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POResize transparent images using C#
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  1. POResize transparent images using C#
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    copied!<p>Does anyone have the secret formula to resizing transparent images (mainly GIFs) <em>without</em> ANY quality loss - what so ever?</p> <p>I've tried a bunch of stuff, the closest I get is not good enough.</p> <p>Take a look at my main image:</p> <p><a href="http://www.thewallcompany.dk/test/main.gif" rel="noreferrer">http://www.thewallcompany.dk/test/main.gif</a></p> <p>And then the scaled image:</p> <p><a href="http://www.thewallcompany.dk/test/ScaledImage.gif" rel="noreferrer">http://www.thewallcompany.dk/test/ScaledImage.gif</a></p> <pre><code>//Internal resize for indexed colored images void IndexedRezise(int xSize, int ySize) { BitmapData sourceData; BitmapData targetData; AdjustSizes(ref xSize, ref ySize); scaledBitmap = new Bitmap(xSize, ySize, bitmap.PixelFormat); scaledBitmap.Palette = bitmap.Palette; sourceData = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly, bitmap.PixelFormat); try { targetData = scaledBitmap.LockBits(new Rectangle(0, 0, xSize, ySize), ImageLockMode.WriteOnly, scaledBitmap.PixelFormat); try { xFactor = (Double)bitmap.Width / (Double)scaledBitmap.Width; yFactor = (Double)bitmap.Height / (Double)scaledBitmap.Height; sourceStride = sourceData.Stride; sourceScan0 = sourceData.Scan0; int targetStride = targetData.Stride; System.IntPtr targetScan0 = targetData.Scan0; unsafe { byte* p = (byte*)(void*)targetScan0; int nOffset = targetStride - scaledBitmap.Width; int nWidth = scaledBitmap.Width; for (int y = 0; y &lt; scaledBitmap.Height; ++y) { for (int x = 0; x &lt; nWidth; ++x) { p[0] = GetSourceByteAt(x, y); ++p; } p += nOffset; } } } finally { scaledBitmap.UnlockBits(targetData); } } finally { bitmap.UnlockBits(sourceData); } } </code></pre> <p>I'm using the above code, to do the indexed resizing.</p> <p>Does anyone have improvement ideas?</p>
 

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