image_ops takes responsibility of treat alpha channel

denoland · Sep 29, 2024 · fc4064e · fc4064e
1 parent 8d8d726
commit fc4064e
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Showing 2 changed files with 21 additions and 41 deletions.
diff --git a/ext/canvas/image_ops.rs b/ext/canvas/image_ops.rs
@@ -89,13 +89,8 @@ where
 /// Premultiply the alpha channel of the image.
 pub(crate) fn premultiply_alpha(
   image: DynamicImage,
-  unmatch_color_handler: fn(
-    ColorType,
-    DynamicImage,
-  ) -> Result<DynamicImage, AnyError>,
 ) -> Result<DynamicImage, AnyError> {
-  let color = image.color();
-  match color {
+  match image.color() {
     ColorType::La8 => Ok(DynamicImage::ImageLumaA8(process_premultiply_alpha(
       image.as_luma_alpha8().unwrap(),
     ))),
@@ -108,7 +103,8 @@ pub(crate) fn premultiply_alpha(
     ColorType::Rgba16 => Ok(DynamicImage::ImageRgba16(
       process_premultiply_alpha(image.as_rgba16().unwrap()),
     )),
-    x => unmatch_color_handler(x, image),
+    // If the image does not have an alpha channel, return the image as is.
+    _ => Ok(image),
   }
 }
 
@@ -218,10 +214,6 @@ where
 /// Invert the premultiplied alpha channel of the image.
 pub(crate) fn unpremultiply_alpha(
   image: DynamicImage,
-  unmatch_color_handler: fn(
-    ColorType,
-    DynamicImage,
-  ) -> Result<DynamicImage, AnyError>,
 ) -> Result<DynamicImage, AnyError> {
   match image.color() {
     ColorType::La8 => Ok(DynamicImage::ImageLumaA8(
@@ -252,7 +244,8 @@ pub(crate) fn unpremultiply_alpha(
         image.into_rgba16()
       },
     )),
-    x => unmatch_color_handler(x, image),
+    // If the image does not have an alpha channel, return the image as is.
+    _ => Ok(image),
   }
 }
 

diff --git a/ext/canvas/op_create_image_bitmap.rs b/ext/canvas/op_create_image_bitmap.rs
@@ -260,37 +260,24 @@ fn apply_premultiply_alpha(
   image_bitmap_source: &ImageBitmapSource,
   premultiply_alpha: &PremultiplyAlpha,
 ) -> Result<DynamicImage, AnyError> {
-  let color = image.color();
-  if !color.has_alpha() {
-    Ok(image)
-  } else {
-    fn unmatch_color_handler(
-      _: ColorType,
-      image: DynamicImage,
-    ) -> Result<DynamicImage, AnyError> {
-      Ok(image)
-    }
-    match premultiply_alpha {
-      // 1.
-      PremultiplyAlpha::Default => Ok(image),
-
-      // https://html.spec.whatwg.org/multipage/canvas.html#convert-from-premultiplied
-
-      // 2.
-      PremultiplyAlpha::Premultiply => {
-        process_premultiply_alpha(image, unmatch_color_handler)
+  match premultiply_alpha {
+    // 1.
+    PremultiplyAlpha::Default => Ok(image),
+
+    // https://html.spec.whatwg.org/multipage/canvas.html#convert-from-premultiplied
+
+    // 2.
+    PremultiplyAlpha::Premultiply => process_premultiply_alpha(image),
+    // 3.
+    PremultiplyAlpha::None => {
+      // NOTE: It's not clear how to handle the case of ImageData.
+      // https://issues.chromium.org/issues/339759426
+      // https://github.com/whatwg/html/issues/5365
+      if *image_bitmap_source == ImageBitmapSource::ImageData {
+        return Ok(image);
       }
-      // 3.
-      PremultiplyAlpha::None => {
-        // NOTE: It's not clear how to handle the case of ImageData.
-        // https://issues.chromium.org/issues/339759426
-        // https://github.com/whatwg/html/issues/5365
-        if *image_bitmap_source == ImageBitmapSource::ImageData {
-          return Ok(image);
-        }
 
-        unpremultiply_alpha(image, unmatch_color_handler)
-      }
+      unpremultiply_alpha(image)
     }
   }
 }