/*!\brief Set the rectangle identifying the displayed portion of the image
*
* Updates the displayed rectangle (aka viewport) on the image surface to
- * match the specified coordinates and size.
+ * match the specified coordinates and size. Specifically, sets img->d_w,
+ * img->d_h, and elements of the img->planes[] array.
*
* \param[in] img Image descriptor
* \param[in] x leftmost column
* \param[in] w width
* \param[in] h height
*
- * \return 0 if the requested rectangle is valid, nonzero otherwise.
+ * \return 0 if the requested rectangle is valid, nonzero (-1) otherwise.
*/
int vpx_img_set_rect(vpx_image_t *img, unsigned int x, unsigned int y,
unsigned int w, unsigned int h);