如何使用UIImage作为Objective-C中的颜色的遮罩Objective-C

Question

我有一个全黑的UIImage，所以有些部分是灰色的，有些部分是完全透明的。我想用这些图片作为其他颜色的遮罩（让我们说白色让它变得容易），所以最终产品现在是一个白色图像，其中部分是透明的。

我一直环顾这里的苹果文档站点： http://developer.apple.com/library/mac/#documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_images/dq_images.html#//apple_ref/doc/uid/TP30001066-CH212-CJBHIJEB

但我完全新的石英/核芯显卡，所以我并不真的不能做的那些例子感。

有没有人知道我可以用来看一些完整的代码示例的链接？

Answer 1

在iOS 7+中，您应该使用UIImageRenderingModeAlwaysTemplate来代替。见https://stackoverflow.com/a/26965557/870313

---

创建从黑与-α主图像（IOS）任意颜色的图标。

// Usage: UIImage *buttonImage = [UIImage ipMaskedImageNamed:@"UIButtonBarAction.png" color:[UIColor redColor]]; 

+ (UIImage *)ipMaskedImageNamed:(NSString *)name color:(UIColor *)color 
{ 
    UIImage *image = [UIImage imageNamed:name]; 
    CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height); 
    UIGraphicsBeginImageContextWithOptions(rect.size, NO, image.scale); 
    CGContextRef c = UIGraphicsGetCurrentContext(); 
    [image drawInRect:rect]; 
    CGContextSetFillColorWithColor(c, [color CGColor]); 
    CGContextSetBlendMode(c, kCGBlendModeSourceAtop); 
    CGContextFillRect(c, rect); 
    UIImage *result = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 
    return result; 
} 

贷记奥莱佐恩：https://gist.github.com/1102091

Answer 2

我转换此的OSX here作为类别和下面复制。请注意，这是针对非ARC项目的。对于ARC项目，autorelease可以被删除。

- (NSImage *)cdsMaskedWithColor:(NSColor *)color 
{ 
    CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height); 

    NSImage *result = [[NSImage alloc] initWithSize:self.size]; 
    [result lockFocusFlipped:self.isFlipped]; 

    NSGraphicsContext *context = [NSGraphicsContext currentContext]; 
    CGContextRef c = (CGContextRef)[context graphicsPort]; 

    [self drawInRect:NSRectFromCGRect(rect)]; 

    CGContextSetFillColorWithColor(c, [color CGColor]); 
    CGContextSetBlendMode(c, kCGBlendModeSourceAtop); 
    CGContextFillRect(c, rect); 

    [result unlockFocus]; 

    return [result autorelease]; 
} 
+ (NSImage *)cdsMaskedImageNamed:(NSString *)name color:(NSColor *)color 
{ 
    NSImage *image = [NSImage imageNamed:name]; 
    return [image cdsMaskedWithColor:color]; 
} 

Answer 3

翻译Jano的的回答到斯威夫特：

func ipMaskedImageNamed(name:String, color:UIColor) -> UIImage { 
    let image = UIImage(named: name) 
    let rect:CGRect = CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: image!.size.width, height: image!.size.height)) 
    UIGraphicsBeginImageContextWithOptions(rect.size, false, image!.scale) 
    let c:CGContextRef = UIGraphicsGetCurrentContext() 
    image?.drawInRect(rect) 
    CGContextSetFillColorWithColor(c, color.CGColor) 
    CGContextSetBlendMode(c, kCGBlendModeSourceAtop) 
    CGContextFillRect(c, rect) 
    let result:UIImage = UIGraphicsGetImageFromCurrentImageContext() 
    UIGraphicsEndImageContext() 
    return result 
} 

用法：

myButton.setImage(ipMaskedImageNamed("grayScalePNG", color: UIColor.redColor()), forState: .Normal) 

编辑：这一article，你可以把图像变成面具，其不透明的领域是以色调颜色表示。在资产目录中，在图像的Attributes Inspector下，将渲染为至模板图片。没有必要的代码。

Answer 4

下面是斯威夫特3的变化，写为一个扩展的UIImage：

extension UIImage { 
    func tinted(color:UIColor) -> UIImage? { 
     let image = self 
     let rect:CGRect = CGRect(origin: CGPoint(x: 0, y: 0), size: image.size) 
     UIGraphicsBeginImageContextWithOptions(rect.size, false, image.scale) 
     let context = UIGraphicsGetCurrentContext()! 
     image.draw(in: rect) 
     context.setFillColor(color.cgColor) 
     context.setBlendMode(.sourceAtop) 
     context.fill(rect) 
     if let result:UIImage = UIGraphicsGetImageFromCurrentImageContext() { 
      UIGraphicsEndImageContext() 
      return result 
     } 
     else { 
      return nil 
     } 
    } 
} 

// Usage 
let myImage = #imageLiteral(resourceName: "Check.png") // any image 
let blueImage = myImage.tinted(color: .blue)