不久前，我發(fā)布了一個(gè)關(guān)于僅將視圖的兩個(gè)角取整的問題，并獲得了不錯(cuò)的答復(fù)，但是在實(shí)現(xiàn)它時(shí)遇到了問題。這是我的drawRect：方法：- (void)drawRect:(CGRect)rect { //[super drawRect:rect]; <------Should I uncomment this? int radius = 5; CGContextRef context = UIGraphicsGetCurrentContext(); CGContextBeginPath(context); CGContextAddArc(context, rect.origin.x + radius, rect.origin.y + rect.size.height - radius, radius, M_PI, M_PI / 2, 1); CGContextAddArc(context, rect.origin.x + rect.size.width - radius, rect.origin.y + rect.size.height - radius, radius, M_PI / 2, 0.0f, 1); CGContextClosePath(context); CGContextClip(context);}該方法正在被調(diào)用，但似乎并不影響視圖的結(jié)果。有什么想法嗎？
3 回答
當(dāng)年話下
TA貢獻(xiàn)1890條經(jīng)驗(yàn) 獲得超9個(gè)贊
iOS 11中引入的CACornerMask可幫助在視圖層中定義左上，右上，左下，右下。以下是使用示例。
在這里，我嘗試僅舍入兩個(gè)上角：
myView.clipsToBounds = true
myView.layer.cornerRadius = 10
myView.layer.maskedCorners = [.layerMinXMinYCorner,.layerMaxXMinYCorner]
提前致謝。
僅供參考：
POPMUISE
TA貢獻(xiàn)1765條經(jīng)驗(yàn) 獲得超5個(gè)贊
據(jù)我所知，如果還需要遮罩子視圖，則可以使用CALayer遮罩。有兩種方法可以做到這一點(diǎn)。第一個(gè)比較優(yōu)雅，第二個(gè)是一種解決方法:-)，但它也很快。兩者都是基于CALayer遮罩的。去年，我在幾個(gè)項(xiàng)目中都使用了這兩種方法，然后希望您能找到有用的東西。
解決方案1
首先，我創(chuàng)建了此函數(shù)以動(dòng)態(tài)生成UIImage帶有所需圓角的圖像蒙版（）。此函數(shù)本質(zhì)上需要5個(gè)參數(shù)：圖像的邊界和4個(gè)角半徑（左上，右上，左下和右下）。
static inline UIImage* MTDContextCreateRoundedMask( CGRect rect, CGFloat radius_tl, CGFloat radius_tr, CGFloat radius_bl, CGFloat radius_br ) {
CGContextRef context;
CGColorSpaceRef colorSpace;
colorSpace = CGColorSpaceCreateDeviceRGB();
// create a bitmap graphics context the size of the image
context = CGBitmapContextCreate( NULL, rect.size.width, rect.size.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast );
// free the rgb colorspace
CGColorSpaceRelease(colorSpace);
if ( context == NULL ) {
return NULL;
}
// cerate mask
CGFloat minx = CGRectGetMinX( rect ), midx = CGRectGetMidX( rect ), maxx = CGRectGetMaxX( rect );
CGFloat miny = CGRectGetMinY( rect ), midy = CGRectGetMidY( rect ), maxy = CGRectGetMaxY( rect );
CGContextBeginPath( context );
CGContextSetGrayFillColor( context, 1.0, 0.0 );
CGContextAddRect( context, rect );
CGContextClosePath( context );
CGContextDrawPath( context, kCGPathFill );
CGContextSetGrayFillColor( context, 1.0, 1.0 );
CGContextBeginPath( context );
CGContextMoveToPoint( context, minx, midy );
CGContextAddArcToPoint( context, minx, miny, midx, miny, radius_bl );
CGContextAddArcToPoint( context, maxx, miny, maxx, midy, radius_br );
CGContextAddArcToPoint( context, maxx, maxy, midx, maxy, radius_tr );
CGContextAddArcToPoint( context, minx, maxy, minx, midy, radius_tl );
CGContextClosePath( context );
CGContextDrawPath( context, kCGPathFill );
// Create CGImageRef of the main view bitmap content, and then
// release that bitmap context
CGImageRef bitmapContext = CGBitmapContextCreateImage( context );
CGContextRelease( context );
// convert the finished resized image to a UIImage
UIImage *theImage = [UIImage imageWithCGImage:bitmapContext];
// image is retained by the property setting above, so we can
// release the original
CGImageRelease(bitmapContext);
// return the image
return theImage;
}
現(xiàn)在，您只需要幾行代碼。我把東西在我的viewController viewDidLoad的方法，因?yàn)樗乃俣雀欤憧梢栽谧远x也用它UIView與layoutSubviews實(shí)例方法。
- (void)viewDidLoad {
// Create the mask image you need calling the previous function
UIImage *mask = MTDContextCreateRoundedMask( self.view.bounds, 50.0, 50.0, 0.0, 0.0 );
// Create a new layer that will work as a mask
CALayer *layerMask = [CALayer layer];
layerMask.frame = self.view.bounds;
// Put the mask image as content of the layer
layerMask.contents = (id)mask.CGImage;
// set the mask layer as mask of the view layer
self.view.layer.mask = layerMask;
// Add a backaground color just to check if it works
self.view.backgroundColor = [UIColor redColor];
// Add a test view to verify the correct mask clipping
UIView *testView = [[UIView alloc] initWithFrame:CGRectMake( 0.0, 0.0, 50.0, 50.0 )];
testView.backgroundColor = [UIColor blueColor];
[self.view addSubview:testView];
[testView release];
[super viewDidLoad];
}
解決方案2
這個(gè)解決方案有點(diǎn)“骯臟”。本質(zhì)上，您可以使用所需的圓角（所有角）創(chuàng)建遮罩層。然后，應(yīng)通過角半徑的值增加蒙版層的高度。這樣，底部的圓角被隱藏了，您只能看到上面的圓角。我把代碼只是在viewDidLoad方法，因?yàn)樗乃俣雀?，但你可以在自定義也用它UIView與layoutSubviews實(shí)例方法。
- (void)viewDidLoad {
// set the radius
CGFloat radius = 50.0;
// set the mask frame, and increase the height by the
// corner radius to hide bottom corners
CGRect maskFrame = self.view.bounds;
maskFrame.size.height += radius;
// create the mask layer
CALayer *maskLayer = [CALayer layer];
maskLayer.cornerRadius = radius;
maskLayer.backgroundColor = [UIColor blackColor].CGColor;
maskLayer.frame = maskFrame;
// set the mask
self.view.layer.mask = maskLayer;
// Add a backaground color just to check if it works
self.view.backgroundColor = [UIColor redColor];
// Add a test view to verify the correct mask clipping
UIView *testView = [[UIView alloc] initWithFrame:CGRectMake( 0.0, 0.0, 50.0, 50.0 )];
testView.backgroundColor = [UIColor blueColor];
[self.view addSubview:testView];
[testView release];
[super viewDidLoad];
}
希望這可以幫助。再見！
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