Merge pull request #136 from noppefoxwolf/dawn

Add notSkipAlphaChannel options.
onevcat · Oct 4, 2023 · 0e8bd63 · 0e8bd63
2 parents 930dd3a + 8509f45
commit 0e8bd63
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Showing 2 changed files with 16 additions and 4 deletions.
diff --git a/Source/APNGKit/APNGImageRenderer.swift b/Source/APNGKit/APNGImageRenderer.swift
@@ -24,19 +24,27 @@ class APNGImageRenderer {
     private var foundMultipleAnimationControl: Bool = false
     private var expectedSequenceNumber: Int = 0
 
-    init(decoder: APNGDecoder) throws {
+    init(decoder: APNGDecoder, shouldRenderWithAlpha: Bool = false) throws {
         self.decoder = decoder
         self.reader = try decoder.reader.clone()
 
         let imageHeader = decoder.imageHeader
+
+        let bitmapInfo: CGBitmapInfo
+        if shouldRenderWithAlpha {
+            bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedLast.rawValue)
+        } else {
+            bitmapInfo = imageHeader.bitmapInfo
+        }
+
         guard let outputBuffer = CGContext(
             data: nil,
             width: imageHeader.width,
             height: imageHeader.height,
             bitsPerComponent: imageHeader.bitDepthPerComponent,
             bytesPerRow: imageHeader.bytesPerRow,
             space: imageHeader.colorSpace,
-            bitmapInfo: imageHeader.bitmapInfo.rawValue
+            bitmapInfo: bitmapInfo.rawValue
         ) else {
             throw APNGKitError.decoderError(.canvasCreatingFailed)
         }

diff --git a/Source/APNGKit/APNGImageView.swift b/Source/APNGKit/APNGImageView.swift
@@ -25,6 +25,9 @@ open class APNGImageView: PlatformView {
     /// of `self`. Default is `true`.
     open var autoStartAnimationWhenSetImage = true
 
+    /// Enable this option to always reference the alpha channel during rendering. Default is `false`.
+    open var shouldRenderWithAlpha = false
+
     /// A delegate called every time when a "play" (a single loop of the animated image) is done. The parameter number
     /// is the count of played loops.
     ///
@@ -95,9 +98,10 @@ open class APNGImageView: PlatformView {
 
     /// Creates an APNG image view with the specified animated image.
     /// - Parameter image: The initial image to display in the image view.
-    public convenience init(image: APNGImage?, autoStartAnimating: Bool = true) {
+    public convenience init(image: APNGImage?, autoStartAnimating: Bool = true, shouldRenderWithAlpha: Bool = false) {
         self.init(frame: .zero)
         self.autoStartAnimationWhenSetImage = autoStartAnimating
+        self.shouldRenderWithAlpha = shouldRenderWithAlpha
         self.image = image
     }
 
@@ -212,7 +216,7 @@ open class APNGImageView: PlatformView {
             unsetImage()
 
             do {
-                renderer = try APNGImageRenderer(decoder: nextImage.decoder)
+                renderer = try APNGImageRenderer(decoder: nextImage.decoder, shouldRenderWithAlpha: shouldRenderWithAlpha)
             } catch {
                 printLog("Error happens while creating renderer for image. \(error)")
                 defaultDecodingErrored(