MapTypeStyle in MapKit | 易学教程

问题

I wonder to know if there is any way to configure our MapKit maps like we do with the MapTypeStyle object in the Google Maps API.

If I refer to Apple doc's, MKMapView has a mapType option that takes MKMapType constant but no styles parameters like MapOptions with the MapTypeStyle and the MapTypeStyler wich is very powerfull for fast maps customizing.

So my question is : Is there any way to achieve something similar with the MapKit framework, if not, what is the best framework/library to do this ? I'm thinking of MapBox and similar products.

回答1:

There are a few options for you my friend. You could use one of these frameworks

http://cloudmade.com/products/iphone-sdk

https://github.com/route-me/route-me

Or you could just use mapbox. Their api looks pretty good. Alternatively you supply you own map tiles and overlay mapkit. Something like this in a MKOverlayView

- (void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context {

NSURL* fileURL = [(HeatMap*)self.overlay localUrlForStyle:@"alien" withMapRect:mapRect andZoomScale:zoomScale];
NSData *imageData = [NSData dataWithContentsOfURL:fileURL ];
if (imageData != nil) {
    UIImage* img = [UIImage imageNamed:@"aTileX.png"];
    // Perform the image render on the current UI context
    UIGraphicsPushContext(context);
    [img drawInRect:[self rectForMapRect:mapRect] blendMode:kCGBlendModeNormal alpha:1.0];
    UIGraphicsPopContext();
    }
}

Also check this out if you want unsupported "terrain" mode http://openradar.appspot.com/9621632

I'm actually in the middle of a program that requires overlaying tiles over a map. This example has been very helpful. You'll want to look into MKOverlay and MKOverlayView. The project that I am doing involves using gheat. I am accessing the tiles through an NSURLConnection and storing them locally. A gist of my implementation.

回答2:

There is no way to customize the map styles natively with mapkit. Your only option for this is to opt for a hybrid app approach, and then customize the styles using html/javascript in the page itself.

回答3:

As drawing the tiles takes place in a private class called MKMapTileView you can not simply write a category. You have to implement another class for the custom drawing. The Methods of this class will be used to overload the implementation of MKMapTileView during runtime:

Header file:

@interface MyColorMap : NSObject
+ (void)overLoadMethods:(Class)destinationClass;
@end

Imlementation:

#import "MyColorMap.h"
#import <objc/runtime.h>

@implementation MyColorMap

+ (void)overLoadMethods:(Class)destinationClass {
    // get the original method for drawing a tile
    Method originalDrawLayer = class_getInstanceMethod(destinationClass, @selector(drawLayer:inContext:));

    // get the method we will replace with the original implementation of 'drawLayer:inContext:' later
    Method backupDrawLayer = class_getInstanceMethod([self class], @selector(backupDrawLayer:inContext:));

    // get the method we will use to draw our own colors
    Method myDrawLayer = class_getInstanceMethod([self class], @selector(myDrawLayer:inContext:));

    // dito with the implementations
    IMP impOld = method_getImplementation(originalDrawLayer);
    IMP impNew = method_getImplementation(myDrawLayer);

    // replace the original 'drawLayer:inContext:' with our own implementation
    method_setImplementation(originalDrawLayer, impNew);

    // set the original 'drawLayer:inContext:' implementation to our stub-method, so wie can call it later on
    SEL selector = method_getName(backupDrawLayer);
    const char *types = method_getTypeEncoding(backupDrawLayer);
    class_addMethod(destinationClass, selector, impOld, types);
}


- (void)backupDrawLayer:(CALayer*)l inContext:(CGContextRef)c {
    // stub method, implementation will never be called. The only reason we implement this is so we can call the original method durring runtime
}

- (void)myDrawLayer:(CALayer*)l inContext:(CGContextRef)c {
    // set background to white so wie can use it for blendmode
    CGContextSetFillColorWithColor(c, [[UIColor whiteColor] CGColor]); 
    CGContextFillRect(c, CGContextGetClipBoundingBox(c));

    // set blendmode so the map will show as grayscale
    CGContextSetBlendMode(c, kCGBlendModeLuminosity);
    // kCGBlendModeExclusion for inverted colors etc.

    // calling the stub-method which will become the original method durring runtime
    [self backupDrawLayer:l inContext:c];

    // if you want more advanced manipulations you can alter the context after drawing:

//    int w = CGBitmapContextGetWidth(c);
//    int h = CGBitmapContextGetHeight(c);
//    
//    unsigned char* data = CGBitmapContextGetData(c);
//    if (data != NULL) {
//        int maxY = h;
//        for(int y = 0; y<maxY; y++) {
//            for(int x = 0; x<w; x++) {
//                
//                int offset = 4*((w*y)+x);
//                char r = data[offset];
//                char g = data[offset+1];
//                char b = data[offset+2]; 
//                char a = data[offset+3]; 
//                
//                // do what ever you want with the pixels
//                
//                data[offset] = r;
//                data[offset+1] = g; 
//                data[offset+2] = b;
//                data[offset+3] = a;
//            }
//        }
//    }
}

now you have to call [MyColorMap overLoadMethods:NSClassFromString(@"MKMapTileView")] at some point before using a MKMapView

来源：https://stackoverflow.com/questions/10354925/maptypestyle-in-mapkit

标签

ios

google-maps

ios5

map

mapkit