Fix tweak/drag event use with gizmos

It was possible to use a drag event for a gizmo
that dragged away from the gizmo, changing the active gizmo.

Now use gizmo located at the location that was clicked on.

4 files changed, 34 insertions, 7 deletions

diff --git a/source/blender/windowmanager/gizmo/intern/wm_gizmo_group.c b/source/blender/windowmanager/gizmo/intern/wm_gizmo_group.c
index ded308f4b7b..03e8717012c 100644
--- a/source/blender/windowmanager/gizmo/intern/wm_gizmo_group.c
+++ b/source/blender/windowmanager/gizmo/intern/wm_gizmo_group.c
@@ -174,12 +174,12 @@ int WM_gizmo_cmp_temp_fl_reverse(const void *gz_a_ptr, const void *gz_b_ptr)
 
 wmGizmo *wm_gizmogroup_find_intersected_gizmo(const wmGizmoGroup *gzgroup,
                                               bContext *C,
-                                              const wmEvent *event,
+                                              const int mval[2],
                                               int *r_part)
 {
   for (wmGizmo *gz = gzgroup->gizmos.first; gz; gz = gz->next) {
     if (gz->type->test_select && (gz->flag & (WM_GIZMO_HIDDEN | WM_GIZMO_HIDDEN_SELECT)) == 0) {
-      if ((*r_part = gz->type->test_select(C, gz, event->mval)) != -1) {
+      if ((*r_part = gz->type->test_select(C, gz, mval)) != -1) {
         return gz;
       }
     }
diff --git a/source/blender/windowmanager/gizmo/intern/wm_gizmo_intern.h b/source/blender/windowmanager/gizmo/intern/wm_gizmo_intern.h
index 3a4f303fda8..9874b0e12af 100644
--- a/source/blender/windowmanager/gizmo/intern/wm_gizmo_intern.h
+++ b/source/blender/windowmanager/gizmo/intern/wm_gizmo_intern.h
@@ -63,7 +63,7 @@ void wm_gizmogroup_free(bContext *C, struct wmGizmoGroup *gzgroup);
 void wm_gizmogroup_gizmo_register(struct wmGizmoGroup *gzgroup, struct wmGizmo *gz);
 struct wmGizmo *wm_gizmogroup_find_intersected_gizmo(const struct wmGizmoGroup *gzgroup,
                                                      struct bContext *C,
-                                                     const struct wmEvent *event,
+                                                     const int mval[2],
                                                      int *r_part);
 void wm_gizmogroup_intersectable_gizmos_to_list(const struct wmGizmoGroup *gzgroup,
                                                 struct BLI_Buffer *visible_gizmos);
diff --git a/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c b/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c
index 9c18406b84d..56de2202731 100644
--- a/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c
+++ b/source/blender/windowmanager/gizmo/intern/wm_gizmo_map.c
@@ -683,6 +683,15 @@ wmGizmo *wm_gizmomap_highlight_find(wmGizmoMap *gzmap,
   BLI_buffer_declare_static(wmGizmo *, visible_3d_gizmos, BLI_BUFFER_NOP, 128);
   bool do_step[WM_GIZMOMAP_DRAWSTEP_MAX];
 
+  int mval[2] = {UNPACK2(event->mval)};
+
+  /* Ensure for drag events we use the location where the user clicked.
+   * Without this click-dragging on a gizmo can accidentally act on the wrong gizmo. */
+  if (ISTWEAK(event->type) || (event->val == KM_CLICK_DRAG)) {
+    mval[0] += event->x - event->prevclickx;
+    mval[1] += event->y - event->prevclicky;
+  }
+
   for (int i = 0; i < ARRAY_SIZE(do_step); i++) {
     do_step[i] = WM_gizmo_context_check_drawstep(C, i);
   }
@@ -715,7 +724,7 @@ wmGizmo *wm_gizmomap_highlight_find(wmGizmoMap *gzmap,
           wm_gizmogroup_intersectable_gizmos_to_list(gzgroup, &visible_3d_gizmos);
         }
         else if (step == WM_GIZMOMAP_DRAWSTEP_2D) {
-          if ((gz = wm_gizmogroup_find_intersected_gizmo(gzgroup, C, event, r_part))) {
+          if ((gz = wm_gizmogroup_find_intersected_gizmo(gzgroup, C, mval, r_part))) {
             break;
           }
         }
@@ -727,7 +736,7 @@ wmGizmo *wm_gizmomap_highlight_find(wmGizmoMap *gzmap,
     /* 2D gizmos get priority. */
     if (gz == NULL) {
       gz = gizmo_find_intersected_3d(
-          C, event->mval, visible_3d_gizmos.data, visible_3d_gizmos.count, r_part);
+          C, mval, visible_3d_gizmos.data, visible_3d_gizmos.count, r_part);
     }
   }
   BLI_buffer_free(&visible_3d_gizmos);
diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index 07d5f4b0d59..70044e059c8 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -2721,8 +2721,25 @@ static int wm_handlers_do_intern(bContext *C, wmEvent *event, ListBase *handlers
         wm_gizmomap_handler_context_gizmo(C, handler);
         wm_region_mouse_co(C, event);
 
+        /* Drag events use the previous click location to highlight the gizmos,
+         * Get the highlight again in case the user dragged off the gizmo. */
+        const bool is_event_drag = ISTWEAK(event->type) || (event->val == KM_CLICK_DRAG);
+
+        bool handle_highlight = false;
+        bool handle_keymap = false;
+
         /* handle gizmo highlighting */
-        if (event->type == MOUSEMOVE && !wm_gizmomap_modal_get(gzmap)) {
+        if (!wm_gizmomap_modal_get(gzmap) && ((event->type == MOUSEMOVE) || is_event_drag)) {
+          handle_highlight = true;
+          if (is_event_drag) {
+            handle_keymap = true;
+          }
+        }
+        else {
+          handle_keymap = true;
+        }
+
+        if (handle_highlight) {
           int part;
           gz = wm_gizmomap_highlight_find(gzmap, C, event, &part);
           if (wm_gizmomap_highlight_set(gzmap, C, gz, part) && gz != NULL) {
@@ -2731,7 +2748,8 @@ static int wm_handlers_do_intern(bContext *C, wmEvent *event, ListBase *handlers
             }
           }
         }
-        else {
+
+        if (handle_keymap) {
           /* Handle highlight gizmo. */
           if (gz != NULL) {
             wmGizmoGroup *gzgroup = gz->parent_gzgroup;