uilabel中的内部阴影

dmaclach的答案只适用于容易反转的形状。我的解决方案是一个自定义视图,可以处理任何形状和文本。它需要iOS 4,并且与分辨率无关。

首先,对代码的作用进行图形解释。这里的形状是一个圆。

代码用白色阴影绘制文本。如果不需要,可以进一步重构代码,因为Dropshadow需要以不同的方式进行屏蔽。如果在旧版本的iOS上需要它,则必须替换块并使用(恼人的)cgBitmapContext。

—(uiimage*)blackquareofsize:(cgsize)大小{
uigraphicsbeginimagecontextwithoptions(大小,否,0);
[[uicolor blackcolor]setfill];
cContextFillRect(uigraphicsgetCurrentContext(),cDirectMake(0,0,size.width,size.height));
uiimage*blacksquare=uigraphicsGetImageFromCurrentImageContext();
uigraphicsEndImageContext();
返回黑方;
}


-(cgImageRef)CreateMaskWithSize:(cgSize)大小形状:(void(^)(void))块{
uigraphicsbeginimagecontextwithoptions(大小,否,0);
块();
cgimageref shape=[uigraphicsGetImageFromCurrentImageContext()cgimage];
uigraphicsEndImageContext();
cgImageRef Mask=cgImageMaskCreate(cgImageGetWidth(shape)),
CGImageGetHeight(形状),
CGImageGetBitsPerComponent(形状),
CGImageGetBitsPerPixel(形状),
CGImageGetBytesPerow(形状),
cImageGetDataProvider(shape),空,假);
返回掩模;
}


-(无效)drawrect:(cgrect)rect{
uiFONT*FONT=[uiFONT FONTWITHNAME:@“Helveticaneue-bold”尺寸:40.0F];
cgsize fontsize=[文本大小带字体:字体];

cgimageref mask=[自我创建的maskwithsize:rect.size形状:]^{
[[uicolor blackcolor]setfill];
cContextFillRect(uigraphicsgetCurrentContext(),rect);
[[uicolor whitecolor]setfill];
//此处显示自定义形状
[文本绘制点:cgpointmake((self.bounds.size.width/2)-(font size.width/2),0),字体:字体];
[文本绘制点:cgpointmake((self.bounds.size.width/2)-(font size.width/2),-1)带字体:字体];
};

cImageRef CutoureRef=cImageCreateWithMask([Self BlackQuareOfSize:rect.size].cImage,Mask);
CGIMAGERELEASE(掩模);
uiimage*cutout=[uiimage imagewithcgimage:cututoref scale:[uiscreen mainscreen]scale]方向:uiimageoritionup];
CGIMAGERELEASE(剪切参考);

CGIMAGEREF SHADEDMASK=[自我创建掩码WITHSIZE:rect.SIZE形状:]^{
[[uicolor whitecolor]setfill];
cContextFillRect(uigraphicsgetCurrentContext(),rect);
cgContextSetsHadowWithColor(uigraphicsGetCurrentContext(),cgSizemake(0,1),1.0f,[[uicolor colorWithWhite:0.0 alpha:0.5]cgColor]);
[剪切绘图点:cgpointzero];
};

//创建负像
uigraphicsbeginimagecontextwithoptions(rect.size,no,0);
[[uicolor blackcolor]setfill];
//此处显示自定义形状
[文本绘制点:cgpointmake((self.bounds.size.width/2)-(font size.width/2),-1)带字体:字体];
uiimage*负=uigraphicsGetImageFromCurrentImageContext();
uigraphicsEndImageContext();

cImageRef innershadowRef=cImageCreateWithMask(negative.cgImage,shaddedmask);
CGIMAGERELEASE(阴影任务);
uiimage*innershadow=[uiimage imagewithcgimage:innershadowref scale:[uiscreen mainscreen]scale]方向:uiimageoritionup];
CGIMAGERELEASE(InnershadowRef);

//绘制实际图像
[[uicolor whitecolor]setfill];
[文本绘制点:cgpointmake((self.bounds.size.width/2)-(font size.width/2),-0.5),字体:字体];
[uicolor colorwithwhite:0.76 alpha:1.0]setfill];
[文本绘制点:cgpointmake((self.bounds.size.width/2)-(font size.width/2),-1)带字体:字体];

//最后应用阴影
[innershadow drawAtpoint:cgpointzero];
}
< /代码> 
很容易倒转。我的解决方案是一个自定义视图,可以处理任何形状和文本。它需要iOS 4,并且与分辨率无关。


首先,对代码的作用进行图形解释。这里的形状是一个圆。


代码用白色的阴影绘制文本。如果不需要,可以进一步重构代码,因为Dropshadow需要以不同的方式进行屏蔽。如果您在旧版本的iOS上需要它,您必须替换块并使用(恼人的)cgBitmapContext。

- (UIImage*)blackSquareOfSize:(CGSize)size {
  UIGraphicsBeginImageContextWithOptions(size, NO, 0);  
  [[UIColor blackColor] setFill];
  CGContextFillRect(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, size.width, size.height));
  UIImage *blackSquare = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return blackSquare;
}


- (CGImageRef)createMaskWithSize:(CGSize)size shape:(void (^)(void))block {
  UIGraphicsBeginImageContextWithOptions(size, NO, 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;
}


- (void)drawRect:(CGRect)rect {
  UIFont *font = [UIFont fontWithName:@"HelveticaNeue-Bold" size:40.0f];
  CGSize fontSize = [text_ sizeWithFont:font];

  CGImageRef mask = [self createMaskWithSize:rect.size shape:^{
    [[UIColor blackColor] setFill];
    CGContextFillRect(UIGraphicsGetCurrentContext(), rect);
    [[UIColor whiteColor] setFill];
    // custom shape goes here
    [text_ drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2), 0) withFont:font];
    [text_ drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2), -1) withFont:font];
  }];

  CGImageRef cutoutRef = CGImageCreateWithMask([self blackSquareOfSize:rect.size].CGImage, mask);
  CGImageRelease(mask);
  UIImage *cutout = [UIImage imageWithCGImage:cutoutRef scale:[[UIScreen mainScreen] scale] orientation:UIImageOrientationUp];
  CGImageRelease(cutoutRef);  

  CGImageRef shadedMask = [self createMaskWithSize:rect.size shape:^{
    [[UIColor whiteColor] setFill];
    CGContextFillRect(UIGraphicsGetCurrentContext(), rect);
    CGContextSetShadowWithColor(UIGraphicsGetCurrentContext(), CGSizeMake(0, 1), 1.0f, [[UIColor colorWithWhite:0.0 alpha:0.5] CGColor]);
    [cutout drawAtPoint:CGPointZero];
  }];

  // create negative image
  UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0);
  [[UIColor blackColor] setFill];
  // custom shape goes here
  [text_ drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2), -1) withFont:font];
  UIImage *negative = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext(); 

  CGImageRef innerShadowRef = CGImageCreateWithMask(negative.CGImage, shadedMask);
  CGImageRelease(shadedMask);
  UIImage *innerShadow = [UIImage imageWithCGImage:innerShadowRef scale:[[UIScreen mainScreen] scale] orientation:UIImageOrientationUp];
  CGImageRelease(innerShadowRef);

  // draw actual image
  [[UIColor whiteColor] setFill];
  [text_ drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2), -0.5) withFont:font];
  [[UIColor colorWithWhite:0.76 alpha:1.0] setFill];
  [text_ drawAtPoint:CGPointMake((self.bounds.size.width/2)-(fontSize.width/2), -1) withFont:font];  

  // finally apply shadow
  [innerShadow drawAtPoint:CGPointZero];
}

虽然史蒂夫的回答确实有效,但它并没有按我的具体情况进行缩放,因此我在剪切上下文后,通过将阴影应用到cgpath,最终创建了一个内部阴影:

cgContextRef context=uigraphicsGetCurrentContext();

//剪辑上下文,使阴影仅显示在内部
cgpathref roundedrect=[uibezierpath bezierpathwithroundedrect:rect cornerradius:4].cgpath;
cContextAddPath(上下文,RoundedRect);
cContextClip(上下文);

cContextAddPath(上下文,RoundedRect);
cgContextSetsHadowWithColor(uigraphicsGetCurrentContext(),cgSizemake(0,0),3,[uicolor colorWithWhite:0 alpha:1].cgColor);
cgContextSetStrokeColorWithColor(上下文,[uicolor colorWithWhite:0 alpha:1].cgColor);
cContextStrokePath(上下文);
< /代码> 

结果是:



可以更改阴影偏移和模糊以更改阴影样式。如果您需要它变暗,您也可以依次添加和删除相同的cgpath,这将使阴影堆积起来。

因此,在剪切上下文后,我将阴影应用到cgpath,从而创建了一个内部阴影:

CGContextRef context = UIGraphicsGetCurrentContext();

// clip context so shadow only shows on the inside
CGPathRef roundedRect = [UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:4].CGPath;
CGContextAddPath(context, roundedRect);
CGContextClip(context);

CGContextAddPath(context, roundedRect);
CGContextSetShadowWithColor(UIGraphicsGetCurrentContext(), CGSizeMake(0, 0), 3, [UIColor colorWithWhite:0 alpha:1].CGColor);
CGContextSetStrokeColorWithColor(context, [UIColor colorWithWhite:0 alpha:1].CGColor);
CGContextStrokePath(context);


结果是:



可以更改阴影偏移和模糊以更改阴影样式。如果你需要它更暗,你也可以依次添加,然后划相同的cgpath,这将使阴影堆积起来。

我用fxlabel做内阴影,看这里 https://github.com/nicklockwood/FXLabel .

是的,我有一篇关于它的博客文章 here . 简单的答案是借用jtainnershadowlayer here ,为uilabel子类,并通过重写来更改其layerClass + (Class)layerClass 因此它返回jtainnershadowlayer类,如下所示:

+ (Class)layerClass
{
  return [JTAInnerShadowLayer class];
}

然后在层的init方法中设置jtainnershadowlayer,如下所示:

[self setBackgroundColor:[UIColor clearColor]];
JTAInnerShadowLayer *innerShadow = (JTAInnerShadowLayer *)[self layer];
[innerShadow setClipForAnyAlpha:YES];
[innerShadow setOutsideShadowSize:CGSizeMake(0.0, 1.0) radius:1.0];
[innerShadow setInsideShadowSize:CGSizeMake (0.0, 4.0) radius:6.0];
/* Uncomment this to make the label also draw the text (won't work well
   with black text!*/
//[innerShadow drawOriginalImage];

(或者只是借用jtaindentLabel类)。

你将不得不做你自己的自定义绘图,以获得一个内部阴影。目前没有办法使用标准的uilabel。

下面是一个关于用石英做内阴影的合理解释。

Inner shadow in Core Graphics

尝试 PaintCode 试用版!对于初学者,您将学习如何创建自定义绘图。非常好!:3您可以使用它进行练习或学习,但不要一直使用它,您还应该学习如何自己创建图形。

免责声明:我不是一个代言人,我只是惊讶于我的发现。;)