1 #import <MAMapKit/MAMapKit.h> 2 3 @interface MAMapView (ZoomLevel) 4 - (NSUInteger)getZoomLevel; 5 6 - (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate 7 zoomLevel:(NSUInteger)zoomLevel 8 animated:(BOOL)animated; 9 10 - (void)zoomToFitMapAnnotations; 11 @end
1 // 2 // MAMapView+ZoomLevel.m 3 // Yjf 4 // 5 // Created by iMac on 14/12/2. 6 // Copyright (c) 2014年 POTech. All rights reserved. 7 // 8 9 #import "MAMapView+ZoomLevel.h" 10 11 #define MERCATOR_OFFSET 268435456 12 #define MERCATOR_RADIUS 85445659.44705395 13 14 @implementation MAMapView (ZoomLevel) 15 16 #pragma mark - Map conversion methods 17 18 - (double)longitudeToPixelSpaceX:(double)longitude 19 { 20 return round(MERCATOR_OFFSET + MERCATOR_RADIUS * longitude * M_PI / 180.0); 21 } 22 23 - (double)latitudeToPixelSpaceY:(double)latitude 24 { 25 return round(MERCATOR_OFFSET - MERCATOR_RADIUS * logf((1 + sinf(latitude * M_PI / 180.0)) / (1 - sinf(latitude * M_PI / 180.0))) / 2.0); 26 } 27 28 - (double)pixelSpaceXToLongitude:(double)pixelX 29 { 30 return ((round(pixelX) - MERCATOR_OFFSET) / MERCATOR_RADIUS) * 180.0 / M_PI; 31 } 32 33 - (double)pixelSpaceYToLatitude:(double)pixelY 34 { 35 return (M_PI / 2.0 - 2.0 * atan(exp((round(pixelY) - MERCATOR_OFFSET) / MERCATOR_RADIUS))) * 180.0 / M_PI; 36 } 37 38 #pragma mark - Helper methods 39 40 - (MACoordinateSpan)coordinateSpanWithMapView:(MAMapView *)mapView 41 centerCoordinate:(CLLocationCoordinate2D)centerCoordinate 42 andZoomLevel:(NSUInteger)zoomLevel 43 { 44 // convert center coordiate to pixel space 45 double centerPixelX = [self longitudeToPixelSpaceX:centerCoordinate.longitude]; 46 double centerPixelY = [self latitudeToPixelSpaceY:centerCoordinate.latitude]; 47 48 // determine the scale value from the zoom level 49 NSInteger zoomExponent = 20 - zoomLevel; 50 double zoomScale = pow(2, zoomExponent); 51 52 // scale the map’s size in pixel space 53 CGSize mapSizeInPixels = mapView.bounds.size; 54 double scaledMapWidth = mapSizeInPixels.width * zoomScale; 55 double scaledMapHeight = mapSizeInPixels.height * zoomScale; 56 57 // figure out the position of the top-left pixel 58 double topLeftPixelX = centerPixelX - (scaledMapWidth / 2); 59 double topLeftPixelY = centerPixelY - (scaledMapHeight / 2); 60 61 // find delta between left and right longitudes 62 CLLocationDegrees minLng = [self pixelSpaceXToLongitude:topLeftPixelX]; 63 CLLocationDegrees maxLng = [self pixelSpaceXToLongitude:topLeftPixelX + scaledMapWidth]; 64 CLLocationDegrees longitudeDelta = maxLng - minLng; 65 66 // find delta between top and bottom latitudes 67 CLLocationDegrees minLat = [self pixelSpaceYToLatitude:topLeftPixelY]; 68 CLLocationDegrees maxLat = [self pixelSpaceYToLatitude:topLeftPixelY + scaledMapHeight]; 69 CLLocationDegrees latitudeDelta = -1 * (maxLat - minLat); 70 71 // create and return the lat/lng span 72 MACoordinateSpan span = MACoordinateSpanMake(latitudeDelta, longitudeDelta); 73 return span; 74 } 75 76 #pragma mark - Public methods 77 78 - (NSUInteger)getZoomLevel 79 { 80 return 21-round(log2(self.region.span.longitudeDelta * MERCATOR_RADIUS * M_PI / (180.0 * self.bounds.size.width))); 81 } 82 83 - (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate 84 zoomLevel:(NSUInteger)zoomLevel 85 animated:(BOOL)animated 86 { 87 // clamp large numbers to 28 88 zoomLevel = MIN(zoomLevel, 28); 89 90 // use the zoom level to compute the region 91 MACoordinateSpan span = [self coordinateSpanWithMapView:self centerCoordinate:centerCoordinate andZoomLevel:zoomLevel]; 92 MACoordinateRegion region = MACoordinateRegionMake(centerCoordinate, span); 93 94 // set the region like normal 95 [self setRegion:region animated:animated]; 96 } 97 98 - (void)zoomToFitMapAnnotations 99 { 100 if ([self.annotations count] == 0) return; 101 102 CLLocationCoordinate2D topLeftCoord; 103 topLeftCoord.latitude = -90; 104 topLeftCoord.longitude = 180; 105 106 CLLocationCoordinate2D bottomRightCoord; 107 bottomRightCoord.latitude = 90; 108 bottomRightCoord.longitude = -180; 109 110 for(id<MAAnnotation> annotation in self.annotations) { 111 if ([annotation isKindOfClass:[MAUserLocation class]]) { 112 continue; 113 } 114 topLeftCoord.longitude = fmin(topLeftCoord.longitude, annotation.coordinate.longitude); 115 topLeftCoord.latitude = fmax(topLeftCoord.latitude, annotation.coordinate.latitude); 116 bottomRightCoord.longitude = fmax(bottomRightCoord.longitude, annotation.coordinate.longitude); 117 bottomRightCoord.latitude = fmin(bottomRightCoord.latitude, annotation.coordinate.latitude); 118 } 119 120 MACoordinateRegion region; 121 region.center.latitude = topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.5; 122 region.center.longitude = topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5; 123 region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.2; 124 region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.2; 125 126 region = [self regionThatFits:region]; 127 [self setRegion:region animated:YES]; 128 } 129 130 @end