diff --git a/src/app/commands/cmd_flip.cpp b/src/app/commands/cmd_flip.cpp
index ac136bfda..bcaba4cef 100644
--- a/src/app/commands/cmd_flip.cpp
+++ b/src/app/commands/cmd_flip.cpp
@@ -96,22 +96,20 @@ void FlipCommand::onExecute(Context* context)
       // whole image.
       if (document->isMaskVisible()) {
         mask = document->getMask();
-        gfx::Rect maskBounds = mask->getBounds();
-
-        // Adjust the mask depending on the cel position.
-        maskBounds.offset(-x, -y);
 
         // Intersect the full area of the image with the mask's
         // bounds, so we don't request to flip an area outside the
         // image's bounds.
-        bounds = bounds.createIntersect(maskBounds);
+        bounds = bounds.createIntersect(gfx::Rect(mask->getBounds()).offset(-x, -y));
 
         // If the mask isn't a rectangular area, we've to flip the mask too.
         if (mask->getBitmap() != NULL && !mask->isRectangular()) {
           int bgcolor = app_get_color_to_clear_layer(writer.layer());
 
           // Flip the portion of image specified by the mask.
+          mask->offsetOrigin(-x, -y);
           api.flipImageWithMask(image, mask, m_flipType, bgcolor);
+          mask->offsetOrigin(x, y);
           alreadyFlipped = true;
 
           // Flip the mask.
@@ -121,8 +119,7 @@ void FlipCommand::onExecute(Context* context)
             base::UniquePtr<Mask> newMask(new Mask(*mask));
             newMask->freeze();
             raster::algorithm::flip_image(newMask->getBitmap(),
-                                          maskBitmap->getBounds(),
-                                          m_flipType);
+              maskBitmap->getBounds(), m_flipType);
             newMask->unfreeze();
 
             // Change the current mask and generate the new boundaries.
diff --git a/src/app/document_api.cpp b/src/app/document_api.cpp
index aff94454c..e9e045ef6 100644
--- a/src/app/document_api.cpp
+++ b/src/app/document_api.cpp
@@ -990,9 +990,8 @@ void DocumentApi::clearMask(Layer* layer, Cel* cel, int bgcolor)
   }
 }
 
-void DocumentApi::flipImage(Image* image,
-                                const gfx::Rect& bounds,
-                                raster::algorithm::FlipType flipType)
+void DocumentApi::flipImage(Image* image, const gfx::Rect& bounds,
+  raster::algorithm::FlipType flipType)
 {
   // Insert the undo operation.
   if (undoEnabled()) {
diff --git a/src/raster/algorithm/flip_image.cpp b/src/raster/algorithm/flip_image.cpp
index 0256072b5..8bfe0b8aa 100644
--- a/src/raster/algorithm/flip_image.cpp
+++ b/src/raster/algorithm/flip_image.cpp
@@ -50,18 +50,14 @@ void flip_image(Image* image, const gfx::Rect& bounds, FlipType flipType)
       break;
 
     case FlipVertical: {
-      int section_size = image->getRowStrideSize(bounds.w);
-      std::vector<uint8_t> tmpline(section_size);
-
       int v = bounds.y+bounds.h-1;
       for (int y=bounds.y; y<bounds.y+bounds.h/2; ++y, --v) {
-        uint8_t* address1 = image->getPixelAddress(bounds.x, y);
-        uint8_t* address2 = image->getPixelAddress(bounds.x, v);
-
-        // Swap lines.
-        std::copy(address1, address1+section_size, tmpline.begin());
-        std::copy(address2, address2+section_size, address1);
-        std::copy(tmpline.begin(), tmpline.end(), address2);
+        for (int x=bounds.x; x<bounds.x+bounds.w; ++x) {
+          uint32_t c1 = get_pixel(image, x, y);
+          uint32_t c2 = get_pixel(image, x, v);
+          put_pixel(image, x, y, c2);
+          put_pixel(image, x, v, c1);
+        }
       }
       break;
     }
@@ -75,7 +71,7 @@ void flip_image_with_mask(Image* image, const Mask* mask, FlipType flipType, int
   switch (flipType) {
 
     case FlipHorizontal: {
-      base::UniquePtr<Image> originalRow(Image::create(image->getPixelFormat(), mask->getBounds().w, 1));
+      base::UniquePtr<Image> originalRow(Image::create(image->getPixelFormat(), bounds.w, 1));
 
       for (int y=bounds.y; y<bounds.y+bounds.h; ++y) {
         // Copy the current row.
@@ -93,8 +89,8 @@ void flip_image_with_mask(Image* image, const Mask* mask, FlipType flipType, int
       break;
     }
 
-    case FlipVertical:{
-      base::UniquePtr<Image> originalCol(Image::create(image->getPixelFormat(), 1, mask->getBounds().h));
+    case FlipVertical: {
+      base::UniquePtr<Image> originalCol(Image::create(image->getPixelFormat(), 1, bounds.h));
 
       for (int x=bounds.x; x<bounds.x+bounds.w; ++x) {
         // Copy the current column.