Merge pull request #16722 from calixteman/dont_set_filter

Don't uselessly change the filter when drawing (bug 1508765)

src/display/canvas.js

@@ -790,9 +790,12 @@ function resetCtxToDefault(ctx) {
     (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
     !isNodeJS
   ) {
+    const { filter } = ctx;
+    if (filter !== "none" && filter !== "") {
       ctx.filter = "none";
     }
   }
+}
 
 function composeSMaskBackdrop(bytes, r0, g0, b0) {
   const length = bytes.length;
@@ -2961,8 +2964,11 @@ class CanvasGraphics {
       // It must be applied to the image before rescaling else some artifacts
       // could appear.
       // The final restore will reset it to its value.
+      const { filter } = ctx;
+      if (filter !== "none" && filter !== "") {
         ctx.filter = "none";
       }
+    }
 
     // scale the image to the unit square
     ctx.scale(1 / width, -1 / height);