Kb = 0.114f;
    static const float Kg = 1.0f - Kr - Kb;

    float r = SkColorGetR(col) / 255.0f;
    float g = SkColorGetG(col) / 255.0f;
    float b = SkColorGetB(col) / 255.0f;

    float Ey = Kr * r + Kg * g + Kb * b;
    float Ecb = (b - Ey) / 1.402f;
    float Ecr = (r - Ey) / 1.772;

    yuv[0] = SkScalarRoundToInt( range * Ey + off );
    yuv[1] = SkScalarRoundToInt( 224 * Ecb + 128 );
    yuv[2] = SkScalarRoundToInt( 224 * Ecr + 128 );
    yuv[3] = SkColorGetA(col);
}

static void convert_rgba_to_yuva_jpeg(SkColor col, uint8_t yuv[4]) {
    // full swing from 0..255
    convert_rgba_to_yuva_601_shared(col, yuv, 0, 255);
}

static void convert_rgba_to_yuva_601(SkColor col, uint8_t yuv[4]) {
    // partial swing from 16..235
    convert_rgba_to_yuva_601_shared(col, yuv, 16, 219);

}

static void convert_rgba_to_yuva_709(SkColor col, uint8_t yuv[4]) {
    static const float Kr = 0.2126f;
    static const float Kb = 0.0722f;
    static const float Kg = 1.0f - Kr - Kb;

    float r = SkColorGetR(col) / 255.0f;
    float g = SkColorGetG(col) / 255.0f;
    float b = SkColorGetB(col) / 255.0f;

    float Ey = Kr * r + Kg * g + Kb * b;
    float Ecb = (b - Ey) / 1.8556f;
    float Ecr = (r - Ey) / 1.5748;

    yuv[0] = SkScalarRoundToInt( 219 * Ey +  16 );
    yuv[1] = SkScalarRoundToInt( 224 * Ecb + 128 );
    yuv[2] = SkScalarRoundToInt( 224 * Ecr + 128 );

    yuv[3] = SkColorGetA(col);
}


static SkPMColor convert_yuva_to_rgba_jpeg(uint8_t y, uint8_t u, uint8_t v, uint8_t a) {
    uint8_t r = SkScalarPin(SkScalarRoundToInt( 1.0f * y                   +  1.402f    * v  - 0.703749f * 255),
                            0, 255);
    uint8_t g = SkScalarPin(SkScalarRoundToInt( 1.0f * y - (0.344136f * u) - (0.714136f * v) + 0.531211f * 255),
                            0, 255);
    uint8_t b = SkScalarPin(SkScalarRoundToInt( 1.0f * y +  1.772f    * u                    - 0.889475f * 255),
                            0, 255);

    SkPMColor c = SkPremultiplyARGBInline(a, b, g, r);
    return c;
}

static SkPMColor convert_yuva_to_rgba_601(uint8_t y, uint8_t u, uint8_t v, uint8_t a) {
    uint8_t r = SkScalarPin(SkScalarRoundToInt( 1.164f * y                +  1.596f * v  - 0.87075f * 255), 0, 255);
    uint8_t g = SkScalarPin(SkScalarRoundToInt( 1.164f * y - (0.391f * u) - (0.813f * v) + 0.52925f * 255), 0, 255);
    uint8_t b = SkScalarPin(SkScalarRoundToInt( 1.164f * y +  2.018f * u                 - 1.08175f * 255), 0, 255);

    SkPMColor c = SkPremultiplyARGBInline(a, b, g, r);
    return c;
}

static SkPMColor convert_yuva_to_rgba_709(uint8_t y, uint8_t u, uint8_t v, uint8_t a) {
    uint8_t r = SkScalarPin(SkScalarRoundToInt( 1.164f * y                + (1.793f * v) - 0.96925f * 255), 0, 255);
    uint8_t g = SkScalarPin(SkScalarRoundToInt( 1.164f * y - (0.213f * u) - (0.533f * v) + 0.30025f * 255), 0, 255);
    uint8_t b = SkScalarPin(SkScalarRoundToInt( 1.164f * y + (2.112f * u)                - 1.12875f * 255), 0, 255);

    SkPMColor c = SkPremultiplyARGBInline(a, b, g, r);
    return c;
}

static void extract_planes(const SkBitmap& bm, SkYUVColorSpace yuvColorSpace, PlaneData* planes) {
    if (kIdentity_SkYUVColorSpace == yuvColorSpace) {
        // To test the identity color space we use JPEG YUV planes
        yuvColorSpace = kJPEG_SkYUVColorSpace;
    }

    SkASSERT(!(bm.width() % 2));
    SkASSERT(!(bm.height() % 2));

    planes->fYFull.allocPixels(SkImageInfo::MakeA8(bm.width(), bm.height()));
    planes->fUFull.allocPixels(SkImageInfo::MakeA8(bm.width(), bm.height()));
    planes->fVFull.allocPixels(SkImageInfo::MakeA8(bm.width(), bm.height()));
    planes->fAFull.allocPixels(SkImageInfo::MakeA8(bm.width(), bm.height()));
    planes->fUQuarter.allocPixels(SkImageInfo::MakeA8(bm.width()/2, bm.height()/2));
    planes->fVQuarter.allocPixels(SkImageInfo::MakeA8(bm.width()/2, bm.height()/2));

    for (int y = 0; y < bm.height(); ++y) {
        for (int x = 0; x < bm.width(); ++x) {
            SkColor col = bm.getColor(x, y);

            uint8_t yuva[4];

            if (kJPEG_SkYUVColorSpace == yuvColorSpace) {
                convert_rgba_to_yuva_jpeg(col, yuva);
            } else if (kRec601_SkYUVColorSpace == yuvColorSpace) {
                convert_rgba_to_yuva_601(col, yuva);
            } else {
                SkASSERT(kRec709_SkYUVColorSpace == yuvColorSpace);
                convert_rgba_to_yuva_709(col, yuva);
            }

            *planes->fYFull.getAddr8(x, y) = yuva[0];
            *planes->fUFull.getAddr8(x, y) = yuva[1];
            *planes->fVFull.getAddr8(x, y) = yuva[2];
            *planes->fAFull.getAddr8(x, y) = yuva[3];
        }
    }

    for (int y = 0; y < bm.height()/2; ++y) {
        for (int x = 0; x < bm.width()/2; ++x) {
            uint32_t uAccum = 0, vAccum = 0;

            uAccum += *planes->fUFull.getAddr8(2*x, 2*y);
            uAccum += *planes->fUFull.getAddr8(2*x+1, 2*y);
            uAccum += *planes->fUFull.getAddr8(2*x, 2*y+1);
            uAccum += *planes->fUFull.getAddr8(2*x+1, 2*y+1);

            *planes->fUQuarter.getAddr8(x, y) = uAccum / 4.0f;

            vAccum += *planes->fVFull.getAddr8(2*x, 2*y);
            vAccum += *planes->fVFull.getAddr8(2*x+1, 2*y);
            vAccum += *planes->fVFull.getAddr8(2*x, 2*y+1);
            vAccum += *planes->fVFull.getAddr8(2*x+1, 2*y+1);

            *planes->fVQuarter.getAddr8(x, y) = vAccum / 4.0f;
        }
    }
}

// Recombine the separate planes into some YUV format
static void create_YUV(const PlaneData& planes, YUVFormat yuvFormat,
                       SkBitmap resultBMs[], SkYUVAIndex yuvaIndices[4], bool opaque) {
    int nextLayer = 0;

    switch (yuvFormat) {
        case kAYUV_YUVFormat: {
            SkBitmap yuvaFull;

            yuvaFull.allocPixels(SkImageInfo::Make(planes.fYFull.width(), planes.fYFull.height(),
                                                   kRGBA_8888_SkColorType, kUnpremul_SkAlphaType));

            for (int y = 0; y < planes.fYFull.height(); ++y) {
                for (int x = 0; x < planes.fYFull.width(); ++x) {

                    uint8_t Y = *planes.fYFull.getAddr8(x, y);
                    uint8_t U = *planes.fUFull.getAddr8(x, y);
                    uint8_t V = *planes.fVFull.getAddr8(x, y);
                    uint8_t A = *planes.fAFull.getAddr8(x, y);

                    // NOT premul!
                    // V and Y swapped to match RGBA layout
                    SkColor c = SkColorSetARGB(A, V, U, Y);
                    *yuvaFull.getAddr32(x, y) = c;
                }
            }

            resultBMs[nextLayer++] = yuvaFull;

            setup_yuv_indices(yuvFormat, false, yuvaIndices);
            break;
        }
        case kY410_YUVFormat: {
            SkBitmap yuvaFull;
            uint32_t Y, U, V;
            uint8_t A;

            yuvaFull.allocPixels(SkImageInfo::Make(planes.fYFull.width(), planes.fYFull.height(),
                                                   kRGBA_1010102_SkColorType,
                                                   kUnpremul_SkAlphaType));

            for (int y = 0; y < planes.fYFull.height(); ++y) {
                for (int x = 0; x < planes.fYFull.width(); ++x) {

                    Y = SkScalarRoundToInt((*planes.fYFull.getAddr8(x, y) / 255.0f) * 1023.0f);
                    U = SkScalarRoundToInt((*planes.fUFull.getAddr8(x, y) / 255.0f) * 1023.0f);
                    V = SkScalarRoundToInt((*planes.fVFull.getAddr8(x, y) / 255.0f) * 1023.0f);
                    A = SkScalarRoundToInt((*planes.fAFull.getAddr8(x, y) / 255.0f) * 3.0f);

                    // NOT premul!
                    // AVYU but w/ V and U swapped to match RGBA layout
                    *yuvaFull.getAddr32(x, y) = (A << 30) | (U << 20) | (Y << 10) | (V << 0);
                }
            }

            resultBMs[nextLayer++] = yuvaFull;

            setup_yuv_indices(yuvFormat, false, yuvaIndices);
            break;
        }
        case kNV12_YUVFormat: {
            SkBitmap uvQuarter;

            // There isn't a RG color type. Approx w/ RGBA.
            uvQuarter.allocPixels(SkImageInfo::Make(planes.fYFull.width()/2,
                                                    planes.fYFull.height()/2,
                                                    kRGBA_8888_SkColorType,
                                                    kUnpremul_SkAlphaType));

            for (int y = 0; y < planes.fYFull.height()/2; ++y) {
                for (int x = 0; x < planes.fYFull.width()/2; ++x) {
                    uint8_t U = *planes.fUQuarter.getAddr8(x, y);
                    uint8_t V = *planes.fVQuarter.getAddr8(x, y);

                    // NOT premul!
                    // U and 0 swapped to match RGBA layout
                    *uvQuarter.getAddr32(x, y) = SkColorSetARGB(0xFF, 0, V, U);
                }
            }

            resultBMs[nextLayer++] = planes.fYFull;
            resultBMs[nextLayer++] = uvQuarter;

            setup_yuv_indices(yuvFormat, !opaque, yuvaIndices);
            break;
        }
        case kNV21_YUVFormat: {
            SkBitmap vuQuarter;

            // There isn't a RG color type. Approx w/ RGBA.
            vuQuarter.allocPixels(SkImageInfo::Make(planes.fYFull.width()/2,
                                                    planes.fYFull.height()/2,
                                                    kRGBA_8888_SkColorType,
                                                    kUnpremul_SkAlphaType));

            for (int y = 0; y < planes.fYFull.height()/2; ++y) {
                for (int x = 0; x < planes.fYFull.width()/2; ++x) {
                    uint8_t U = *planes.fUQuarter.getAddr8(x, y);
                    uint8_t V = *planes.fVQuarter.getAddr8(x, y);

                    // NOT premul!
                    // V and 0 swapped to match RGBA layout
                    *vuQuarter.getAddr32(x, y) = SkColorSetARGB(0xFF, 0, U, V);
                }
            }

            resultBMs[nextLayer++] = planes.fYFull;
            resultBMs[nextLayer++] = vuQuarter;

            setup_yuv_indices(yuvFormat, !opaque, yuvaIndices);
            break;
        }
        case kI420_YUVFormat:
            resultBMs[nextLayer++] = planes.fYFull;
            resultBMs[nextLayer++] = planes.fUQuarter;
            resultBMs[nextLayer++] = planes.fVQuarter;

            setup_yuv_indices(yuvFormat, !opaque, yuvaIndices);
            break;
        case kYV12_YUVFormat:
            resultBMs[nextLayer++] = planes.fYFull;
            resultBMs[nextLayer++] = planes.fVQuarter;
            resultBMs[nextLayer++] = planes.fUQuarter;

            setup_yuv_indices(yuvFormat, !opaque, yuvaIndices);
            break;
    }

    if (kAYUV_YUVFormat != yuvFormat && kY410_YUVFormat != yuvFormat && !opaque) {
        resultBMs[nextLayer] = planes.fAFull;
    }
}

static uint8_t look_up(float x1, float y1, const SkBitmap& bm, SkColorChannel channel) {
    uint8_t result;

    SkASSERT(x1 > 0 && x1 < 1.0f);
    SkASSERT(y1 > 0 && y1 < 1.0f);
    int x = SkScalarFloorToInt(x1 * bm.width());
    int y = SkScalarFloorToInt(y1 * bm.height());

    if (kAlpha_8_SkColorType == bm.colorType()) {
        SkASSERT(SkColorChannel::kA == channel);
        result = *bm.getAddr8(x, y);
    } else if (kRGBA_8888_SkColorType == bm.colorType()) {
        SkColor c = *bm.getAddr32(x, y);

        switch (channel) {
            case SkColorChannel::kR:
                result = SkColorGetB(c);
                break;
            case SkColorChannel::kG:
                result = SkColorGetG(c);
                break;
            case SkColorChannel::kB:
                result = SkColorGetR(c);
                break;
            case SkColorChannel::kA:
                result = SkColorGetA(c);
                break;
        }
    } else {
        SkASSERT(kRGBA_1010102_SkColorType == bm.colorType());

        SkColor c = *bm.getAddr32(x, y);

        switch (channel) {
            case SkColorChannel::kR:
                result = SkScalarRoundToInt(((c >>  0) & 0x3ff) * (255.0f/1023.0f));
                break;
            case SkColorChannel::kG:
                result = SkScalarRoundToInt(((c >> 10) & 0x3ff) * (255.0f/1023.0f));
                break;
            case SkColorChannel::kB:
                result = SkScalarRoundToInt(((c >> 20) & 0x3ff) * (255.0f/1023.0f));
                break;
            case SkColorChannel::kA:
                result = SkScalarRoundToInt(((c >> 30) & 0x3) * (255.0f/3.0f));
                break;
        }
    }

    return result;
}

class YUVGenerator : public SkImageGenerator {
public:
    YUVGenerator(const SkImageInfo& ii,
                 SkYUVColorSpace yuvColorSpace,
                 SkYUVAIndex yuvaIndices[SkYUVAIndex::kIndexCount],
                 SkBitmap bitmaps[SkYUVASizeInfo::kMaxCount])
            : SkImageGenerator(ii)
            , fYUVColorSpace(yuvColorSpace)
            , fAllA8(true) {
        memcpy(fYUVAIndices, yuvaIndices, sizeof(fYUVAIndices));

        SkAssertResult(SkYUVAIndex::AreValidIndices(fYUVAIndices, &fNumBitmaps));
        SkASSERT(fNumBitmaps > 0 && fNumBitmaps <= SkYUVASizeInfo::kMaxCount);

        for (int i = 0; i < fNumBitmaps; ++i) {
            fYUVBitmaps[i] = bitmaps[i];
            if (kAlpha_8_SkColorType != fYUVBitmaps[i].colorType()) {
                fAllA8 = false;
            }
        }
    }

protected:
    bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
                     const Options&) override {

        if (kUnknown_SkColorType == fFlattened.colorType()) {
            fFlattened.allocPixels(info);
            SkASSERT(kPremul_SkAlphaType == info.alphaType());

            for (int y = 0; y < info.height(); ++y) {
                for (int x = 0; x < info.width(); ++x) {

                    float x1 = (x + 0.5f) / info.width();
                    float y1 = (y + 0.5f) / info.height();

                    uint8_t Y = look_up(x1, y1,
                                        fYUVBitmaps[fYUVAIndices[0].fIndex],
                                        fYUVAIndices[0].fChannel);

                    uint8_t U = look_up(x1, y1,
                                        fYUVBitmaps[fYUVAIndices[1].fIndex],
                                        fYUVAIndices[1].fChannel);


                    uint8_t V = look_up(x1, y1,
                                        fYUVBitmaps[fYUVAIndices[2].fIndex],
                                        fYUVAIndices[2].fChannel);

                    uint8_t A = 255;
                    if (fYUVAIndices[3].fIndex >= 0) {
                        A = look_up(x1, y1,
                                    fYUVBitmaps[fYUVAIndices[3].fIndex],
                                    fYUVAIndices[3].fChannel);
                    }

                    // Making premul here.
                    switch (fYUVColorSpace) {
                        case kJPEG_SkYUVColorSpace:
                            *fFlattened.getAddr32(x, y) = convert_yuva_to_rgba_jpeg(Y, U, V, A);
                            break;
                        case kRec601_SkYUVColorSpace:
                            *fFlattened.getAddr32(x, y) = convert_yuva_to_rgba_601(Y, U, V, A);
                            break;
                        case kRec709_SkYUVColorSpace:
                            *fFlattened.getAddr32(x, y) = convert_yuva_to_rgba_709(Y, U, V, A);
                            break;
                        case kIdentity_SkYUVColorSpace:
                            *fFlattened.getAddr32(x, y) = SkPremultiplyARGBInline(A, V, U, Y);
                            break;
                    }
                }
            }
        }

        return fFlattened.readPixels(info, pixels, rowBytes, 0, 0);
    }

    bool onQueryYUVA8(SkYUVASizeInfo* size,
                      SkYUVAIndex yuvaIndices[SkYUVAIndex::kIndexCount],
                      SkYUVColorSpace* yuvColorSpace) const override {

        // The onQueryYUVA8/onGetYUVA8Planes can only handle A8 planes
        if (!fAllA8) {
            return false;
        }

        memcpy(yuvaIndices, fYUVAIndices, sizeof(fYUVAIndices));
        *yuvColorSpace = fYUVColorSpace;

        int i = 0;
        for ( ; i < fNumBitmaps; ++i) {
            size->fSizes[i].fWidth = fYUVBitmaps[i].width();
            size->fSizes[i].fHeight = fYUVBitmaps[i].height();
            size->fWidthBytes[i] = fYUVBitmaps[i].rowBytes();
        }
        for ( ; i < SkYUVASizeInfo::kMaxCount; ++i) {
            size->fSizes[i].fWidth = 0;
            size->fSizes[i].fHeight = 0;
            size->fWidthBytes[i] = 0;
        }

        return true;
    }

    bool onGetYUVA8Planes(const SkYUVASizeInfo&, const SkYUVAIndex[SkYUVAIndex::kIndexCount],
                          void* planes[SkYUVASizeInfo::kMaxCount]) override {
        SkASSERT(fAllA8);
        for (int i = 0; i < fNumBitmaps; ++i) {
            planes[i] = fYUVBitmaps[i].getPixels();
        }
        return true;
    }

private:
    SkYUVColorSpace fYUVColorSpace;
    SkYUVAIndex     fYUVAIndices[SkYUVAIndex::kIndexCount];
    int             fNumBitmaps;
    SkBitmap        fYUVBitmaps[SkYUVASizeInfo::kMaxCount];
    SkBitmap        fFlattened;
    bool            fAllA8;     // are all the SkBitmaps in "fYUVBitmaps" A8?

};

static sk_sp<SkImage> make_yuv_gen_image(const SkImageInfo& ii,
                                         SkYUVColorSpace yuvColorSpace,
                                         SkYUVAIndex yuvaIndices[SkYUVAIndex::kIndexCount],
                                         SkBitmap bitmaps[]) {
    std::unique_ptr<SkImageGenerator> gen(new YUVGenerator(ii, yuvColorSpace,
                                                           yuvaIndices, bitmaps));

    return SkImage::MakeFromGenerator(std::move(gen));
}

static void draw_col_label(SkCanvas* canvas, int x, int yuvColorSpace, bool opaque) {
    static const char* kYUVColorSpaceNames[] = { "JPEG", "601", "709", "Identity" };
    GR_STATIC_ASSERT(SK_ARRAY_COUNT(kYUVColorSpaceNames) == kLastEnum_SkYUVColorSpace+1);

    SkPaint paint;
    SkFont  font(ToolUtils::create_portable_typeface(nullptr, SkFontStyle::Bold()), 16);
    font.setEdging(SkFont::Edging::kAlias);

    SkRect textRect;
    SkString colLabel;

    colLabel.printf("%s", kYUVColorSpaceNames[yuvColorSpace]);
    font.measureText(colLabel.c_str(), colLabel.size(), SkTextEncoding::kUTF8, &textRect);
    int y = textRect.height();

    SkTextUtils::DrawString(canvas, colLabel.c_str(), x, y, font, paint, SkTextUtils::kCenter_Align);

    colLabel.printf("%s", opaque ? "Opaque" : "Transparent");

    font.measureText(colLabel.c_str(), colLabel.size(), SkTextEncoding::kUTF8, &textRect);
    y += textRect.height();

    SkTextUtils::DrawString(canvas, colLabel.c_str(), x, y, font, paint, SkTextUtils::kCenter_Align);
}

static void draw_row_label(SkCanvas* canvas, int y, int yuvFormat) {
    static const char* kYUVFormatNames[] = { "AYUV", "Y410", "NV12", "NV21", "I420", "YV12" };
    GR_STATIC_ASSERT(SK_ARRAY_COUNT(kYUVFormatNames) == kLast_YUVFormat+1);

    SkPaint paint;
    SkFont  font(ToolUtils::create_portable_typeface(nullptr, SkFontStyle::Bold()), 16);
    font.setEdging(SkFont::Edging::kAlias);

    SkRect textRect;
    SkString rowLabel;

    rowLabel.printf("%s", kYUVFormatNames[yuvFormat]);
    font.measureText(rowLabel.c_str(), rowLabel.size(), SkTextEncoding::kUTF8, &textRect);
    y += kTileWidthHeight/2 + textRect.height()/2;

    canvas->drawString(rowLabel, 0, y, font, paint);
}

static GrBackendTexture create_yuva_texture(GrGpu* gpu, const SkBitmap& bm,
                                            SkYUVAIndex yuvaIndices[4], int texIndex) {
    const GrCaps* caps = gpu->caps();

    SkASSERT(texIndex >= 0 && texIndex <= 3);
    int channelCount = 0;
    for (int i = 0; i < SkYUVAIndex::kIndexCount; ++i) {
        if (yuvaIndices[i].fIndex == texIndex) {
            ++channelCount;
        }
    }
    // Need to create an RG texture for two-channel planes
    GrBackendTexture tex;
    if (2 == channelCount) {
        SkASSERT(kRGBA_8888_SkColorType == bm.colorType());
        SkAutoTMalloc<char> pixels(2 * bm.width()*bm.height());
        char* currPixel = pixels;
        for (int y = 0; y < bm.height(); ++y) {
            for (int x = 0; x < bm.width(); ++x) {
                SkColor color = bm.getColor(x, y);
                currPixel[0] = SkColorGetR(color);
                currPixel[1] = SkColorGetG(color);
                currPixel += 2;
            }
        }
        GrBackendFormat format = caps->getBackendFormatFromGrColorType(GrColorType::kRG_88,
                                                                       GrSRGBEncoded::kNo);
        tex = gpu->createBackendTexture(bm.width(), bm.height(), format,
                                        GrMipMapped::kNo, GrRenderable::kNo,
                                        pixels, 2*bm.width());
    }
    if (!tex.isValid()) {
        tex = gpu->createTestingOnlyBackendTexture(
            bm.width(),
            bm.height(),
            bm.colorType(),
            GrMipMapped::kNo, GrRenderable::kNo,
            bm.getPixels(), bm.rowBytes());
    }
    return tex;
}

static sk_sp<SkColorFilter> yuv_to_rgb_colorfilter() {
    static const float kJPEGConversionMatrix[20] = {
        1.0f,  0.0f,       1.402f,    0.0f, -180.0f/255,
        1.0f, -0.344136f, -0.714136f, 0.0f,  136.0f/255,
        1.0f,  1.772f,     0.0f,      0.0f, -227.6f/255,
        0.0f,  0.0f,       0.0f,      1.0f,    0.0f
    };

    return SkColorFilters::Matrix(kJPEGConversionMatrix);
}

namespace skiagm {

// This GM creates an opaque and transparent bitmap, extracts the planes and then recombines
// them into various YUV formats. It then renders the results in the grid:
//
//                 JPEG                  601                   709                Identity
//        Transparent  Opaque   Transparent  Opaque   Transparent  Opaque   Transparent Opaque
// AYUV
// Y410
// NV12
// NV21
// I420
// YV12
class WackyYUVFormatsGM : public GM {
public:
    WackyYUVFormatsGM(bool useTargetColorSpace, bool useDomain)
            : fUseTargetColorSpace(useTargetColorSpace)
            , fUseDomain(useDomain) {
        this->setBGColor(0xFFCCCCCC);
    }

protected:

    SkString onShortName() override {
        SkString name("wacky_yuv_formats");
        if (fUseTargetColorSpace) {
            name += "_cs";
        }
        if (fUseDomain) {
            name += "_domain";
        }

        return name;
    }

    SkISize onISize() override {
        int numCols = 2 * (kLastEnum_SkYUVColorSpace + 1); // opacity x color-space
        int numRows = 1 + (kLast_YUVFormat + 1);  // origin + # yuv formats
        int wh = SkScalarCeilToInt(kTileWidthHeight * (fUseDomain ? 1.5f : 1.f));
        return SkISize::Make(kLabelWidth  + numCols * (wh + kPad),
                             kLabelHeight + numRows * (wh + kPad));
    }

    void onOnceBeforeDraw() override {
        SkPoint origin = { kTileWidthHeight/2.0f, kTileWidthHeight/2.0f };
        float outerRadius = kTileWidthHeight/2.0f - 20.0f;
        float innerRadius = 20.0f;

        {
            // transparent
            SkTDArray<SkRect> circles;
            SkPath path = create_splat(origin, innerRadius, outerRadius, 1.0f, 5, &circles);
            fOriginalBMs[0] = make_bitmap(kRGBA_8888_SkColorType, path, circles, false, fUseDomain);
        }

        {
            // opaque
            SkTDArray<SkRect> circles;
            SkPath path = create_splat(origin, innerRadius, outerRadius, 1.0f, 7, &circles);
            fOriginalBMs[1] = make_bitmap(kRGBA_8888_SkColorType, path, circles, true, fUseDomain);
        }

        if (fUseTargetColorSpace) {
            fTargetColorSpace = SkColorSpace::MakeSRGB()->makeColorSpin();
        }
    }

    void createImages(GrContext* context) {
        int counter = 0;
        for (bool opaque : { false, true }) {
            for (int cs = kJPEG_SkYUVColorSpace; cs <= kLastEnum_SkYUVColorSpace; ++cs) {
                PlaneData planes;
                extract_planes(fOriginalBMs[opaque], (SkYUVColorSpace) cs, &planes);

                for (int format = kAYUV_YUVFormat; format <= kLast_YUVFormat; ++format) {
                    SkBitmap resultBMs[4];
                    SkYUVAIndex yuvaIndices[4];

                    create_YUV(planes, (YUVFormat) format, resultBMs, yuvaIndices, opaque);

                    int numTextures;
                    if (!SkYUVAIndex::AreValidIndices(yuvaIndices, &numTextures)) {
                        continue;
                    }

                    if (context) {
                        if (context->abandoned()) {
                            return;
                        }

                        GrGpu* gpu = context->priv().getGpu();
                        if (!gpu) {
                            return;
                        }

                        GrBackendTexture yuvaTextures[4];
                        SkPixmap yuvaPixmaps[4];

                        for (int i = 0; i < numTextures; ++i) {
                            yuvaTextures[i] = create_yuva_texture(gpu, resultBMs[i],
                                                                  yuvaIndices, i);
                            if (yuvaTextures[i].isValid()) {
                                fBackendTextures.push_back(yuvaTextures[i]);
                            }
                            yuvaPixmaps[i] = resultBMs[i].pixmap();
                        }

                        int counterMod = counter % 3;
                        if (format == kY410_YUVFormat && counterMod == 2) {
                            // This format doesn't work as pixmaps
                            counterMod = 1;
                        } else if (fUseDomain && counterMod == 0) {
                            // Copies flatten to RGB when they copy the YUVA data, which doesn't
                            // know about the intended domain and the domain padding bleeds in
                            counterMod = 1;
                        }
                        switch (counterMod) {
                        case 0:
                            fImages[opaque][cs][format] = SkImage::MakeFromYUVATexturesCopy(
                                context,
                                (SkYUVColorSpace)cs,
                                yuvaTextures,
                                yuvaIndices,
                                { fOriginalBMs[opaque].width(), fOriginalBMs[opaque].height() },
                                kTopLeft_GrSurfaceOrigin);
                            break;
                        case 1:
                            fImages[opaque][cs][format] = SkImage::MakeFromYUVATextures(
                                context,
                                (SkYUVColorSpace)cs,
                                yuvaTextures,
                                yuvaIndices,
                                { fOriginalBMs[opaque].width(), fOriginalBMs[opaque].height() },
                                kTopLeft_GrSurfaceOrigin);
                            break;
                        case 2:
                        default:
                            fImages[opaque][cs][format] = SkImage::MakeFromYUVAPixmaps(
                                context,
                                (SkYUVColorSpace)cs,
                                yuvaPixmaps,
                                yuvaIndices,
                                { fOriginalBMs[opaque].width(), fOriginalBMs[opaque].height() },
                                kTopLeft_GrSurfaceOrigin, true);
                            break;
                        }
                        ++counter;
                    } else {
                        fImages[opaque][cs][format] = make_yuv_gen_image(
                                                                fOriginalBMs[opaque].info(),
                                                                (SkYUVColorSpace) cs,
                                                                yuvaIndices,
                                                                resultBMs);
                    }
                }
            }
        }
    }

    void onDraw(SkCanvas* canvas) override {
        this->createImages(canvas->getGrContext());

        SkRect srcRect = SkRect::MakeWH(fOriginalBMs[0].width(), fOriginalBMs[0].height());
        SkRect dstRect = SkRect::MakeXYWH(kLabelWidth, 0.f, srcRect.width(), srcRect.height());

        SkCanvas::SrcRectConstraint constraint = SkCanvas::kFast_SrcRectConstraint;
        if (fUseDomain) {
            srcRect.inset(kDomainPadding, kDomainPadding);
            // Draw a larger rectangle to ensure bilerp filtering would normally read outside the
            // srcRect and hit the red pixels, if strict constraint weren't used.
            dstRect.fRight = kLabelWidth + 1.5f * srcRect.width();
            dstRect.fBottom = 1.5f * srcRect.height();
            constraint = SkCanvas::kStrict_SrcRectConstraint;
        }

        for (int cs = kJPEG_SkYUVColorSpace; cs <= kLastEnum_SkYUVColorSpace; ++cs) {
            SkPaint paint;
            paint.setFilterQuality(kLow_SkFilterQuality);
            if (kIdentity_SkYUVColorSpace == cs) {
                // The identity color space needs post processing to appear correctly
                paint.setColorFilter(yuv_to_rgb_colorfilter());
            }

            for (int opaque : { 0, 1 }) {
                dstRect.offsetTo(dstRect.fLeft, kLabelHeight);

                draw_col_label(canvas, dstRect.fLeft + dstRect.height() / 2, cs, opaque);

                canvas->drawBitmapRect(fOriginalBMs[opaque], srcRect, dstRect, nullptr, constraint);
                dstRect.offset(0.f, dstRect.height() + kPad);

                for (int format = kAYUV_YUVFormat; format <= kLast_YUVFormat; ++format) {
                    draw_row_label(canvas, dstRect.fTop, format);
                    if (fUseTargetColorSpace && fImages[opaque][cs][format]) {
                        // Making a CS-specific version of a kIdentity_SkYUVColorSpace YUV image
                        // doesn't make a whole lot of sense. The colorSpace conversion will
                        // operate on the YUV components rather than the RGB components.
                        sk_sp<SkImage> csImage =
                            fImages[opaque][cs][format]->makeColorSpace(fTargetColorSpace);
                        canvas->drawImageRect(csImage, srcRect, dstRect, &paint, constraint);
                    } else {
                        canvas->drawImageRect(fImages[opaque][cs][format], srcRect, dstRect, &paint,
                                              constraint);
                    }
                    dstRect.offset(0.f, dstRect.height() + kPad);
                }

                dstRect.offset(dstRect.width() + kPad, 0.f);
            }
        }
        if (auto context = canvas->getGrContext()) {
            if (!context->abandoned()) {
                context->flush();
                GrGpu* gpu = context->priv().getGpu();
                SkASSERT(gpu);
                gpu->testingOnly_flushGpuAndSync();
                for (const auto& tex : fBackendTextures) {
                    context->deleteBackendTexture(tex);
                }
                fBackendTextures.reset();
            }
        }
        SkASSERT(!fBackendTextures.count());
    }

private:
    SkBitmap                   fOriginalBMs[2];
    sk_sp<SkImage>             fImages[2][kLastEnum_SkYUVColorSpace + 1][kLast_YUVFormat + 1];
    SkTArray<GrBackendTexture> fBackendTextures;
    bool                       fUseTargetColorSpace;
    bool                       fUseDomain;
    sk_sp<SkColorSpace>        fTargetColorSpace;

    typedef GM INHERITED;
};

//////////////////////////////////////////////////////////////////////////////

DEF_GM(return new WackyYUVFormatsGM(/* cs */ false, /* domain */ false);)
DEF_GM(return new WackyYUVFormatsGM(/* cs */ true,  /* domain */ false);)
DEF_GM(return new WackyYUVFormatsGM(/* cs */ false, /* domain */ true);)

class YUVMakeColorSpaceGM : public GpuGM {
public:
    YUVMakeColorSpaceGM() {
        this->setBGColor(0xFFCCCCCC);
    }

protected:
    SkString onShortName() override {
        return SkString("yuv_make_color_space");
    }

    SkISize onISize() override {
        int numCols = 4; // (transparent, opaque) x (untagged, tagged)
        int numRows = 5; // original, YUV, subset, readPixels, makeNonTextureImage
        return SkISize::Make(numCols * (kTileWidthHeight + kPad) + kPad,
                             numRows * (kTileWidthHeight + kPad) + kPad);
    }

    void onOnceBeforeDraw() override {
        SkPoint origin = { kTileWidthHeight/2.0f, kTileWidthHeight/2.0f };
        float outerRadius = kTileWidthHeight/2.0f - 20.0f;
        float innerRadius = 20.0f;

        {
            // transparent
            SkTDArray<SkRect> circles;
            SkPath path = create_splat(origin, innerRadius, outerRadius, 1.0f, 5, &circles);
            fOriginalBMs[0] = make_bitmap(kN32_SkColorType, path, circles, false, false);
        }

        {
            // opaque
            SkTDArray<SkRect> circles;
            SkPath path = create_splat(origin, innerRadius, outerRadius, 1.0f, 7, &circles);
            fOriginalBMs[1] = make_bitmap(kN32_SkColorType, path, circles, true, false);
        }

        fTargetColorSpace = SkColorSpace::MakeSRGB()->makeColorSpin();
    }

    void createImages(GrContext* context) {
        for (bool opaque : { false, true }) {
            PlaneData planes;
            extract_planes(fOriginalBMs[opaque], kJPEG_SkYUVColorSpace, &planes);

            SkBitmap resultBMs[4];
            SkYUVAIndex yuvaIndices[4];

            create_YUV(planes, kAYUV_YUVFormat, resultBMs, yuvaIndices, opaque);

            int numTextures;
            if (!SkYUVAIndex::AreValidIndices(yuvaIndices, &numTextures)) {
                continue;
            }

            GrGpu* gpu = context->priv().getGpu();
            if (!gpu) {
                return;
            }

            GrBackendTexture yuvaTextures[4];
            for (int i = 0; i < numTextures; ++i) {
                yuvaTextures[i] = create_yuva_texture(gpu, resultBMs[i], yuvaIndices, i);
                if (yuvaTextures[i].isValid()) {
                    fBackendTextures.push_back(yuvaTextures[i]);
                }
            }

            fImages[opaque][0] = SkImage::MakeFromYUVATextures(
                    context,
                    kJPEG_SkYUVColorSpace,
                    yuvaTextures,
                    yuvaIndices,
                    { fOriginalBMs[opaque].width(), fOriginalBMs[opaque].height() },
                    kTopLeft_GrSurfaceOrigin);
            fImages[opaque][1] = SkImage::MakeFromYUVATextures(
                    context,
                    kJPEG_SkYUVColorSpace,
                    yuvaTextures,
                    yuvaIndices,
                    { fOriginalBMs[opaque].width(), fOriginalBMs[opaque].height() },
                    kTopLeft_GrSurfaceOrigin,
                    SkColorSpace::MakeSRGB());
        }
    }

    void onDraw(GrContext* context, GrRenderTargetContext*, SkCanvas* canvas) override {
        this->createImages(context);

        int x = kPad;
        for (int tagged : { 0, 1 }) {
            for (int opaque : { 0, 1 }) {
                int y = kPad;

                auto raster = SkImage::MakeFromBitmap(fOriginalBMs[opaque])
                    ->makeColorSpace(fTargetColorSpace);
                canvas->drawImage(raster, x, y);
                y += kTileWidthHeight + kPad;

                auto yuv = fImages[opaque][tagged]->makeColorSpace(fTargetColorSpace);
                SkASSERT(SkColorSpace::Equals(yuv->colorSpace(), fTargetColorSpace.get()));
                canvas->drawImage(yuv, x, y);
                y += kTileWidthHeight + kPad;

                auto subset = yuv->makeSubset(SkIRect::MakeWH(kTileWidthHeight / 2,
                                                              kTileWidthHeight / 2));
                canvas->drawImage(subset, x, y);
                y += kTileWidthHeight + kPad;

                auto nonTexture = yuv->makeNonTextureImage();
                canvas->drawImage(nonTexture, x, y);
                y += kTileWidthHeight + kPad;

                SkBitmap readBack;
                readBack.allocPixels(yuv->imageInfo());
                yuv->readPixels(readBack.pixmap(), 0, 0);
                canvas->drawBitmap(readBack, x, y);

                x += kTileWidthHeight + kPad;
            }
        }

        context->flush();
        GrGpu* gpu = context->priv().getGpu();
        SkASSERT(gpu);
        gpu->testingOnly_flushGpuAndSync();
        for (const auto& tex : fBackendTextures) {
            context->deleteBackendTexture(tex);
        }
        fBackendTextures.reset();
    }

private:
    SkBitmap fOriginalBMs[2];
    sk_sp<SkImage> fImages[2][2];
    SkTArray<GrBackendTexture> fBackendTextures;
    sk_sp<SkColorSpace> fTargetColorSpace;

    typedef GM INHERITED;
};

DEF_GM(return new YUVMakeColorSpaceGM();)

}

///////////////

#include "include/effects/SkColorMatrix.h"
#include "src/core/SkAutoPixmapStorage.h"
#include "src/core/SkYUVMath.h"
#include "tools/Resources.h"

static void draw_into_alpha(const SkImage* img, sk_sp<SkColorFilter> cf, const SkPixmap& dst) {
    auto canvas = SkCanvas::MakeRasterDirect(dst.info(), dst.writable_addr(), dst.rowBytes());
    canvas->scale(1.0f * dst.width() / img->width(), 1.0f * dst.height() / img->height());
    SkPaint paint;
    paint.setFilterQuality(kLow_SkFilterQuality);
    paint.setColorFilter(cf);
    paint.setBlendMode(SkBlendMode::kSrc);
    canvas->drawImage(img, 0, 0, &paint);
}

static void split_into_yuv(const SkImage* img, SkYUVColorSpace cs, const SkPixmap dst[3]) {
    float m[20];
    SkColorMatrix_RGB2YUV(cs, m);

    memcpy(m + 15, m + 0, 5 * sizeof(float));   // copy Y into A
    draw_into_alpha(img, SkColorFilters::Matrix(m), dst[0]);

    memcpy(m + 15, m + 5, 5 * sizeof(float));   // copy U into A
    draw_into_alpha(img, SkColorFilters::Matrix(m), dst[1]);

    memcpy(m + 15, m + 10, 5 * sizeof(float));   // copy V into A
    draw_into_alpha(img, SkColorFilters::Matrix(m), dst[2]);
}

static void draw_diff(SkCanvas* canvas, SkScalar x, SkScalar y,
                      const SkImage* a, const SkImage* b) {
    auto sh = SkShaders::Blend(SkBlendMode::kDifference, a->makeShader(), b->makeShader());
    SkPaint paint;
    paint.setShader(sh);
    canvas->save();
    canvas->translate(x, y);
    canvas->drawRect(SkRect::MakeWH(a->width(), a->height()), paint);

    SkColorMatrix cm;
    cm.setScale(64, 64, 64);
    paint.setShader(sh->makeWithColorFilter(SkColorFilters::Matrix(cm)));
    canvas->translate(0, a->height());
    canvas->drawRect(SkRect::MakeWH(a->width(), a->height()), paint);

    canvas->restore();
}

// Exercises SkColorMatrix_RGB2YUV for yuv colorspaces, showing the planes, and the
// resulting (recombined) images (gpu only for now).
//
class YUVSplitterGM : public skiagm::GM {
    sk_sp<SkImage>      fOrig;
    SkAutoPixmapStorage fStorage[3];
    SkPixmap            fPM[3];

public:
    YUVSplitterGM() {}

protected:

    SkString onShortName() override {
        return SkString("yuv_splitter");
    }

    SkISize onISize() override {
        return SkISize::Make(1024, 768);
    }

    void onOnceBeforeDraw() override {
        fOrig = GetResourceAsImage("images/mandrill_256.png");

        SkImageInfo info = SkImageInfo::Make(fOrig->width(), fOrig->height(), kAlpha_8_SkColorType,
                                             kPremul_SkAlphaType);
        fStorage[0].alloc(info);
        if (0) {
            // if you want to scale U,V down by 1/2
            info = info.makeWH(info.width()/2, info.height()/2);
        }
        fStorage[1].alloc(info);
        fStorage[2].alloc(info);
        for (int i = 0; i < 3; ++i) {
            fPM[i] = fStorage[i];
        }
    }

    void onDraw(SkCanvas* canvas) override {
        SkYUVAIndex indices[4];
        indices[SkYUVAIndex::kY_Index] = {0, SkColorChannel::kR};
        indices[SkYUVAIndex::kU_Index] = {1, SkColorChannel::kR};
        indices[SkYUVAIndex::kV_Index] = {2, SkColorChannel::kR};
        indices[SkYUVAIndex::kA_Index] = {-1, SkColorChannel::kR};

        canvas->translate(fOrig->width(), 0);
        canvas->save();
        for (auto cs : {kRec709_SkYUVColorSpace, kRec601_SkYUVColorSpace, kJPEG_SkYUVColorSpace}) {
            split_into_yuv(fOrig.get(), cs, fPM);
            auto img = SkImage::MakeFromYUVAPixmaps(canvas->getGrContext(), cs, fPM, indices,
                                                    fPM[0].info().dimensions(),
                                                    kTopLeft_GrSurfaceOrigin,
                                                    false, false, nullptr);
            if (img) {
                canvas->drawImage(img, 0, 0, nullptr);
                draw_diff(canvas, 0, fOrig->height(), fOrig.get(), img.get());
            }
            canvas->translate(fOrig->width(), 0);
        }
        canvas->restore();
        canvas->translate(-fOrig->width(), 0);

        canvas->drawImage(SkImage::MakeRasterCopy(fPM[0]), 0, 0, nullptr);
        canvas->drawImage(SkImage::MakeRasterCopy(fPM[1]), 0, fPM[0].height(), nullptr);
        canvas->drawImage(SkImage::MakeRasterCopy(fPM[2]),
                          0, fPM[0].height() + fPM[1].height(), nullptr);
    }

private:
    typedef GM INHERITED;
};
DEF_GM( return new YUVSplitterGM; )