学步园

1.UIImageView圆角

CALayer *l = [cell.imgAvatarImage layer];   
[l setMasksToBounds:YES];
[l setCornerRadius:6.0];

2.UIImageView显示圆形

    UIImageView *imageView1 = [[UIImageViewalloc] initWithImage:[UIImageimageNamed:@"image.png"]];

    imageView1.frame = CGRectMake(60,100, 100, 100);

    imageView1.layer.masksToBounds =YES;

    imageView1.layer.cornerRadius =50;

    [self.view addSubview:imageView1];

3.UIImageView变灰效果

+ (UIImage*)getGrayImage:(UIImage*)sourceImage
{
    int width = sourceImage.size.width;
    int height = sourceImage.size.height;
    
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
    CGContextRef context = CGBitmapContextCreate (nil,width,height,8,0,colorSpace,kCGImageAlphaNone);
    CGColorSpaceRelease(colorSpace);
    
    if (context == NULL) {
        return nil;
    }
    
    CGContextDrawImage(context,CGRectMake(0, 0, width, height), sourceImage.CGImage);
    CGImageRef grayImageRef = CGBitmapContextCreateImage(context);
    UIImage *grayImage = [UIImage imageWithCGImage:grayImageRef];
    CGContextRelease(context);
    CGImageRelease(grayImageRef);
    
    return grayImage;
}

4 UIImage设置显示大小

- (UIImage *)scaleToSize:(UIImage *)img size:(CGSize)size{
     UIGraphicsBeginImageContext(size);
         [img drawInRect:CGRectMake(0, 0, size.width, size.height)];
        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;
}