Skia Fiddle

void draw(SkCanvas* canvas) {
    const char* colors[] = { "Unknown", "Alpha_8", "RGB_565", "ARGB_4444", "RGBA_8888", "RGB_888x",
                             "BGRA_8888", "RGBA_1010102", "RGB_101010x", "Gray_8", "RGBA_F16Norm",
                             "RGBA_F16" };
    const char* alphas[] = {"Unknown ", "Opaque  ", "Premul  ", "Unpremul"};
    SkAlphaType alphaTypes[] = { kUnknown_SkAlphaType, kOpaque_SkAlphaType, kPremul_SkAlphaType,
    kUnpremul_SkAlphaType
                               };
    SkPaint paint;
    SkFont font(SkTypeface::MakeFromName("monospace", SkFontStyle()), 10);
    int y = 15;
    canvas->drawString("   colorType   alphaType  canonical", 10, y, font, paint);
    for (SkColorType colorType : {
    kUnknown_SkColorType, kAlpha_8_SkColorType, kRGB_565_SkColorType,
    kARGB_4444_SkColorType, kRGBA_8888_SkColorType, kRGB_888x_SkColorType,
    kBGRA_8888_SkColorType, kRGBA_1010102_SkColorType, kRGB_101010x_SkColorType,
    kGray_8_SkColorType, kRGBA_F16_SkColorType
                                 } ) {
        for (SkAlphaType alphaType : alphaTypes) {
            SkAlphaType canonicalAlphaType  = kUnknown_SkAlphaType;
            bool result = SkColorTypeValidateAlphaType(colorType, alphaType, &canonicalAlphaType);
            SkString string;
            string.printf("%13s %10s %10s", colors[(int) colorType], alphas[(int) alphaType],
                     result ? alphas[(int) canonicalAlphaType] : "------  ");
            canvas->drawString(string, 10, y += 14, font, paint);
        }
    }
}

Skia API Documentation