Circular UIImageView in UITableView without perfor

问题:

I have a UIImageView on each of my UITableView cells, that display a remote image (using SDWebImage). I've done some QuartzCore layer styling to the image view, as such:

UIImageView *itemImageView = (UIImageView *)[cell viewWithTag:100];
    itemImageView.layer.borderWidth = 1.0f;
    itemImageView.layer.borderColor = [UIColor concreteColor].CGColor;
    itemImageView.layer.masksToBounds = NO;
    itemImageView.clipsToBounds = YES;

So now I have a 50x50 square with a faint grey border, but I'd like to make it circular instead of squared. The app Hemoglobe uses circular images in table views, and that's the effect I'd like to achieve. However, I don't want to use cornerRadius, as that degrades my scrolling FPS.

Here's Hemoglobe showing circular UIImageViews:

Is there any way to get this effect? Thanks.

回答1:

Simply set the cornerRadius to half of the width or height (assuming your object's view is square).

For example, if your object's view's width and height are both 50:

itemImageView.layer.cornerRadius = 25;

Update - As user atulkhatri points out, it won't work if you don't add:

itemImageView.layer.masksToBounds = YES;

回答2:

To Add border

self.ImageView.layer.borderWidth = 3.0f;

self.ImageView.layer.borderColor = [UIColor whiteColor].CGColor;

For Circular Shape

self.ImageView.layer.cornerRadius = self.ImageView.frame.size.width / 2;
self.ImageView.clipsToBounds = YES;

Refer this link

http://www.appcoda.com/ios-programming-circular-image-calayer/

回答3:

Use this code.. This will be helpful..

    UIImage* image = ...;
    UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, NO, 1.0);
    // Add a clip before drawing anything, in the shape of an rounded rect
    [[UIBezierPath bezierPathWithRoundedRect:imageView.bounds
                                cornerRadius:50.0] addClip];
    // Draw your image
    [image drawInRect:imageView.bounds];

    // Get the image, here setting the UIImageView image
    imageView.image = UIGraphicsGetImageFromCurrentImageContext();

    // Lets forget about that we were drawing
    UIGraphicsEndImageContext();

It works fine for me. :)

回答4:

Here is a more up to date method in swift using IBDesignable and IBInspectable to subclass UIImageView

@IBDesignable class RoundableUIImageView: UIImageView {
    private var _round = false
    @IBInspectable var round: Bool {
        set {
            _round = newValue
            makeRound()
        }
        get {
            return self._round
        }
    }
    override internal var frame: CGRect {
        set {
            super.frame = newValue
            makeRound()
        }
        get {
            return super.frame
        }

    }

    private func makeRound() {
        if self.round == true {
            self.clipsToBounds = true
            self.layer.cornerRadius = (self.frame.width + self.frame.height) / 4
        } else {
            self.layer.cornerRadius = 0
        }
    }

    override func layoutSubviews() {
            makeRound()
    }
}

回答5:

Yes, it is possible to give layer.cornerRadius (need to add #import <QuartzCore/QuartzCore.h>)
for create circular any control but in your case instead of set layer of UIImageView it is The Best Way to Create Your Image as circular and add it on UIImageView Which have backGroundColor is ClearColor.

Also refer this Two Source of code.

https://www.cocoacontrols.com/controls/circleview

and

https://www.cocoacontrols.com/controls/mhlazytableimages

This might be helpful in your case:

回答6:

Set the height & width of the of the UIImageView to be the same e.g.:Height=60 & Width = 60, then the cornerRadius should be exactly the half.I have kept it 30 in my case.It worked for me.

 self.imageView.layer.cornerRadius = 30;
 self.imageView.layer.borderWidth = 3;
 self.imageView.layer.borderColor = [UIColor whiteColor].CGColor;
 self.imageView.layer.masksToBounds = YES;

回答7:

If use some autolayout and different cells heights, u better do it this way:

   override func layoutSubviews() {
        super.layoutSubviews()
        logo.layer.cornerRadius = logo.frame.size.height / 2;
        logo.clipsToBounds      = true;
    }

回答8:

I use a Round Image View class… So I just use it instead of UIImageView, and have nothing to tweak…

This class also draws an optional border around the circle. There is often a border around rounded pictures.

It is not a UIImageView subclass because UIImageView has its own rendering mechanism, and does not call the drawRect method..

Interface :

#import <UIKit/UIKit.h>

@interface MFRoundImageView : UIView

@property(nonatomic,strong) UIImage* image;

@property(nonatomic,strong) UIColor* strokeColor;
@property(nonatomic,assign) CGFloat strokeWidth;

@end

Implementation :

#import "MFRoundImageView.h"


@implementation MFRoundImageView

-(void)setImage:(UIImage *)image
{
    _image = image;
    [self setNeedsDisplay];
}

-(void)setStrokeColor:(UIColor *)strokeColor
{
    _strokeColor = strokeColor;
    [self setNeedsDisplay];
}

-(void)setStrokeWidth:(CGFloat)strokeWidth
{
    _strokeWidth = strokeWidth;
    [self setNeedsDisplay];
}

- (void)drawRect:(CGRect)rect {
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGPathRef path = CGPathCreateWithEllipseInRect(self.bounds, NULL);
    CGContextAddPath(ctx, path);
    CGContextClip(ctx);
    [self.image drawInRect:rect];

    if ( ( _strokeWidth > 0.0f ) && _strokeColor ) {
        CGContextSetLineWidth(ctx, _strokeWidth*2); // Half border is clipped
        [_strokeColor setStroke];
        CGContextAddPath(ctx, path);
        CGContextStrokePath(ctx);
    }
    CGPathRelease(path);
}

@end

回答9:

Usable solution in Swift using extension:

extension UIView{
  func circleMe(){
      let radius = CGRectGetWidth(self.bounds) / 2
      self.layer.cornerRadius = radius
      self.layer.masksToBounds = true
  }
}

Usage:

self.venueImageView.circleMe()

回答10:

Creating circular image view and thats quite easy with the below SO link, just have custom cells for your table view instead of allocating every thing in your cellForRowAtIndexPath method.

how to make button round with image background in IPhone?

The above link gives you example for buttons just use it for your image views.

回答11:

If you showing the images over a solid background color, an easy solution could be to use an overlay image with a transparent circle in the middle.

This way you can still use square images and add the circle image above them to get the circular effect.

If you don't need to manipulate your images or show them on a complex background color, this can be a simple solution with no performance hit.

回答12:

In swift, inside your viewDidLoad method, with the userImage outlet:

self.userImage.layer.borderWidth = 1;
self.userImage.layer.borderColor = UIColor.whiteColor().CGColor;
self.userImage.layer.cornerRadius = self.userImage.frame.size.width / 2;
self.userImage.clipsToBounds = true;

回答13:

In Swift use this Extension for CircularImageView or RoundedImageView :

extension UIView {

    func circular(borderWidth: CGFloat = 0, borderColor: UIColor = UIColor.whiteColor()) {
        let radius = CGRectGetWidth(self.bounds) / 2
        self.layer.cornerRadius = radius
        self.layer.masksToBounds = true

        self.layer.borderWidth = borderWidth
        self.layer.borderColor = borderColor.CGColor
    }

    func roundedCorner(borderWidth: CGFloat = 0, borderColor: UIColor = UIColor.whiteColor()) {
        let radius = CGRectGetWidth(self.bounds) / 2
        self.layer.cornerRadius = radius / 5
        self.layer.masksToBounds = true

        self.layer.borderWidth = borderWidth
        self.layer.borderColor = borderColor.CGColor
    }

}

Usage:

self.ImageView.circular()
self.ImageView.roundedCorner()