How to Resize Images in C# for High Quality?

C#high -quality image zoom method

It is not easy to adjust the image size when running in C#. Although has ,

and

properties, the setting of these attributes does not adjust the image size. System.Drawing.Image Size To adjust the size of the image, you need to use the new size to create a new Width object and draw the original image to the object. You can use the following code to implement: Height

However, this method will lead to a decline in image quality. To achieve high -quality zoom, the Bitmap class is needed. How to operate the example below:

Bitmap objBitmap = new Bitmap(objImage, new Size(227, 171));

This function provides high -quality zoom in the following ways: Graphics

/// <summary>
/// 将图像调整为指定宽度和高度。
/// </summary>
/// <param name="image">要调整大小的图像。</param>
/// <param name="width">要调整到的宽度。</param>
/// <param name="height">要调整到的高度。</param>
/// <returns>调整大小后的图像。</returns>
public static Bitmap ResizeImage(Image image, int width, int height)
{
    var destRect = new Rectangle(0, 0, width, height);
    var destImage = new Bitmap(width, height);

    destImage.SetResolution(image.HorizontalResolution, image.VerticalResolution);

    using (var graphics = Graphics.FromImage(destImage))
    {
        graphics.CompositingMode = CompositingMode.SourceCopy;
        graphics.CompositingQuality = CompositingQuality.HighQuality;
        graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
        graphics.SmoothingMode = SmoothingMode.HighQuality;
        graphics.PixelOffsetMode = PixelOffsetMode.HighQuality;

        using (var wrapMode = new ImageAttributes())
        {
            wrapMode.SetWrapMode(WrapMode.TileFlipXY);
            graphics.DrawImage(image, destRect, 0, 0, image.Width, image.Height, GraphicsUnit.Pixel, wrapMode);
        }
    }

    return destImage;
}

Set to

to prevent heavy shadows around the image boundary.

Set the target image
• to keep DPI. WrapMode TileFlipXY Use high -quality
,
• , Resolution and
Settings.
• Compositing Interpolation Other considerations include the longitudinal ratio of the image (reserved for readers as exercises), and the trap where the image zoom in the image when saving the image. Smoothing

The above is the detailed content of How to Resize Images in C# for High Quality?. For more information, please follow other related articles on the PHP Chinese website!