MKOverlay 视图模糊
我正在尝试使用 MKOverlayView 添加 png 图像作为自定义地图。我就快到了 - 我能够将图像排列在正确的位置，并且我知道 MKOverlayView 子类中的 -drawMapRect: 方法正在被定期调用；我似乎无法正确渲染图像。完全模糊了，几乎认不出来了。我还知道图像足够大（1936 × 2967）。这是我的 -drawMapRect 代码：
- (void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context{
// Load image from applicaiton bundle
NSString* imageFileName = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"map.jpg"];
CGDataProviderRef provider = CGDataProviderCreateWithFilename([imageFileName UTF8String]);
CGImageRef image = CGImageCreateWithJPEGDataProvider(provider, NULL, true, kCGRenderingIntentDefault);
CGDataProviderRelease(provider);
// save context before screwing with it
CGContextSaveGState(context);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextSetAlpha(context, 1.0);
// get the overlay bounds
MKMapRect theMapRect = [self.overlay boundingMapRect];
CGRect theRect = [self rectForMapRect:theMapRect];
// Draw image
CGContextDrawImage(context, theRect, image);
CGImageRelease(image);
CGContextRestoreGState(context);
有人知道发生了什么事吗？
谢谢！ -马特
I'm trying to add a png image as a custom map using MKOverlayView. I'm almost there - I am able to get the image lined up in the right place, and I know that the -drawMapRect: method in the subclass of MKOverlayView is being called periodically; I just can't seem to get the image to render properly. It's totally blurry, almost beyond recognition. I also know the image is large enough (it is 1936 × 2967). Here is my code for -drawMapRect:
- (void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context{
// Load image from applicaiton bundle
NSString* imageFileName = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"map.jpg"];
CGDataProviderRef provider = CGDataProviderCreateWithFilename([imageFileName UTF8String]);
CGImageRef image = CGImageCreateWithJPEGDataProvider(provider, NULL, true, kCGRenderingIntentDefault);
CGDataProviderRelease(provider);
// save context before screwing with it
CGContextSaveGState(context);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextSetAlpha(context, 1.0);
// get the overlay bounds
MKMapRect theMapRect = [self.overlay boundingMapRect];
CGRect theRect = [self rectForMapRect:theMapRect];
// Draw image
CGContextDrawImage(context, theRect, image);
CGImageRelease(image);
CGContextRestoreGState(context);
Does anyone have a clue what's going on?
Thanks!
-Matt
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我也遇到过类似的问题。问题是我的boundingMapRect定义不正确。当图块上的比例较小时，完整图像会按比例缩小呈现。然后地图被缩放，并且并非所有图像图块都在boundingMapRect图块中，因此它们不会以正确的比例重新绘制，并且缩小的版本被缩放。至少我认为是这样的。
希望这有帮助。
I've had a similar problem. The problem was that my boundingMapRect was defined incorrectly. The full image is rendered scaled down when the scale is small on a tile. Then the map is zoomed and not all the image tiles are in the boundingMapRect tiles so they are not redrawn in the correct scale and the scaled down version is zoomed. At least that's what I think happens.
Hope this helps.
摆脱 CGContextScaleCTM(context, 1.0, -1.0);并在预览中对图像进行垂直翻转。 Mapkit 似乎使用上下文信息来确定图像的哪一部分渲染得更清晰。知道已经有一段时间了，但希望它有所帮助！
Get rid of CGContextScaleCTM(context, 1.0, -1.0); and do a vertical flip on your image in preview instead. the mapkit seems to use the context information to determine which part of the image to render more clearly. Know it's been a while, but hope it helps!
谢谢罗布，你让我很开心。 ，我的模糊叠加图像变得锐化
当我替换为时
Thanks Rob, you made my day. My blur overlay image got sharpen when I replaced
with