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

正如Ric已经在他的帖子中提到的,你可以在代码中设置渲染模式,你也可以直接在图像目录中这样做,见下面所附的图像。只需要设置渲染为模板图像

注意,我在使用iOS 7和这种方法时遇到过问题。如果你也使用iOS 7,你可能也想在代码中完成,就像这里描述的。

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

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)

改变按钮图像或图像视图色调颜色

btn.imageView?.image = btn.imageView?.image?.withRenderingMode(.alwaysTemplate)

btn.imageView?.tintColor = #colorLiteral(red: 0, green: 0, blue: 0, alpha: 1)
let button = UIButton(type: .custom)
let image = UIImage(named: "image_name")?.withRenderingMode(.alwaysTemplate)
button.setImage(image, for: .normal)
button.tintColor = UIColor.red

如果你在设置UIButton。tintColor by UIColor(r:g:b:alpha:),记住值除以255。这些RGB值应该在0和1之间。