iOS 从相册取出的图片默认 取中间部分 裁剪成方形的

iOS 获取相册之后，图片是不规则的，想要默认取中间部分裁剪成方形，可以用下面方法，这是我自己工程中用到的，所以绝对可用。废话不多少，直接上代码：

转载请注明出处：http://www.cnblogs.com/shisishao/p/6000999.html

- (void)addImageModelToPostVCModelArray:(NSArray *)array {
    if (array && array.count > 0) {
        NSMutableArray *imageModelArray = [NSMutableArray array];
        for (int i = 0; i < array.count; i++) {
            ZXCropImageModel *cropModel = [[ZXCropImageModel alloc] init];
            UIImage *image = array[i];
            NSValue *sizeValue = [NSValue valueWithCGSize:CGSizeMake(image.size.width, image.size.height)];
            cropModel.sizeValue = sizeValue;
            CGRect rect = [self getImageRect:image];
            UIImage *cropImage = [self getCropImage:image andRect:rect];
            NSValue *rectValue = [NSValue valueWithCGRect:rect];
            cropModel.rectValue = rectValue;
            cropModel.cropImage = cropImage;
            [imageModelArray addObject:cropModel];
        }
        [self getPostEditModelArray:imageModelArray];
    }
}

- (void)getPostEditModelArray:(NSArray *)imageModelArray {
    // 处理后的图片对象
}

- (CGRect)getImageRect:(UIImage *)tempImage {
    CGRect rect;
    if (tempImage.size.width > tempImage.size.height) {
        rect = CGRectMake((tempImage.size.width-tempImage.size.height)/2, 0, tempImage.size.height, tempImage.size.height);
    } else if (tempImage.size.width < tempImage.size.height) {
        rect = CGRectMake(0, (tempImage.size.height-tempImage.size.width)/2, tempImage.size.width, tempImage.size.width);
    } else {
        rect = CGRectMake(0, 0, tempImage.size.width, tempImage.size.width);
    }
    return rect;
}

- (UIImage *)getCropImage:(UIImage *)image andRect:(CGRect)rect {
    rect = CGRectMake(ceilf(rect.origin.x), ceilf(rect.origin.y), ceilf(rect.size.width), ceilf(rect.size.height));
    UIGraphicsBeginImageContext(rect.size);
    [image drawAtPoint:CGPointMake(-rect.origin.x, -rect.origin.y)];
    UIImage *cropImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return cropImage;
}

 其中的 对象 ZXCropImageModel 为：

@interface ZXCropImageModel : NSObject

@property (nonatomic, strong) UIImage *cropImage;  // 裁剪后图片
@property (nonatomic, strong) NSValue *sizeValue;    // 图片size
@property (nonatomic, strong) NSValue *rectValue;    // 裁剪之后图片的 在原图中 的 frame

@end

 处理之后，会返回原图大小，裁剪之后图片的在原图中的  frame ，裁剪图片等。