图片缩放图片剪切功能代码,CSharp代码库,德仔网

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【CSharp】图片缩放图片剪切功能
作者:zhensoft163 / 发布于2014/4/10/ 512
图片缩放图片剪切功能
using system;
using system.collections.generic;
using system.text;
using system.io;
using system.drawing;
using system.drawing.drawing2d;
using system.drawing.imaging;

namespace wujian.common
{
 /// <summary>
 /// 图片处理类
 /// </summary>
 public class ptimage
 {
 #region 正方型裁剪并缩放
 /// <summary>
 /// 正方型裁剪
 /// 以图片中心为轴心，截取正方型，然后等比缩放
 /// 用于头像处理
 /// </summary>
 /// <param name="postedfile">原图httppostedfile对象</param>
 /// <param name="filesaveurl">缩略图存放地址</param>
 /// <param name="side">指定的边长（正方型）</param>
 /// <param name="quality">质量（范围0-100）</param>
 public static void cutforsquare(system.web.httppostedfile postedfile, string filesaveurl, int side, int quality)
 {
 //创建目录
 string dir = path.getdirectoryname(filesaveurl);
 if (!directory.exists(dir))
 directory.createdirectory(dir);

 //原始图片（获取原始图片创建对象，并使用流中嵌入的颜色管理信息）
 system.drawing.image initimage = system.drawing.image.fromstream(postedfile.inputstream, true);

 //原图宽高均小于模版，不作处理，直接保存
 if (initimage.width <= side && initimage.height <= side)
 {
 initimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
 }
 else
 {
 //原始图片的宽、高
 int initwidth = initimage.width;
 int initheight = initimage.height;

 //非正方型先裁剪为正方型
 if (initwidth != initheight)
 {
 //截图对象
 system.drawing.image pickedimage = null;
 system.drawing.graphics pickedg = null;

 //宽大于高的横图
 if (initwidth > initheight)
 {
 //对象实例化
 pickedimage = new system.drawing.bitmap(initheight, initheight);
 pickedg = system.drawing.graphics.fromimage(pickedimage);
 //设置质量
 pickedg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 pickedg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 //定位
 rectangle fromr = new rectangle((initwidth - initheight) / 2, 0, initheight, initheight);
 rectangle tor = new rectangle(0, 0, initheight, initheight);
 //画图
 pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
 //重置宽
 initwidth = initheight;
 }
 //高大于宽的竖图
 else
 {
 //对象实例化
 pickedimage = new system.drawing.bitmap(initwidth, initwidth);
 pickedg = system.drawing.graphics.fromimage(pickedimage);
 //设置质量
 pickedg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 pickedg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 //定位
 rectangle fromr = new rectangle(0, (initheight - initwidth) / 2, initwidth, initwidth);
 rectangle tor = new rectangle(0, 0, initwidth, initwidth);
 //画图
 pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
 //重置高
 initheight = initwidth;
 }

 //将截图对象赋给原图
 initimage = (system.drawing.image)pickedimage.clone();
 //释放截图资源
 pickedg.dispose();
 pickedimage.dispose();
 }

 //缩略图对象
 system.drawing.image resultimage = new system.drawing.bitmap(side, side);
 system.drawing.graphics resultg = system.drawing.graphics.fromimage(resultimage);
 //设置质量
 resultg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 resultg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 //用指定背景色清空画布
 resultg.clear(color.white);
 //绘制缩略图
 resultg.drawimage(initimage, new system.drawing.rectangle(0, 0, side, side), new system.drawing.rectangle(0, 0, initwidth, initheight), system.drawing.graphicsunit.pixel);

 //关键质量控制
 //获取系统编码类型数组,包含了jpeg,bmp,png,gif,tiff
 imagecodecinfo[] icis = imagecodecinfo.getimageencoders();
 imagecodecinfo ici = null;
 foreach (imagecodecinfo i in icis)
 {
 if (i.mimetype == "image/jpeg" || i.mimetype == "image/bmp" || i.mimetype == "image/png" || i.mimetype == "image/gif")
 {
 ici = i;
 }
 }
 encoderparameters ep = new encoderparameters(1);
 ep.param[0] = new encoderparameter(system.drawing.imaging.encoder.quality, (long)quality);

 //保存缩略图
 resultimage.save(filesaveurl, ici, ep);

 //释放关键质量控制所用资源
 ep.dispose();

 //释放缩略图资源
 resultg.dispose();
 resultimage.dispose();

 //释放原始图片资源
 initimage.dispose();
 }
 }

 /// <summary>
 /// 正方型裁剪
 /// 以图片中心为轴心，截取正方型，然后等比缩放
 /// 用于头像处理
 /// </summary>
 /// <param name="postedfile">原图httppostedfile对象</param>
 /// <param name="filesaveurl">缩略图存放地址</param>
 /// <param name="side">指定的边长（正方型）</param>
 /// <param name="quality">质量（范围0-100）</param>
 public static void cutforsquare(system.io.stream fromfile, string filesaveurl, int side, int quality)
 {
 //创建目录
 string dir = path.getdirectoryname(filesaveurl);
 if (!directory.exists(dir))
 directory.createdirectory(dir);

 //原始图片（获取原始图片创建对象，并使用流中嵌入的颜色管理信息）
 system.drawing.image initimage = system.drawing.image.fromstream(fromfile, true);

 //原图宽高均小于模版，不作处理，直接保存
 if (initimage.width <= side && initimage.height <= side)
 {
 initimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
 }
 else
 {
 //原始图片的宽、高
 int initwidth = initimage.width;
 int initheight = initimage.height;

 //非正方型先裁剪为正方型
 if (initwidth != initheight)
 {
 //截图对象
 system.drawing.image pickedimage = null;
 system.drawing.graphics pickedg = null;

 //宽大于高的横图
 if (initwidth > initheight)
 {
 //对象实例化
 pickedimage = new system.drawing.bitmap(initheight, initheight);
 pickedg = system.drawing.graphics.fromimage(pickedimage);
 //设置质量
 pickedg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 pickedg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 //定位
 rectangle fromr = new rectangle((initwidth - initheight) / 2, 0, initheight, initheight);
 rectangle tor = new rectangle(0, 0, initheight, initheight);
 //画图
 pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
 //重置宽
 initwidth = initheight;
 }
 //高大于宽的竖图
 else
 {
 //对象实例化
 pickedimage = new system.drawing.bitmap(initwidth, initwidth);
 pickedg = system.drawing.graphics.fromimage(pickedimage);
 //设置质量
 pickedg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 pickedg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 //定位
 rectangle fromr = new rectangle(0, (initheight - initwidth) / 2, initwidth, initwidth);
 rectangle tor = new rectangle(0, 0, initwidth, initwidth);
 //画图
 pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
 //重置高
 initheight = initwidth;
 }

 //将截图对象赋给原图
 initimage = (system.drawing.image)pickedimage.clone();
 //释放截图资源
 pickedg.dispose();
 pickedimage.dispose();
 }

 //缩略图对象
 system.drawing.image resultimage = new system.drawing.bitmap(side, side);
 system.drawing.graphics resultg = system.drawing.graphics.fromimage(resultimage);
 //设置质量
 resultg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 resultg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 //用指定背景色清空画布
 resultg.clear(color.white);
 //绘制缩略图
 resultg.drawimage(initimage, new system.drawing.rectangle(0, 0, side, side), new system.drawing.rectangle(0, 0, initwidth, initheight), system.drawing.graphicsunit.pixel);

 //关键质量控制
 //获取系统编码类型数组,包含了jpeg,bmp,png,gif,tiff
 imagecodecinfo[] icis = imagecodecinfo.getimageencoders();
 imagecodecinfo ici = null;
 foreach (imagecodecinfo i in icis)
 {
 if (i.mimetype == "image/jpeg" || i.mimetype == "image/bmp" || i.mimetype == "image/png" || i.mimetype == "image/gif")
 {
 ici = i;
 }
 }
 encoderparameters ep = new encoderparameters(1);
 ep.param[0] = new encoderparameter(system.drawing.imaging.encoder.quality, (long)quality);

 //保存缩略图
 resultimage.save(filesaveurl, ici, ep);

 //释放关键质量控制所用资源
 ep.dispose();

 //释放缩略图资源
 resultg.dispose();
 resultimage.dispose();

 //释放原始图片资源
 initimage.dispose();
 }
 }
 #endregion

 #region 固定模版裁剪并缩放
 /// <summary>
 /// 指定长宽裁剪
 /// 按模版比例最大范围的裁剪图片并缩放至模版尺寸
 /// </summary>
 /// <param name="postedfile">原图httppostedfile对象</param>
 /// <param name="filesaveurl">保存路径</param>
 /// <param name="maxwidth">最大宽(单位:px)</param>
 /// <param name="maxheight">最大高(单位:px)</param>
 /// <param name="quality">质量（范围0-100）</param>
 public static void cutforcustom(system.web.httppostedfile postedfile, string filesaveurl, int maxwidth, int maxheight, int quality)
 {
 //从文件获取原始图片，并使用流中嵌入的颜色管理信息
 system.drawing.image initimage = system.drawing.image.fromstream(postedfile.inputstream, true);

 //原图宽高均小于模版，不作处理，直接保存
 if (initimage.width <= maxwidth && initimage.height <= maxheight)
 {
 initimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
 }
 else
 {
 //模版的宽高比例
 double templaterate = (double)maxwidth / maxheight;
 //原图片的宽高比例
 double initrate = (double)initimage.width / initimage.height;

 //原图与模版比例相等，直接缩放
 if (templaterate == initrate)
 {
 //按模版大小生成最终图片
 system.drawing.image templateimage = new system.drawing.bitmap(maxwidth, maxheight);
 system.drawing.graphics templateg = system.drawing.graphics.fromimage(templateimage);
 templateg.interpolationmode = system.drawing.drawing2d.interpolationmode.high;
 templateg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 templateg.clear(color.white);
 templateg.drawimage(initimage, new system.drawing.rectangle(0, 0, maxwidth, maxheight), new system.drawing.rectangle(0, 0, initimage.width, initimage.height), system.drawing.graphicsunit.pixel);
 templateimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
 }
 //原图与模版比例不等，裁剪后缩放
 else
 {
 //裁剪对象
 system.drawing.image pickedimage = null;
 system.drawing.graphics pickedg = null;

 //定位
 rectangle fromr = new rectangle(0, 0, 0, 0);//原图裁剪定位
 rectangle tor = new rectangle(0, 0, 0, 0);//目标定位

 //宽为标准进行裁剪
 if (templaterate > initrate)
 {
 //裁剪对象实例化
 pickedimage = new system.drawing.bitmap(initimage.width, (int)math.floor(initimage.width / templaterate));
 pickedg = system.drawing.graphics.fromimage(pickedimage);

 //裁剪源定位
 fromr.x = 0;
 fromr.y = (int)math.floor((initimage.height - initimage.width / templaterate) / 2);
 fromr.width = initimage.width;
 fromr.height = (int)math.floor(initimage.width / templaterate);

 //裁剪目标定位
 tor.x = 0;
 tor.y = 0;
 tor.width = initimage.width;
 tor.height = (int)math.floor(initimage.width / templaterate);
 }
 //高为标准进行裁剪
 else
 {
 pickedimage = new system.drawing.bitmap((int)math.floor(initimage.height * templaterate), initimage.height);
 pickedg = system.drawing.graphics.fromimage(pickedimage);

 fromr.x = (int)math.floor((initimage.width - initimage.height * templaterate) / 2);
 fromr.y = 0;
 fromr.width = (int)math.floor(initimage.height * templaterate);
 fromr.height = initimage.height;

 tor.x = 0;
 tor.y = 0;
 tor.width = (int)math.floor(initimage.height * templaterate);
 tor.height = initimage.height;
 }

 //设置质量
 pickedg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 pickedg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;

 //裁剪
 pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);

 //按模版大小生成最终图片
 system.drawing.image templateimage = new system.drawing.bitmap(maxwidth, maxheight);
 system.drawing.graphics templateg = system.drawing.graphics.fromimage(templateimage);
 templateg.interpolationmode = system.drawing.drawing2d.interpolationmode.high;
 templateg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
 templateg.clear(color.white);
 templateg.drawimage(pickedimage, new system.drawing.rectangle(0, 0, maxwidth, maxheight), new system.drawing.rectangle(0, 0, pickedimage.width, pickedimage.height), system.drawing.graphicsunit.pixel);

 //关键质量控制
 //获取系统编码类型数组,包含了jpeg,bmp,png,gif,tiff
 imagecodecinfo[] icis = imagecodecinfo.getimageencoders();
 imagecodecinfo ici = null;
 foreach (imagecodecinfo i in icis)
 {
 if (i.mimetype == "image/jpeg" || i.mimetype == "image/bmp" || i.mimetype == "image/png" || i.mimetype == "image/gif")
 {
 ici = i;
 }
 }
 encoderparameters ep = new encoderparameters(1);
 ep.param[0] = new encoderparameter(system.drawing.imaging.encoder.quality, (long)quality);

 //保存缩略图
 templateimage.save(filesaveurl, ici, ep);
 //templateimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);

 //释放资源
 templateg.dispose();
 templateimage.dispose();

 pickedg.dispose();
 pickedimage.dispose();
 }
 }

 //释放资源
 initimage.dispose();
 }
 #endregion

 #region 等比缩放
 /// <summary>
 /// 图片等比缩放
 /// </summary>
 /// <param name="postedfile">原图httppostedfile对象</param>
 /// <param name="savepath">缩略图存放地址</param>
 /// <param name="targetwidth">指定的最大宽度</param>
 /// <param name="targetheight">指定的最大高度</param>
 /// <param name="watermarktext">水印文字(为""表示不使用水印)</param>
 /// <param name="watermarkimage">水印图片路径(为""表示不使用水印)</param>
 public static void zoomauto(system.web.httppostedfile postedfile, string savepath, system.double targetwidth, system.double targetheight, string watermarktext, string watermarkimage)
 {
 //创建目录
 string dir = path.getdirectoryname(savepath);
 if (!directory.exists(dir))
 directory.createdirectory(dir);

 //原始图片（获取原始图片创建对象，并使用流中嵌入的颜色管理信息）
 system.drawing.image initimage = system.drawing.image.fromstream(postedfile.inputstream, true);

 //原图宽高均小于模版，不作处理，直接保存
 if (initimage.width <= targetwidth && initimage.height <= targetheight)
 {
 //文字水印
 if (watermarktext != "")
 {
 using (system.drawing.graphics gwater = system.drawing.graphics.fromimage(initimage))
 {
 system.drawing.font fontwater = new font("黑体", 10);
 system.drawing.brush brushwater = new solidbrush(color.white);
 gwater.drawstring(watermarktext, fontwater, brushwater, 10, 10);
 gwater.dispose();
 }
 }

 //透明图片水印
 if (watermarkimage != "")
 {
 if (file.exists(watermarkimage))
 {
 //获取水印图片
 using (system.drawing.image wrimage = system.drawing.image.fromfile(watermarkimage))
 {
 //水印绘制条件：原始图片宽高均大于或等于水印图片
 if (initimage.width >= wrimage.width && initimage.height >= wrimage.height)
 {
 graphics gwater = graphics.fromimage(initimage);

 //透明属性
 imageattributes imgattributes = new imageattributes();
 colormap colormap = new colormap();
 colormap.oldcolor = color.fromargb(255, 0, 255, 0);
 colormap.newcolor = color.fromargb(0, 0, 0, 0);
 colormap[] remaptable = { colormap };
 imgattributes.setremaptable(remaptable, coloradjusttype.bitmap);

 float[][] colormatrixelements = {
 new float[] {1.0f, 0.0f, 0.0f, 0.0f, 0.0f},
 new float[] {0.0f, 1.0f, 0.0f, 0.0f, 0.0f},
 new float[] {0.0f, 0.0f, 1.0f, 0.0f, 0.0f},
 new float[] {0.0f, 0.0f, 0.0f, 0.5f, 0.0f},//透明度:0.5
 new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}
 };

 colormatrix wmcolormatrix = new colormatrix(colormatrixelements);
 imgattributes.setcolormatrix(wmcolormatrix, colormatrixflag.default, coloradjusttype.bitmap);
 gwater.drawimage(wrimage, new rectangle(initimage.width - wrimage.width, initimage.height - wrimage.height, wrimage.width, wrimage.height), 0, 0, wrimage.width, wrimage.height, graphicsunit.pixel, imgattributes);

 gwater.dispose();
 }
 wrimage.dispose();
 }
 }
 }

 //保存
 initimage.save(savepath, system.drawing.imaging.imageformat.jpeg);
 }
 else
 {
 //缩略图宽、高计算
 double newwidth = initimage.width;
 double newheight = initimage.height;

 //宽大于高或宽等于高（横图或正方）
 if (initimage.width > initimage.height || initimage.width == initimage.height)
 {
 //如果宽大于模版
 if (initimage.width > targetwidth)
 {
 //宽按模版，高按比例缩放
 newwidth = targetwidth;
 newheight = initimage.height * (targetwidth / initimage.width);
 }
 }
 //高大于宽（竖图）
 else
 {
 //如果高大于模版
 if (initimage.height > targetheight)
 {
 //高按模版，宽按比例缩放
 newheight = targetheight;
 newwidth = initimage.width * (targetheight / initimage.height);
 }
 }

 //生成新图
 //新建一个bmp图片
 system.drawing.image newimage = new system.drawing.bitmap((int)newwidth, (int)newheight);
 //新建一个画板
 system.drawing.graphics newg = system.drawing.graphics.fromimage(newimage);

 //设置质量
 newg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
 newg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;

 //置背景色
 newg.clear(color.white);
 //画图
 newg.drawimage(initimage, new system.drawing.rectangle(0, 0, newimage.width, newimage.height), new system.drawing.rectangle(0, 0, initimage.width, initimage.height), system.drawing.graphicsunit.pixel);

 //文字水印
 if (watermarktext != "")
 {
 using (system.drawing.graphics gwater = system.drawing.graphics.fromimage(newimage))
 {
 system.drawing.font fontwater = new font("宋体", 10);
 system.drawing.brush brushwater = new solidbrush(color.white);
 gwater.drawstring(watermarktext, fontwater, brushwater, 10, 10);
 gwater.dispose();
 }
 }

 //透明图片水印
 if (watermarkimage != "")
 {
 if (file.exists(watermarkimage))
 {
 //获取水印图片
 using (system.drawing.image wrimage = system.drawing.image.fromfile(watermarkimage))
 {
 //水印绘制条件：原始图片宽高均大于或等于水印图片
 if (newimage.width >= wrimage.width && newimage.height >= wrimage.height)
 {
 graphics gwater = graphics.fromimage(newimage);

 //透明属性
 imageattributes imgattributes = new imageattributes();
 colormap colormap = new colormap();
 colormap.oldcolor = color.fromargb(255, 0, 255, 0);
 colormap.newcolor = color.fromargb(0, 0, 0, 0);
 colormap[] remaptable = { colormap };
 imgattributes.setremaptable(remaptable, coloradjusttype.bitmap);

 float[][] colormatrixelements = {
 new float[] {1.0f, 0.0f, 0.0f, 0.0f, 0.0f},
 new float[] {0.0f, 1.0f, 0.0f, 0.0f, 0.0f},
 new float[] {0.0f, 0.0f, 1.0f, 0.0f, 0.0f},
 new float[] {0.0f, 0.0f, 0.0f, 0.5f, 0.0f},//透明度:0.5
 new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}
 };

 colormatrix wmcolormatrix = new colormatrix(colormatrixelements);
 imgattributes.setcolormatrix(wmcolormatrix, colormatrixflag.default, coloradjusttype.bitmap);
 gwater.drawimage(wrimage, new rectangle(newimage.width - wrimage.width, newimage.height - wrimage.height, wrimage.width, wrimage.height), 0, 0, wrimage.width, wrimage.height, graphicsunit.pixel, imgattributes);
 gwater.dispose();
 }
 wrimage.dispose();
 }
 }
 }

 //保存缩略图
 newimage.save(savepath, system.drawing.imaging.imageformat.jpeg);

 //释放资源
 newg.dispose();
 newimage.dispose();
 initimage.dispose();
 }
 }

 #endregion

 #region 其它
 /// <summary>
 /// 判断文件类型是否为web格式图片
 /// (注：jpg,gif,bmp,png)
 /// </summary>
 /// <param name="contenttype">httppostedfile.contenttype</param>
 /// <returns></returns>
 public static bool iswebimage(string contenttype)
 {
 if (contenttype == "image/pjpeg" || contenttype == "image/jpeg" || contenttype == "image/gif" || contenttype == "image/bmp" || contenttype == "image/png")
 {
 return true;
 }
 else
 {
 return false;
 }
 }

 #endregion
 }//end class
}
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