C# 生成缩略图方法
发表时间：2021-3-19
发布人：葵宇科技
浏览次数：46
拿记事本写的，没有调试，大概就是这么个原理，参考参考得了~
可以按宽度，高度缩放及指定高宽裁剪
private void MakeThumbnail(string sourcePath, string newPath, int width, int height)
{
System.Drawing.Image ig = System.Drawing.Image.FromFile(sourcePath);
int towidth = width;
int toheight = height;
int x = 0;
int y = 0;
int ow = ig.Width;
int oh = ig.Height;
if (height == 0)
{
toheight = oh * width / ow;
}
else if (width == 0)
{
towidth = ow * height / oh;
}
else
{
if ((double)ig.Width / (double)ig.Height > (double)towidth / (double)toheight)
{
oh = ig.Height;
ow = ig.Height * towidth / toheight;
y = 0;
x = (ig.Width - ow) / 2;
}
else
{
ow = ig.Width;
oh = ig.Width * height / towidth;
x = 0;
y = (ig.Height - oh) / 2;
}
}
System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.Clear(System.Drawing.Color.Transparent);
g.DrawImage(ig, new System.Drawing.Rectangle(0, 0, towidth, toheight), new System.Drawing.Rectangle(x, y, ow, oh), System.Drawing.GraphicsUnit.Pixel);
try
{
bitmap.Save(newPath, System.Drawing.Imaging.ImageFormat.Jpeg);
}
catch (Exception ex)
{
throw ex;
}
finally
{
ig.Dispose();
bitmap.Dispose();
g.Dispose();
}
}
