我试图为UILabel实现这种发光效果,如下所示：
我已经将UILabel子类化,并创建了一个自定义标签类,可以添加外部阴影.
编辑：这是我在自定义Label类中用于外部阴影/发光的代码：
- (void)drawTextInRect:(CGRect)rect {
UIColor *insideColor;
UIColor *blurColor;
CGContextRef ctx = UIGraphicsGetCurrentContext();
insideColor =[UIColor colorWithRed:255/255.0 green:255/255.0 blue:191/255.0 alpha:1];
blurColor =[UIColor orangeColor];
CGContextSetFillColorWithColor(ctx,insideColor.CGColor);
CGContextSetShadowWithColor(ctx,CGSizeMake(0,0),self.glowAmount,blurColor.CGColor);
CGContextSetTextDrawingMode(ctx,kCGTextFillStroke);
[self.text drawInRect:self.bounds withFont:self.font lineBreakMode:self.lineBreakMode alignment:self.textAlignment];
}
但这给了我以下结果
正如你所看到的,由于缺少内阴影,这缺乏预期的效果.谁能建议如何实现这一目标？
谢谢！
解决方法
我将史蒂芬XM的答案提到了
Inner Shadow in UILabel.这是一个很大的帮助.
这是我为实现结果所做的工作,但我想知道这是否可以更优化？
-(void)setInnerGlowWithColor:(UIColor *)shadowColor fillColor:(UIColor *)insideColor inRect:(CGRect)rect
{
UIFont *font = self.font;
// UIFont *font = [UIFont fontWithName:@"HelveticaNeue-Bold" size:17];
CGSize fontSize = [self.text sizeWithFont:font];
/**** Following are the steps to create an inside shadow ****/
// STEP 1 : Create a image mask of your text.
CGImageRef mask = [self createMaskWithSize:rect.size shape:^{
[[UIColor blackColor] setFill];
CGContextFillRect(UIGraphicsGetCurrentContext(),rect);
[[UIColor whiteColor] setFill];
// custom shape goes here
[self.text drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2),0) withFont:font];
}];
// STEP 2 : Invert that mask.
CGImageRef cutoutRef = CGImageCreateWithMask([self blackSquareOfSize:rect.size].CGImage,mask);
CGImageRelease(mask);
UIImage *cutout = [UIImage imageWithCGImage:cutoutRef scale:[[UIScreen mainScreen] scale] orientation:UIImageOrientationUp];
CGImageRelease(cutoutRef);
// STEP 3 : Use this inverted mask to draw a shadow around the inside edges of the text.
CGImageRef shadedMask = [self createMaskWithSize:rect.size shape:^{
[[UIColor whiteColor] setFill];
CGContextFillRect(UIGraphicsGetCurrentContext(),rect);
//****************For inner shadow/glow
NSLog(@"in custom label----> %f",self.glowAmount);
CGContextSetShadowWithColor(UIGraphicsGetCurrentContext(),shadowColor.CGColor);
[cutout drawAtPoint:CGPointZero];
}];
// STEP 4 : Create negative image
UIGraphicsBeginImageContextWithOptions(rect.size,NO,0);
[shadowColor setFill];
// custom shape goes here
[self.text drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2),0) withFont:font];
UIImage *negative = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// STEP 5 : Create the shadow image
CGImageRef innerShadowRef = CGImageCreateWithMask(negative.CGImage,shadedMask);
CGImageRelease(shadedMask);
UIImage *innerShadow = [UIImage imageWithCGImage:innerShadowRef scale:[[UIScreen mainScreen] scale] orientation:UIImageOrientationUp];
CGImageRelease(innerShadowRef);
// STEP 6 : Draw actual text
[insideColor setFill];
[self.text drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2),0) withFont:font];
// STEP 7 : Finally apply the shadow image
[innerShadow drawAtPoint:CGPointZero];
}
- (UIImage*)blackSquareOfSize:(CGSize)size {
UIGraphicsBeginImageContextWithOptions(size,0);
[[UIColor blackColor] setFill];
CGContextFillRect(UIGraphicsGetCurrentContext(),CGRectMake(0,size.width,size.height));
UIImage *blackSquare = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return blackSquare;
}
- (CGImageRef)createMaskWithSize:(CGSize)size shape:(void (^)(void))block {
UIGraphicsBeginImageContextWithOptions(size,0);
block();
CGImageRef shape = [UIGraphicsGetImageFromCurrentImageContext() CGImage];
UIGraphicsEndImageContext();
CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(shape),CGImageGetHeight(shape),CGImageGetBitsPerComponent(shape),CGImageGetBitsPerPixel(shape),CGImageGetBytesPerRow(shape),CGImageGetDataProvider(shape),NULL,false);
return mask;
}
