Question

我想制作一个UITableView，在每个单元格中，我都可以看到联系人资料图片中的图像。

我制作了一个UIView制作自定义绘图，在draw rect中，它在iPhone 5c中运行FINE 但是当我滚动表格视图时它会杀死iPhone 4和iPhone4s

这就是我所做的：

// _image is iVar

// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
    CGContextRef context = UIGraphicsGetCurrentContext();
    UIColor *patternRed = [UIColor colorWithPatternImage:[self imageWithImage:_image scaledToSize:CGSizeMake(self.frame.size.width,self.frame.size.height)]];//recale image to self bounds 
    CGContextSetLineWidth(context, 0.0);
    CGContextSetFillColorWithColor(context, patternRed.CGColor);
    CGContextAddEllipseInRect(context, rect);
    CGContextDrawPath(context, kCGPathFill); // Or kCGPathFill //kCGPathFillStroke
}

- (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize
{
    //UIGraphicsBeginImageContext(newSize);
    // In next line, pass 0.0 to use the current device's pixel scaling factor (and thus account for Retina resolution).
    // Pass 1.0 to force exact pixel size.
    UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

我在这个图形上下文中并不擅长也许我做错了什么：（

有没有办法加快这个过程？

Answer 1

首先将其导入您的班级#import <QuartzCore/QuartzCore.h> 然后将以下方法添加到您的类

    -(UIImageView * )createRoundedImageview:(UIImageView*)imageView
    {
        //  this works in the case of width and height of image view are same
        imageView.layer.cornerRadius = imageView.frame.size.width/2.0; //or imageView.frame.size.height/2.0
        imageView.layer.masksToBounds = YES;
        return imageView;
    }

然后调用你想要的圆形图像，如...

UIImageView * yourImageView = [[UIImageView alloc]initWithframe:CGRectMake(100,150,200,200)];
yourImageView.image = [UIImage ImageNamed:@"yourimageName"];
yourImageView = [self createRoundedImageview: yourImageView];
[self.view addSubView: yourImageView];

Answer 2

button.clipsToBounds = YES;
button.layer.cornerRadius = 2.0f
button.layer.borderColor=[UIColor <colorname>].CGColor;
button.layer.borderWidth=2.0f; //

以上代码适合您

Answer 3

你不需要像这样自己画画;您可以使用标准UIImageView并设置其cornerRadius以使其具有圆形效果（将其设置为edgeLength / 2将创建一个完美的圆圈。）

Answer 4

您可以使用以下代码创建圆角边框。

newImage.layer.cornerRadius = newImage.frame.size.width / 2.0;
newImage.clipsToBounds = YES;
newImage.layer.borderWidth = 2.0f;

使用imageview的cornerRadius属性的代码，它将半径等于图像的宽度2.0。下一个语句允许您剪辑图像。第三步是可选的。

带有圆形边框的UIImage，如联系人

4 个答案: