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UIImage 裁剪图片和等比列缩放图片

时间:2015-04-21 22:04:38      阅读:192      评论:0      收藏:0      [点我收藏+]

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本文转载至 http://blog.csdn.net/cuiweijie3/article/details/9514293 

转自 http://www.tedz.me/ios/uiimage-crop-resize-image

 

@interface UIImage(UIImageScale)
-(UIImage*)getSubImage:(CGRect)rect;
-(UIImage*)scaleToSize:(CGSize)size;
@end
 
@implementation UIImage(UIImageScale)
 
//截取部分图像
-(UIImage*)getSubImage:(CGRect)rect
{
    CGImageRef subImageRef = CGImageCreateWithImageInRect(self.CGImage, rect);
    CGRect smallBounds = CGRectMake(0, 0, CGImageGetWidth(subImageRef), CGImageGetHeight(subImageRef));
 
    UIGraphicsBeginImageContext(smallBounds.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextDrawImage(context, smallBounds, subImageRef);
    UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
    UIGraphicsEndImageContext();
 
    return smallImage;
}
 
//等比例缩放
-(UIImage*)scaleToSize:(CGSize)size
{
    CGFloat width = CGImageGetWidth(self.CGImage);
    CGFloat height = CGImageGetHeight(self.CGImage);
 
    float verticalRadio = size.height*1.0/height;
    float horizontalRadio = size.width*1.0/width;
 
    float radio = 1;
    if(verticalRadio>1 && horizontalRadio>1)
    {
        radio = verticalRadio > horizontalRadio ? horizontalRadio : verticalRadio;
    }
    else
    {
        radio = verticalRadio < horizontalRadio ? verticalRadio : horizontalRadio;
    }
 
    width = width*radio;
    height = height*radio;
 
    int xPos = (size.width - width)/2;
    int yPos = (size.height-height)/2;
 
    // 创建一个bitmap的context
    // 并把它设置成为当前正在使用的context
    UIGraphicsBeginImageContext(size);  
 
    // 绘制改变大小的图片
    [self drawInRect:CGRectMake(xPos, yPos, width, height)];  
 
    // 从当前context中创建一个改变大小后的图片
    UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();  
 
    // 使当前的context出堆栈
    UIGraphicsEndImageContext();  
 
    // 返回新的改变大小后的图片
    return scaledImage;
}
@end
 
然后在下面方法里面调用就可以了!
 
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURLURLWithString:@"http://img21.mtime.cn/mg/2011/09/24/112524.53149978.jpg"]] ];
 
    // 裁剪图片
    //image = [image getSubImage:CGRectMake(10, 10, 70, 80)];
 
    //等比列缩放
 
    image = [image scaleToSize:CGSizeMake(200, 300)];
 
    UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
 
    [self.window addSubview:imageView];
 
    NSLog(@"image.size:%@",NSStringFromCGSize(CGSizeMake(imageView.image.size.width, imageView.image.size.height)));   //打印获取的网络图片的宽度和高度
 
    [self.window makeKeyAndVisible];
    return YES;
}
 
//--------------截取部分图片到指定位置-------------------------
 
图片(UIImage*) img
要截取的起始坐标sx:(int) sx1 sy:(int)sy1
要截取的长度和宽度sw:(int) sw1 sh:(int) sh1
最终要显示的坐标desx:(int) desx1 desy:(int)desy1
 
-(UIImage*)objectiveDrawRegion:(UIImage*) img sx:(int) sx1 sy:(int)sy1 sw:(int) sw1 sh:(int) sh1 desx:(int) desx1 desy:(int)desy1{
[self saveImage:img name:@"objectiveDrawRegion1.png"];
 
//创建图片缓冲
void *imageDataRegion=malloc(screenWidth*screenHeight*32);
CGColorSpaceRef iColorSpaceRegion=CGColorSpaceCreateDeviceRGB();
    CGContextRefiDeviceRegion=CGBitmapContextCreate(imageDataRegion,screenWidth,screenHeight,8,4*screenWidth,iColorSpaceRegion,kCGImageAlphaPremultipliedLast);
 
//剪切区域
    CGRect clipRegion=CGRectMake(sx1,sy1,sw1,sh1);
    CGContextClipToRect(iDeviceRegion, clipRegion);
 
    CGFloat widthf=img.size.width;
    CGFloat heightf=img.size.height;
 
CGRect  cg=CGRectMake(0.0, 0.0, widthf, heightf);
//画底图
    CGContextDrawImage(iDeviceRegion,cg, img.CGImage);
 
//将缓冲形成图片
    CGImageRef ioffRegion=CGBitmapContextCreateImage(iDeviceRegion);
 
CGRect  cg1=CGRectMake(desx1, desy1, sw1, sh1);
UIImage *ui=[UIImage imageWithCGImage:ioffRegion];
 
CGContextDrawImage(当前context,cg1, ui.CGImage);
 
//清除缓冲
   CGColorSpaceRelease(iColorSpaceRegion);
   CGContextRelease(iDeviceRegion);
   CGImageRelease(ioffRegion);
   free(imageDataRegion);
//    iDeviceRegion=NULL;
//    imageDataRegion=0;
 
return ui;
}

UIImage 裁剪图片和等比列缩放图片

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原文地址:http://www.cnblogs.com/Camier-myNiuer/p/4445400.html

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