调整图像大小而不会丢失任何质量

Question

我需要调整图像大小,但图像质量不会受此影响.

Answer 1

正如rcar所说,你不能没有失去一些品质,你可以用c#做的最好的事情是:

Bitmap newImage = new Bitmap(newWidth, newHeight);
using (Graphics gr = Graphics.FromImage(newImage))
{
    gr.SmoothingMode = SmoothingMode.HighQuality;
    gr.InterpolationMode = InterpolationMode.HighQualityBicubic;
    gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
    gr.DrawImage(srcImage, new Rectangle(0, 0, newWidth, newHeight));
}

Answer 2

除非您正在进行矢量图形处理,否则无法在不丢失图像质量的情况下调整图像大小.

Answer 3

private static Image resizeImage(Image imgToResize, Size size)
{
    int sourceWidth = imgToResize.Width;
    int sourceHeight = imgToResize.Height;

    float nPercent = 0;
    float nPercentW = 0;
    float nPercentH = 0;

    nPercentW = ((float)size.Width / (float)sourceWidth);
    nPercentH = ((float)size.Height / (float)sourceHeight);

    if (nPercentH < nPercentW)
        nPercent = nPercentH;
    else
        nPercent = nPercentW;

    int destWidth = (int)(sourceWidth * nPercent);
    int destHeight = (int)(sourceHeight * nPercent);

    Bitmap b = new Bitmap(destWidth, destHeight);
    Graphics g = Graphics.FromImage((Image)b);
    g.InterpolationMode = InterpolationMode.HighQualityBicubic;

    g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
    g.Dispose();

    return (Image)b;
}

从这里开始

Answer 4

我相信你要做的是"调整/重新采样"你的图像.这是一个很好的网站,提供说明并提供实用程序类(我也碰巧使用):

http://www.codeproject.com/KB/GDI-plus/imgresizoutperfgdiplus.aspx