public static Bitmap Cut(this Image source, Rectangle destrect, ImageQuality quality)
{
Bitmap target = null;
try
{
target = new Bitmap(destrect.Width, destrect.Height);
using (var gh = Graphics.FromImage(target))
{
gh.CompositingQuality = quality.Compositing;
gh.SmoothingMode = quality.Smoothing;
gh.InterpolationMode = quality.Interpolation;
gh.PixelOffsetMode = quality.PixelOffset;
gh.DrawImage(source, destrect, 0, 0, destrect.Width,
destrect.Height, GraphicsUnit.Pixel);
gh.DrawImage(source, new Rectangle(0, 0, destrect.Width, destrect.Height), destrect, GraphicsUnit.Pixel);
}
}
catch (Exception ex)
{
if (target != null)
{
target.Dispose();
}
throw ex;
}
return(target);
}
/// <summary>
/// 根据指定的宽高，等比缩放图片，多余的部分会以白边补全
/// </summary>
/// <param name="source"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="quality">质量，这个参数并不太会影响图像的呈现质量，主要是可以提高速度,质量越低速度越快</param>
/// <param name="background"></param>
/// <returns></returns>
public static Bitmap Scale(this Image source, int width, int height, ImageQuality quality, Color background)
{
var rawRect = new DynamicRectangle()
{
X = 0,
Y = 0,
Width = source.Width,
Height = source.Height
};
var targetRect = rawRect.Scale(width, height, true);
Bitmap target = null;
try
{
target = new Bitmap(width, height);
using (var gh = Graphics.FromImage(target))
{
gh.CompositingQuality = quality.Compositing;
gh.SmoothingMode = quality.Smoothing;
gh.InterpolationMode = quality.Interpolation;
gh.PixelOffsetMode = quality.PixelOffset;
//gh.FillRectangle(new SolidBrush(background), 0, 0, width, height);
//清空画布并以指定的背景色填充
gh.Clear(background);
Rectangle destrect = targetRect.ToRectangle();
gh.DrawImage(source, destrect, 0, 0, source.Width,
source.Height, GraphicsUnit.Pixel);
}
}
catch (Exception ex)
{
if (target != null)
{
target.Dispose();
}
throw ex;
}
return(target);
}
