UIImage 图片处理

//等比率缩放
- (UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize {
//设置图片的上下文
UIGraphicsBeginImageContext(CGSizeMake(image.size.width*scaleSize, image.size.height*scaleSize));
//绘制图片的大小
[image drawInRect:CGRectMake(0, 0, image.size.width*scaleSize, image.size.height*scaleSize)];
//生成新的图片
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
//结束上下文的编辑
UIGraphicsEndImageContext();
//返回图片
return scaledImage;
}

//自定长宽
- (UIImage *)reSizeImage:(UIImage *)image toSize:(CGSize)reSize {
//设置上下文
UIGraphicsBeginImageContext(CGSizeMake(reSize.width, reSize.height));
//重定义大小
[image drawInRect:CGRectMake(0, 0, reSize.width, reSize.height)];
//生成新图片
UIImage *reSizeImage = UIGraphicsGetImageFromCurrentImageContext();
//结束上下文
UIGraphicsEndImageContext();
//返回图片
return reSizeImage;
}

//处理某个特定的view
- (UIImage *)captureView:(UIView *)theView {
//取得当前view的frame
CGRect rect = theView.frame;
//开始上下文
UIGraphicsBeginImageContext(rect.size);
//
CGContextRef context = UIGraphicsGetCurrentContext();
//
[theView.layer renderInContext:context];
//将view转换为图片
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
//结束上下文
UIGraphicsEndImageContext();
//返回图片
return img;
}

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
imageView.image = [UIImage imageNamed:@"1.jpg"];
[self addSubview:imageView];

- (void)saveImage:(UIImage *)image image:(int)location{
if (location == 1) {
//存储路径，以及存储的文件名字
NSString *path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"xiaoye.png"];
//将图片写入文件
[UIImagePNGRepresentation(image) writeToFile:path atomically:YES];
//找到Documents文件目录
NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
//输出Documents目录下得文件名字
NSLog(@"存储到docments目录下的文件有:%@",[[NSFileManager defaultManager] subpathsAtPath:docPath]);
}
}

UIImage *image = [UIImage imageNamed:@"1.jpg"];

//等比率的缩放
UIImage *scaledImage = [self scaleImage:image toScale:0.5f];
NSLog(@"%@",scaledImage);

//自定长宽
UIImage *reSizeImage = [self reSizeImage:image toSize:CGSizeMake(100.0f, 50.0f)];
NSLog(@"%@",reSizeImage);

//处理特定的view，继承自uiview，需要导入QuzrtzCore.framework
MyView *view = [[MyView alloc] initWithFrame:CGRectMake(0, 0, 160, 240)];
UIImage *img = [self captureView:view];
NSLog(@"%@",img);

//存储图片到Documents目录下
[self saveImage:image image:1];

//测试图片，scaledImage，reSizeImage，img
self.view.backgroundColor = [UIColor colorWithPatternImage:img];