Image quality is not good

Problem:

I found this function here a few days ago but I couldn't find it again. It resizes images but the output quality is not good. It looks like the color depth is 8 bit.

First photo is the original, 2nd is Photoshopped and the last one is resized by the code:

Samples:

Function:

Image ResizeImage(Image original, int targetWidth)
{
    double percent = (double)original.Width / targetWidth;
    int destWidth = (int)(original.Width / percent);
    int destHeight = (int)(original.Height / percent);

    Bitmap b = new Bitmap(destWidth, destHeight);
    Graphics g = Graphics.FromImage((Image)b);
    try
    {

        g.InterpolationMode = InterpolationMode.HighQualityBicubic;
        g.SmoothingMode = SmoothingMode.HighQuality;
        g.PixelOffsetMode = PixelOffsetMode.HighQuality;
        g.CompositingQuality = CompositingQuality.HighQuality;

        g.DrawImage(original, 0, 0, destWidth, destHeight);
    }
    finally
    {
        g.Dispose();
    }

    return (Image)b;
}

---

Looks like the image being transformed to indexed-color pixel format at some stage. Check this article and try to set up PixelFormat and Resolution properties explicitly.

链接地址: http://www.djcxy.com/p/8874.html

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