Merge pull request #21094 from calixteman/issue17784

Correctly sync the transform on the scratch canvas

Author: calixteman

src/display/canvas.js

@@ -147,8 +147,13 @@ function mirrorContextOperations(ctx, destCtx) {
   };
 
   ctx.setTransform = function (a, b, c, d, e, f) {
-    destCtx.setTransform(a, b, c, d, e, f);
-    this.__originalSetTransform(a, b, c, d, e, f);
+    if (b === undefined) {
+      destCtx.setTransform(a);
+      this.__originalSetTransform(a);
+    } else {
+      destCtx.setTransform(a, b, c, d, e, f);
+      this.__originalSetTransform(a, b, c, d, e, f);
+    }
   };
 
   ctx.resetTransform = function () {
@@ -1467,6 +1472,13 @@ class CanvasGraphics {
       // Graphics state is stored on the main(suspended) canvas. Restore its
       // state then copy it over to the temporary canvas.
       copyCtxState(this.suspendedCtx, this.ctx);
+      // The scratch canvas may have been freshly created by beginSMaskMode
+      // (called from checkSMaskState during a previous endGroup), in which
+      // case its save/restore stack is empty and ctx.restore() above was a
+      // no-op. Explicitly sync the CTM from the main canvas so that any CTM
+      // change that the mirrored restore applied to the main canvas is also
+      // reflected on the scratch canvas.
+      this.ctx.setTransform(this.suspendedCtx.getTransform());
     }
     this.checkSMaskState(opIdx);
 
@@ -2805,6 +2817,13 @@ class CanvasGraphics {
       this.restore(opIdx);
       if (this.dependencyTracker) {
         this.ctx.restore();
+        // beginSMaskMode() may have been called inside restore(opIdx) above
+        // (via checkSMaskState), creating a fresh scratch canvas. If so,
+        // the mirrored ctx.restore() just synced main's CTM but left the
+        // scratch at the stale CTM set by beginSMaskMode(). Re-sync it.
+        if (this.inSMaskMode) {
+          this.ctx.setTransform(this.suspendedCtx.getTransform());
+        }
       }
     } else {
       this.ctx.restore();

test/pdfs/issue17784.pdf.link

@@ -0,0 +1 @@
+https://web.archive.org/web/20240320131329/https://lp.entro.security/hubfs/Gated%20Assets/Onboarding-offboarding-checklist.pdf

test/test_manifest.json

@@ -14126,5 +14126,15 @@
     "md5": "5a690e2303604441308f808b5fc33e22",
     "rounds": 1,
     "type": "eq"
+  },
+  {
+    "id": "issue17784",
+    "file": "pdfs/issue17784.pdf",
+    "md5": "e92178bb5ca8d6cd6f79868470adbe1d",
+    "link": true,
+    "rounds": 1,
+    "firstPage": 3,
+    "lastPage": 3,
+    "type": "eq"
   }
 ]