- /** @return Image (which must be aligned) */
- virtual boost::shared_ptr<Image> image () const = 0;
+ struct Result {
+ Result (boost::shared_ptr<Image> image_, int log2_scaling_)
+ : image (image_)
+ , log2_scaling (log2_scaling_)
+ , error (false)
+ {}
+
+ Result (boost::shared_ptr<Image> image_, int log2_scaling_, bool error_)
+ : image (image_)
+ , log2_scaling (log2_scaling_)
+ , error (error_)
+ {}
+
+ /** Image (which will be aligned) */
+ boost::shared_ptr<Image> image;
+ /** log2 of any scaling down that has already been applied to the image;
+ * e.g. if the image is already half the size of the original, this value
+ * will be 1.
+ */
+ int log2_scaling;
+ /** true if there was an error during image decoding, otherwise false */
+ bool error;
+ };
+
+ /** @param log Log to write to, or 0.
+ * @param size Size that the returned image will be scaled to, in case this
+ * can be used as an optimisation.
+ */
+ virtual Result image (
+ boost::optional<dcp::Size> size = boost::optional<dcp::Size> ()
+ ) const = 0;
+