t.Errorf("%s: %v", tc+".progressive.jpeg", err)
			continue
		}
		if m0.Bounds() != m1.Bounds() {
			t.Errorf("%s: bounds differ: %v and %v", tc, m0.Bounds(), m1.Bounds())
			continue
		}
		// All of the video-*.jpeg files are 150x103.
		if m0.Bounds() != image.Rect(0, 0, 150, 103) {
			t.Errorf("%s: bad bounds: %v", tc, m0.Bounds())
			continue
		}

		switch m0 := m0.(type) {
		case *image.YCbCr:

		bounds := d.img3.Bounds()
		img := image.NewRGBA(bounds)
		imageutil.DrawYCbCr(img, bounds, d.img3, bounds.Min)
		for iBase, y := 0, bounds.Min.Y; y < bounds.Max.Y; iBase, y = iBase+img.Stride, y+1 {
			for i, x := iBase+3, bounds.Min.X; x < bounds.Max.X; i, x = i+4, x+1 {
				img.Pix[i] = 255 - d.blackPix[(y-bounds.Min.Y)*d.blackStride+(x-bounds.Min.X)]
			}
		}
		return &image.CMYK{

				b := dst.Bounds()
				// Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
				golden := makeGolden(dst, b, src, src.Bounds().Min, nil, image.Point{}, op)
				if !b.Eq(golden.Bounds()) {
					t.Errorf("drawOverlap xoff=%d,yoff=%d: bounds %v versus %v", xoff, yoff, dst.Bounds(), golden.Bounds())
					continue
				}

   * Returns {@code ? extends X} if any of {@code bounds} is a subtype of {@code X[]}; or null
   * otherwise.
   */
  @CheckForNull
  private static Type subtypeOfComponentType(Type[] bounds) {
    for (Type bound : bounds) {
      Type componentType = getComponentType(bound);
      if (componentType != null) {
        // Only the first bound can be a class or array.
        // Bounds after the first can only be interfaces.

	// Write the IMAGE.
	io.WriteString(w, "IMAGE {\n    pixels hex\n")
	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
		switch {
		case cm == color.GrayModel:
			for x := bounds.Min.X; x < bounds.Max.X; x++ {
				gray := png.At(x, y).(color.Gray)
				fmt.Fprintf(w, "%02x", gray.Y)
			}
		case cm == color.Gray16Model:
			for x := bounds.Min.X; x < bounds.Max.X; x++ {
				gray16 := png.At(x, y).(color.Gray16)

	copy(gif, testGIF)
	// Make the bounds too big, just by one.
	gif[32] = 2
	want := "gif: frame bounds larger than image bounds"
	try(t, gif, want)

	// Make the bounds too small; does not trigger bounds
	// check, but now there's too much data.
	gif[32] = 0
	want = "gif: too much image data"
	try(t, gif, want)
	gif[32] = 1

	// Make the bounds really big, expect an error.

   * Returns {@code ? extends X} if any of {@code bounds} is a subtype of {@code X[]}; or null
   * otherwise.
   */
  @CheckForNull
  private static Type subtypeOfComponentType(Type[] bounds) {
    for (Type bound : bounds) {
      Type componentType = getComponentType(bound);
      if (componentType != null) {
        // Only the first bound can be a class or array.
        // Bounds after the first can only be interfaces.

	// that call returning and now the stack may have changed (perhaps the
	// C thread is running a coroutine library). We need to update the
	// stack bounds for this case.
	//
	// N.B. we need to update the stack bounds even if SP appears to
	// already be in bounds. Our "bounds" may actually be estimated dummy
	// bounds (below). The actual stack bounds could have shifted but still

		cb, cr [4]block
		// DC components are delta-encoded.
		prevDCY, prevDCCb, prevDCCr int32
	)
	bounds := m.Bounds()
	switch m := m.(type) {
	// TODO(wathiede): switch on m.ColorModel() instead of type.
	case *image.Gray:
		for y := bounds.Min.Y; y < bounds.Max.Y; y += 8 {
			for x := bounds.Min.X; x < bounds.Max.X; x += 8 {
				p := image.Pt(x, y)
				grayToY(m, p, &b)
				prevDCY = e.writeBlock(&b, 0, prevDCY)
			}

		tname := types.NewTypeName(pos, pkg, name, nil)
		r.dict.tparams[i] = types.NewTypeParam(tname, nil)
	}

	typs := make([]types.Type, len(r.dict.bounds))
	for i, bound := range r.dict.bounds {
		typs[i] = r.p.typIdx(bound, r.dict)
	}

	// TODO(mdempsky): This is subtle, elaborate further.
	//
	// We have to save tparams outside of the closure, because