UIView层的内阴影效果?
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【中文标题】UIView层的内阴影效果?【英文标题】:Inner shadow effect on UIView layer? 【发布时间】:2011-05-24 19:06:37 【问题描述】:我有以下 CALayer:
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = CGRectMake(8, 57, 296, 30);
gradient.cornerRadius = 3.0f;
gradient.colors = [NSArray arrayWithObjects:(id)[RGB(130, 0, 140) CGColor], (id)[RGB(108, 0, 120) CGColor], nil];
[self.layer insertSublayer:gradient atIndex:0];
我想给它添加一个内阴影效果,但我不太确定怎么做。我想我需要在 drawRect 中绘制,但是这会将图层添加到其他 UIView 对象之上,因为它应该是一些按钮后面的栏,所以我不知道该怎么做?
我可以再添加一层,但又不知道如何实现内阴影效果(像这样:
帮助感谢...
【问题讨论】:
【参考方案1】:我知道我参加这个聚会迟到了,但这会帮助我在旅行中尽早找到......
为了在应得的地方给予肯定,这实质上是对 Daniel Thorpe 对 Costique 的从较大区域中减去较小区域的解决方案的阐述的修改。此版本适用于那些使用层组合而不是覆盖-drawRect:
CAShapeLayer
类可以达到同样的效果:
CAShapeLayer *shadowLayer = [CAShapeLayer layer];
[shadowLayer setFrame:[self bounds]];
// Standard shadow stuff
[shadowLayer setShadowColor:[[UIColor colorWithWhite:0 alpha:1] CGColor]];
[shadowLayer setShadowOffset:CGSizeMake(0.0f, 0.0f)];
[shadowLayer setShadowOpacity:1.0f];
[shadowLayer setShadowRadius:5];
// Causes the inner region in this example to NOT be filled.
[shadowLayer setFillRule:kCAFillRuleEvenOdd];
// Create the larger rectangle path.
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectInset(bounds, -42, -42));
// Add the inner path so it's subtracted from the outer path.
// someInnerPath could be a simple bounds rect, or maybe
// a rounded one for some extra fanciness.
CGPathAddPath(path, NULL, someInnerPath);
CGPathCloseSubpath(path);
[shadowLayer setPath:path];
CGPathRelease(path);
[[self layer] addSublayer:shadowLayer];
此时,如果您的父图层未屏蔽到其边界,您将看到图层边缘周围的蒙版图层的额外区域。如果您只是直接复制示例,这将是 42 像素的黑色。要摆脱它,您可以简单地使用另一个具有相同路径的CAShapeLayer
,并将其设置为阴影层的遮罩:
CAShapeLayer *maskLayer = [CAShapeLayer layer];
[maskLayer setPath:someInnerPath];
[shadowLayer setMask:maskLayer];
我自己没有对此进行基准测试,但我怀疑将这种方法与光栅化结合使用比覆盖 -drawRect:
更高效。
【讨论】:
someInnerPath?请您再解释一下。 @Moe 可以是任何你想要的任意 CGPath。[[UIBezierPath pathWithRect:[shadowLayer bounds]] CGPath]
是最简单的选择。
我得到了一个黑色(外部)矩形,用于正确绘制内部阴影的 shadowLayer.path。我怎样才能摆脱它(黑色外矩形)?看起来你只能在上下文中设置 fillColor 而你不使用一个。
@Olivier 我无法完全描述您的问题,但这可能是某处其他代码的副作用。你的意思是你得到了外部和内部阴影?
这很好用!我上传到 github 并添加了一些内容。试试看:)github.com/inamiy/YIInnerShadowView【参考方案2】:
对于其他想知道如何按照 Costique 的建议使用 Core Graphics 绘制内部阴影的人,这就是:(在 ios 上根据需要进行调整)
在你的 drawRect: 方法中...
CGRect bounds = [self bounds];
CGContextRef context = UIGraphicsGetCurrentContext();
CGFloat radius = 0.5f * CGRectGetHeight(bounds);
// Create the "visible" path, which will be the shape that gets the inner shadow
// In this case it's just a rounded rect, but could be as complex as your want
CGMutablePathRef visiblePath = CGPathCreateMutable();
CGRect innerRect = CGRectInset(bounds, radius, radius);
CGPathMoveToPoint(visiblePath, NULL, innerRect.origin.x, bounds.origin.y);
CGPathAddLineToPoint(visiblePath, NULL, innerRect.origin.x + innerRect.size.width, bounds.origin.y);
CGPathAddArcToPoint(visiblePath, NULL, bounds.origin.x + bounds.size.width, bounds.origin.y, bounds.origin.x + bounds.size.width, innerRect.origin.y, radius);
CGPathAddLineToPoint(visiblePath, NULL, bounds.origin.x + bounds.size.width, innerRect.origin.y + innerRect.size.height);
CGPathAddArcToPoint(visiblePath, NULL, bounds.origin.x + bounds.size.width, bounds.origin.y + bounds.size.height, innerRect.origin.x + innerRect.size.width, bounds.origin.y + bounds.size.height, radius);
CGPathAddLineToPoint(visiblePath, NULL, innerRect.origin.x, bounds.origin.y + bounds.size.height);
CGPathAddArcToPoint(visiblePath, NULL, bounds.origin.x, bounds.origin.y + bounds.size.height, bounds.origin.x, innerRect.origin.y + innerRect.size.height, radius);
CGPathAddLineToPoint(visiblePath, NULL, bounds.origin.x, innerRect.origin.y);
CGPathAddArcToPoint(visiblePath, NULL, bounds.origin.x, bounds.origin.y, innerRect.origin.x, bounds.origin.y, radius);
CGPathCloseSubpath(visiblePath);
// Fill this path
UIColor *aColor = [UIColor redColor];
[aColor setFill];
CGContextAddPath(context, visiblePath);
CGContextFillPath(context);
// Now create a larger rectangle, which we're going to subtract the visible path from
// and apply a shadow
CGMutablePathRef path = CGPathCreateMutable();
//(when drawing the shadow for a path whichs bounding box is not known pass "CGPathGetPathBoundingBox(visiblePath)" instead of "bounds" in the following line:)
//-42 cuould just be any offset > 0
CGPathAddRect(path, NULL, CGRectInset(bounds, -42, -42));
// Add the visible path (so that it gets subtracted for the shadow)
CGPathAddPath(path, NULL, visiblePath);
CGPathCloseSubpath(path);
// Add the visible paths as the clipping path to the context
CGContextAddPath(context, visiblePath);
CGContextClip(context);
// Now setup the shadow properties on the context
aColor = [UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.5f];
CGContextSaveGState(context);
CGContextSetShadowWithColor(context, CGSizeMake(0.0f, 1.0f), 3.0f, [aColor CGColor]);
// Now fill the rectangle, so the shadow gets drawn
[aColor setFill];
CGContextSaveGState(context);
CGContextAddPath(context, path);
CGContextEOFillPath(context);
// Release the paths
CGPathRelease(path);
CGPathRelease(visiblePath);
所以,基本上有以下步骤:
-
创建您的路径
设置你想要的填充颜色,将此路径添加到上下文中,然后填充上下文
现在创建一个更大的矩形来限制可见路径。在关闭此路径之前,添加可见路径。然后关闭路径,以便创建一个从中减去可见路径的形状。您可能需要根据您创建这些路径的方式来研究填充方法(偶数/奇数的非零缠绕)。本质上,要在将子路径相加时“减去”它们,您需要以相反的方向绘制(或更确切地说是构造它们),一个顺时针方向,另一个逆时针方向。
然后你需要将你的可见路径设置为上下文中的剪切路径,这样你就不会在它之外绘制任何东西到屏幕上。
然后在上下文中设置阴影,包括偏移、模糊和颜色。
然后用其中的孔填充大形状。颜色无关紧要,因为如果一切都做对了,您就不会看到这种颜色,只会看到阴影。
【讨论】:
谢谢,但是可以调整半径吗?它目前基于边界,但我想改为基于设定的半径(如 5.0f)。使用上面的代码,它的舍入太多了。 @runmad 好吧,你可以创建任何你想要的可见的 CGPath,这里使用的例子就是为了简洁而选择的例子。如果您想创建一个圆角矩形,那么您可以执行以下操作:CGPath visiblePath = [UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:radius].CGPath 希望对您有所帮助。 @DanielThorpe:+1 的好答案。我修复了圆角矩形路径代码(更改半径时你的代码坏了)并简化了外部矩形路径代码。希望你不要介意。 如何正确设置 4 个方向的内阴影,而不仅仅是 2 个? @Protocole 您可以将偏移量设置为 0,0,但使用阴影半径,例如 4.f。【参考方案3】:有一个简单的解决方案 - 只需绘制正常的阴影并旋转,就像这样
@objc func shadowView() -> UIView
let shadowView = UIView(frame: .zero)
shadowView.backgroundColor = .white
shadowView.layer.shadowColor = UIColor.grey.cgColor
shadowView.layer.shadowOffset = CGSize(width: 0, height: 2)
shadowView.layer.shadowOpacity = 1.0
shadowView.layer.shadowRadius = 4
shadowView.layer.compositingFilter = "multiplyBlendMode"
return shadowView
func idtm_addBottomShadow()
let shadow = shadowView()
shadow.transform = transform.rotated(by: 180 * CGFloat(Double.pi))
shadow.transform = transform.rotated(by: -1 * CGFloat(Double.pi))
shadow.translatesAutoresizingMaskIntoConstraints = false
addSubview(shadow)
NSLayoutConstraint.activate([
shadow.leadingAnchor.constraint(equalTo: leadingAnchor),
shadow.trailingAnchor.constraint(equalTo: trailingAnchor),
shadow.bottomAnchor.constraint(equalTo: bottomAnchor),
shadow.heightAnchor.constraint(equalToConstant: 1),
])
【讨论】:
【参考方案4】:在 Swift 中使用 CALayer 的可扩展解决方案
使用所描述的InnerShadowLayer
,您还可以仅为特定边缘启用内部阴影,不包括其他边缘。 (例如,您只能在视图的左边缘和上边缘启用内部阴影)
然后您可以使用以下方法将InnerShadowLayer
添加到您的视图中:
init(...)
// ... your initialization code ...
super.init(frame: .zero)
layer.addSublayer(shadowLayer)
public override func layoutSubviews()
super.layoutSubviews()
shadowLayer.frame = bounds
InnerShadowLayer
实现
/// Shadow is a struct defining the different kinds of shadows
public struct Shadow
let x: CGFloat
let y: CGFloat
let blur: CGFloat
let opacity: CGFloat
let color: UIColor
/// A layer that applies an inner shadow to the specified edges of either its path or its bounds
public class InnerShadowLayer: CALayer
private let shadow: Shadow
private let edge: UIRectEdge
public init(shadow: Shadow, edge: UIRectEdge)
self.shadow = shadow
self.edge = edge
super.init()
setupShadow()
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
public override func layoutSublayers()
updateShadow()
private func setupShadow()
shadowColor = shadow.color.cgColor
shadowOpacity = Float(shadow.opacity)
shadowRadius = shadow.blur / 2.0
masksToBounds = true
private func updateShadow()
shadowOffset =
let topWidth: CGFloat = 0
let leftWidth = edge.contains(.left) ? shadow.y / 2 : 0
let bottomWidth: CGFloat = 0
let rightWidth = edge.contains(.right) ? -shadow.y / 2 : 0
let topHeight = edge.contains(.top) ? shadow.y / 2 : 0
let leftHeight: CGFloat = 0
let bottomHeight = edge.contains(.bottom) ? -shadow.y / 2 : 0
let rightHeight: CGFloat = 0
return CGSize(width: [topWidth, leftWidth, bottomWidth, rightWidth].reduce(0, +),
height: [topHeight, leftHeight, bottomHeight, rightHeight].reduce(0, +))
()
let insets = UIEdgeInsets(top: edge.contains(.top) ? -bounds.height : 0,
left: edge.contains(.left) ? -bounds.width : 0,
bottom: edge.contains(.bottom) ? -bounds.height : 0,
right: edge.contains(.right) ? -bounds.width : 0)
let path = UIBezierPath(rect: bounds.inset(by: insets))
let cutout = UIBezierPath(rect: bounds).reversing()
path.append(cutout)
shadowPath = path.cgPath
【讨论】:
【参考方案5】:这是我在 Swift 4.2 中的解决方案。你想试试吗?
final class ACInnerShadowLayer : CAShapeLayer
var innerShadowColor: CGColor? = UIColor.black.cgColor
didSet setNeedsDisplay()
var innerShadowOffset: CGSize = .zero
didSet setNeedsDisplay()
var innerShadowRadius: CGFloat = 8
didSet setNeedsDisplay()
var innerShadowOpacity: Float = 1
didSet setNeedsDisplay()
override init()
super.init()
masksToBounds = true
contentsScale = UIScreen.main.scale
setNeedsDisplay()
override init(layer: Any)
if let layer = layer as? InnerShadowLayer
innerShadowColor = layer.innerShadowColor
innerShadowOffset = layer.innerShadowOffset
innerShadowRadius = layer.innerShadowRadius
innerShadowOpacity = layer.innerShadowOpacity
super.init(layer: layer)
required init?(coder aDecoder: NSCoder)
fatalError("init(coder:) has not been implemented")
override func draw(in ctx: CGContext)
ctx.setAllowsAntialiasing(true)
ctx.setShouldAntialias(true)
ctx.interpolationQuality = .high
let colorspace = CGColorSpaceCreateDeviceRGB()
var rect = bounds
var radius = cornerRadius
if borderWidth != 0
rect = rect.insetBy(dx: borderWidth, dy: borderWidth)
radius -= borderWidth
radius = max(radius, 0)
let innerShadowPath = UIBezierPath(roundedRect: rect, cornerRadius: radius).cgPath
ctx.addPath(innerShadowPath)
ctx.clip()
let shadowPath = CGMutablePath()
let shadowRect = rect.insetBy(dx: -rect.size.width, dy: -rect.size.width)
shadowPath.addRect(shadowRect)
shadowPath.addPath(innerShadowPath)
shadowPath.closeSubpath()
if let innerShadowColor = innerShadowColor, let oldComponents = innerShadowColor.components
var newComponets = Array<CGFloat>(repeating: 0, count: 4) // [0, 0, 0, 0] as [CGFloat]
let numberOfComponents = innerShadowColor.numberOfComponents
switch numberOfComponents
case 2:
newComponets[0] = oldComponents[0]
newComponets[1] = oldComponents[0]
newComponets[2] = oldComponents[0]
newComponets[3] = oldComponents[1] * CGFloat(innerShadowOpacity)
case 4:
newComponets[0] = oldComponents[0]
newComponets[1] = oldComponents[1]
newComponets[2] = oldComponents[2]
newComponets[3] = oldComponents[3] * CGFloat(innerShadowOpacity)
default:
break
if let innerShadowColorWithMultipliedAlpha = CGColor(colorSpace: colorspace, components: newComponets)
ctx.setFillColor(innerShadowColorWithMultipliedAlpha)
ctx.setShadow(offset: innerShadowOffset, blur: innerShadowRadius, color: innerShadowColorWithMultipliedAlpha)
ctx.addPath(shadowPath)
ctx.fillPath(using: .evenOdd)
【讨论】:
如果我没有将它用作单独的类,而是像在我的代码中使用一样,当我得到这个时,上下文 (ctx) 为零:let ctx = UIGraphicsGetCurrentContext
@MohsinKhubaibAhmed 您可以通过UIGraphicsGetCurrentContext
方法获取当前上下文,以便在某些视图将其上下文推送到堆栈时获取。
@Arco 我在旋转设备时遇到了一些麻烦。我添加了“覆盖便利初始化(层:任何)self.init()”。现在没有错误显示!
添加了 init(layer: Any) 来修复崩溃。【参考方案6】:
这段代码对我有用
class InnerDropShadowView: UIView
override func draw(_ rect: CGRect)
//Drawing code
let context = UIGraphicsGetCurrentContext()
//// Shadow Declarations
let shadow: UIColor? = UIColor.init(hexString: "a3a3a3", alpha: 1.0) //UIColor.black.withAlphaComponent(0.6) //UIColor.init(hexString: "d7d7da", alpha: 1.0)
let shadowOffset = CGSize(width: 0, height: 0)
let shadowBlurRadius: CGFloat = 7.5
//// Rectangle Drawing
let rectanglePath = UIBezierPath(rect: bounds)
UIColor.groupTableViewBackground.setFill()
rectanglePath.fill()
////// Rectangle Inner Shadow
context?.saveGState()
UIRectClip(rectanglePath.bounds)
context?.setShadow(offset: CGSize.zero, blur: 0, color: nil)
context?.setAlpha((shadow?.cgColor.alpha)!)
context?.beginTransparencyLayer(auxiliaryInfo: nil)
do
let opaqueShadow: UIColor? = shadow?.withAlphaComponent(1)
context?.setShadow(offset: shadowOffset, blur: shadowBlurRadius, color: opaqueShadow?.cgColor)
context!.setBlendMode(.sourceOut)
context?.beginTransparencyLayer(auxiliaryInfo: nil)
opaqueShadow?.setFill()
rectanglePath.fill()
context!.endTransparencyLayer()
context!.endTransparencyLayer()
context?.restoreGState()
【讨论】:
【参考方案7】:在 Swift 中仅使用 CALayer 的简化版本:
import UIKit
final class FrameView : UIView
init()
super.init(frame: CGRect.zero)
backgroundColor = UIColor.white
@available(*, unavailable)
required init?(coder decoder: NSCoder) fatalError("unavailable")
override func layoutSubviews()
super.layoutSubviews()
addInnerShadow()
private func addInnerShadow()
let innerShadow = CALayer()
innerShadow.frame = bounds
// Shadow path (1pt ring around bounds)
let path = UIBezierPath(rect: innerShadow.bounds.insetBy(dx: -1, dy: -1))
let cutout = UIBezierPath(rect: innerShadow.bounds).reversing()
path.append(cutout)
innerShadow.shadowPath = path.cgPath
innerShadow.masksToBounds = true
// Shadow properties
innerShadow.shadowColor = UIColor(white: 0, alpha: 1).cgColor // UIColor(red: 0.71, green: 0.77, blue: 0.81, alpha: 1.0).cgColor
innerShadow.shadowOffset = CGSize.zero
innerShadow.shadowOpacity = 1
innerShadow.shadowRadius = 3
// Add
layer.addSublayer(innerShadow)
请注意,innerShadow 图层不应具有不透明的背景颜色,因为这将呈现在阴影前面。
【讨论】:
最后一行包含“层”。这是哪里来的? @CharlieSeligman 这是父层,可以是任何层。您可以使用自定义层或视图层(UIView 具有层属性)。 应该是let innerShadow = CALayer(); innerShadow.frame = bounds
。如果没有适当的界限,它就不会绘制适当的阴影。还是谢谢
@noir_eagle 是的,尽管您可能希望在 layoutSubviews()
中设置它以保持同步
对!在layoutSubviews()
或draw(_ rect)
【参考方案8】:
有点迂回的方式,但它避免了必须使用图像(阅读:易于更改颜色、阴影半径等)并且只有几行代码。
添加一个 UIImageView 作为您希望在其上放置阴影的 UIView 的第一个子视图。我使用 IB,但您可以通过编程方式执行相同操作。
假设对 UIImageView 的引用是 'innerShadow'
`
[[innerShadow layer] setMasksToBounds:YES];
[[innerShadow layer] setCornerRadius:12.0f];
[[innerShadow layer] setBorderColor:[UIColorFromRGB(180, 180, 180) CGColor]];
[[innerShadow layer] setBorderWidth:1.0f];
[[innerShadow layer] setShadowColor:[UIColorFromRGB(0, 0, 0) CGColor]];
[[innerShadow layer] setShadowOffset:CGSizeMake(0, 0)];
[[innerShadow layer] setShadowOpacity:1];
[[innerShadow layer] setShadowRadius:2.0];
警告:你必须有一个边框,否则阴影不会出现。 [UIColor clearColor] 不起作用。在示例中,我使用了不同的颜色,但您可以将其弄乱以使其具有与阴影开头相同的颜色。 :)
请参阅下面 bbrame 关于 UIColorFromRGB
宏的评论。
【讨论】:
我忽略了它,但假设您会在添加图像视图时这样做 - 确保将框架设置为与父 UIView 相同的矩形。如果您使用的是 IB,如果您要更改父视图的框架,请将 struts 和 springs 设置为具有视图的阴影大小。在代码中应该有一个调整大小的掩码,你可以或者做同样的事情,AFAIK。 这是目前最简单的方法,但请注意 CALayer 阴影方法仅适用于 iOS 3.2 及更高版本。我支持 3.1,所以我将这些属性设置在 if ([layer respondsToSelector:@selector(setShadowColor:)]) 这似乎对我不起作用。至少在 xcode 4.2 和 ios 模拟器 4.3 上。为了使阴影出现,我必须添加背景颜色......此时阴影只出现在外面。 @Andrea - 请记住我上面提到的警告。我认为背景颜色或边框可能具有“给它添加阴影的东西”的相同效果。至于它出现在外面,如果 UIImageView 不是您想要内部阴影的那个的子视图,那可能就是它 - 我必须查看您的代码才能看到。 只是为了纠正我之前的陈述......代码确实有效......我错过了一些东西,但不幸的是我现在不记得了。 :) 所以...感谢分享此代码 sn-p。【参考方案9】:使用渐变层:
UIView * mapCover = [UIView new];
mapCover.frame = map.frame;
[view addSubview:mapCover];
CAGradientLayer * vertical = [CAGradientLayer layer];
vertical.frame = mapCover.bounds;
vertical.colors = [NSArray arrayWithObjects:(id)[UIColor whiteColor].CGColor,
(id)[[UIColor whiteColor] colorWithAlphaComponent:0.0f].CGColor,
(id)[[UIColor whiteColor] colorWithAlphaComponent:0.0f].CGColor,
(id)[UIColor whiteColor].CGColor, nil];
vertical.locations = @[@0.01,@0.1,@0.9,@0.99];
[mapCover.layer insertSublayer:vertical atIndex:0];
CAGradientLayer * horizontal = [CAGradientLayer layer];
horizontal.frame = mapCover.bounds;
horizontal.colors = [NSArray arrayWithObjects:(id)[UIColor whiteColor].CGColor,
(id)[[UIColor whiteColor] colorWithAlphaComponent:0.0f].CGColor,
(id)[[UIColor whiteColor] colorWithAlphaComponent:0.0f].CGColor,
(id)[UIColor whiteColor].CGColor, nil];
horizontal.locations = @[@0.01,@0.1,@0.9,@0.99];
horizontal.startPoint = CGPointMake(0.0, 0.5);
horizontal.endPoint = CGPointMake(1.0, 0.5);
[mapCover.layer insertSublayer:horizontal atIndex:0];
【讨论】:
【参考方案10】:查看Chris Emery 撰写的Inner Shadows in Quartz 的精彩文章,其中解释内部阴影是如何由PaintCode 绘制的,并给出了干净整洁的代码 sn-p:
- (void)drawInnerShadowInContext:(CGContextRef)context
withPath:(CGPathRef)path
shadowColor:(CGColorRef)shadowColor
offset:(CGSize)offset
blurRadius:(CGFloat)blurRadius
CGContextSaveGState(context);
CGContextAddPath(context, path);
CGContextClip(context);
CGColorRef opaqueShadowColor = CGColorCreateCopyWithAlpha(shadowColor, 1.0);
CGContextSetAlpha(context, CGColorGetAlpha(shadowColor));
CGContextBeginTransparencyLayer(context, NULL);
CGContextSetShadowWithColor(context, offset, blurRadius, opaqueShadowColor);
CGContextSetBlendMode(context, kCGBlendModeSourceOut);
CGContextSetFillColorWithColor(context, opaqueShadowColor);
CGContextAddPath(context, path);
CGContextFillPath(context);
CGContextEndTransparencyLayer(context);
CGContextRestoreGState(context);
CGColorRelease(opaqueShadowColor);
【讨论】:
【参考方案11】:这里是swift的一个版本,把startPoint
和endPoint
改成两边。
let layer = CAGradientLayer()
layer.startPoint = CGPointMake(0.5, 0.0);
layer.endPoint = CGPointMake(0.5, 1.0);
layer.colors = [UIColor(white: 0.1, alpha: 1.0).CGColor, UIColor(white: 0.1, alpha: 0.5).CGColor, UIColor.clearColor().CGColor]
layer.locations = [0.05, 0.2, 1.0 ]
layer.frame = CGRectMake(0, 0, self.view.frame.width, 60)
self.view.layer.insertSublayer(layer, atIndex: 0)
【讨论】:
为我工作!!谢谢。【参考方案12】:这是我从PaintCode 导出的解决方案:
-(void) drawRect:(CGRect)rect
CGContextRef context = UIGraphicsGetCurrentContext();
//// Shadow Declarations
UIColor* shadow = UIColor.whiteColor;
CGSize shadowOffset = CGSizeMake(0, 0);
CGFloat shadowBlurRadius = 10;
//// Rectangle Drawing
UIBezierPath* rectanglePath = [UIBezierPath bezierPathWithRect: self.bounds];
[[UIColor blackColor] setFill];
[rectanglePath fill];
////// Rectangle Inner Shadow
CGContextSaveGState(context);
UIRectClip(rectanglePath.bounds);
CGContextSetShadowWithColor(context, CGSizeZero, 0, NULL);
CGContextSetAlpha(context, CGColorGetAlpha([shadow CGColor]));
CGContextBeginTransparencyLayer(context, NULL);
UIColor* opaqueShadow = [shadow colorWithAlphaComponent: 1];
CGContextSetShadowWithColor(context, shadowOffset, shadowBlurRadius, [opaqueShadow CGColor]);
CGContextSetBlendMode(context, kCGBlendModeSourceOut);
CGContextBeginTransparencyLayer(context, NULL);
[opaqueShadow setFill];
[rectanglePath fill];
CGContextEndTransparencyLayer(context);
CGContextEndTransparencyLayer(context);
CGContextRestoreGState(context);
【讨论】:
【参考方案13】:迟到总比没有好...
这是另一种方法,可能并不比已经发布的方法更好,但它很好且简单 -
-(void)drawInnerShadowOnView:(UIView *)view
UIImageView *innerShadowView = [[UIImageView alloc] initWithFrame:view.bounds];
innerShadowView.contentMode = UIViewContentModeScaleToFill;
innerShadowView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[view addSubview:innerShadowView];
[innerShadowView.layer setMasksToBounds:YES];
[innerShadowView.layer setBorderColor:[UIColor lightGrayColor].CGColor];
[innerShadowView.layer setShadowColor:[UIColor blackColor].CGColor];
[innerShadowView.layer setBorderWidth:1.0f];
[innerShadowView.layer setShadowOffset:CGSizeMake(0, 0)];
[innerShadowView.layer setShadowOpacity:1.0];
// this is the inner shadow thickness
[innerShadowView.layer setShadowRadius:1.5];
【讨论】:
@SomaMan 是否可以仅在特定一侧设置阴影?就像只在顶部或顶部/底部或顶部/右侧等..【参考方案14】:而不是通过drawRect绘制内阴影或将UIView添加到View。你可以直接在边框上添加CALayer,例如:如果我想要UIView V底部的内阴影效果。
innerShadowOwnerLayer = [[CALayer alloc]init];
innerShadowOwnerLayer.frame = CGRectMake(0, V.frame.size.height+2, V.frame.size.width, 2);
innerShadowOwnerLayer.backgroundColor = [UIColor whiteColor].CGColor;
innerShadowOwnerLayer.shadowColor = [UIColor blackColor].CGColor;
innerShadowOwnerLayer.shadowOffset = CGSizeMake(0, 0);
innerShadowOwnerLayer.shadowRadius = 10.0;
innerShadowOwnerLayer.shadowOpacity = 0.7;
[V.layer addSubLayer:innerShadowOwnerLayer];
这会为目标 UIView 添加一个底部内阴影
【讨论】:
【参考方案15】:有一些代码here 可以为您执行此操作。如果您将视图中的图层(通过覆盖+ (Class)layerClass
)更改为 JTAInnerShadowLayer,那么您可以在 init 方法中设置缩进图层上的内部阴影,它会为您完成工作。如果您还想绘制原始内容,请确保在缩进层上调用setDrawOriginalImage:yes
。有一篇关于其工作原理的博文here。
【讨论】:
@MiteshDobareeya 刚刚测试了两个链接,它们似乎工作正常(包括在私人标签中)。哪个链接给您带来了问题? 你能看看这个内部阴影代码的实现吗?它仅适用于 ViewDidAppear 方法。并显示一些闪烁。 drive.google.com/open?id=1VtCt7UFYteq4UteT0RoFRjMfFnbibD0E【参考方案16】:我参加聚会很晚了,但我想回馈社区.. 这是我在提供静态库和无资源时编写的删除 UITextField 背景图像的方法... 我将它用于四个 UITextField 实例的 PIN 输入屏幕,这些实例可以在 ViewController 中显示一个原始字符或 (BOOL)[self isUsingBullets] 或 (BOOL)[self usingAsterisks]。 应用程序适用于 iPhone/iPhone 视网膜/iPad/iPad 视网膜,所以我不必提供四张图像...
#import <QuartzCore/QuartzCore.h>
- (void)setTextFieldInnerGradient:(UITextField *)textField
[textField setSecureTextEntry:self.isUsingBullets];
[textField setBackgroundColor:[UIColor blackColor]];
[textField setTextColor:[UIColor blackColor]];
[textField setBorderStyle:UITextBorderStyleNone];
[textField setClipsToBounds:YES];
[textField.layer setBorderColor:[[UIColor blackColor] CGColor]];
[textField.layer setBorderWidth:1.0f];
// make a gradient off-white background
CAGradientLayer *gradient = [CAGradientLayer layer];
CGRect gradRect = CGRectInset([textField bounds], 3, 3); // Reduce Width and Height and center layer
gradRect.size.height += 2; // minimise Bottom shadow, rely on clipping to remove these 2 pts.
gradient.frame = gradRect;
struct CGColor *topColor = [UIColor colorWithWhite:0.6f alpha:1.0f].CGColor;
struct CGColor *bottomColor = [UIColor colorWithWhite:0.9f alpha:1.0f].CGColor;
// We need to use this fancy __bridge object in order to get the array we want.
gradient.colors = [NSArray arrayWithObjects:(__bridge id)topColor, (__bridge id)bottomColor, nil];
[gradient setCornerRadius:4.0f];
[gradient setShadowOffset:CGSizeMake(0, 0)];
[gradient setShadowColor:[[UIColor whiteColor] CGColor]];
[gradient setShadowOpacity:1.0f];
[gradient setShadowRadius:3.0f];
// Now we need to Blur the edges of this layer "so it blends"
// This rasterizes the view down to 4x4 pixel chunks then scales it back up using bilinear filtering...
// it's EXTREMELY fast and looks ok if you are just wanting to blur a background view under a modal view.
// To undo it, just set the rasterization scale back to 1.0 or turn off rasterization.
[gradient setRasterizationScale:0.25];
[gradient setShouldRasterize:YES];
[textField.layer insertSublayer:gradient atIndex:0];
if (self.usingAsterisks)
[textField setFont:[UIFont systemFontOfSize:80.0]];
else
[textField setFont:[UIFont systemFontOfSize:40.0]];
[textField setTextAlignment:UITextAlignmentCenter];
[textField setEnabled:NO];
我希望这对某人有所帮助,因为这个论坛对我有所帮助。
【讨论】:
【参考方案17】:可以使用 Core Graphics 绘制内部阴影,方法是在边界之外创建一个大矩形路径,减去一个边界大小的矩形路径,然后用“正常”阴影填充生成的路径。
但是,由于您需要将其与渐变层相结合,我认为更简单的解决方案是创建内部阴影的 9 部分透明 PNG 图像并将其拉伸到合适的大小。 9 部分阴影图像如下所示(其大小为 21x21 像素):
CALayer *innerShadowLayer = [CALayer layer];
innerShadowLayer.contents = (id)[UIImage imageNamed: @"innershadow.png"].CGImage;
innerShadowLayer.contentsCenter = CGRectMake(10.0f/21.0f, 10.0f/21.0f, 1.0f/21.0f, 1.0f/21.0f);
然后设置innerShadowLayer的框架,它应该可以正确拉伸阴影。
【讨论】:
是的,我想你是对的。只是希望图层尽可能平坦。我可以在 Photoshop 中创建具有内部阴影和渐变外观的图像,但在使用图像时,我遇到了设备上 100% 匹配的颜色问题。 是的,这是所有渐变和阴影的问题,我只是无法在 iOS 上 1:1 重现这些 Photoshop 效果,我尽力了。以上是关于UIView层的内阴影效果?的主要内容,如果未能解决你的问题,请参考以下文章
在视图大小更改时更改 UIView 阴影大小会产生奇怪的效果