bug: fix process crash in getImageData for PDF/SVG canvases

Fixes #1853

CHANGELOG.md

@@ -12,6 +12,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Fixed
 * Stringify CanvasGradient, CanvasPattern and ImageData like browsers do. (#1639, #1646)
 * Add missing include for `toupper`.
+* Throw an error instead of crashing the process if `getImageData` or `putImageData` is called on a PDF or SVG canvas (#1853)
 
 2.9.0
 ==================

src/CanvasRenderingContext2d.cc

@@ -937,8 +937,8 @@ NAN_METHOD(Context2d::PutImageData) {
   }
 #endif
   default: {
-    Nan::ThrowError("Invalid pixel format");
-    break;
+    Nan::ThrowError("Invalid pixel format or not an image canvas");
+    return;
   }
   }
 
@@ -1111,8 +1111,8 @@ NAN_METHOD(Context2d::GetImageData) {
 #endif
   default: {
     // Unlikely
-    Nan::ThrowError("Invalid pixel format");
-    break;
+    Nan::ThrowError("Invalid pixel format or not an image canvas");
+    return;
   }
   }
 

test/canvas.test.js

@@ -1189,6 +1189,14 @@ describe('Canvas', function () {
       const ctx = createTestCanvas()
       assert.throws(function () { ctx.getImageData(0, 0, 0, 0) }, /IndexSizeError/)
     })
+
+    it('throws if canvas is a PDF canvas (#1853)', function () {
+      const canvas = createCanvas(3, 6, 'pdf')
+      const ctx = canvas.getContext('2d')
+      assert.throws(() => {
+        ctx.getImageData(0, 0, 3, 6)
+      })
+    })
   })
 
   it('Context2d#createPattern(Canvas)', function () {
@@ -1402,6 +1410,18 @@ describe('Canvas', function () {
       assert.throws(function () { ctx.putImageData(undefined, 0, 0) }, TypeError)
     })
 
+    it('throws if canvas is a PDF canvas (#1853)', function () {
+      const canvas = createCanvas(3, 6, 'pdf')
+      const ctx = canvas.getContext('2d')
+      const srcImageData = createImageData(new Uint8ClampedArray([
+        1, 2, 3, 255, 5, 6, 7, 255,
+        0, 1, 2, 255, 4, 5, 6, 255
+      ]), 2)
+      assert.throws(() => {
+        ctx.putImageData(srcImageData, -1, -1)
+      })
+    })
+
     it('works for negative source values', function () {
       const canvas = createCanvas(2, 2)
       const ctx = canvas.getContext('2d')