readpixels.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 "Resources.h"
#include "SkCodec.h"
#include "SkColorSpace.h"
#include "SkColorSpaceXform.h"
#include "SkColorSpaceXformPriv.h"
#include "SkHalf.h"
#include "SkImage.h"
#include "SkImageInfoPriv.h"
#include "SkPictureRecorder.h"

static void clamp_if_necessary(const SkImageInfo& info, void* pixels) {
    if (kRGBA_F16_SkColorType != info.colorType()) {
        return;
    }

    for (int y = 0; y < info.height(); y++) {
        for (int x = 0; x < info.width(); x++) {
            uint64_t pixel = ((uint64_t*) pixels)[y * info.width() + x];

            Sk4f rgba = SkHalfToFloat_finite_ftz(pixel);
            if (kUnpremul_SkAlphaType == info.alphaType()) {
                rgba = Sk4f::Max(0.0f, Sk4f::Min(rgba, 1.0f));
            } else {
                SkASSERT(kPremul_SkAlphaType == info.alphaType());
                rgba = Sk4f::Max(0.0f, Sk4f::Min(rgba, rgba[3]));
            }
            SkFloatToHalf_finite_ftz(rgba).store(&pixel);

            ((uint64_t*) pixels)[y * info.width() + x] = pixel;
        }
    }
}

sk_sp<SkColorSpace> fix_for_colortype(SkColorSpace* colorSpace, SkColorType colorType) {
    if (kRGBA_F16_SkColorType == colorType) {
        return colorSpace->makeLinearGamma();
    }

    return sk_ref_sp(colorSpace);
}

static const int kWidth = 64;
static const int kHeight = 64;

static sk_sp<SkImage> make_raster_image(SkColorType colorType) {
    std::unique_ptr<SkStream> stream(GetResourceAsStream("images/google_chrome.ico"));
    std::unique_ptr<SkCodec> codec = SkCodec::MakeFromStream(std::move(stream));

    SkBitmap bitmap;
    SkImageInfo info = codec->getInfo().makeWH(kWidth, kHeight)
                                       .makeColorType(colorType)
                                       .makeAlphaType(kPremul_SkAlphaType)
            .makeColorSpace(fix_for_colortype(codec->getInfo().colorSpace(), colorType));
    bitmap.allocPixels(info);
    codec->getPixels(info, bitmap.getPixels(), bitmap.rowBytes());
    bitmap.setImmutable();
    return SkImage::MakeFromBitmap(bitmap);
}

static sk_sp<SkImage> make_codec_image() {
    sk_sp<SkData> encoded = GetResourceAsData("images/randPixels.png");
    return SkImage::MakeFromEncoded(encoded);
}

static void draw_contents(SkCanvas* canvas) {
    SkPaint paint;
    paint.setStyle(SkPaint::kStroke_Style);
    paint.setStrokeWidth(20);
    paint.setColor(0xFF800000);
    canvas->drawCircle(40, 40, 35, paint);
    paint.setColor(0xFF008000);
    canvas->drawCircle(50, 50, 35, paint);
    paint.setColor(0xFF000080);
    canvas->drawCircle(60, 60, 35, paint);
}

static sk_sp<SkImage> make_picture_image() {
    SkPictureRecorder recorder;
    draw_contents(recorder.beginRecording(SkRect::MakeIWH(kWidth, kHeight)));
    return SkImage::MakeFromPicture(recorder.finishRecordingAsPicture(),
                                    SkISize::Make(kWidth, kHeight), nullptr, nullptr,
                                    SkImage::BitDepth::kU8,
                                    SkColorSpace::MakeSRGB());
}

static sk_sp<SkColorSpace> make_parametric_transfer_fn(const SkColorSpacePrimaries& primaries) {
    SkMatrix44 toXYZD50(SkMatrix44::kUninitialized_Constructor);
    SkAssertResult(primaries.toXYZD50(&toXYZD50));
    SkColorSpaceTransferFn fn;
    fn.fA = 1.f; fn.fB = 0.f; fn.fC = 0.f; fn.fD = 0.f; fn.fE = 0.f; fn.fF = 0.f; fn.fG = 1.8f;
    return SkColorSpace::MakeRGB(fn, toXYZD50);
}

static sk_sp<SkColorSpace> make_wide_gamut() {
    // ProPhoto
    SkColorSpacePrimaries primaries;
    primaries.fRX = 0.7347f;
    primaries.fRY = 0.2653f;
    primaries.fGX = 0.1596f;
    primaries.fGY = 0.8404f;
    primaries.fBX = 0.0366f;
    primaries.fBY = 0.0001f;
    primaries.fWX = 0.34567f;
    primaries.fWY = 0.35850f;
    return make_parametric_transfer_fn(primaries);
}

static sk_sp<SkColorSpace> make_small_gamut() {
    SkColorSpacePrimaries primaries;
    primaries.fRX = 0.50f;
    primaries.fRY = 0.33f;
    primaries.fGX = 0.30f;
    primaries.fGY = 0.50f;
    primaries.fBX = 0.25f;
    primaries.fBY = 0.16f;
    primaries.fWX = 0.3127f;
    primaries.fWY = 0.3290f;
    return make_parametric_transfer_fn(primaries);
}

static void draw_image(SkCanvas* canvas, SkImage* image, SkColorType dstColorType,
                       SkAlphaType dstAlphaType, sk_sp<SkColorSpace> dstColorSpace,
                       SkImage::CachingHint hint) {
    size_t rowBytes = image->width() * SkColorTypeBytesPerPixel(dstColorType);
    sk_sp<SkData> data = SkData::MakeUninitialized(rowBytes * image->height());
    dstColorSpace = fix_for_colortype(dstColorSpace.get(), dstColorType);
    SkImageInfo dstInfo = SkImageInfo::Make(image->width(), image->height(), dstColorType,
                                            dstAlphaType, dstColorSpace);
    if (!image->readPixels(dstInfo, data->writable_data(), rowBytes, 0, 0, hint)) {
        memset(data->writable_data(), 0, rowBytes * image->height());
    }

    // SkImage must be premul, so manually premul the data if we unpremul'd during readPixels
    if (kUnpremul_SkAlphaType == dstAlphaType) {
        auto xform = SkColorSpaceXform::New(dstColorSpace.get(), dstColorSpace.get());
        if (!xform->apply(select_xform_format(dstColorType), data->writable_data(),
                          select_xform_format(dstColorType), data->data(),
                          image->width() * image->height(), kPremul_SkAlphaType)) {
            memset(data->writable_data(), 0, rowBytes * image->height());
        }
        dstInfo = dstInfo.makeAlphaType(kPremul_SkAlphaType);
    }

    // readPixels() does not always clamp F16.  The drawing code expects pixels in the 0-1 range.
    clamp_if_necessary(dstInfo, data->writable_data());

    // Now that we have called readPixels(), dump the raw pixels into an srgb image.
    sk_sp<SkColorSpace> srgb = fix_for_colortype(
            SkColorSpace::MakeSRGB().get(), dstColorType);
    sk_sp<SkImage> raw = SkImage::MakeRasterData(dstInfo.makeColorSpace(srgb), data, rowBytes);
    canvas->drawImage(raw.get(), 0.0f, 0.0f, nullptr);
}

class ReadPixelsGM : public skiagm::GM {
public:
    ReadPixelsGM() {}

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

    SkISize onISize() override {
        return SkISize::Make(6 * kWidth, 9 * kHeight);
    }

    void onDraw(SkCanvas* canvas) override {
        if (!canvas->imageInfo().colorSpace()) {
            // This gm is only interesting in color correct modes.
            return;
        }

        const SkAlphaType alphaTypes[] = {
                kUnpremul_SkAlphaType,
                kPremul_SkAlphaType,
        };
        const SkColorType colorTypes[] = {
                kRGBA_8888_SkColorType,
                kBGRA_8888_SkColorType,
                kRGBA_F16_SkColorType,
        };
        const sk_sp<SkColorSpace> colorSpaces[] = {
                make_wide_gamut(),
                SkColorSpace::MakeSRGB(),
                make_small_gamut(),
        };

        for (sk_sp<SkColorSpace> dstColorSpace : colorSpaces) {
            for (SkColorType srcColorType : colorTypes) {
                canvas->save();
                sk_sp<SkImage> image = make_raster_image(srcColorType);
                if (GrContext* context = canvas->getGrContext()) {
                    image = image->makeTextureImage(context, canvas->imageInfo().colorSpace());
                }
                if (image) {
                    for (SkColorType dstColorType : colorTypes) {
                        for (SkAlphaType dstAlphaType : alphaTypes) {
                            draw_image(canvas, image.get(), dstColorType, dstAlphaType,
                                       dstColorSpace, SkImage::kAllow_CachingHint);
                            canvas->translate((float)kWidth, 0.0f);
                        }
                    }
                }
                canvas->restore();
                canvas->translate(0.0f, (float) kHeight);
            }
        }
    }

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

class ReadPixelsCodecGM : public skiagm::GM {
public:
    ReadPixelsCodecGM() {}

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

    SkISize onISize() override {
        return SkISize::Make(3 * (kEncodedWidth + 1), 12 * (kEncodedHeight + 1));
    }

    void onDraw(SkCanvas* canvas) override {
        if (!canvas->imageInfo().colorSpace()) {
            // This gm is only interesting in color correct modes.
            return;
        }

        const SkAlphaType alphaTypes[] = {
                kUnpremul_SkAlphaType,
                kPremul_SkAlphaType,
        };
        const SkColorType colorTypes[] = {
                kRGBA_8888_SkColorType,
                kBGRA_8888_SkColorType,
                kRGBA_F16_SkColorType,
        };
        const sk_sp<SkColorSpace> colorSpaces[] = {
                make_wide_gamut(),
                SkColorSpace::MakeSRGB(),
                make_small_gamut(),
        };
        const SkImage::CachingHint hints[] = {
                SkImage::kAllow_CachingHint,
                SkImage::kDisallow_CachingHint,
        };

        sk_sp<SkImage> image = make_codec_image();
        for (sk_sp<SkColorSpace> dstColorSpace : colorSpaces) {
            canvas->save();
            for (SkColorType dstColorType : colorTypes) {
                for (SkAlphaType dstAlphaType : alphaTypes) {
                    for (SkImage::CachingHint hint : hints) {
                        draw_image(canvas, image.get(), dstColorType, dstAlphaType, dstColorSpace,
                                   hint);
                        canvas->translate(0.0f, (float) kEncodedHeight + 1);
                    }
                }
            }
            canvas->restore();
            canvas->translate((float) kEncodedWidth + 1, 0.0f);
        }
    }

private:
    static const int kEncodedWidth = 8;
    static const int kEncodedHeight = 8;

    typedef skiagm::GM INHERITED;
};
DEF_GM( return new ReadPixelsCodecGM; )

class ReadPixelsPictureGM : public skiagm::GM {
public:
    ReadPixelsPictureGM() {}

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

    SkISize onISize() override {
        return SkISize::Make(3 * kWidth, 12 * kHeight);
    }

    void onDraw(SkCanvas* canvas) override {
        if (!canvas->imageInfo().colorSpace()) {
            // This gm is only interesting in color correct modes.
            return;
        }

        const sk_sp<SkImage> images[] = {
                make_picture_image(),
        };
        const SkAlphaType alphaTypes[] = {
                kUnpremul_SkAlphaType,
                kPremul_SkAlphaType,
        };
        const SkColorType colorTypes[] = {
                kRGBA_8888_SkColorType,
                kBGRA_8888_SkColorType,
                kRGBA_F16_SkColorType,
        };
        const sk_sp<SkColorSpace> colorSpaces[] = {
                make_wide_gamut(),
                SkColorSpace::MakeSRGB(),
                make_small_gamut(),
        };
        const SkImage::CachingHint hints[] = {
                SkImage::kAllow_CachingHint,
                SkImage::kDisallow_CachingHint,
        };

        for (sk_sp<SkImage> image : images) {
            for (sk_sp<SkColorSpace> dstColorSpace : colorSpaces) {
                canvas->save();
                for (SkColorType dstColorType : colorTypes) {
                    for (SkAlphaType dstAlphaType : alphaTypes) {
                        for (SkImage::CachingHint hint : hints) {
                            draw_image(canvas, image.get(), dstColorType, dstAlphaType,
                                       dstColorSpace, hint);
                            canvas->translate(0.0f, (float) kHeight);
                        }
                    }
                }
                canvas->restore();
                canvas->translate((float) kWidth, 0.0f);
            }
        }
    }

private:

    typedef skiagm::GM INHERITED;
};
DEF_GM( return new ReadPixelsPictureGM; )