+/** Crop this image, scale it to `inter_size' and then place it in a black frame of `out_size' */
+shared_ptr<Image>
+Image::crop_scale_window (Crop crop, libdcp::Size inter_size, libdcp::Size out_size, Scaler const * scaler, AVPixelFormat out_format, bool out_aligned) const
+{
+ assert (scaler);
+ /* Empirical testing suggests that sws_scale() will crash if
+ the input image is not aligned.
+ */
+ assert (aligned ());
+
+ assert (out_size.width >= inter_size.width);
+ assert (out_size.height >= inter_size.height);
+
+ /* Here's an image of out_size */
+ shared_ptr<Image> out (new Image (out_format, out_size, out_aligned));
+ out->make_black ();
+
+ /* Size of the image after any crop */
+ libdcp::Size const cropped_size = crop.apply (size ());
+
+ /* Scale context for a scale from cropped_size to inter_size */
+ struct SwsContext* scale_context = sws_getContext (
+ cropped_size.width, cropped_size.height, pixel_format(),
+ inter_size.width, inter_size.height, out_format,
+ scaler->ffmpeg_id (), 0, 0, 0
+ );
+
+ if (!scale_context) {
+ throw StringError (N_("Could not allocate SwsContext"));
+ }
+
+ /* Prepare input data pointers with crop */
+ uint8_t* scale_in_data[components()];
+ for (int c = 0; c < components(); ++c) {
+ scale_in_data[c] = data()[c] + int (rint (bytes_per_pixel(c) * crop.left)) + stride()[c] * (crop.top / line_factor(c));
+ }
+
+ /* Corner of the image within out_size */
+ Position<int> const corner ((out_size.width - inter_size.width) / 2, (out_size.height - inter_size.height) / 2);
+
+ uint8_t* scale_out_data[out->components()];
+ for (int c = 0; c < out->components(); ++c) {
+ scale_out_data[c] = out->data()[c] + int (rint (out->bytes_per_pixel(c) * corner.x)) + out->stride()[c] * corner.y;
+ }
+
+ sws_scale (
+ scale_context,
+ scale_in_data, stride(),
+ 0, cropped_size.height,
+ scale_out_data, out->stride()
+ );
+
+ sws_freeContext (scale_context);
+
+ return out;
+}
+