C# 图片剪切与缩小的实例

  public void cuttof(stream stream)
            {
                image initimage = image.fromstream(stream, true);
                if (initimage.width <= 480 && initimage.height <= 480)
                {
                    initimage.save("d://test.jpg", imageformat.jpeg);
                }
                else
                {
                    int initwidth = initimage.width;
                    int initheight = initimage.height;
                    if (initwidth != initheight)
                    {
                        image pickedimage = null;
                        graphics pickedg = null;
                        if (initwidth > initheight)
                        {
                            pickedimage = new bitmap(initheight, initheight);
                            pickedg = graphics.fromimage(pickedimage);
                            pickedg.interpolationmode = interpolationmode.highqualitybicubic;
                            pickedg.smoothingmode = smoothingmode.highquality;
                            rectangle fromr = new rectangle(0, 0, initheight, initheight);//(initwidth - initheight) / 2
                            rectangle tor = new rectangle(0, 0, initheight, initheight);
                            pickedg.drawimage(initimage, fromr);
                            pickedimage.save("d://jpg//test2.jpg");
                            initwidth = initheight;
                        }
                        initimage = (image)pickedimage.clone();
                        pickedg.dispose();
                        pickedimage.dispose();
                        initimage.save("d://jpg//test1.jpg");

                    }
                    image resultimage = new bitmap(150, 150);
                    graphics resultg = graphics.fromimage(resultimage);
                    resultg.interpolationmode = interpolationmode.highqualitybicubic;
                    resultg.smoothingmode = smoothingmode.highquality;
                    resultg.clear(color.white);
                    resultg.drawimage(initimage, new rectangle(0, 0, 100, 100), new rectangle(0, 0, initwidth, initheight), graphicsunit.pixel);

                    imagecodecinfo[] icis = imagecodecinfo.getimageencoders();
                    imagecodecinfo ici = null;
                    foreach (imagecodecinfo item in icis)
                    {
                        if (item.mimetype == "image/jpeg" || item.mimetype == "image/bmp" || item.mimetype == "image/png" || item.mimetype =="image/gif")
                        {
                            ici = item;
                        }
                    }
                    encoderparameters ep = new system.drawing.imaging.encoderparameters(1);
                    ep.param[0] = new system.drawing.imaging.encoderparameter(system.drawing.imaging.encoder.quality, (long)100);
                    resultimage.save("d://jpg//test.jpg", ici, ep);
                    ep.dispose();
                    resultg.dispose();
                    resultimage.dispose();
                    initimage.dispose();
                }
            }