ios - 检测使用变换的层是否包含接触点
<p><p>我一直在用这个敲我的头。我有一个基于 <a href="https://stackoverflow.com/questions/13528898/how-can-i-draw-an-arrow-using-core-graphics" rel="noreferrer noopener nofollow">this post</a> 的箭头.当我点击包含箭头的 View 时，我需要知道箭头层是否包含接触点。我已经搜索了两天的解决方案，但还没有找到任何可行的方法。如果有人能指出我正确的方向，那将不胜感激一千倍。 </p>
<pre><code>@implementation ArrowView
{
CGFloat headLength;
UIBezierPath *path;
}
- (id) initWithFrame:(CGRect)frame withColor: (UIColor *) color withWeight: (CGFloat) weight withStartPoint: (CGPoint) startPoint withEndPoint: (CGPoint) endPoint {
if (self = ) {
_arrowColor = color;
_weight = weight;
_startPoint = startPoint;
_endPoint = endPoint;
self.userInteractionEnabled = YES;
UITapGestureRecognizer *tap = [ initWithTarget:self action:@selector(tapped:)];
;
}
return self;
}
- (void) tapped: (UITapGestureRecognizer *) sender {
CGPoint location = ;
if () {
;
}
}
- (void) drawRect:(CGRect)rect {
;
;
;
;
_tailWidth = 5 + _weight;
_headWidth = 25 + _weight;
headLength = 40;
path = [UIBezierPath dqd_bezierPathWithArrowFromPoint:(CGPoint)_startPoint
toPoint:(CGPoint)_endPoint
tailWidth:(CGFloat)_tailWidth
headWidth:(CGFloat)_headWidth
headLength:(CGFloat)headLength];
;
CGFloat width = _endPoint.x - _startPoint.x;
CGFloat height = _endPoint.y - _startPoint.y;
CGFloat offset = 5;
if (ABS(width) < offset) {
width = width > 0 ? offset : -offset;
}
if (ABS(height) < offset) {
height = height > 0 ? offset : -offset;
}
_arrowLayer = ;
_arrowLayer.bounds = CGRectMake(_startPoint.x, _startPoint.y, width, height);
_arrowLayer.position = CGPointMake(((_endPoint.x - _startPoint.x) / 2), (_endPoint.y - _startPoint.y) / 2);
_arrowLayer.path = path.CGPath;
_arrowLayer.fillColor = _arrowColor.CGColor;
//_arrowLayer.backgroundColor = .CGColor;
if (!_isSelected) {
_arrowLayer.strokeColor = _arrowColor.CGColor;
} else {
if (_arrowColor != ) {
_arrowLayer.strokeColor = .CGColor;
} else {
_arrowLayer.strokeColor = .CGColor;
}
}
_arrowLayer.borderColor = .CGColor;
_arrowLayer.borderWidth = 1;
;
}
- (void) setIsSelected: (BOOL) isSelected {
_isSelected = isSelected;
;
}
- (void) updateStartPoint: (CGPoint) startPoint {
_startPoint = startPoint;
;
}
- (void) updateEndPoint: (CGPoint) endPoint {
_endPoint = endPoint;
;
}
- (void) updateColor: (UIColor *) color {
_arrowColor = color;
;
}
- (void) updateWeight: (CGFloat) weight {
_weight = weight;
;
}
@end
#define kArrowPointCount 7
@implementation UIBezierPath (dqd_arrowhead)
+ (UIBezierPath *)dqd_bezierPathWithArrowFromPoint:(CGPoint)startPoint toPoint:(CGPoint)endPoint tailWidth:(CGFloat)tailWidth headWidth:(CGFloat)headWidth headLength:(CGFloat)headLength {
CGFloat length = hypotf(endPoint.x - startPoint.x, endPoint.y - startPoint.y);
CGPoint points;
;
CGAffineTransform transform = ;
CGMutablePathRef cgPath = CGPathCreateMutable();
CGPathAddLines(cgPath, &transform, points, sizeof points / sizeof *points);
CGPathCloseSubpath(cgPath);
UIBezierPath *uiPath = ;
CGPathRelease(cgPath);
return uiPath;
}
+ (void)dqd_getAxisAlignedArrowPoints:(CGPoint)points
forLength:(CGFloat)length
tailWidth:(CGFloat)tailWidth
headWidth:(CGFloat)headWidth
headLength:(CGFloat)headLength {
CGFloat tailLength = length - headLength;
points = CGPointMake(0, tailWidth / 2);
points = CGPointMake(tailLength, tailWidth / 2);
points = CGPointMake(tailLength, headWidth / 2);
points = CGPointMake(length, 0);
points = CGPointMake(tailLength, -headWidth / 2);
points = CGPointMake(tailLength, -tailWidth / 2);
points = CGPointMake(0, -tailWidth / 2);
}
+ (CGAffineTransform)dqd_transformForStartPoint:(CGPoint)startPoint
endPoint:(CGPoint)endPoint
length:(CGFloat)length {
CGFloat cosine = (endPoint.x - startPoint.x) / length;
CGFloat sine = (endPoint.y - startPoint.y) / length;
return (CGAffineTransform){ cosine, sine, -sine, cosine, startPoint.x, startPoint.y };
}
@end
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>我找到了一个替代解决方案。 SpaceDog 让我以不同的方式思考这种情况。我只需要知道是否触摸了有颜色的区域。我找到了这篇文章并将其翻译为Objective C。它工作得很好。虽然我更喜欢检测点在箭头内，但这也适用于我的目的。谢谢大家的回复。我很感激。</p>
<p> <a href="https://stackoverflow.com/questions/27923232/how-to-know-that-if-the-only-visible-area-of-a-png-is-touched-in-xcode-swift-o" rel="noreferrer noopener nofollow">Post I got the code below from.</a> </p>
<pre><code>- (void) tapped: (UITapGestureRecognizer *) sender {
CGPoint location = ;
CGFloat p = ;
if (p > 0) {
;
}
}
- (CGFloat) alphaFromPoint: (CGPoint) point {
UInt8 pixel = {0,0,0,0};
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo alphaInfo = (CGBitmapInfo)kCGImageAlphaPremultipliedLast;
CGContextRef context = CGBitmapContextCreate(&pixel, 1, 1, 8, 4, colorSpace, alphaInfo);
CGContextTranslateCTM(context, -point.x, -point.y);
;
CGFloat floatAlpha = pixel;
return floatAlpha;
}
</code></pre></p>
<p style="font-size: 20px;">关于ios - 检测使用变换的层是否包含接触点，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/32367713/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/32367713/
</a>
</p>
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