Fix T83460: Regression in snap for measure tool

Now the gizmo is drawn only when the eventstate located in
`wm->winactive->eventstate` has not changed.

So it doesn't matter if it's "selected" or not.

This commit also removes the use of the private header "wm.h"

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D9539

3 files changed, 72 insertions, 49 deletions

diff --git a/source/blender/editors/gizmo_library/gizmo_types/snap3d_gizmo.c b/source/blender/editors/gizmo_library/gizmo_types/snap3d_gizmo.c
index f7caf8e4c6a..8755dea51e1 100644
--- a/source/blender/editors/gizmo_library/gizmo_types/snap3d_gizmo.c
+++ b/source/blender/editors/gizmo_library/gizmo_types/snap3d_gizmo.c
@@ -50,7 +50,6 @@
 
 #include "WM_api.h"
 #include "WM_types.h"
-#include "wm.h"
 
 /* own includes */
 #include "../gizmo_geometry.h"
@@ -66,7 +65,13 @@ typedef struct SnapGizmo3D {
 
   /* We could have other snap contexts, for now only support 3D view. */
   SnapObjectContext *snap_context_v3d;
-  int mval[2];
+
+  /* Copy of the parameters of the last event state in order to detect updates. */
+  struct {
+    int x;
+    int y;
+    short shift, ctrl, alt, oskey;
+  } last_eventstate;
 
 #ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
   wmKeyMap *keymap;
@@ -77,6 +82,37 @@ typedef struct SnapGizmo3D {
   short snap_elem;
 } SnapGizmo3D;
 
+/* Checks if the current event is different from the one captured in the last update. */
+static bool eventstate_has_changed(SnapGizmo3D *snap_gizmo, const wmWindowManager *wm)
+{
+  if (wm && wm->winactive) {
+    const wmEvent *event = wm->winactive->eventstate;
+    if ((event->x != snap_gizmo->last_eventstate.x) ||
+        (event->y != snap_gizmo->last_eventstate.y) ||
+        (event->ctrl != snap_gizmo->last_eventstate.ctrl) ||
+        (event->shift != snap_gizmo->last_eventstate.shift) ||
+        (event->alt != snap_gizmo->last_eventstate.alt) ||
+        (event->oskey != snap_gizmo->last_eventstate.oskey)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+/* Copies the current eventstate. */
+static void eventstate_save(SnapGizmo3D *snap_gizmo, const wmWindowManager *wm)
+{
+  if (wm && wm->winactive) {
+    const wmEvent *event = wm->winactive->eventstate;
+    snap_gizmo->last_eventstate.x = event->x;
+    snap_gizmo->last_eventstate.y = event->y;
+    snap_gizmo->last_eventstate.ctrl = event->ctrl;
+    snap_gizmo->last_eventstate.shift = event->shift;
+    snap_gizmo->last_eventstate.alt = event->alt;
+    snap_gizmo->last_eventstate.oskey = event->oskey;
+  }
+}
+
 #ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
 static bool invert_snap(SnapGizmo3D *snap_gizmo, const wmWindowManager *wm)
 {
@@ -84,6 +120,15 @@ static bool invert_snap(SnapGizmo3D *snap_gizmo, const wmWindowManager *wm)
     return false;
   }
 
+  const wmEvent *event = wm->winactive->eventstate;
+  if ((event->ctrl == snap_gizmo->last_eventstate.ctrl) &&
+      (event->shift == snap_gizmo->last_eventstate.shift) &&
+      (event->alt == snap_gizmo->last_eventstate.alt) &&
+      (event->oskey == snap_gizmo->last_eventstate.oskey)) {
+    /* Nothing has changed. */
+    return snap_gizmo->invert_snap;
+  }
+
   if (snap_gizmo->keymap == NULL) {
     /* Lazy initialization. */
     snap_gizmo->keymap = WM_modalkeymap_find(wm->defaultconf, "Generic Gizmo Tweak Modal Map");
@@ -92,7 +137,6 @@ static bool invert_snap(SnapGizmo3D *snap_gizmo, const wmWindowManager *wm)
   const int snap_on = snap_gizmo->snap_on;
 
   wmKeyMap *keymap = WM_keymap_active(wm, snap_gizmo->keymap);
-  const wmEvent *event = wm->winactive->eventstate;
   for (wmKeyMapItem *kmi = keymap->items.first; kmi; kmi = kmi->next) {
     if (kmi->flag & KMI_INACTIVE) {
       continue;
@@ -250,12 +294,6 @@ short ED_gizmotypes_snap_3d_update(wmGizmo *gz,
                                    float r_nor[3])
 {
   SnapGizmo3D *snap_gizmo = (SnapGizmo3D *)gz;
-  Scene *scene = DEG_get_input_scene(depsgraph);
-  float co[3], no[3];
-  short snap_elem = 0;
-  int snap_elem_index[3] = {-1, -1, -1};
-  int index = -1;
-
   if (snap_gizmo->use_snap_override != -1) {
     if (snap_gizmo->use_snap_override == false) {
       snap_gizmo->snap_elem = 0;
@@ -265,7 +303,12 @@ short ED_gizmotypes_snap_3d_update(wmGizmo *gz,
 
 #ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
   snap_gizmo->invert_snap = invert_snap(snap_gizmo, wm);
+#endif
 
+  eventstate_save(snap_gizmo, wm);
+  Scene *scene = DEG_get_input_scene(depsgraph);
+
+#ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
   if (snap_gizmo->use_snap_override == -1) {
     const ToolSettings *ts = scene->toolsettings;
     if (snap_gizmo->invert_snap != !(ts->snap_flag & SCE_SNAP)) {
@@ -273,10 +316,13 @@ short ED_gizmotypes_snap_3d_update(wmGizmo *gz,
       return 0;
     }
   }
-#else
-  UNUSED_VARS(wm);
 #endif
 
+  float co[3], no[3];
+  short snap_elem = 0;
+  int snap_elem_index[3] = {-1, -1, -1};
+  int index = -1;
+
   wmGizmoProperty *gz_prop = WM_gizmo_target_property_find(gz, "snap_elements");
   int snap_elements = RNA_property_enum_get(&gz_prop->ptr, gz_prop->prop);
   if (gz_prop->prop != snap_gizmo->prop_snap_force) {
@@ -381,14 +427,17 @@ static void snap_gizmo_draw(const bContext *C, wmGizmo *gz)
     return;
   }
 
-  ARegion *region = CTX_wm_region(C);
-  RegionView3D *rv3d = region->regiondata;
+  wmWindowManager *wm = CTX_wm_manager(C);
+  if (eventstate_has_changed(snap_gizmo, wm)) {
+    /* The eventstate has changed but the snap has not been updated.
+     * This means that the current position is no longer valid. */
+    snap_gizmo->snap_elem = 0;
+    return;
+  }
 
-  /* Ideally, we shouldn't assign values here.
-   * But `test_select` is not called during navigation.
-   * And `snap_elem` is not really useful in this case. */
-  if ((rv3d->rflag & RV3D_NAVIGATING) ||
-      (!(gz->state & WM_GIZMO_STATE_HIGHLIGHT) && !wm_gizmomap_modal_get(region->gizmo_map))) {
+  RegionView3D *rv3d = CTX_wm_region_data(C);
+  if (rv3d->rflag & RV3D_NAVIGATING) {
+    /* Don't draw the gizmo while navigating. It can be distracting. */
     snap_gizmo->snap_elem = 0;
     return;
   }
@@ -418,30 +467,17 @@ static void snap_gizmo_draw(const bContext *C, wmGizmo *gz)
 static int snap_gizmo_test_select(bContext *C, wmGizmo *gz, const int mval[2])
 {
   SnapGizmo3D *snap_gizmo = (SnapGizmo3D *)gz;
-
-#ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
   wmWindowManager *wm = CTX_wm_manager(C);
-  const bool invert = invert_snap(snap_gizmo, wm);
-  if (snap_gizmo->invert_snap == invert && snap_gizmo->mval[0] == mval[0] &&
-      snap_gizmo->mval[1] == mval[1]) {
+  if (!eventstate_has_changed(snap_gizmo, wm)) {
     /* Performance, do not update. */
     return snap_gizmo->snap_elem ? 0 : -1;
   }
 
-  snap_gizmo->invert_snap = invert;
-#else
-  if (snap_gizmo->mval[0] == mval[0] && snap_gizmo->mval[1] == mval[1]) {
-    /* Performance, do not update. */
-    return snap_gizmo->snap_elem ? 0 : -1;
-  }
-#endif
-  copy_v2_v2_int(snap_gizmo->mval, mval);
-
   ARegion *region = CTX_wm_region(C);
   View3D *v3d = CTX_wm_view3d(C);
   const float mval_fl[2] = {UNPACK2(mval)};
   short snap_elem = ED_gizmotypes_snap_3d_update(
-      gz, CTX_data_ensure_evaluated_depsgraph(C), region, v3d, NULL, mval_fl, NULL, NULL);
+      gz, CTX_data_ensure_evaluated_depsgraph(C), region, v3d, wm, mval_fl, NULL, NULL);
 
   if (snap_elem) {
     ED_region_tag_redraw_editor_overlays(region);
diff --git a/source/blender/editors/space_view3d/view3d_gizmo_ruler.c b/source/blender/editors/space_view3d/view3d_gizmo_ruler.c
index fdba74ed3a6..9b0ce27b1e3 100644
--- a/source/blender/editors/space_view3d/view3d_gizmo_ruler.c
+++ b/source/blender/editors/space_view3d/view3d_gizmo_ruler.c
@@ -315,8 +315,6 @@ static bool view3d_ruler_item_mousemove(struct Depsgraph *depsgraph,
   const float eps_bias = 0.0002f;
   float dist_px = MVAL_MAX_PX_DIST * U.pixelsize; /* snap dist */
 
-  WM_gizmo_set_flag(snap_gizmo, WM_GIZMO_HIDDEN, true);
-
   if (ruler_item) {
     RulerInteraction *inter = ruler_item->gz.interaction_data;
     float *co = ruler_item->co[inter->co_index];
@@ -388,12 +386,8 @@ static bool view3d_ruler_item_mousemove(struct Depsgraph *depsgraph,
             snap_gizmo->ptr, ruler_info->snap_data.prop_prevpoint, prev_point);
       }
 
-      short snap_elem = ED_gizmotypes_snap_3d_update(
+      ED_gizmotypes_snap_3d_update(
           snap_gizmo, depsgraph, ruler_info->region, v3d, ruler_info->wm, mval_fl, co, NULL);
-
-      if (snap_elem) {
-        WM_gizmo_set_flag(snap_gizmo, WM_GIZMO_HIDDEN, false);
-      }
     }
     return true;
   }
@@ -1074,7 +1068,6 @@ static void gizmo_ruler_exit(bContext *C, wmGizmo *gz, const bool cancel)
 
   if (!cancel) {
     if (ruler_info->state == RULER_STATE_DRAG) {
-      WM_gizmo_set_flag(ruler_info->snap_data.gizmo, WM_GIZMO_HIDDEN, false);
       RNA_property_unset(ruler_info->snap_data.gizmo->ptr, ruler_info->snap_data.prop_prevpoint);
       ruler_state_set(ruler_info, RULER_STATE_NORMAL);
     }
diff --git a/source/blender/editors/space_view3d/view3d_placement.c b/source/blender/editors/space_view3d/view3d_placement.c
index 176fc641085..e7df93e0be7 100644
--- a/source/blender/editors/space_view3d/view3d_placement.c
+++ b/source/blender/editors/space_view3d/view3d_placement.c
@@ -35,6 +35,7 @@
 #include "BLI_utildefines.h"
 
 #include "BKE_context.h"
+#include "BKE_global.h"
 #include "BKE_main.h"
 
 #include "RNA_access.h"
@@ -1068,7 +1069,6 @@ static int view3d_interactive_add_modal(bContext *C, wmOperator *op, const wmEve
     const float mval_fl[2] = {UNPACK2(event->mval)};
 
     /* Calculate the snap location on mouse-move or when toggling snap. */
-    bool is_snap_found_prev = ipd->is_snap_found;
     ipd->is_snap_found = false;
     if (ipd->use_snap) {
       if (ipd->snap_gizmo != NULL) {
@@ -1077,7 +1077,7 @@ static int view3d_interactive_add_modal(bContext *C, wmOperator *op, const wmEve
                                          CTX_data_ensure_evaluated_depsgraph(C),
                                          ipd->region,
                                          ipd->v3d,
-                                         NULL,
+                                         G_MAIN->wm.first,
                                          mval_fl,
                                          ipd->snap_co,
                                          NULL)) {
@@ -1087,12 +1087,6 @@ static int view3d_interactive_add_modal(bContext *C, wmOperator *op, const wmEve
       }
     }
 
-    /* Workaround because test_select doesn't run at the same time as the modal operator. */
-    if (is_snap_found_prev != ipd->is_snap_found) {
-      wmGizmoMap *gzmap = ipd->region->gizmo_map;
-      WM_gizmo_highlight_set(gzmap, ipd->is_snap_found ? ipd->snap_gizmo : NULL);
-    }
-
     if (ipd->step_index == STEP_BASE) {
       if (ipd->is_snap_found) {
         closest_to_plane_normalized_v3(ipd->step[0].co_dst, ipd->step[0].plane, ipd->snap_co);