iOS - MKOverlayView自定义视图rect填充工作，但线条绘制不工作 [英] iOS - MKOverlayView custom view rect fills works, but line draws do not
问题描述
地图叠加层新手，但这是一个非常奇怪的问题。
New to Map Overlays, but this is a really weird problem.
我将mapView.visibleMapRect传递给我的overlay实现并将其作为boundingMapRect返回，这现在很好 - 只是试图在整个地图上绘制一条直线。
I pass in the mapView.visibleMapRect to my overlay implementation and return that as the boundingMapRect, which is fine for now - just trying to draw a line on the whole map rect.
我的drawMapRect被调用，在下面的代码中 - 绘制了部分透明的绿色矩形，但线条不是。我已经在uiview子类的drawRect中验证了线条绘制代码，所以我知道它绘制了一些东西： - ）
My drawMapRect is getting called, and in the following code - the partially transparent green rectangle is drawn, but the lines are not. I've verified the line drawing code in drawRect of a uiview subclass, so I know it draws something :-)
我确定我必须遗漏一些简单的东西，但我看不到它： - ）
I'm sure I must be missing something easy, but I can't see it :-)
让我失望的是，当转换为CGRect时，visibleMapRect具有非常奇怪的坐标 - 它们不会看起来像我的屏幕坐标 - 这似乎是我的问题的根源。
The thing that throws me off is that the visibleMapRect, when converted to a CGRect has very strange coordinates - they don't look like screen coordinates to me at all - which seems like the source of the problem to me.
任何帮助将不胜感激：
drawMapRect被多次调用，我正在附加下面的输出。
The drawMapRect is called multiple times, i'm attaching the output below.
谢谢，
Bob
Thanks, Bob
ViewController设置代码：
CLLocationCoordinate2D center;
center.latitude = 29.46;
center.longitude = -98.30;
MKCoordinateRegion region;
MKCoordinateSpan span;
span.latitudeDelta = 0.2;
span.longitudeDelta = 0.2;
region.center = center;
region.span = span;
self.mapView.region = region;
MyOverlay *myoverlay = [[MyOverlay alloc] initWithCoordinate: center andBoundingRect: self.mapView.visibleMapRect];
[self.mapView addOverlay:myoverlay];
MyOverlay代码：
@implementation MyOverlay
@synthesize coordinate;
@synthesize boundingMapRect;
- (id) initWithCoordinate: (CLLocationCoordinate2D) coord andBoundingRect: (MKMapRect) bRect {
if ((self = [super init])) {
//customize here
coordinate = coord;
boundingMapRect = bRect;
}
return self;
}
MyOverlayView绘图代码
- (void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context {
CGRect theRect = [self rectForMapRect:mapRect];
NSLog(@"in drawMapRect ...theRect is %f, %f, size of %f x %f", theRect.origin.x, theRect.origin.y, theRect.size.width, theRect.size.height);
CGContextSetAlpha(context, 1.0);
CGContextSetStrokeColorWithColor(context, [UIColor blueColor].CGColor);
CGContextMoveToPoint(context, theRect.origin.x, theRect.origin.y);
CGContextAddLineToPoint(context, theRect.size.width, theRect.size.width);
CGContextSetAlpha(context, .25);
CGContextSetFillColorWithColor(context, [UIColor greenColor].CGColor);
CGContextFillRect(context, theRect);
}
输出
2011-05-16 11:25:18.037 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 61440.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.038 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 323584.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.042 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 323584.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.044 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -200704.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.046 coolOverlayTest[71661:7903] in drawMapRect ...theRect is -200704.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.048 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 61440.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.052 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 323584.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.054 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 323584.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.056 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -200704.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.057 coolOverlayTest[71661:7903] in drawMapRect ...theRect is -200704.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.059 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 61440.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.061 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 61440.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.063 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 323584.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.064 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 323584.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.066 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -200704.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.068 coolOverlayTest[71661:7903] in drawMapRect ...theRect is -200704.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.070 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 585728.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.072 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 585728.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.074 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -462848.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.075 coolOverlayTest[71661:7903] in drawMapRect ...theRect is -462848.000000, 37888.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.082 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 61440.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.082 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 585728.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.085 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 61440.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.087 coolOverlayTest[71661:7903] in drawMapRect ...theRect is -462848.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.089 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -462848.000000, -224256.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.099 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 585728.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.102 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -462848.000000, 300032.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.106 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 323584.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.109 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -200704.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.111 coolOverlayTest[71661:7903] in drawMapRect ...theRect is -200704.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.116 coolOverlayTest[71661:760b] in drawMapRect ...theRect is 585728.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.119 coolOverlayTest[71661:7903] in drawMapRect ...theRect is 585728.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.124 coolOverlayTest[71661:7903] in drawMapRect ...theRect is -462848.000000, -486400.000000, size of 262144.000000 x 262144.000000
2011-05-16 11:25:18.126 coolOverlayTest[71661:760b] in drawMapRect ...theRect is -462848.000000, -486400.000000, size of 262144.000000 x 262144.000000
推荐答案
要考虑的一点是，出于性能原因，在多个线程上调用 drawMapRect：。这就解释了为什么你看到 drawMapRect：被多次调用。此外，此方法的 mapRect 输入不一定等于可见 mapView.visibleMapRect 。实际上 mapRect 通常是 mapView.visibleMapRect 的一小部分，不同的线程呈现 mapView.visibleMapRect 中，它并不意味着它包含在 mapRect 中传递给所有结果调用 drawMapRect 。
One thing to consider is that for performance reasons, drawMapRect: is called on multiple threads. This explains why you see drawMapRect: getting called multiple times. Additionally the mapRect input to this method is NOT necessarily equal to the visible mapView.visibleMapRect. In fact mapRect is usually a small section of mapView.visibleMapRect and different threads render different regions of mapView.visibleMapRect. Thus just because a point is contained inside mapView.visibleMapRect it does not mean that it is contained within the mapRect passed to all of the resulting calls to drawMapRect.
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