我在一个应用程序上工作了几年,收到了一个简单的设计请求:在UIView上圆角并添加投影。做以下所给的事
我想要一个自定义的UIView…:我只是想要一个空白的白色视图与圆角和光滴阴影(没有照明效果)。我可以逐个执行这些操作,但通常会发生clipToBounds/maskToBounds冲突。
我在一个应用程序上工作了几年,收到了一个简单的设计请求:在UIView上圆角并添加投影。做以下所给的事
我想要一个自定义的UIView…:我只是想要一个空白的白色视图与圆角和光滴阴影(没有照明效果)。我可以逐个执行这些操作,但通常会发生clipToBounds/maskToBounds冲突。
当前回答
使用Swift 4和Xcode 9,这是一个用投影和边框舍入ImageView的工作示例。
//set dimensions and position of image (in this case, centered)
let imageHeight: CGFloat = 150, imageWidth: CGFloat = 150
let xPosition = (self.view.frame.width / 2) - (imageWidth / 2)
let yPosition = (self.view.frame.height / 2) - (imageHeight / 2)
//set desired corner radius
let cornerRadius: CGFloat = 20
//create container for the image
let imageContainer = UIView(frame: CGRect(x: xPosition, y: yPosition, width: imageWidth, height: imageHeight))
//configure the container
imageContainer.clipsToBounds = false
imageContainer.layer.shadowColor = UIColor.black.cgColor
imageContainer.layer.shadowOpacity = 1
imageContainer.layer.shadowOffset = CGSize(width: 3.0, height: 3.0)
imageContainer.layer.shadowRadius = 5
imageContainer.layer.shadowPath = UIBezierPath(roundedRect: imageContainer.bounds, cornerRadius: cornerRadius).cgPath
//create imageView
let imageView = UIImageView(frame: imageContainer.bounds)
//configure the imageView
imageView.clipsToBounds = true
imageView.layer.cornerRadius = cornerRadius
//add a border (if required)
imageView.layer.borderColor = UIColor.black.cgColor
imageView.layer.borderWidth = 1.0
//set the image
imageView.image = UIImage(named: "bird")
//add the views to the superview
view.addSubview(imageContainer)
imageContainer.addSubview(imageView)
如果你想让图像是圆形的:(并且显示为无边框)
let cornerRadius = imageWidth / 2
其他回答
这是我的版本在Swift 3的UIView
let corners:UIRectCorner = [.bottomLeft, .topRight]
let path = UIBezierPath(roundedRect: rect, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
let mask = CAShapeLayer()
mask.path = path.cgPath
mask.fillColor = UIColor.white.cgColor
let shadowLayer = CAShapeLayer()
shadowLayer.shadowColor = UIColor.black.cgColor
shadowLayer.shadowOffset = CGSize(width: 0.0, height: 4.0)
shadowLayer.shadowRadius = 6.0
shadowLayer.shadowOpacity = 0.25
shadowLayer.shadowPath = mask.path
self.layer.insertSublayer(shadowLayer, at: 0)
self.layer.insertSublayer(mask, at: 1)
我在UIView中创建了一个helper
@interface UIView (Helper)
- (void)roundCornerswithRadius:(float)cornerRadius
andShadowOffset:(float)shadowOffset;
@end
你可以这样叫它
[self.view roundCornerswithRadius:5 andShadowOffset:5];
这是实现
- (void)roundCornerswithRadius:(float)cornerRadius
andShadowOffset:(float)shadowOffset
{
const float CORNER_RADIUS = cornerRadius;
const float SHADOW_OFFSET = shadowOffset;
const float SHADOW_OPACITY = 0.5;
const float SHADOW_RADIUS = 3.0;
UIView *superView = self.superview;
CGRect oldBackgroundFrame = self.frame;
[self removeFromSuperview];
CGRect frameForShadowView = CGRectMake(0, 0, oldBackgroundFrame.size.width, oldBackgroundFrame.size.height);
UIView *shadowView = [[UIView alloc] initWithFrame:frameForShadowView];
[shadowView.layer setShadowOpacity:SHADOW_OPACITY];
[shadowView.layer setShadowRadius:SHADOW_RADIUS];
[shadowView.layer setShadowOffset:CGSizeMake(SHADOW_OFFSET, SHADOW_OFFSET)];
[self.layer setCornerRadius:CORNER_RADIUS];
[self.layer setMasksToBounds:YES];
[shadowView addSubview:self];
[superView addSubview:shadowView];
}
当为容器视图分配阴影路径时,我使用以下技巧解决了这个问题:
[UIBezierPath bezierPathWithRoundedRect:cell.bounds cornerRadius:12]
请注意,阴影的路径是一个圆角矩形,与单元格包含的背景具有相同的角半径:
//this is the border for the UIView that is added to a cell
cell.backgroundView.layer.cornerRadius = 12;
cell.backgroundView.layer.masksToBounds = YES;
cell.backgroundView.layer.borderColor = [UIColor darkGrayColor].CGColor;
cell.backgroundView.layer.borderWidth = 1;
//this is the shadow around the cell itself (cannot have round corners with borders and shadow, need to use two views
cell.layer.shadowRadius = 2;
cell.layer.cornerRadius = 12;
cell.layer.masksToBounds = NO;
[[cell layer] setShadowColor:[[UIColor darkGrayColor] CGColor]];
[[cell layer] setShadowOffset:CGSizeMake(0.0,0.0)];
[[cell layer] setShadowOpacity:1.0];
UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:cell.bounds cornerRadius:12];
[[cell layer] setShadowPath:[path CGPath]];
iOS阴影和拐角半径
[iOS CALayer]
[iOS masksToBounds]
[iOS调试渲染]
你可以使用图层设置阴影
view1.layer.shadowColor = UIColor.magenta.cgColor
view1.layer.shadowOffset = CGSize(width: 0, height: 0)
view1.layer.shadowOpacity = 1
view1.layer.shadowRadius = 0
可视化
1. shadowoffset。宽度,2. shadowoffset。高度,3。shadowOpacity 4。shadowRadius
shadowOffset宽度和高度是任意的 shadowOpacity从0到1 shadowRadius从0开始为正
不是简单的任务
请注意,阴影不是仅根据边界和边角raduis计算的。在创建阴影的过程中,需要考虑以下事项:
子视图层 子层 内容(支持图像)
view1.backgroundColor = .clear
view1.layer.contents = UIImage(named: "ring")?.cgImage
view1.layer.contentsScale = UIScreen.main.scale
ScaleFactor(contentsScale, rasterizationScale) -默认为1.0
currentBitmapSize = layerSize * scaleFactor
//non retina
1 point == 1x pixels
//Retina
1 point == 2x pixels
//or
1 point == 3x pixels
//For example to draw line
point(width: 4, height: 2) == 1x pixels(width: 4, height: 2)(8 pixels) == 2x pixels(width: 8, height: 4)(32 pixels)
使用uisscreen .main.scale =当前屏幕的缩放因子
[iOS像素、点数、单位]
的绩效
使用层。角半径,阴影有一些性能影响
至于层。cornerRadius性能:
应用它的颜色混合使用[阅读更多]
至于影子Xcode提示你:
The layer is using dynamic shadows which are expensive to render. If possible try setting shadowPath, or pre-rendering the shadow into an image and putting it under the layer
1. 另外使用shadowPath
用于内部静态层。默认情况下,它是nil,这就是为什么UIKit应该创建一个屏幕外视图,并基于这个信息创建一个阴影。这就是为什么您能够预定义路径并进行设置。另一个优点是,您可以根据需要创建自定义阴影
view1.layer.shadowPath = UIBezierPath(roundedRect: view1.bounds, cornerRadius: 50).cgPath
缺点-缺乏活力。如果视图改变边界(宽度,高度,角半径…),阴影仍然是它是(旧的边界)。如果视图的位置被改变(移动,滚动),shadowPath将是正确的
2. 缓存栅格化
(iOS shouldRasterize)
我写了这个UIView分类方法来解决这个问题,使用单独的视图来表示阴影和角的半径。
-(UIView *)shadowedWrapViewWithBounds:(CGRect)bounds {
UIView *baseView = [[UIView alloc] init];
baseView.bounds = bounds;
baseView.backgroundColor = [UIColor clearColor];
baseView.layer.shadowColor = [UIColor blackColor].CGColor;
baseView.layer.shadowOffset = CGSizeMake(0, 0);
baseView.layer.shadowOpacity = 0.7;
baseView.layer.shadowRadius = 4.0;
// improve performance
baseView.layer.shadowPath = [UIBezierPath bezierPathWithRoundedRect:baseView.bounds cornerRadius:4].CGPath;
baseView.layer.shouldRasterize = YES;
baseView.layer.rasterizationScale = [UIScreen mainScreen].scale;
[baseView addSubview:self];
//use Masonry autolayout, self can set corner radius
[self makeConstraints:^(MASConstraintMaker *make) {
make.edges.equalTo(baseView);
}];
return baseView;
}