From 04b71f8402776fa726225fe46d3fd690586d6bea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Fri, 11 Sep 2020 12:13:30 +0200
Subject: [PATCH] canvas: Properly restore all the remaining items in
 stateStack in endDrawing.

We were correctly finishing the SMask group but not restoring all the extra
transformations applied in stateStack, so if somebody ends up drawing to the
same context after canceling mid-draw we'd get artifacts.

This fixes Mozilla bug 1664178[1].

[1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1664178
---
 src/display/canvas.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/display/canvas.js b/src/display/canvas.js
index abf958e968ba22..b98d0598caa64f 100644
--- a/src/display/canvas.js
+++ b/src/display/canvas.js
@@ -1009,8 +1009,8 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
 
     endDrawing: function CanvasGraphics_endDrawing() {
       // Finishing all opened operations such as SMask group painting.
-      if (this.current.activeSMask !== null) {
-        this.endSMaskGroup();
+      while (this.stateStack.length || this.current.activeSMask !== null) {
+        this.restore();
       }
 
       this.ctx.restore();