关于UIImage图片处理详细使用

 一、使用文件创建(静态方法)

    UIImage *myImage= [UIImage imageNamed:@"ppp"];

二、使用 URL 和原始数据(静态方法)

    NSData *imageData= [ NSData initWithBytes:imagePtr length:imageSize]; 假设 imagePtr 是一个指向原始数据的指针

    UIImage*myImage = [ [ UIImage alloc ]initWithData:imageData ];

    UIImage *myImage2=[UIImageimageWithData:[NSDatadataWithContentsOfURL:[NSURLURLWithString:@"http://www.kutx.cn/xiaotupian/icons/png/200803/20080327095245737.png"]]];

三、使用CoreGraphics (静态方法)

    UIImage*myImage3 = [UIImage imageWithCGImage:myCGImageRef];

四、使用文件(实例方法)

   UIImage*myImage4 = [[UIImage alloc]initWithContentsOfFile:[NSString stringWithFormat:@"%@/Documents/ppp.png",NSHomeDirectory()]];

只要一个视图对象的窗口的某些部分需要绘制，就可以调用它的drawRect方法。要在窗口内部显示一个 UIImage 的内容，可以调用该对象的 drawRect 方法：

- (void)drawRect:(CGRect)rect{

    CGRect myRect;

   myRect.origin.x = 0.0 ;

   myRect.origin.y = 0.0;

    myRect.size= myImage.size;

    [myImagedrawInRect:myRect];

}

设置图像的方向，UIImage 有个只读属性imageOrientation 来标识它的方向。

    UIImageOrientation myOrientation= myImage.imageOrientation;

//    typedefenum {  

//       UIImageOrientationUp,           // defaultorientation  默认方向  

//       UIImageOrientationDown,         // 180 degrotation    旋转180度  

//       UIImageOrientationLeft,         // 90 degCCW         逆时针旋转90度  

//       UIImageOrientationRight,        // 90 degCW          顺时针旋转90度  

//       UIImageOrientationUpMirrored,   // as above but image mirrored along other axis. horizontalflip   向上水平翻转  

//       UIImageOrientationDownMirrored,  // horizontalflip    向下水平翻转  

//       UIImageOrientationLeftMirrored,  // verticalflip      逆时针旋转90度，垂直翻转  

//       UIImageOrientationRightMirrored, // verticalflip      顺时针旋转90度，垂直翻转  

//    }UIImageOrientation;  

   

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根据给定得图片，从其指定区域截取一张新得图片 

-(UIImage*)getImageFromImage{ 

   //大图bigImage 

   //定义myImageRect，截图的区域 

    CGRectmyImageRect = CGRectMake(10.0, 10.0, 57.0,57.0); 

    UIImage*bigImage= [UIImageimageNamed:@"k00030.jpg"]; 

   CGImageRef imageRef =bigImage.CGImage; 

   CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef,myImageRect); 

    CGSizesize; 

   size.width = 57.0; 

   size.height = 57.0; 

   UIGraphicsBeginImageContext(size); 

   CGContextRef context =UIGraphicsGetCurrentContext(); 

   CGContextDrawImage(context, myImageRect,subImageRef); 

    UIImage*smallImage = [UIImageimageWithCGImage:subImageRef]; 

   UIGraphicsEndImageContext(); 

    returnsmallImage; 

}

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等比率缩放

-(UIImage *)scaleImage:(UIImage *)imagetoScale:(float)scaleSize

{

   UIGraphicsBeginImageContext(CGSizeMake(image.size.width *scaleSize, image.size.height * scaleSize);

   [image drawInRect:CGRectMake(0, 0, image.size.width *scaleSize, image.size.height *scaleSize)];

    UIImage *scaledImage= UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return scaledImage;

}

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自定长宽

-(UIImage *)reSizeImage:(UIImage *)imagetoSize:(CGSize)reSize

{

    UIGraphicsBeginImageContext(CGSizeMake(reSize.width,reSize.height));

   [image drawInRect:CGRectMake(0, 0, reSize.width, reSize.height)];

    UIImage *reSizeImage= UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return reSizeImage;

}

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读取网络图片

NSString *urlStr= [result valueForKey:@"profile_image_url"];

        NSURL *url= [NSURLURLWithString:[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

        NSData *imgData= [NSDatadataWithContentsOfURL:url];

      UIImage *img= [UIImageimageWithData:imgData];

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储存图片 

    //1) 储存到app的文件里

    UIImage *image;

    NSString *path= [[NSHomeDirectory()stringByAppendingPathComponent:@"Documents"]stringByAppendingPathComponent:@"image.png"];

   [UIImagePNGRepresentation(image) writeToFile:path  atomically:YES];

    //這樣就把你要處理的圖片, 以image.png這個檔名存到apphome底下的Documents目錄裡

    //2)储存到手机的图片库里

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读取本地图片

NSString *path= [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]stringByAppendingPathComponent:@"headimg.png"];

        NSData *data= [NSDatadataWithContentsOfFile:path];

        UIImage *img= [UIImageimageWithData:data];