UI: show gizmo while transforming

When interacting with translate/rotate/scale gizmo, show the gizmo while
it's in use. There are some exceptions to this, as showing all scale
gizmos while scaling causes the gizmos to become large & distracting so
in this case only the gizmo being dragged is shown.

Resolves T63743.

1 files changed, 13 insertions, 0 deletions

diff --git a/source/blender/editors/transform/transform.h b/source/blender/editors/transform/transform.h
index a3df6a44682..d1c2676169d 100644
--- a/source/blender/editors/transform/transform.h
+++ b/source/blender/editors/transform/transform.h
@@ -533,6 +533,13 @@ typedef struct TransInfo {
   /* Event handler function that determines whether the viewport needs to be redrawn. */
   eRedrawFlag (*handleEvent)(struct TransInfo *, const struct wmEvent *);
 
+  /**
+   * Optional callback to transform a single matrix.
+   *
+   * \note used by the gizmo to transform the matrix used to position it.
+   */
+  void (*transform_matrix)(struct TransInfo *t, float mat_xform[4][4]);
+
   /** Constraint Data. */
   TransCon con;
 
@@ -713,6 +720,12 @@ void removeAspectRatio(TransInfo *t, float vec[2]);
  */
 struct wmKeyMap *transform_modal_keymap(struct wmKeyConfig *keyconf);
 
+/**
+ * Transform a single matrix using the current `t->final_values`.
+ */
+bool transform_apply_matrix(TransInfo *t, float mat[4][4]);
+void transform_final_value_get(const TransInfo *t, float *value, int value_num);
+
 /** \} */
 
 /* -------------------------------------------------------------------- */