docs/examples/Pixmap_info.cpp

// Copyright 2019 Google LLC
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
#include "tools/fiddle/examples.h"

#include <array>

REG_FIDDLE(Pixmap_info, 256, 256, true, 3) {
void draw(SkCanvas* canvas) {
    std::vector<int32_t> pixels;
    pixels.resize(image->height() * image->width() * 4);
    SkPixmap pixmap(SkImageInfo::Make(image->width(), image->height(), kN32_SkColorType,
            image->alphaType()), (const void*) &pixels.front(), image->width() * 4);
    image->readPixels(nullptr, pixmap, 0, 0);
    SkPixmap inset;
    if (pixmap.extractSubset(&inset, {128, 128, 512, 512})) {
        const SkImageInfo& info = inset.info();
        static constexpr auto alphas = std::to_array<const char*>({
                "Unknown",
                "Opaque",
                "Premul",
                "Unpremul",
        });
        static constexpr auto colors = std::to_array<const char*>({
                "Unknown",
                "Alpha_8",
                "RGB_565",
                "ARGB_4444",
                "RGBA_8888",
                "RGB_888x",
                "BGRA_8888",
                "RGBA_1010102",
                "RGB_101010x",
                "Gray_8",
                "RGBA_F16Norm",
                "RGBA_F16",
        });
        SkDebugf("width: %d height: %d color: %s alpha: %s\n", info.width(), info.height(),
                 colors[info.colorType()], alphas[info.alphaType()]);
    }
}
}  // END FIDDLE