Allow override of EXIF Orientation tag #189

Clear Orientation when rotate/flip/flop are used

src/common.cc

@@ -25,6 +25,8 @@
 #endif
 #endif
 
+#define EXIF_IFD0_ORIENTATION "exif-ifd0-Orientation"
+
 namespace sharp {
 
   // How many tasks are in the queue?
@@ -141,14 +143,30 @@ namespace sharp {
     int orientation = 0;
     const char *exif;
     if (
-      vips_image_get_typeof(image, "exif-ifd0-Orientation") != 0 &&
-      !vips_image_get_string(image, "exif-ifd0-Orientation", &exif)
+      vips_image_get_typeof(image, EXIF_IFD0_ORIENTATION) != 0 &&
+      !vips_image_get_string(image, EXIF_IFD0_ORIENTATION, &exif)
     ) {
       orientation = atoi(&exif[0]);
     }
     return orientation;
   }
 
+  /*
+    Set EXIF Orientation of image.
+  */
+  void SetExifOrientation(VipsImage *image, int const orientation) {
+    char exif[3];
+    g_snprintf(exif, sizeof(exif), "%d", orientation);
+    vips_image_set_string(image, EXIF_IFD0_ORIENTATION, exif);
+  }
+
+  /*
+    Remove EXIF Orientation from image.
+  */
+  void RemoveExifOrientation(VipsImage *image) {
+    vips_image_remove(image, EXIF_IFD0_ORIENTATION);
+  }
+
   /*
     Returns the window size for the named interpolator. For example,
     a window size of 3 means a 3x3 pixel grid is used for the calculation.

src/common.h

@@ -64,6 +64,16 @@ namespace sharp {
   */
   int ExifOrientation(VipsImage const *image);
 
+  /*
+    Set EXIF Orientation of image.
+  */
+  void SetExifOrientation(VipsImage *image, int const orientation);
+
+  /*
+    Remove EXIF Orientation from image.
+  */
+  void RemoveExifOrientation(VipsImage *image);
+
   /*
     Returns the window size for the named interpolator. For example,
     a window size of 3 means a 3x3 pixel grid is used for the calculation.

src/pipeline.cc

@@ -36,6 +36,8 @@ using sharp::InterpolatorWindowSize;
 using sharp::HasProfile;
 using sharp::HasAlpha;
 using sharp::ExifOrientation;
+using sharp::SetExifOrientation;
+using sharp::RemoveExifOrientation;
 using sharp::IsJpeg;
 using sharp::IsPng;
 using sharp::IsWebp;
@@ -109,6 +111,7 @@ struct PipelineBaton {
   bool optimiseScans;
   std::string err;
   bool withMetadata;
+  int withMetadataOrientation;
   int tileSize;
   int tileOverlap;
 
@@ -142,6 +145,7 @@ struct PipelineBaton {
     overshootDeringing(false),
     optimiseScans(false),
     withMetadata(false),
+    withMetadataOrientation(-1),
     tileSize(256),
     tileOverlap(0) {
       background[0] = 0.0;
@@ -246,6 +250,7 @@ class PipelineWorker : public NanAsyncWorker {
       }
       vips_object_local(hook, rotated);
       image = rotated;
+      RemoveExifOrientation(image);
     }
 
     // Pre extraction
@@ -563,6 +568,7 @@ class PipelineWorker : public NanAsyncWorker {
       }
       vips_object_local(hook, rotated);
       image = rotated;
+      RemoveExifOrientation(image);
     }
 
     // Flip (mirror about Y axis)
@@ -573,6 +579,7 @@ class PipelineWorker : public NanAsyncWorker {
       }
       vips_object_local(hook, flipped);
       image = flipped;
+      RemoveExifOrientation(image);
     }
 
     // Flop (mirror about X axis)
@@ -583,6 +590,7 @@ class PipelineWorker : public NanAsyncWorker {
       }
       vips_object_local(hook, flopped);
       image = flopped;
+      RemoveExifOrientation(image);
     }
 
     // Crop/embed
@@ -801,6 +809,11 @@ class PipelineWorker : public NanAsyncWorker {
       }
     }
 
+    // Override EXIF Orientation tag
+    if (baton->withMetadata && baton->withMetadataOrientation != -1) {
+      SetExifOrientation(image, baton->withMetadataOrientation);
+    }
+
 #if !(VIPS_MAJOR_VERSION >= 8 || (VIPS_MAJOR_VERSION >= 7 && VIPS_MINOR_VERSION >= 40 && VIPS_MINOR_VERSION >= 5))
     // Generate image tile cache when interlace output is required - no longer required as of libvips 7.40.5+
     if (baton->progressive) {
@@ -1194,6 +1207,7 @@ NAN_METHOD(pipeline) {
   baton->overshootDeringing = options->Get(NanNew<String>("overshootDeringing"))->BooleanValue();
   baton->optimiseScans = options->Get(NanNew<String>("optimiseScans"))->BooleanValue();
   baton->withMetadata = options->Get(NanNew<String>("withMetadata"))->BooleanValue();
+  baton->withMetadataOrientation = options->Get(NanNew<String>("withMetadataOrientation"))->Int32Value();
   // Output filename or __format for Buffer
   baton->output = *String::Utf8Value(options->Get(NanNew<String>("output"))->ToString());
   baton->tileSize = options->Get(NanNew<String>("tileSize"))->Int32Value();