iOS-图片限制

//先限制图片大小，一般用了节省流量iOS和安卓端统一宽度640或者720; 图片大小超过1M，就要循环压缩图片的质量，直到小于1M才去上传。

+ (NSData* )compressionImage:(UIImage* )image WithMaxWidth:(CGFloat )maxWidth limitSize:(NSInteger )limitSize{
    
    if (maxWidth < 0) {
        maxWidth = 1024;
    }
    
    //限制图片大小
    CGSize newSize = CGSizeMake(image.size.width, image.size.height);
    CGFloat scaleH = newSize.height / maxWidth;
    CGFloat scaleW = newSize.width / maxWidth;
    if (scaleW > 1.0 && scaleW > scaleH) {
        newSize = CGSizeMake(ceil(image.size.width / scaleW), ceil(image.size.height / scaleW));
    }else if(scaleH > 1.0 && scaleW < scaleH){
        newSize = CGSizeMake(ceil(image.size.width / scaleH), ceil(image.size.height / scaleH));
    }
    UIGraphicsBeginImageContext(newSize);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    //压缩图片质量
    CGFloat compression = .9f;
    CGFloat minCompression = .1f;
    NSData* imageData = UIImageJPEGRepresentation(newImage, compression);
    while (imageData.length / 1000 >limitSize && compression > minCompression) {
        imageData = nil;
        compression -= .1;
        imageData = UIImageJPEGRepresentation(newImage, compression);
    }
    
    return imageData;
}

+ (UIImage* )getCircleImage:(UIImage* )image withBorderColor:(UIColor* )borderColor withBorderWidth:(CGFloat )borderWidth{
    
    // borderWidth 表示边框的宽度
    CGFloat imageW = image.size.width + 2 * borderWidth;
    CGFloat imageH = imageW;
    CGSize imageSize = CGSizeMake(imageW, imageH);
    UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    // borderColor表示边框的颜色
    [borderColor set];
    CGFloat bigRadius = imageW * 0.5;
    CGFloat centerX = bigRadius;
    CGFloat centerY = bigRadius;
    CGContextAddArc(context, centerX, centerY, bigRadius, 0, M_PI * 2, 0);
    CGContextFillPath(context);
    CGFloat smallRadius = bigRadius - borderWidth;
    CGContextAddArc(context, centerX, centerY, smallRadius, 0, M_PI * 2, 0);
    CGContextClip(context);
    [image drawInRect:CGRectMake(borderWidth, borderWidth, image.size.width, image.size.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}