iPhone MapKit：自定义 MKPolygonView，图像绘制颠倒

发布于 2024-09-15 23:44:15 字数 1432 浏览 4 评论 0原文

有谁知道如何解决这个问题：我在自定义 MKPolygonView 中的图像颠倒了？

这个想法（这已经工作正常）是有一个扩展“MKPolygonView”的类“SnowmapsOverlayView”，用于显示图像。该图像具有默认位置和默认位置。地图上的大小（充当 Google 地图 Web API 中的 GroundOverlay）。这一切工作正常，但图像显示颠倒。我尝试了以下选项，但没有结果：

CGContextDrawImage传递 UIImage.CGImage 时颠倒绘制图像

感谢您的任何帮助或建议！

我的代码：

#import <MapKit/MapKit.h>

@interface SnowmapsOverlayView : MKPolygonView
{
}

@end

-----------------        

#import "SnowmapsOverlayView.h"

@implementation SnowmapsOverlayView

-(id)initWithPolygon:(MKPolygon *)polygon
{
    self = [super initWithPolygon:polygon];

    return self;    
}

-(void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context
{
    UIImage *image = [UIImage imageNamed:@"snowmap.png"];

    //This should do the trick, but is doesn't.. maybe a problem with the "context"?
    //CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height);
    //CGContextTranslateCTM(context, 0, image.size.height);
    //CGContextScaleCTM(context, 1.0, -1.0);

    CGRect overallCGRect = [self rectForMapRect:self.overlay.boundingMapRect];
    CGContextDrawImage(context, overallCGRect, image.CGImage);
}

-(BOOL)canDrawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale
{
    return YES;
}

原文

does anybody know what to do with this problem: my image in a custom MKPolygonView is flipped upside down?

The idea (this is working OK already) is having an class "SnowmapsOverlayView" that extends "MKPolygonView", that displays a image. This image has a default location & size on the map (acts as a GroundOverlay in the Google Maps web API). This is all working fine, but the image is displayed upside down. I've tryed the following options, but with no result:

CGContextDrawImage draws image upside down when passed UIImage.CGImage

Thanks for any help or suggestions!

My code:

#import <MapKit/MapKit.h>

@interface SnowmapsOverlayView : MKPolygonView
{
}

@end

-----------------        

#import "SnowmapsOverlayView.h"

@implementation SnowmapsOverlayView

-(id)initWithPolygon:(MKPolygon *)polygon
{
    self = [super initWithPolygon:polygon];

    return self;    
}

-(void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context
{
    UIImage *image = [UIImage imageNamed:@"snowmap.png"];

    //This should do the trick, but is doesn't.. maybe a problem with the "context"?
    //CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height);
    //CGContextTranslateCTM(context, 0, image.size.height);
    //CGContextScaleCTM(context, 1.0, -1.0);

    CGRect overallCGRect = [self rectForMapRect:self.overlay.boundingMapRect];
    CGContextDrawImage(context, overallCGRect, image.CGImage);
}

-(BOOL)canDrawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale
{
    return YES;
}

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阪姬 2024-09-22 23:44:15

固定的！这是完成工作的代码：

-(void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context
{
    UIImage *image = [UIImage imageNamed:@"snowmap.png"];
    MKMapRect theMapRect = [self.overlay boundingMapRect];
    CGRect theRect = [self rectForMapRect:theMapRect];

    UIGraphicsPushContext(context);
    [image drawInRect:theRect blendMode:kCGBlendModeNormal alpha:1.0];
    UIGraphicsPopContext();
}

Fixed! This is the code that gets the job done:

-(void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context
{
    UIImage *image = [UIImage imageNamed:@"snowmap.png"];
    MKMapRect theMapRect = [self.overlay boundingMapRect];
    CGRect theRect = [self rectForMapRect:theMapRect];

    UIGraphicsPushContext(context);
    [image drawInRect:theRect blendMode:kCGBlendModeNormal alpha:1.0];
    UIGraphicsPopContext();
}

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