heif_image_handle_get_grid_image_tile_id() can now handle image trans…

…formations

libheif/api/libheif/heif.cc

@@ -882,7 +882,9 @@ heif_error heif_image_handle_get_image_tiling(const struct heif_image_handle* ha
 
 
 struct heif_error heif_image_handle_get_grid_image_tile_id(const struct heif_image_handle* handle,
- uint32_t tile_x, uint32_t tile_y, heif_item_id* tile_item_id)
+ int process_image_transformations,
+ uint32_t tile_x, uint32_t tile_y,
+ heif_item_id* tile_item_id)
 {
  if (!handle || !tile_item_id) {
  return { heif_error_Usage_error,
@@ -903,6 +905,10 @@ struct heif_error heif_image_handle_get_grid_image_tile_id(const struct heif_ima
  "Grid tile index out of range" };
  }
 
+ if (process_image_transformations) {
+ gridItem->transform_requested_tile_position_to_original_tile_position(tile_x, tile_y);
+ }
+
  *tile_item_id = gridItem->get_grid_tiles()[tile_y * gridspec.get_columns() + tile_x];
 
  return heif_error_ok;

libheif/api/libheif/heif.h

@@ -1204,11 +1204,14 @@ LIBHEIF_API
 struct heif_error heif_image_handle_get_image_tiling(const struct heif_image_handle* handle, int process_image_transformations, struct heif_image_tiling* out_tiling);
 
 
-// For grid images, return the image item ID of a specific grid tile. Note that the tile position is given in
-// the original, non-transformed image.
+// For grid images, return the image item ID of a specific grid tile.
+// If 'process_image_transformations' is true, the tile positions are given in the transformed image coordinate system and
+// are internally mapped to the original image tile positions.
 LIBHEIF_API
 struct heif_error heif_image_handle_get_grid_image_tile_id(const struct heif_image_handle* handle,
- uint32_t tile_x, uint32_t tile_y, heif_item_id* tile_item_id);
+ int process_image_transformations,
+ uint32_t tile_x, uint32_t tile_y,
+ heif_item_id* tile_item_id);
 
 
 struct heif_decoding_options;

libheif/image-items/image_item.cc

@@ -669,6 +669,63 @@ Error ImageItem::check_for_valid_image_size(uint32_t width, uint32_t height) con
 }
 
 
+Error ImageItem::transform_requested_tile_position_to_original_tile_position(uint32_t& tile_x, uint32_t& tile_y) const
+{
+ Result<std::vector<std::shared_ptr<Box>>> propertiesResult = get_properties();
+ if (propertiesResult.error) {
+ return propertiesResult.error;
+ }
+
+ heif_image_tiling tiling = get_heif_image_tiling();
+
+ //for (auto& prop : std::ranges::reverse_view(propertiesResult.value)) {
+ for (auto propIter = propertiesResult.value.rbegin(); propIter != propertiesResult.value.rend(); propIter++) {
+ if (auto irot = std::dynamic_pointer_cast<Box_irot>(*propIter)) {
+ switch (irot->get_rotation_ccw()) {
+ case 90: {
+ uint32_t tx0 = tiling.num_columns - 1 - tile_y;
+ uint32_t ty0 = tile_x;
+ tile_y = ty0;
+ tile_x = tx0;
+ break;
+ }
+ case 270: {
+ uint32_t tx0 = tile_y;
+ uint32_t ty0 = tiling.num_rows - 1 - tile_x;
+ tile_y = ty0;
+ tile_x = tx0;
+ break;
+ }
+ case 180: {
+ tile_x = tiling.num_columns - 1 - tile_x;
+ tile_y = tiling.num_rows - 1 - tile_y;
+ break;
+ }
+ default:
+ assert(false);
+ break;
+ }
+ }
+
+ if (auto imir = std::dynamic_pointer_cast<Box_imir>(*propIter)) {
+ switch (imir->get_mirror_direction()) {
+ case heif_transform_mirror_direction_horizontal:
+ tile_x = tiling.num_columns - 1 - tile_x;
+ break;
+ case heif_transform_mirror_direction_vertical:
+ tile_y = tiling.num_rows - 1 - tile_y;
+ break;
+ default:
+ assert(false);
+ break;
+ }
+ }
+ }
+
+ return Error::Ok;
+}
+
+
 Result<std::shared_ptr<HeifPixelImage>> ImageItem::decode_image(const struct heif_decoding_options& options,
  bool decode_tile_only, uint32_t tile_x0, uint32_t tile_y0) const
 {
@@ -688,55 +745,8 @@ Result<std::shared_ptr<HeifPixelImage>> ImageItem::decode_image(const struct hei
  // --- transform tile position
 
  if (decode_tile_only && options.ignore_transformations == false) {
- Result<std::vector<std::shared_ptr<Box>>> propertiesResult = get_properties();
- if (propertiesResult.error) {
- return propertiesResult.error;
- }
-
- heif_image_tiling tiling = get_heif_image_tiling();
-
- //for (auto& prop : std::ranges::reverse_view(propertiesResult.value)) {
- for (auto propIter = propertiesResult.value.rbegin(); propIter != propertiesResult.value.rend(); propIter++) {
- if (auto irot = std::dynamic_pointer_cast<Box_irot>(*propIter)) {
- switch (irot->get_rotation_ccw()) {
- case 90: {
- uint32_t tx0 = tiling.num_columns - 1 - tile_y0;
- uint32_t ty0 = tile_x0; //tiling.num_rows - 1 - tile_x0;
- tile_y0 = ty0;
- tile_x0 = tx0;
- break;
- }
- case 270: {
- uint32_t tx0 = tile_y0;
- uint32_t ty0 = tiling.num_rows - 1 - tile_x0;
- tile_y0 = ty0;
- tile_x0 = tx0;
- break;
- }
- case 180: {
- tile_x0 = tiling.num_columns - 1 - tile_x0;
- tile_y0 = tiling.num_rows - 1 - tile_y0;
- break;
- }
- default:
- assert(false);
- break;
- }
- }
-
- if (auto imir = std::dynamic_pointer_cast<Box_imir>(*propIter)) {
- switch (imir->get_mirror_direction()) {
- case heif_transform_mirror_direction_horizontal:
- tile_x0 = tiling.num_columns - 1 - tile_x0;
- break;
- case heif_transform_mirror_direction_vertical:
- tile_y0 = tiling.num_rows - 1 - tile_y0;
- break;
- default:
- assert(false);
- break;
- }
- }
+ if (Error error = transform_requested_tile_position_to_original_tile_position(tile_x0, tile_y0)) {
+ return error;
  }
  }
 

libheif/image-items/image_item.h

@@ -354,6 +354,8 @@ class ImageItem : public ErrorBuffer
 
  Error process_image_transformations_on_tiling(heif_image_tiling&) const;
 
+ Error transform_requested_tile_position_to_original_tile_position(uint32_t& tile_x, uint32_t& tile_y) const;
+
  virtual std::shared_ptr<class Decoder> get_decoder() const { return nullptr; }
 
 private: