access tiles in rotated image items

strukturag · Oct 6, 2024 · e83e36c · e83e36c
1 parent eeb1afb
commit e83e36c
Showing 1 changed file with 53 additions and 0 deletions.
diff --git a/libheif/image-items/image_item.cc b/libheif/image-items/image_item.cc
@@ -38,6 +38,7 @@
 #include <limits>
 #include <cassert>
 #include <cstring>
+#include <ranges>
 
 #if WITH_UNCOMPRESSED_CODEC
 #include "image-items/unc_image.h"
@@ -697,6 +698,58 @@ Result<std::shared_ptr<HeifPixelImage>> ImageItem::decode_image(const struct hei
     }
   }
 
+  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)) {
+      if (auto irot = std::dynamic_pointer_cast<Box_irot>(prop)) {
+        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>(prop)) {
+        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;
+        }
+      }
+    }
+  }
+
   // --- decode image
 
   Result<std::shared_ptr<HeifPixelImage>> decodingResult = decode_compressed_image(options, decode_tile_only, tile_x0, tile_y0);