c#圖片縮放圖片剪切功能實現(xiàn)(等比縮放)
所謂c#圖片處理高級應，多數(shù)是基于.net framework類庫完成
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>
/// 圖片處理類
/// </summary>
public class ptimage
{
#region 正方型裁剪并縮放
/// <summary>
/// 正方型裁剪
/// 以圖片中心為軸心，截取正方型，然后等比縮放
/// 用于頭像處理
/// </summary>
/// <param name="postedfile">原圖httppostedfile對象</param>
/// <param name="filesaveurl">縮略圖存放地址</param>
/// <param name="side">指定的邊長（正方型）</param>
/// <param name="quality">質(zhì)量（范圍0-100）</param>
public static void cutforsquare(system.web.httppostedfile postedfile, string filesaveurl, int side, int quality)
{
//創(chuàng)建目錄
string dir = path.getdirectoryname(filesaveurl);
if (!directory.exists(dir))
directory.createdirectory(dir);
//原始圖片（獲取原始圖片創(chuàng)建對象，并使用流中嵌入的顏色管理信息）
system.drawing.image initimage = system.drawing.image.fromstream(postedfile.inputstream, true);
//原圖寬高均小于模版，不作處理，直接保存
if (initimage.width <= side && initimage.height <= side)
{
initimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
}
else
{
//原始圖片的寬、高
int initwidth = initimage.width;
int initheight = initimage.height;
//非正方型先裁剪為正方型
if (initwidth != initheight)
{
//截圖對象
system.drawing.image pickedimage = null;
system.drawing.graphics pickedg = null;
//寬大于高的橫圖
if (initwidth > initheight)
{
//對象實例化
pickedimage = new system.drawing.bitmap(initheight, initheight);
pickedg = system.drawing.graphics.fromimage(pickedimage);
//設置質(zhì)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);
//畫圖
pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
//重置寬
initwidth = initheight;
}
//高大于寬的豎圖
else
{
//對象實例化
pickedimage = new system.drawing.bitmap(initwidth, initwidth);
pickedg = system.drawing.graphics.fromimage(pickedimage);
//設置質(zhì)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);
//畫圖
pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
//重置高
initheight = initwidth;
}
//將截圖對象賦給原圖
initimage = (system.drawing.image)pickedimage.clone();
//釋放截圖資源
pickedg.dispose();
pickedimage.dispose();
}
//縮略圖對象
system.drawing.image resultimage = new system.drawing.bitmap(side, side);
system.drawing.graphics resultg = system.drawing.graphics.fromimage(resultimage);
//設置質(zhì)量
resultg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
resultg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
//用指定背景色清空畫布
resultg.clear(color.white);
//繪制縮略圖
resultg.drawimage(initimage, new system.drawing.rectangle(0, 0, side, side), new system.drawing.rectangle(0, 0, initwidth, initheight), system.drawing.graphicsunit.pixel);
//關鍵質(zhì)量控制
//獲取系統(tǒng)編碼類型數(shù)組,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);
//保存縮略圖
resultimage.save(filesaveurl, ici, ep);
//釋放關鍵質(zhì)量控制所用資源
ep.dispose();
//釋放縮略圖資源
resultg.dispose();
resultimage.dispose();
//釋放原始圖片資源
initimage.dispose();
}
}
/// <summary>
/// 正方型裁剪
/// 以圖片中心為軸心，截取正方型，然后等比縮放
/// 用于頭像處理
/// </summary>
/// <param name="postedfile">原圖httppostedfile對象</param>
/// <param name="filesaveurl">縮略圖存放地址</param>
/// <param name="side">指定的邊長（正方型）</param>
/// <param name="quality">質(zhì)量（范圍0-100）</param>
public static void cutforsquare(system.io.stream fromfile, string filesaveurl, int side, int quality)
{
//創(chuàng)建目錄
string dir = path.getdirectoryname(filesaveurl);
if (!directory.exists(dir))
directory.createdirectory(dir);
//原始圖片（獲取原始圖片創(chuàng)建對象，并使用流中嵌入的顏色管理信息）
system.drawing.image initimage = system.drawing.image.fromstream(fromfile, true);
//原圖寬高均小于模版，不作處理，直接保存
if (initimage.width <= side && initimage.height <= side)
{
initimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
}
else
{
//原始圖片的寬、高
int initwidth = initimage.width;
int initheight = initimage.height;
//非正方型先裁剪為正方型
if (initwidth != initheight)
{
//截圖對象
system.drawing.image pickedimage = null;
system.drawing.graphics pickedg = null;
//寬大于高的橫圖
if (initwidth > initheight)
{
//對象實例化
pickedimage = new system.drawing.bitmap(initheight, initheight);
pickedg = system.drawing.graphics.fromimage(pickedimage);
//設置質(zhì)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);
//畫圖
pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
//重置寬
initwidth = initheight;
}
//高大于寬的豎圖
else
{
//對象實例化
pickedimage = new system.drawing.bitmap(initwidth, initwidth);
pickedg = system.drawing.graphics.fromimage(pickedimage);
//設置質(zhì)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);
//畫圖
pickedg.drawimage(initimage, tor, fromr, system.drawing.graphicsunit.pixel);
//重置高
initheight = initwidth;
}
//將截圖對象賦給原圖
initimage = (system.drawing.image)pickedimage.clone();
//釋放截圖資源
pickedg.dispose();
pickedimage.dispose();
}
//縮略圖對象
system.drawing.image resultimage = new system.drawing.bitmap(side, side);
system.drawing.graphics resultg = system.drawing.graphics.fromimage(resultimage);
//設置質(zhì)量
resultg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
resultg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
//用指定背景色清空畫布
resultg.clear(color.white);
//繪制縮略圖
resultg.drawimage(initimage, new system.drawing.rectangle(0, 0, side, side), new system.drawing.rectangle(0, 0, initwidth, initheight), system.drawing.graphicsunit.pixel);
//關鍵質(zhì)量控制
//獲取系統(tǒng)編碼類型數(shù)組,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);
//保存縮略圖
resultimage.save(filesaveurl, ici, ep);
//釋放關鍵質(zhì)量控制所用資源
ep.dispose();
//釋放縮略圖資源
resultg.dispose();
resultimage.dispose();
//釋放原始圖片資源
initimage.dispose();
}
}
#endregion
#region 固定模版裁剪并縮放
/// <summary>
/// 指定長寬裁剪
/// 按模版比例最大范圍的裁剪圖片并縮放至模版尺寸
/// </summary>
/// <param name="postedfile">原圖httppostedfile對象</param>
/// <param name="filesaveurl">保存路徑</param>
/// <param name="maxwidth">最大寬(單位:px)</param>
/// <param name="maxheight">最大高(單位:px)</param>
/// <param name="quality">質(zhì)量（范圍0-100）</param>
public static void cutforcustom(system.web.httppostedfile postedfile, string filesaveurl, int maxwidth, int maxheight, int quality)
{
//從文件獲取原始圖片，并使用流中嵌入的顏色管理信息
system.drawing.image initimage = system.drawing.image.fromstream(postedfile.inputstream, true);
//原圖寬高均小于模版，不作處理，直接保存
if (initimage.width <= maxwidth && initimage.height <= maxheight)
{
initimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
}
else
{
//模版的寬高比例
double templaterate = (double)maxwidth / maxheight;
//原圖片的寬高比例
double initrate = (double)initimage.width / initimage.height;
//原圖與模版比例相等，直接縮放
if (templaterate == initrate)
{
//按模版大小生成最終圖片
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);
}
//原圖與模版比例不等，裁剪后縮放
else
{
//裁剪對象
system.drawing.image pickedimage = null;
system.drawing.graphics pickedg = null;
//定位
rectangle fromr = new rectangle(0, 0, 0, 0);//原圖裁剪定位
rectangle tor = new rectangle(0, 0, 0, 0);//目標定位
//寬為標準進行裁剪
if (templaterate > initrate)
{
//裁剪對象實例化
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);
//裁剪目標定位
tor.x = 0;
tor.y = 0;
tor.width = initimage.width;
tor.height = (int)math.floor(initimage.width / templaterate);
}
//高為標準進行裁剪
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;
}
//設置質(zhì)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);
//按模版大小生成最終圖片
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);
//關鍵質(zhì)量控制
//獲取系統(tǒng)編碼類型數(shù)組,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);
//保存縮略圖
templateimage.save(filesaveurl, ici, ep);
//templateimage.save(filesaveurl, system.drawing.imaging.imageformat.jpeg);
//釋放資源
templateg.dispose();
templateimage.dispose();
pickedg.dispose();
pickedimage.dispose();
}
}
//釋放資源
initimage.dispose();
}
#endregion
#region 等比縮放
/// <summary>
/// 圖片等比縮放
/// </summary>
/// <param name="postedfile">原圖httppostedfile對象</param>
/// <param name="savepath">縮略圖存放地址</param>
/// <param name="targetwidth">指定的最大寬度</param>
/// <param name="targetheight">指定的最大高度</param>
/// <param name="watermarktext">水印文字(為""表示不使用水印)</param>
/// <param name="watermarkimage">水印圖片路徑(為""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)
{
//創(chuàng)建目錄
string dir = path.getdirectoryname(savepath);
if (!directory.exists(dir))
directory.createdirectory(dir);
//原始圖片（獲取原始圖片創(chuàng)建對象，并使用流中嵌入的顏色管理信息）
system.drawing.image initimage = system.drawing.image.fromstream(postedfile.inputstream, true);
//原圖寬高均小于模版，不作處理，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("黑體", 10);
system.drawing.brush brushwater = new solidbrush(color.white);
gwater.drawstring(watermarktext, fontwater, brushwater, 10, 10);
gwater.dispose();
}
}
//透明圖片水印
if (watermarkimage != "")
{
if (file.exists(watermarkimage))
{
//獲取水印圖片
using (system.drawing.image wrimage = system.drawing.image.fromfile(watermarkimage))
{
//水印繪制條件：原始圖片寬高均大于或等于水印圖片
if (initimage.width >= wrimage.width && initimage.height >= wrimage.height)
{
graphics gwater = graphics.fromimage(initimage);
//透明屬性
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
{
//縮略圖寬、高計算
double newwidth = initimage.width;
double newheight = initimage.height;
//寬大于高或寬等于高（橫圖或正方）
if (initimage.width > initimage.height || initimage.width == initimage.height)
{
//如果寬大于模版
if (initimage.width > targetwidth)
{
//寬按模版，高按比例縮放
newwidth = targetwidth;
newheight = initimage.height * (targetwidth / initimage.width);
}
}
//高大于寬（豎圖）
else
{
//如果高大于模版
if (initimage.height > targetheight)
{
//高按模版，寬按比例縮放
newheight = targetheight;
newwidth = initimage.width * (targetheight / initimage.height);
}
}
//生成新圖
//新建一個bmp圖片
system.drawing.image newimage = new system.drawing.bitmap((int)newwidth, (int)newheight);
//新建一個畫板
system.drawing.graphics newg = system.drawing.graphics.fromimage(newimage);
//設置質(zhì)量
newg.interpolationmode = system.drawing.drawing2d.interpolationmode.highqualitybicubic;
newg.smoothingmode = system.drawing.drawing2d.smoothingmode.highquality;
//置背景色
newg.clear(color.white);
//畫圖
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("宋體", 10);
system.drawing.brush brushwater = new solidbrush(color.white);
gwater.drawstring(watermarktext, fontwater, brushwater, 10, 10);
gwater.dispose();
}
}
//透明圖片水印
if (watermarkimage != "")
{
if (file.exists(watermarkimage))
{
//獲取水印圖片
using (system.drawing.image wrimage = system.drawing.image.fromfile(watermarkimage))
{
//水印繪制條件：原始圖片寬高均大于或等于水印圖片
if (newimage.width >= wrimage.width && newimage.height >= wrimage.height)
{
graphics gwater = graphics.fromimage(newimage);
//透明屬性
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();
}
}
}
//保存縮略圖
newimage.save(savepath, system.drawing.imaging.imageformat.jpeg);
//釋放資源
newg.dispose();
newimage.dispose();
initimage.dispose();
}
}
#endregion
#region 其它
/// <summary>
/// 判斷文件類型是否為web格式圖片
/// (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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