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

从ios7开始,在UIImage上有一个新的方法来指定渲染模式。使用渲染模式UIImageRenderingModeAlwaysTemplate将允许图像颜色由按钮的色调颜色控制。

objective - c

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
UIImage *image = [[UIImage imageNamed:@"image_name"] imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
[button setImage:image forState:UIControlStateNormal]; 
button.tintColor = [UIColor redColor];

斯威夫特

let button = UIButton(type: .custom)
let image = UIImage(named: "image_name")?.withRenderingMode(.alwaysTemplate)
button.setImage(image, for: .normal)
button.tintColor = UIColor.red

其他回答

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)

如果你有一个带有背景图像的自定义按钮。您可以设置您的按钮的色调颜色和覆盖以下图像。

在资产中选择你想设置色调的按钮背景。

在图像的属性检查器中设置渲染值为“Template image”

现在当你setbutton时。tintColor = UIColor。红色“您”按钮将以红色显示。

如果你想手动屏蔽你的图像,这里是更新的代码,适用于视网膜屏幕

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

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

    CGImageRef cImage = CGBitmapContextCreateImage(bitmapContext);
    UIImage *coloredImage = [UIImage imageWithCGImage:cImage scale:self.scale orientation:self.imageOrientation];

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

    return coloredImage;
}

在Swift中,你可以这样做:

var exampleImage = UIImage(named: "ExampleImage.png")?.imageWithRenderingMode(.AlwaysTemplate)

然后在viewDidLoad中

exampleButtonOutlet.setImage(exampleImage, forState: UIControlState.Normal)

并修改颜色

exampleButtonOutlet.tintColor = UIColor(red: 1, green: 0, blue: 0, alpha: 1) //your color

编辑Xcode 8 现在你也可以在你的.xcassets to Template image中设置图像的呈现模式,然后你就不需要在var exampleImage中特别声明它了

为了在按钮上设置白色的图像(箭头图标),我们使用:

let imageOnButton = UIImage(named: "navForwardArrow")?.imageWithColor(color: UIColor.white)
button.setImage(imageOnButton, for: .normal)

已知问题:当按下按钮时,图标会失去白色。

截图: