c#图片缩放图片剪切功能实现(等比缩放)

所谓c#图片处理高级应,多数是基于.net framework类库完成


复制代码 代码如下:

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

{

    ///


    /// 图片处理类

    ///


    public class ptimage

    {

        #region 正方型裁剪并缩放

        ///


        /// 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

        ///


        /// 原图httppostedfile对象

        /// 缩略图存放地址

        /// 指定的边长(正方型)

        /// 质量(范围0-100)

        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();

            }

        }

        ///


        /// 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

        ///


        /// 原图httppostedfile对象

        /// 缩略图存放地址

        /// 指定的边长(正方型)

        /// 质量(范围0-100)

        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

        ///


        /// 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

        ///


        /// 原图httppostedfile对象

        /// 保存路径

        /// 最大宽(单位:px)

        /// 最大高(单位:px)

        /// 质量(范围0-100)

        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

        ///


        /// 图片等比缩放

        ///


        /// 原图httppostedfile对象

        /// 缩略图存放地址

        /// 指定的最大宽度

        /// 指定的最大高度

        /// 水印文字(为""表示不使用水印)

        /// 水印图片路径(为""表示不使用水印)

        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

        ///


        /// 判断文件类型是否为web格式图片

        /// (注:jpg,gif,bmp,png)

        ///


        /// httppostedfile.contenttype

        ///

        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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