UI: Add an outer boundary for edge panning, use in outliner

Currently if you drag and drop an item from the outliner elsewhere in
the Blender window, the outliner will scroll the entire time, even if the
mouse is far away. This commit adds optional behavior for the edge pan
operator that makes it only act if the mouse is close enough to the region.

Differential Revision: https://developer.blender.org/D8193

1 files changed, 31 insertions, 12 deletions

diff --git a/source/blender/editors/interface/view2d_ops.c b/source/blender/editors/interface/view2d_ops.c
index c37a7279773..64cacd44e3d 100644
--- a/source/blender/editors/interface/view2d_ops.c
+++ b/source/blender/editors/interface/view2d_ops.c
@@ -475,20 +475,29 @@ static int view_edge_pan_modal(bContext *C, wmOperator *op, const wmEvent *event
    * On successful handling, always pass events on to other handlers. */
   const int success_retval = OPERATOR_PASS_THROUGH;
 
-  /* Find whether the mouse is beyond X and Y edges. */
+  int outside_padding = RNA_int_get(op->ptr, "outside_padding") * UI_UNIT_X;
+  rcti padding_rect;
+  if (outside_padding != 0) {
+    padding_rect = region->winrct;
+    BLI_rcti_pad(&padding_rect, outside_padding, outside_padding);
+  }
+
   int pan_dir_x = 0;
   int pan_dir_y = 0;
-  if (event->x > region->winrct.xmax - EDGE_PAN_REGION_PAD) {
-    pan_dir_x = 1;
-  }
-  else if (event->x < region->winrct.xmin + EDGE_PAN_REGION_PAD) {
-    pan_dir_x = -1;
-  }
-  if (event->y > region->winrct.ymax - EDGE_PAN_REGION_PAD) {
-    pan_dir_y = 1;
-  }
-  else if (event->y < region->winrct.ymin + EDGE_PAN_REGION_PAD) {
-    pan_dir_y = -1;
+  if ((outside_padding == 0) || BLI_rcti_isect_pt(&padding_rect, event->x, event->y)) {
+    /* Find whether the mouse is beyond X and Y edges. */
+    if (event->x > region->winrct.xmax - EDGE_PAN_REGION_PAD) {
+      pan_dir_x = 1;
+    }
+    else if (event->x < region->winrct.xmin + EDGE_PAN_REGION_PAD) {
+      pan_dir_x = -1;
+    }
+    if (event->y > region->winrct.ymax - EDGE_PAN_REGION_PAD) {
+      pan_dir_y = 1;
+    }
+    else if (event->y < region->winrct.ymin + EDGE_PAN_REGION_PAD) {
+      pan_dir_y = -1;
+    }
   }
 
   const double current_time = PIL_check_seconds_timer();
@@ -532,6 +541,16 @@ static void VIEW2D_OT_edge_pan(wmOperatorType *ot)
 
   /* operator is modal */
   ot->flag = OPTYPE_INTERNAL;
+  RNA_def_int(ot->srna,
+              "outside_padding",
+              0,
+              0,
+              100,
+              "Outside Padding",
+              "Padding around the region in UI units within which panning is activated (0 to "
+              "disable boundary)",
+              0,
+              100);
 }
 
 #undef EDGE_PAN_REGION_PAD