Support Optional Content in Image-/XObjects (issue 13931)

Currently, in the `PartialEvaluator`, we only support Optional Content in Form-/XObjects. Hence this patch adds support for Image-/XObjects as well, which looks like a simple oversight in PR 12095 since the canvas-implementation already contains the necessary code to support this.

Author: Snuffleupagus

src/core/evaluator.js

@@ -567,12 +567,21 @@ class PartialEvaluator {
 
     if (!(w && isNum(w)) || !(h && isNum(h))) {
       warn("Image dimensions are missing, or not numbers.");
-      return undefined;
+      return;
     }
     const maxImageSize = this.options.maxImageSize;
     if (maxImageSize !== -1 && w * h > maxImageSize) {
       warn("Image exceeded maximum allowed size and was removed.");
-      return undefined;
+      return;
+    }
+
+    let optionalContent = null;
+    if (dict.has("OC")) {
+      optionalContent = await this.parseMarkedContentProps(
+        dict.get("OC"),
+        resources
+      );
+      operatorList.addOp(OPS.beginMarkedContentProps, ["OC", optionalContent]);
     }
 
     const imageMask = dict.get("ImageMask", "IM") || false;
@@ -610,7 +619,11 @@ class PartialEvaluator {
           args,
         });
       }
-      return undefined;
+
+      if (optionalContent) {
+        operatorList.addOp(OPS.endMarkedContent, []);
+      }
+      return;
     }
 
     const softMask = dict.get("SMask", "SM") || false;
@@ -631,7 +644,11 @@ class PartialEvaluator {
       // any other kind.
       imgData = imageObj.createImageData(/* forceRGBA = */ true);
       operatorList.addOp(OPS.paintInlineImageXObject, [imgData]);
-      return undefined;
+
+      if (optionalContent) {
+        operatorList.addOp(OPS.endMarkedContent, []);
+      }
+      return;
     }
 
     // If there is no imageMask, create the PDFImage and a lot
@@ -699,7 +716,10 @@ class PartialEvaluator {
         }
       }
     }
-    return undefined;
+
+    if (optionalContent) {
+      operatorList.addOp(OPS.endMarkedContent, []);
+    }
   }
 
   handleSMask(

test/pdfs/.gitignore

@@ -442,6 +442,7 @@
 !issue8097_reduced.pdf
 !quadpoints.pdf
 !transparent.pdf
+!issue13931.pdf
 !xobject-image.pdf
 !issue6605.pdf
 !ccitt_EndOfBlock_false.pdf

test/pdfs/issue13931.pdf

@@ -5019,6 +5019,12 @@
        "rounds": 1,
        "type": "eq"
     },
+    {  "id": "issue13931-default",
+       "file": "pdfs/issue13931.pdf",
+       "md5": "799d5025787115d22863ae23a3042491",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "issue2829",
       "file": "pdfs/issue2829.pdf",
       "md5": "f32b28cf8792f6ccc470446bfbb38584",