我正在创建一个UIview并以这种方式在其上应用蒙版:
baseView = [[ViewTutorialSubclass alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]];
//self.view = baseView;
[self.view addSubview:baseView];
[baseView setBackgroundColor:[UIColor blackColor]];
baseView.userInteractionEnabled = YES;
baseView.alpha = 0.7;
mask = [[CAShapeLayer alloc] init];
mask.frame = baseView.layer.bounds;
CGRect biggerRect = CGRectMake(mask.frame.origin.x, mask.frame.origin.y, mask.frame.size.width, mask.frame.size.height);
CGRect smallerRect = CGRectMake(7.0f, 160.0f, 590.0f, 43.0f);
UIBezierPath *maskPath = [UIBezierPath bezierPath];
[maskPath moveToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMaxY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMaxY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(biggerRect), CGRectGetMinY(biggerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(biggerRect), CGRectGetMinY(biggerRect))];
[maskPath moveToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMaxY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMaxY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMaxX(smallerRect), CGRectGetMinY(smallerRect))];
[maskPath addLineToPoint:CGPointMake(CGRectGetMinX(smallerRect), CGRectGetMinY(smallerRect))];
mask.path = maskPath.CGPath;
[mask setFillRule:kCAFillRuleEvenOdd];
mask.fillColor = [[UIColor blackColor] CGColor];
baseView.layer.mask = mask;
在我的ViewTutorialSubclass.m中,我有:
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
for (UIView *v in self.subviews) {
CGPoint localPoint = [v convertPoint:point fromView:self];
if (v.alpha > 0.8 && [v pointInside:localPoint withEvent:event])
return YES;
}
return NO;
}
如果用户使用蒙版触摸UIview的任何部分(如此透明),则所有用户触摸都会传递到此视图下方的UIview,而如果用户触摸其他任何位置,则触摸将应用于此当前UIView的。我该怎么办? pointInside是最好的解决方案吗?
答案 0 :(得分:3)
包含遮罩层的视图类应覆盖pointInside,并根据遮罩状态返回YES或NO。如果蒙版始终是一个矩形,那么你可以在矩形测试中做一个点,但我打赌这不是你想要的。您希望此测试适用于任意形状的蒙版。设置(在dispatch_once中)一个像素宽的CGBitmapContext。在pointInside中:withEvent:将遮罩层渲染到位图上下文中,看看它是否绘制了任何东西。这是一个例子:
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
static CGContextRef context;
static CGColorSpaceRef rgbColorSpace;
static unsigned char bitmapData[4];
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
rgbColorSpace = CGColorSpaceCreateDeviceRGB();
context = CGBitmapContextCreate(bitmapData, 1, 1, 8, 4, rgbColorSpace, kCGBitmapAlphaInfoMask & kCGImageAlphaPremultipliedLast);
});
if ([super pointInside:point withEvent:event]) {
CGContextTranslateCTM(context, -point.x, -point.y);
[self.layer.mask renderInContext:context];
CGContextTranslateCTM(context, point.x, point.y);
BOOL result = (bitmapData[3] > 0);
memset(bitmapData, 0, sizeof(bitmapData));
return result;
}
return NO;
}
编辑:如果将kCGImageAlphaPremultipliedLast(单独)传递给CGBitmapContextCreate
,Xcode 5中的编译器会生成有关枚举类型不匹配的警告。参数的类型应为CGBitmapInfo
,但kCGImageAlphaPremultipliedLast
来自枚举类型CGImageAlphaInfo
。要消除警告,您可以将kCGImageAlphaPremultipliedLast
与CGBitmapInfo
枚举类型中的值结合使用,例如kCGBitmapAlphaInfoMask & kCGImageAlphaPremultipliedLast
。无论如何这样做更好,因为新代码明确表示我们正在发送一般的“位图信息”,但我们感兴趣的是仅位图信息与alpha通道的处理方式有关。