fix(ext/web): properly handle `Blob` case for `createImageBitmap` (#23518)

fixes https://github.com/denoland/deno/issues/22649

4 files changed, 16 insertions, 2 deletions

diff --git a/ext/canvas/01_image.js b/ext/canvas/01_image.js
index a738f7992..6fb1ee62f 100644
--- a/ext/canvas/01_image.js
+++ b/ext/canvas/01_image.js
@@ -238,7 +238,9 @@ function createImageBitmap(
           "InvalidStateError",
         );
       }
-      const { data: imageData, width, height } = op_image_decode_png(data);
+      const { data: imageData, width, height } = op_image_decode_png(
+        new Uint8Array(data),
+      );
       const processedImage = processImage(
         imageData,
         width,
diff --git a/ext/canvas/lib.rs b/ext/canvas/lib.rs
index b05332c3f..72173f133 100644
--- a/ext/canvas/lib.rs
+++ b/ext/canvas/lib.rs
@@ -130,7 +130,8 @@ fn op_image_decode_png(#[buffer] buf: &[u8]) -> Result<DecodedPng, AnyError> {
     )));
   }
 
-  let mut png_data = Vec::with_capacity(png.total_bytes() as usize);
+  // read_image will assert that the buffer is the correct size, so we need to fill it with zeros
+  let mut png_data = vec![0_u8; png.total_bytes() as usize];
 
   png.read_image(&mut png_data)?;
 
diff --git a/tests/testdata/image/1x1-white.png b/tests/testdata/image/1x1-white.png
new file mode 100644
index 000000000..dd43faec5
--- /dev/null
+++ b/tests/testdata/image/1x1-white.png
diff --git a/tests/unit/image_bitmap_test.ts b/tests/unit/image_bitmap_test.ts
index 364f2a167..006631182 100644
--- a/tests/unit/image_bitmap_test.ts
+++ b/tests/unit/image_bitmap_test.ts
@@ -90,3 +90,14 @@ Deno.test(async function imageBitmapFlipY() {
     1, 0, 0, 1,   2, 0, 0, 1,   3, 0, 0, 1,
   ]));
 });
+
+Deno.test(async function imageBitmapFromBlob() {
+  const path = "tests/testdata/image/1x1-white.png";
+  const imageData = new Blob([await Deno.readFile(path)], {
+    type: "image/png",
+  });
+  const imageBitmap = await createImageBitmap(imageData);
+  // @ts-ignore: Deno[Deno.internal].core allowed
+  // deno-fmt-ignore
+  assertEquals(Deno[Deno.internal].getBitmapData(imageBitmap), new Uint8Array([255,255,255,255]));
+});