截取图片的某个部分(C#源代码) css截取图片一部分

方法一(get/setpixel)

核心语句：

resultBitmap.SetPixel(x,y, sourceBitmap.GetPixel(offsetX + x, offsetY+y))

1. ///<summary>
2. ///getacertainrectanglepartofaknowngraphic
3. ///</summary>
4. ///<paramname="bitmapPathAndName">pathandnameofthesourcegraphic</param>
5. ///<paramname="width">widthofthepartgraphic</param>
6. ///<paramname="height">heightofthepartgraphic</param>
7. ///<paramname="offsetX">thewidthoffsetinthesourcegraphic</param>
8. ///<paramname="offsetY">theheightoffsetinthesourcegraphic</param>
9. ///<returns>wantedgraphic</returns>
10. publicBitmapGetPartOfImage(stringbitmapPathAndName,intwidth,intheight,intoffsetX,intoffsetY)
11. {
12. BitmapsourceBitmap=newBitmap(bitmapPathAndName);
13. BitmapresultBitmap=newBitmap(width,height);
14. for(intx=0;x<width;x++)
15. {
16. for(inty=0;y<height;y++)
17. {
18. if(offsetX+x<sourceBitmap.Size.Width&offsetY+y<sourceBitmap.Size.Height)
19. {
20. resultBitmap.SetPixel(x,y,sourceBitmap.GetPixel(offsetX+x,offsetY+y));
21. }
22. }
23. }
24. returnresultBitmap;
25. }

        /// <summary>        /// get a certain rectangle part of a known graphic        /// </summary>        /// <param name="bitmapPathAndName">path and name of the source graphic</param>        /// <param name="width">width of the part graphic</param>        /// <param name="height">height of the part graphic</param>        /// <param name="offsetX">the width offset in the source graphic</param>        /// <param name="offsetY">the height offset in the source graphic</param>        /// <returns>wanted graphic</returns>        public Bitmap GetPartOfImage(string bitmapPathAndName, int width, int height,int offsetX,int offsetY)        {            Bitmap sourceBitmap = new Bitmap(bitmapPathAndName);            Bitmap resultBitmap = new Bitmap(width, height);            for (int x = 0; x < width; x++)            {                for (int y = 0; y < height; y++)                {                    if (offsetX + x < sourceBitmap.Size.Width & offsetY + y < sourceBitmap.Size.Height)                     {                        resultBitmap.SetPixel(x, y, sourceBitmap.GetPixel(offsetX + x, offsetY+y));                    }                }            }            return resultBitmap;        } 

该方法速度较慢

方法二(graphics.drawimage)

核心代码：

Graphics g =Graphics.FromImage(resultBitmap)

g.DrawImage(sourceBitmap,resultRectangle, sourceRectangle, GraphicsUnit.Pixel)

1. ///<summary>
2. ///getacertainrectanglepartofaknowngraphic
3. ///</summary>
4. ///<paramname="bitmapPathAndName">pathandnameofthesourcegraphic</param>
5. ///<paramname="width">widthofthepartgraphic</param>
6. ///<paramname="height">heightofthepartgraphic</param>
7. ///<paramname="offsetX">thewidthoffsetinthesourcegraphic</param>
8. ///<paramname="offsetY">theheightoffsetinthesourcegraphic</param>
9. ///<returns>wantedgraphic</returns>
10. publicBitmapGetPartOfImage(stringbitmapPathAndName,intwidth,intheight,intoffsetX,intoffsetY)
11. {
12. BitmapsourceBitmap=newBitmap(bitmapPathAndName);
13. BitmapresultBitmap=newBitmap(width,height);
14. using(Graphicsg=Graphics.FromImage(resultBitmap))
15. {
16. RectangleresultRectangle=newRectangle(0,0,Width,height);
17. RectanglesourceRectangle=newRectangle(0+offsetX,0+offsetY,Width,height);
18. g.DrawImage(sourceBitmap,resultRectangle,sourceRectangle,GraphicsUnit.Pixel);
19. }
20. returnresultBitmap;
21. }

        /// <summary>        /// get a certain rectangle part of a known graphic        /// </summary>        /// <param name="bitmapPathAndName">path and name of the source graphic</param>        /// <param name="width">width of the part graphic</param>        /// <param name="height">height of the part graphic</param>        /// <param name="offsetX">the width offset in the source graphic</param>        /// <param name="offsetY">the height offset in the source graphic</param>        /// <returns>wanted graphic</returns>        public Bitmap GetPartOfImage(string bitmapPathAndName, int width, int height, int offsetX, int offsetY)        {            Bitmap sourceBitmap = new Bitmap(bitmapPathAndName);            Bitmap resultBitmap = new Bitmap(width, height);            using (Graphics g = Graphics.FromImage(resultBitmap))            {                Rectangle resultRectangle = new Rectangle(0, 0, Width, height);                Rectangle sourceRectangle = new Rectangle(0+offsetX, 0+offsetY, Width, height);                g.DrawImage(sourceBitmap, resultRectangle, sourceRectangle, GraphicsUnit.Pixel);            }            return resultBitmap;        }

速度较快，可完全鄙视掉方法一

using(Graphicsg=this.CreateGraphics())
{

g.CopyFromScreen(0,0,100,100,newSize(100,100));
}

原帖地址:http://wostyh.javaeye.com/blog/471765

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