Nodes: Improvements to edge panning in the node editor.

- New operator property to toggle edge panning in the keymap:
  This is disabled by default to avoid edge-panning in cases where it
  gets distracting, such as adding a new node. Only the explicit
  translate operator(s) (GKEY or drag) have this enabled now.

- Restore the initial view rect on edge pan cancel:
  The initial view rect is now stored in the edge pan operator data.
  When an operator with edge panning is cancelled it can now call the
  `UI_view2d_edge_pan_cancel` function to restore the original View2D
  rect.

- Less delay in node editor scrolling:
  Delay is useful when scrolling through long lists, such as in the
  outliner, but makes node scrolling feel sluggish and unresponsive.
  The lower scroll speed here makes a faster response the better option.

- Zoom influence feature:
  Somewhat slower scrolling in UI-space when zoomed out. With the 0.5
  zoom influence factor nodes behave as if zoom factor is halved,
  otherwise it gets too fast when zoomed out. Previously scrolling would
  always be constant-speed in UI space, now it's half-way between UI
  space and node (view) space.

1 files changed, 48 insertions, 6 deletions

diff --git a/source/blender/editors/interface/view2d_edge_pan.c b/source/blender/editors/interface/view2d_edge_pan.c
index 1d300c7b275..eaf8ef30311 100644
--- a/source/blender/editors/interface/view2d_edge_pan.c
+++ b/source/blender/editors/interface/view2d_edge_pan.c
@@ -71,7 +71,8 @@ void UI_view2d_edge_pan_init(bContext *C,
                              float outside_pad,
                              float speed_ramp,
                              float max_speed,
-                             float delay)
+                             float delay,
+                             float zoom_influence)
 {
   if (!UI_view2d_edge_pan_poll(C)) {
     return;
@@ -89,6 +90,7 @@ void UI_view2d_edge_pan_init(bContext *C,
   vpd->speed_ramp = speed_ramp;
   vpd->max_speed = max_speed;
   vpd->delay = delay;
+  vpd->zoom_influence = zoom_influence;
 
   /* Calculate translation factor, based on size of view. */
   const float winx = (float)(BLI_rcti_size_x(&vpd->region->winrct) + 1);
@@ -104,6 +106,7 @@ void UI_view2d_edge_pan_reset(View2DEdgePanData *vpd)
   vpd->edge_pan_start_time_x = 0.0;
   vpd->edge_pan_start_time_y = 0.0;
   vpd->edge_pan_last_time = PIL_check_seconds_timer();
+  vpd->initial_rect = vpd->region->v2d.cur;
 }
 
 /**
@@ -168,9 +171,15 @@ static float edge_pan_speed(View2DEdgePanData *vpd,
 
   /* Apply a fade in to the speed based on a start time delay. */
   const double start_time = x_dir ? vpd->edge_pan_start_time_x : vpd->edge_pan_start_time_y;
-  const float delay_factor = smootherstep(vpd->delay, (float)(current_time - start_time));
+  const float delay_factor = vpd->delay > 0.01f ?
+                                 smootherstep(vpd->delay, (float)(current_time - start_time)) :
+                                 1.0f;
 
-  return distance_factor * delay_factor * vpd->max_speed * U.widget_unit * (float)U.dpi_fac;
+  /* Zoom factor increases speed when zooming in and decreases speed when zooming out. */
+  const float zoomx = (float)(BLI_rcti_size_x(&region->winrct) + 1) / BLI_rctf_size_x(&region->v2d.cur);
+  const float zoom_factor = 1.0f + CLAMPIS(vpd->zoom_influence, 0.0f, 1.0f) * (zoomx - 1.0f);
+
+  return distance_factor * delay_factor * zoom_factor * vpd->max_speed * U.widget_unit * (float)U.dpi_fac;
 }
 
 static void edge_pan_apply_delta(bContext *C, View2DEdgePanData *vpd, float dx, float dy)
@@ -264,6 +273,27 @@ void UI_view2d_edge_pan_apply_event(bContext *C, View2DEdgePanData *vpd, const w
   UI_view2d_edge_pan_apply(C, vpd, event->x, event->y);
 }
 
+void UI_view2d_edge_pan_cancel(bContext *C, View2DEdgePanData *vpd)
+{
+  View2D *v2d = vpd->v2d;
+  if (!v2d) {
+    return;
+  }
+
+  v2d->cur = vpd->initial_rect;
+
+  /* Inform v2d about changes after this operation. */
+  UI_view2d_curRect_changed(C, v2d);
+
+  /* Don't rebuild full tree in outliner, since we're just changing our view. */
+  ED_region_tag_redraw_no_rebuild(vpd->region);
+
+  /* Request updates to be done. */
+  WM_event_add_mousemove(CTX_wm_window(C));
+
+  UI_view2d_sync(vpd->screen, vpd->area, v2d, V2D_LOCK_COPY);
+}
+
 void UI_view2d_edge_pan_operator_properties(wmOperatorType *ot)
 {
   /* Default values for edge panning operators. */
@@ -272,7 +302,8 @@ void UI_view2d_edge_pan_operator_properties(wmOperatorType *ot)
                                             /*outside_pad*/ 0.0f,
                                             /*speed_ramp*/ 1.0f,
                                             /*max_speed*/ 500.0f,
-                                            /*delay*/ 1.0f);
+                                            /*delay*/ 1.0f,
+                                            /*zoom_influence*/ 0.0f);
 }
 
 void UI_view2d_edge_pan_operator_properties_ex(struct wmOperatorType *ot,
@@ -280,7 +311,8 @@ void UI_view2d_edge_pan_operator_properties_ex(struct wmOperatorType *ot,
                                                float outside_pad,
                                                float speed_ramp,
                                                float max_speed,
-                                               float delay)
+                                               float delay,
+                                               float zoom_influence)
 {
   RNA_def_float(
       ot->srna,
@@ -329,6 +361,15 @@ void UI_view2d_edge_pan_operator_properties_ex(struct wmOperatorType *ot,
                 "Delay in seconds before maximum speed is reached",
                 0.0f,
                 10.0f);
+  RNA_def_float(ot->srna,
+                "zoom_influence",
+                zoom_influence,
+                0.0f,
+                1.0f,
+                "Zoom Influence",
+                "Influence of the zoom factor on scroll speed",
+                0.0f,
+                1.0f);
 }
 
 void UI_view2d_edge_pan_operator_init(bContext *C, View2DEdgePanData *vpd, wmOperator *op)
@@ -339,7 +380,8 @@ void UI_view2d_edge_pan_operator_init(bContext *C, View2DEdgePanData *vpd, wmOpe
                           RNA_float_get(op->ptr, "outside_padding"),
                           RNA_float_get(op->ptr, "speed_ramp"),
                           RNA_float_get(op->ptr, "max_speed"),
-                          RNA_float_get(op->ptr, "delay"));
+                          RNA_float_get(op->ptr, "delay"),
+                          RNA_float_get(op->ptr, "zoom_influence"));
 }
 
 /** \} */