skia2/docs/examples/Pixmap_scalePixels.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"
// HASH=8e3c8a9c1d0d2e9b8bf66e24d274f792
REG_FIDDLE(Pixmap_scalePixels, 256, 256, false, 3) {
void draw(SkCanvas* canvas) {
    SkImageInfo info = SkImageInfo::MakeN32Premul(image->width(), image->height());
    std::vector<int32_t> srcPixels;
    int rowBytes = image->width() * 4;
    srcPixels.resize(image->height() * rowBytes);
    SkPixmap pixmap(info, (const void*) &srcPixels.front(), rowBytes);
    image->readPixels(nullptr, pixmap, 0, 0);
    for (int offset : { 32, 64, 96 } ) {
        info = SkImageInfo::MakeN32Premul(image->width() + offset, image->height());
        rowBytes = info.width() * 4;
        std::vector<int32_t> dstPixels;
        dstPixels.resize(image->height() * rowBytes);
        SkPixmap dstmap(info, &dstPixels.front(), rowBytes);
        pixmap.scalePixels(dstmap, SkSamplingOptions(SkFilterMode::kLinear,
                                                     SkMipmapMode::kNearest));
        SkBitmap bitmap;
        bitmap.installPixels(dstmap);
        canvas->translate(32, 32);
        canvas->drawBitmap(bitmap, 0, 0);
    }
}
}  // END FIDDLE