Fix T38670: Mask transform without a movieclip crashes

Disable transform and mask display when there's no active clip.

It's not a matter of returning fallback dimensions if there's no
slip, it's also matter of making it so stabilization and distortion
routines are aware of clip == NULL which is really crappy.

Also almost all the operators are disabled in clip editor without
active clip already anyway.

Also tweaked header UI a bit to not display mask stuff when there's
no active clip,

release/scripts/startup/bl_ui/space_clip.py

@@ -124,17 +124,18 @@ class CLIP_HT_header(Header):
 
         layout.prop(sc, "mode", text="")
 
-        row = layout.row()
-        row.template_ID(sc, "mask", new="mask.new")
+        if clip:
+            row = layout.row()
+            row.template_ID(sc, "mask", new="mask.new")
 
-        layout.prop(sc, "pivot_point", text="", icon_only=True)
+            layout.prop(sc, "pivot_point", text="", icon_only=True)
 
-        row = layout.row(align=True)
-        row.prop(toolsettings, "use_proportional_edit_mask",
-                 text="", icon_only=True)
-        if toolsettings.use_proportional_edit_mask:
-            row.prop(toolsettings, "proportional_edit_falloff",
-                     text="", icon_only=True)
+            row = layout.row(align=True)
+            row.prop(toolsettings, "use_proportional_edit_mask",
+	             text="", icon_only=True)
+            if toolsettings.use_proportional_edit_mask:
+                row.prop(toolsettings, "proportional_edit_falloff",
+                         text="", icon_only=True)
 
     def draw(self, context):
         layout = self.layout

source/blender/editors/space_clip/space_clip.c

@@ -1186,7 +1186,7 @@ static void clip_main_area_draw(const bContext *C, ARegion *ar)
 
 	if (sc->mode == SC_MODE_MASKEDIT) {
 		Mask *mask = CTX_data_edit_mask(C);
-		if (mask) {
+		if (mask && clip) {
 			ScrArea *sa = CTX_wm_area(C);
 			int mask_width, mask_height;
 			ED_mask_get_size(sa, &mask_width, &mask_height);

source/blender/editors/transform/transform.c

@@ -414,26 +414,34 @@ void projectIntViewEx(TransInfo *t, const float vec[3], int adr[2], const eV3DPr
 		SpaceClip *sc = t->sa->spacedata.first;
 
 		if (t->options & CTX_MASK) {
-			/* not working quite right, TODO (see above too) */
-			float aspx, aspy;
-			float v[2];
+			MovieClip *clip = ED_space_clip_get_clip(sc);
 
-			ED_space_clip_get_aspect(sc, &aspx, &aspy);
+			if (clip) {
+				/* not working quite right, TODO (see above too) */
+				float aspx, aspy;
+				float v[2];
 
-			copy_v2_v2(v, vec);
+				ED_space_clip_get_aspect(sc, &aspx, &aspy);
 
-			v[0] = v[0] / aspx;
-			v[1] = v[1] / aspy;
+				copy_v2_v2(v, vec);
 
-			BKE_mask_coord_to_movieclip(sc->clip, &sc->user, v, v);
+				v[0] = v[0] / aspx;
+				v[1] = v[1] / aspy;
 
-			v[0] = v[0] / aspx;
-			v[1] = v[1] / aspy;
+				BKE_mask_coord_to_movieclip(sc->clip, &sc->user, v, v);
 
-			ED_clip_point_stable_pos__reverse(sc, t->ar, v, v);
+				v[0] = v[0] / aspx;
+				v[1] = v[1] / aspy;
 
-			adr[0] = v[0];
-			adr[1] = v[1];
+				ED_clip_point_stable_pos__reverse(sc, t->ar, v, v);
+
+				adr[0] = v[0];
+				adr[1] = v[1];
+			}
+			else {
+				adr[0] = 0;
+				adr[1] = 0;
+			}
 		}
 		else if (t->options & CTX_MOVIECLIP) {
 			float v[2], aspx, aspy;

source/blender/editors/transform/transform_conversions.c

@@ -6763,6 +6763,14 @@ static void createTransMaskingData(bContext *C, TransInfo *t)
 	if (!mask)
 		return;
 
+	if (t->spacetype == SPACE_CLIP) {
+		SpaceClip *sc = t->sa->spacedata.first;
+		MovieClip *clip = ED_space_clip_get_clip(sc);
+		if (!clip) {
+			return;
+		}
+	}
+
 	/* count */
 	for (masklay = mask->masklayers.first; masklay; masklay = masklay->next) {
 		MaskSpline *spline;