Revert "Compositor: Support backdrop offset for the Viewer node"

This reverts commit 33409f9f1cd42e899f2706fe7878e5e89b50d617, as it breaks
panning in the image editor.

Fixes T96543

2 files changed, 35 insertions, 14 deletions

diff --git a/source/blender/compositor/operations/COM_ViewerOperation.cc b/source/blender/compositor/operations/COM_ViewerOperation.cc
index 7f0eaecfff7..bc7e08ee98a 100644
--- a/source/blender/compositor/operations/COM_ViewerOperation.cc
+++ b/source/blender/compositor/operations/COM_ViewerOperation.cc
@@ -10,10 +10,10 @@
 #include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
 
-#include "DNA_node_types.h"
-
 namespace blender::compositor {
 
+static int MAX_VIEWER_TRANSLATION_PADDING = 12000;
+
 ViewerOperation::ViewerOperation()
 {
   this->set_image(nullptr);
@@ -137,12 +137,23 @@ void ViewerOperation::init_image()
     return;
   }
 
-  if (ibuf->x != get_width() || ibuf->y != get_height()) {
+  int padding_x = abs(canvas_.xmin) * 2;
+  int padding_y = abs(canvas_.ymin) * 2;
+  if (padding_x > MAX_VIEWER_TRANSLATION_PADDING) {
+    padding_x = MAX_VIEWER_TRANSLATION_PADDING;
+  }
+  if (padding_y > MAX_VIEWER_TRANSLATION_PADDING) {
+    padding_y = MAX_VIEWER_TRANSLATION_PADDING;
+  }
+
+  display_width_ = get_width() + padding_x;
+  display_height_ = get_height() + padding_y;
+  if (ibuf->x != display_width_ || ibuf->y != display_height_) {
     imb_freerectImBuf(ibuf);
     imb_freerectfloatImBuf(ibuf);
     IMB_freezbuffloatImBuf(ibuf);
-    ibuf->x = get_width();
-    ibuf->y = get_height();
+    ibuf->x = display_width_;
+    ibuf->y = display_height_;
     /* zero size can happen if no image buffers exist to define a sensible resolution */
     if (ibuf->x > 0 && ibuf->y > 0) {
       imb_addrectfloatImBuf(ibuf);
@@ -176,13 +187,11 @@ void ViewerOperation::update_image(const rcti *rect)
     return;
   }
 
-  image_->display_offset_x = canvas_.xmin;
-  image_->display_offset_y = canvas_.ymin;
   float *buffer = output_buffer_;
   IMB_partial_display_buffer_update(ibuf_,
                                     buffer,
                                     nullptr,
-                                    get_width(),
+                                    display_width_,
                                     0,
                                     0,
                                     view_settings_,
@@ -215,23 +224,32 @@ void ViewerOperation::update_memory_buffer_partial(MemoryBuffer *UNUSED(output),
     return;
   }
 
+  const int offset_x = area.xmin + (canvas_.xmin > 0 ? canvas_.xmin * 2 : 0);
+  const int offset_y = area.ymin + (canvas_.ymin > 0 ? canvas_.ymin * 2 : 0);
   MemoryBuffer output_buffer(
-      output_buffer_, COM_DATA_TYPE_COLOR_CHANNELS, get_width(), get_height());
+      output_buffer_, COM_DATA_TYPE_COLOR_CHANNELS, display_width_, display_height_);
   const MemoryBuffer *input_image = inputs[0];
-  output_buffer.copy_from(input_image, area);
+  output_buffer.copy_from(input_image, area, offset_x, offset_y);
   if (use_alpha_input_) {
     const MemoryBuffer *input_alpha = inputs[1];
-    output_buffer.copy_from(input_alpha, area, 0, COM_DATA_TYPE_VALUE_CHANNELS, 3);
+    output_buffer.copy_from(
+        input_alpha, area, 0, COM_DATA_TYPE_VALUE_CHANNELS, offset_x, offset_y, 3);
   }
 
   if (depth_buffer_) {
     MemoryBuffer depth_buffer(
-        depth_buffer_, COM_DATA_TYPE_VALUE_CHANNELS, get_width(), get_height());
+        depth_buffer_, COM_DATA_TYPE_VALUE_CHANNELS, display_width_, display_height_);
     const MemoryBuffer *input_depth = inputs[2];
-    depth_buffer.copy_from(input_depth, area);
+    depth_buffer.copy_from(input_depth, area, offset_x, offset_y);
   }
 
-  update_image(&area);
+  rcti display_area;
+  BLI_rcti_init(&display_area,
+                offset_x,
+                offset_x + BLI_rcti_size_x(&area),
+                offset_y,
+                offset_y + BLI_rcti_size_y(&area));
+  update_image(&display_area);
 }
 
 void ViewerOperation::clear_display_buffer()
diff --git a/source/blender/compositor/operations/COM_ViewerOperation.h b/source/blender/compositor/operations/COM_ViewerOperation.h
index ed9e5871eae..1ad6cc51269 100644
--- a/source/blender/compositor/operations/COM_ViewerOperation.h
+++ b/source/blender/compositor/operations/COM_ViewerOperation.h
@@ -35,6 +35,9 @@ class ViewerOperation : public MultiThreadedOperation {
   SocketReader *alpha_input_;
   SocketReader *depth_input_;
 
+  int display_width_;
+  int display_height_;
+
  public:
   ViewerOperation();
   void init_execution() override;