Fix T84850: "Lock to Selection" causes unwanted jumps

Adding new tracks, mask points, mask primitives, changing selection was
causing an unwanted jumps in the view.

This change makes it so those operations are preserving view offset.

Differential Revision: https://developer.blender.org/D10146

1 files changed, 36 insertions, 0 deletions

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);
+  }
+}
+
+/** \} */