void draw(SkCanvas* canvas) {

    GrContext* context = canvas->getGrContext();

​

    if(!context)

        return;

​

    SkScalar ss = 2.0;

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    SkImageInfo texInfo = SkImageInfo::MakeN32(256, 256, kOpaque_SkAlphaType);

    SkImageInfo renInfo = SkImageInfo::MakeN32(256 * ss, 256 * ss, kOpaque_SkAlphaType);

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    sk_sp<SkSurface> texSurface(SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, texInfo));

    sk_sp<SkSurface> renSurface(SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, renInfo));

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    SkCanvas* texCanvas = texSurface->getCanvas();

    SkCanvas* renCanvas = renSurface->getCanvas();

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    SkPaint cirPaint;

    cirPaint.setAntiAlias(true);

    cirPaint.setColor(SK_ColorBLUE);

    texCanvas->clear(SK_ColorRED);

    texCanvas->drawCircle(128, 128, 128, cirPaint);

​

    sk_sp<SkImage> texture(texSurface->makeImageSnapshot());

​

    SkPaint triPaint;

    triPaint.setShader(texture->makeShader(SkTileMode::kClamp, SkTileMode::kClamp, nullptr));

    SkPoint pts[] = {{0, 0}, {256 * ss, 0}, {0, 220 * ss}};

    SkPoint cds[] = {{0, 0}, {256, 0}, {0, 256}};

    auto verts = SkVertices::MakeCopy(SkVertices::kTriangles_VertexMode, 3, pts, cds, nullptr);

    renCanvas->drawVertices(verts.get(), SkBlendMode::kSrc, triPaint);

​

    sk_sp<SkImage> render(renSurface->makeImageSnapshot());

​

    SkPaint paint;

    paint.setFilterQuality(kLow_SkFilterQuality);

    canvas->scale(1.0 / ss, 1.0 / ss);

    canvas->drawImage(render, 0, 0, &paint);

}