I noticed that when I place a white or black UIImage into a UISegmentedControl it automatically color masks it to match the tint of the segmented control. I thought this was really cool, and was wondering if I could do this elsewhere as well. For example, I have a bunch of buttons that have a uniform shape but varied colors. Instead of making a PNG for each button, could I somehow use this color masking to use the same image for all of them but then set a tint color or something to change their actual color?


当前回答

不确定你到底想要什么,但这个category方法会用指定的颜色掩盖一个UIImage,所以你可以有一个单独的图像,改变它的颜色为任何你想要的。

ImageUtils.h

- (UIImage *) maskWithColor:(UIColor *)color;

ImageUtils.m

-(UIImage *) maskWithColor:(UIColor *)color 
{
    CGImageRef maskImage = self.CGImage;
    CGFloat width = self.size.width;
    CGFloat height = self.size.height;
    CGRect bounds = CGRectMake(0,0,width,height);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef bitmapContext = CGBitmapContextCreate(NULL, width, height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
    CGContextClipToMask(bitmapContext, bounds, maskImage);
    CGContextSetFillColorWithColor(bitmapContext, color.CGColor);    
    CGContextFillRect(bitmapContext, bounds);

    CGImageRef cImage = CGBitmapContextCreateImage(bitmapContext);
    UIImage *coloredImage = [UIImage imageWithCGImage:cImage];

    CGContextRelease(bitmapContext);
    CGColorSpaceRelease(colorSpace);
    CGImageRelease(cImage);

    return coloredImage;    
}

导入ImageUtils类别并执行如下操作…

#import "ImageUtils.h"

...

UIImage *icon = [UIImage imageNamed:ICON_IMAGE];

UIImage *redIcon = [icon maskWithColor:UIColor.redColor];
UIImage *blueIcon = [icon maskWithColor:UIColor.blueColor];

其他回答

Xamarin的。iOS (c#):

UIButton messagesButton = new UIButton(UIButtonType.Custom);
UIImage icon = UIImage.FromBundle("Images/icon.png");
messagesButton.SetImage(icon.ImageWithRenderingMode(UIImageRenderingMode.AlwaysTemplate), UIControlState.Normal);
messagesButton.TintColor = UIColor.White;
messagesButton.Frame = new RectangleF(0, 0, 25, 25);

斯威夫特3.0

    let image = UIImage(named:"NoConnection")!

 warningButton = UIButton(type: .system)        
    warningButton.setImage(image, for: .normal)
    warningButton.tintColor = UIColor.lightText
    warningButton.frame = CGRect(origin: CGPoint(x:-100,y:0), size: CGSize(width: 59, height: 56))

    self.addSubview(warningButton)

自定义按钮以各自的图像颜色显示。在故事板中将按钮类型设置为“System”(或者在代码中设置为UIButtonTypeSystem),将以默认的色调呈现按钮的图像。

(在iOS9, Xcode 7.3上测试)

Swift 4与customType:

let button = UIButton(frame: aRectHere)
    let buttonImage = UIImage(named: "imageName")
    button.setImage(buttonImage?.withRenderingMode(.alwaysTemplate), for: .normal)
    button.tintColor = .white

我有一个问题,掩蔽图像在突出显示的状态。我不希望发生这种事。如果你有同样的问题,看看这个:adjustsImageWhenHighlighted = false