1 files changed, 33 insertions, 2 deletions

diff --git a/source/blender/editors/transform/transform_mode_resize.c b/source/blender/editors/transform/transform_mode_resize.c
index 65f4623b3be..28323460626 100644
--- a/source/blender/editors/transform/transform_mode_resize.c
+++ b/source/blender/editors/transform/transform_mode_resize.c
@@ -201,14 +201,45 @@ static void applyResize(TransInfo *t, const int UNUSED(mval[2]))
   ED_area_status_text(t->area, str);
 }
 
-void initResize(TransInfo *t)
+void initResize(TransInfo *t, float mouse_dir_constraint[3])
 {
   t->mode = TFM_RESIZE;
   t->transform = applyResize;
   t->tsnap.applySnap = ApplySnapResize;
   t->tsnap.distance = ResizeBetween;
 
-  initMouseInputMode(t, &t->mouse, INPUT_SPRING_FLIP);
+  if (is_zero_v3(mouse_dir_constraint)) {
+    initMouseInputMode(t, &t->mouse, INPUT_SPRING_FLIP);
+  }
+  else {
+    int mval_start[2], mval_end[2];
+    float mval_dir[3], t_mval[2];
+    float viewmat[3][3];
+
+    copy_m3_m4(viewmat, t->viewmat);
+    mul_v3_m3v3(mval_dir, viewmat, mouse_dir_constraint);
+    normalize_v2(mval_dir);
+    if (is_zero_v2(mval_dir)) {
+      /* The screen space direction is orthogonal to the view.
+       * Fall back to constraining on the Y axis. */
+      mval_dir[0] = 0;
+      mval_dir[1] = 1;
+    }
+
+    mval_start[0] = t->center2d[0];
+    mval_start[1] = t->center2d[1];
+
+    t_mval[0] = t->mval[0] - mval_start[0];
+    t_mval[1] = t->mval[1] - mval_start[1];
+    project_v2_v2v2(mval_dir, t_mval, mval_dir);
+
+    mval_end[0] = t->center2d[0] + mval_dir[0];
+    mval_end[1] = t->center2d[1] + mval_dir[1];
+
+    setCustomPoints(t, &t->mouse, mval_end, mval_start);
+
+    initMouseInputMode(t, &t->mouse, INPUT_CUSTOM_RATIO);
+  }
 
   t->flag |= T_NULL_ONE;
   t->num.val_flag[0] |= NUM_NULL_ONE;