.net 作图 GDI

.NET对GDI的支持是强大的，在此不讨论。只是对System.Drawing.Image及其相关的几个类做一个简单的描述，通过简单方法实现几个常用功能，抛砖引玉。

一、多个图片合并为一个图片

Bitmap bmp1 = new Bitmap(@"1.bmp");
Bitmap bmp2 = new Bitmap(@"2.bmp");
Bitmap bmp3 = new Bitmap(64,32);
Graphics g = Graphics.FromImage(bmp3);
g.draw(bmp1,0,0);
g.draw(bmp2,32,0);
g.save();
bmp3.save(@"3.bmp")

二、生成缩略图

System.Drawing.Image newImage = image.GetThumbnailImage(bmp.Width,mp.Height, null, new IntPtr());

三、图片格式转化

Dim img As System.Drawing.Image = System.Drawing.Image.FromFile(orgionImgFileFullName)
img.Save(targetImgFileFullName, System.Drawing.Imaging.ImageFormat.Jpeg)

其中这里可以通过ImageFormat枚举指定各种格式。

四、获取图片的尺寸

System.Drawing.Image img= System.Drawing.Image.FromStream(origionImgStream);
int Width = img.Width;
int Height = img.Height;

五、给图片加文字水印

System.Drawing.Image img = System.Drawing.Image.FromFile(orgImgPath);
Graphics g = Graphics.FromImage(image);
g.DrawImage(image, 0, 0, image.Width, image.Height);
g.DrawString("喝口水就走的图片水印文字", new Font("Verdana", 32), new SolidBrush(Color.White), 10, 10);
g.Dispose();

http://blog.xdnice.com/user1/3877/archives/2007/66229.shtml