refactor: use WriteableBitmap instead of Bitmap for .tif images

love-linger · love-linger · commit 13c40da9b6e0 · 2025-11-21T11:07:32.000+08:00
Signed-off-by: leo &lt;longshuang@msn.cn&gt;
diff --git a/src/ViewModels/ImageSource.cs b/src/ViewModels/ImageSource.cs
@@ -169,17 +169,18 @@ private static ImageSource DecodeWithTiff(Stream stream, long size)
 if (tiff == null)
 return new ImageSource(null, 0);
 
+ // Currently only supports image when its `BITSPERSAMPLE` is one in [1,2,4,8,16]
 var width = tiff.GetField(TiffTag.IMAGEWIDTH)[0].ToInt();
 var height = tiff.GetField(TiffTag.IMAGELENGTH)[0].ToInt();
 var pixels = new int[width * height];
-
- // Currently only supports image when its `BITSPERSAMPLE` is one in [1,2,4,8,16]
 tiff.ReadRGBAImageOriented(width, height, pixels, Orientation.TOPLEFT);
 
- var ptr = Marshal.UnsafeAddrOfPinnedArrayElement(pixels, 0);
 var pixelSize = new PixelSize(width, height);
 var dpi = new Vector(96, 96);
- var bitmap = new Bitmap(PixelFormats.Rgba8888, AlphaFormat.Unpremul, ptr, pixelSize, dpi, width * 4);
+ var bitmap = new WriteableBitmap(pixelSize, dpi, PixelFormats.Rgba8888, AlphaFormat.Unpremul);
+
+ using var frameBuffer = bitmap.Lock();
+ Marshal.Copy(pixels, 0, frameBuffer.Address, pixels.Length);
 return new ImageSource(bitmap, size);
 }
 }

-Original file line number
+Diff line change
 if(tiff==null)
 returnnewImageSource(null,0);
 +// Currently only supports image when its `BITSPERSAMPLE` is one in [1,2,4,8,16]
 varwidth=tiff.GetField(TiffTag.IMAGEWIDTH)[0].ToInt();
 varheight=tiff.GetField(TiffTag.IMAGELENGTH)[0].ToInt();
 varpixels=newint[width*height];
+-
 -// Currently only supports image when its `BITSPERSAMPLE` is one in [1,2,4,8,16]
 tiff.ReadRGBAImageOriented(width,height,pixels,Orientation.TOPLEFT);
 -varptr=Marshal.UnsafeAddrOfPinnedArrayElement(pixels,0);
 varpixelSize=newPixelSize(width,height);
 vardpi=newVector(96,96);
 -varbitmap=newBitmap(PixelFormats.Rgba8888,AlphaFormat.Unpremul,ptr,pixelSize,dpi,width*4);
 +varbitmap=newWriteableBitmap(pixelSize,dpi,PixelFormats.Rgba8888,AlphaFormat.Unpremul);
++
 +usingvarframeBuffer=bitmap.Lock();
 +Marshal.Copy(pixels,0,frameBuffer.Address,pixels.Length);
 returnnewImageSource(bitmap,size);
+}
+}