6 files changed, 122 insertions, 4 deletions

diff --git a/source/blender/editors/mask/mask_add.c b/source/blender/editors/mask/mask_add.c
index d7b3d74bc7e..1226cc57359 100644
--- a/source/blender/editors/mask/mask_add.c
+++ b/source/blender/editors/mask/mask_add.c
@@ -507,6 +507,9 @@ static int add_vertex_handle_cyclic(
 
 static int add_vertex_exec(bContext *C, wmOperator *op)
 {
+  MaskViewLockState lock_state;
+  ED_mask_view_lock_state_store(C, &lock_state);
+
   Mask *mask = CTX_data_edit_mask(C);
   if (mask == NULL) {
     /* if there's no active mask, create one */
@@ -548,6 +551,8 @@ static int add_vertex_exec(bContext *C, wmOperator *op)
 
   DEG_id_tag_update(&mask->id, ID_RECALC_GEOMETRY);
 
+  ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
+
   return OPERATOR_FINISHED;
 }
 
@@ -690,6 +695,9 @@ void MASK_OT_add_feather_vertex(wmOperatorType *ot)
 static int create_primitive_from_points(
     bContext *C, wmOperator *op, const float (*points)[2], int num_points, char handle_type)
 {
+  MaskViewLockState lock_state;
+  ED_mask_view_lock_state_store(C, &lock_state);
+
   ScrArea *area = CTX_wm_area(C);
   int size = RNA_float_get(op->ptr, "size");
 
@@ -752,6 +760,8 @@ static int create_primitive_from_points(
 
   DEG_id_tag_update(&mask->id, ID_RECALC_GEOMETRY);
 
+  ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
+
   return OPERATOR_FINISHED;
 }
 
diff --git a/source/blender/editors/mask/mask_edit.c b/source/blender/editors/mask/mask_edit.c
index 663ae0097ad..e6c6424e5f0 100644
--- a/source/blender/editors/mask/mask_edit.c
+++ b/source/blender/editors/mask/mask_edit.c
@@ -184,3 +184,39 @@ void ED_operatormacros_mask(void)
 }
 
 /** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Lock-to-selection viewport preservation
+ * \{ */
+
+void ED_mask_view_lock_state_store(const bContext *C, MaskViewLockState *state)
+{
+  SpaceClip *space_clip = CTX_wm_space_clip(C);
+  if (space_clip != NULL) {
+    ED_clip_view_lock_state_store(C, &state->space_clip_state);
+  }
+}
+
+void ED_mask_view_lock_state_restore_no_jump(const bContext *C, const MaskViewLockState *state)
+{
+  SpaceClip *space_clip = CTX_wm_space_clip(C);
+  if (space_clip != NULL) {
+    if ((space_clip->flag & SC_LOCK_SELECTION) == 0) {
+      /* Early output if the editor is not locked to selection.
+       * Avoids forced dependency graph evaluation here. */
+      return;
+    }
+
+    /* Mask's lock-to-selection requres deformed splines to be evaluated to calculate bounds of
+     * points after animation has been evaluated. The restore-no-jump type of function does
+     * calculation of new offset for the view for an updated state of mask to cancel the offset out
+     * by modifying locked offset. In order to do such calculation mask needs to be evaluated after
+     * modification by an operator. */
+    struct Depsgraph *depsgraph = CTX_data_ensure_evaluated_depsgraph(C);
+    (void)depsgraph;
+
+    ED_clip_view_lock_state_restore_no_jump(C, &state->space_clip_state);
+  }
+}
+
+/** \} */
diff --git a/source/blender/editors/mask/mask_intern.h b/source/blender/editors/mask/mask_intern.h
index f6990583383..ee1784011ea 100644
--- a/source/blender/editors/mask/mask_intern.h
+++ b/source/blender/editors/mask/mask_intern.h
@@ -23,6 +23,8 @@
 
 #pragma once
 
+#include "ED_clip.h"
+
 struct Mask;
 struct bContext;
 struct wmOperatorType;
@@ -92,6 +94,19 @@ void ED_mask_select_flush_all(struct Mask *mask);
 bool ED_maskedit_poll(struct bContext *C);
 bool ED_maskedit_mask_poll(struct bContext *C);
 
+/* Generalized solution for preserving editor viewport when making changes while lock-to-selection
+ * is enabled.
+ * Any mask operator can use this API, without worrying that some editors do not have an idea of
+ * lock-to-selection. */
+
+typedef struct MaskViewLockState {
+  ClipViewLockState space_clip_state;
+} MaskViewLockState;
+
+void ED_mask_view_lock_state_store(const struct bContext *C, MaskViewLockState *state);
+void ED_mask_view_lock_state_restore_no_jump(const struct bContext *C,
+                                             const MaskViewLockState *state);
+
 /* mask_query.c */
 bool ED_mask_find_nearest_diff_point(const struct bContext *C,
                                      struct Mask *mask,
diff --git a/source/blender/editors/mask/mask_ops.c b/source/blender/editors/mask/mask_ops.c
index 25cc39bf9a0..00a1dfb7d87 100644
--- a/source/blender/editors/mask/mask_ops.c
+++ b/source/blender/editors/mask/mask_ops.c
@@ -226,6 +226,12 @@ typedef struct SlidePointData {
   int width, height;
 
   float prev_mouse_coord[2];
+
+  /* Previous clip coordinate which was resolved from mouse position (0, 0).
+   * Is used to compansate for view offste moving in-between of mouse events when
+   * lock-to-selection is enabled. */
+  float prev_zero_coord[2];
+
   float no[2];
 
   bool is_curvature_only, is_accurate, is_initial_feather, is_overall_feather;
@@ -431,6 +437,9 @@ static void *slide_point_customdata(bContext *C, wmOperator *op, const wmEvent *
   const float threshold = 19;
   eMaskWhichHandle which_handle;
 
+  MaskViewLockState lock_state;
+  ED_mask_view_lock_state_store(C, &lock_state);
+
   ED_mask_mouse_pos(area, region, event->mval, co);
   ED_mask_get_size(area, &width, &height);
 
@@ -530,7 +539,15 @@ static void *slide_point_customdata(bContext *C, wmOperator *op, const wmEvent *
     }
     customdata->which_handle = which_handle;
 
+    {
+      WM_event_add_notifier(C, NC_MASK | NA_EDITED, mask);
+      DEG_id_tag_update(&mask->id, 0);
+
+      ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
+    }
+
     ED_mask_mouse_pos(area, region, event->mval, customdata->prev_mouse_coord);
+    ED_mask_mouse_pos(area, region, (int[2]){0, 0}, customdata->prev_zero_coord);
   }
 
   return customdata;
@@ -655,10 +672,24 @@ static int slide_point_modal(bContext *C, wmOperator *op, const wmEvent *event)
 
       ED_mask_mouse_pos(area, region, event->mval, co);
       sub_v2_v2v2(delta, co, data->prev_mouse_coord);
+      copy_v2_v2(data->prev_mouse_coord, co);
+
+      /* Compensate for possibly moved view offset since the last event.
+       * The idea is to see how mapping of a fixed and known position did change. */
+      {
+        float zero_coord[2];
+        ED_mask_mouse_pos(area, region, (int[2]){0, 0}, zero_coord);
+
+        float zero_delta[2];
+        sub_v2_v2v2(zero_delta, zero_coord, data->prev_zero_coord);
+        sub_v2_v2(delta, zero_delta);
+
+        copy_v2_v2(data->prev_zero_coord, zero_coord);
+      }
+
       if (data->is_accurate) {
         mul_v2_fl(delta, 0.2f);
       }
-      copy_v2_v2(data->prev_mouse_coord, co);
 
       if (data->action == SLIDE_ACTION_HANDLE) {
         float new_handle[2];
@@ -966,6 +997,9 @@ static SlideSplineCurvatureData *slide_spline_curvature_customdata(bContext *C,
   float u, co[2];
   BezTriple *next_bezt;
 
+  MaskViewLockState lock_state;
+  ED_mask_view_lock_state_store(C, &lock_state);
+
   ED_mask_mouse_pos(CTX_wm_area(C), CTX_wm_region(C), event->mval, co);
 
   if (!ED_mask_find_nearest_diff_point(C,
@@ -1047,6 +1081,9 @@ static SlideSplineCurvatureData *slide_spline_curvature_customdata(bContext *C,
   mask_layer->act_point = point;
   ED_mask_select_flush_all(mask);
 
+  DEG_id_tag_update(&mask->id, 0);
+  ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
+
   return slide_data;
 }
 
diff --git a/source/blender/editors/mask/mask_query.c b/source/blender/editors/mask/mask_query.c
index cfd57ca3477..8f4f14a1ba8 100644
--- a/source/blender/editors/mask/mask_query.c
+++ b/source/blender/editors/mask/mask_query.c
@@ -604,7 +604,7 @@ void ED_mask_point_pos__reverse(
   *yr = co[1];
 }
 
-bool ED_mask_selected_minmax(const bContext *C, float min[2], float max[2])
+bool ED_mask_selected_minmax(const bContext *C, float min[2], float max[2], bool include_handles)
 {
   Depsgraph *depsgraph = CTX_data_depsgraph_pointer(C);
   Mask *mask = CTX_data_edit_mask(C);
@@ -638,22 +638,29 @@ bool ED_mask_selected_minmax(const bContext *C, float min[2], float max[2])
         }
         if (bezt->f2 & SELECT) {
           minmax_v2v2_v2(min, max, deform_point->bezt.vec[1]);
+          ok = true;
         }
-        if (BKE_mask_point_handles_mode_get(point) == MASK_HANDLE_MODE_STICK) {
+
+        if (!include_handles) {
+          /* Ignore handles. */
+        }
+        else if (BKE_mask_point_handles_mode_get(point) == MASK_HANDLE_MODE_STICK) {
           BKE_mask_point_handle(deform_point, MASK_WHICH_HANDLE_STICK, handle);
           minmax_v2v2_v2(min, max, handle);
+          ok = true;
         }
         else {
           if ((bezt->f1 & SELECT) && (bezt->h1 != HD_VECT)) {
             BKE_mask_point_handle(deform_point, MASK_WHICH_HANDLE_LEFT, handle);
             minmax_v2v2_v2(min, max, handle);
+            ok = true;
           }
           if ((bezt->f3 & SELECT) && (bezt->h2 != HD_VECT)) {
             BKE_mask_point_handle(deform_point, MASK_WHICH_HANDLE_RIGHT, handle);
             minmax_v2v2_v2(min, max, handle);
+            ok = true;
           }
         }
-        ok = true;
       }
     }
   }
diff --git a/source/blender/editors/mask/mask_select.c b/source/blender/editors/mask/mask_select.c
index cdc6ece1e84..5c369afc4cd 100644
--- a/source/blender/editors/mask/mask_select.c
+++ b/source/blender/editors/mask/mask_select.c
@@ -214,12 +214,17 @@ static int select_all_exec(bContext *C, wmOperator *op)
   Mask *mask = CTX_data_edit_mask(C);
   int action = RNA_enum_get(op->ptr, "action");
 
+  MaskViewLockState lock_state;
+  ED_mask_view_lock_state_store(C, &lock_state);
+
   ED_mask_select_toggle_all(mask, action);
   ED_mask_select_flush_all(mask);
 
   DEG_id_tag_update(&mask->id, ID_RECALC_SELECT);
   WM_event_add_notifier(C, NC_MASK | ND_SELECT, mask);
 
+  ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
+
   return OPERATOR_FINISHED;
 }
 
@@ -261,6 +266,9 @@ static int select_exec(bContext *C, wmOperator *op)
   eMaskWhichHandle which_handle;
   const float threshold = 19;
 
+  MaskViewLockState lock_state;
+  ED_mask_view_lock_state_store(C, &lock_state);
+
   RNA_float_get_array(op->ptr, "location", co);
 
   point = ED_mask_point_find_nearest(
@@ -324,6 +332,8 @@ static int select_exec(bContext *C, wmOperator *op)
     DEG_id_tag_update(&mask->id, ID_RECALC_SELECT);
     WM_event_add_notifier(C, NC_MASK | ND_SELECT, mask);
 
+    ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
+
     return OPERATOR_FINISHED;
   }
 
@@ -364,12 +374,15 @@ static int select_exec(bContext *C, wmOperator *op)
     DEG_id_tag_update(&mask->id, ID_RECALC_SELECT);
     WM_event_add_notifier(C, NC_MASK | ND_SELECT, mask);
 
+    ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
+
     return OPERATOR_FINISHED;
   }
   if (deselect_all) {
     /* For clip editor tracks, leave deselect all to clip editor. */
     if (!ED_clip_can_select(C)) {
       ED_mask_deselect_all(C);
+      ED_mask_view_lock_state_restore_no_jump(C, &lock_state);
       return OPERATOR_FINISHED;
     }
   }