ASPolylineView/ASPolylineRenderer.m at master · nighthawk/ASPolylineView · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
//
//  ASPolylineRenderer.m
//
//  Created by Adrian Schoenig on 01/08/13.
//
//

#import "ASPolylineRenderer.h"

@interface ASPolylineRenderer () {
  CGMutablePathRef _mutablePath;
}

@property (nonatomic, strong) MKPolyline *polyline;

@end

@implementation ASPolylineRenderer

- (id)initWithPolyline:(MKPolyline *)polyline
{
	self = [super initWithOverlay:polyline];
	if (self) {
		self.polyline    = polyline;
    _mutablePath = CGPathCreateMutable();
    [self constructPath];

		// defaults
		self.borderColor      = [ASColor blackColor];
		self.backgroundColor  = [ASColor whiteColor];
		self.borderMultiplier = 2.0;
	}
	return self;
}

- (void)dealloc
{
  CGPathRelease(_mutablePath);
  _mutablePath = NULL;
}

- (void)drawMapRect:(MKMapRect)mapRect
					zoomScale:(MKZoomScale)zoomScale
					inContext:(CGContextRef)context
{
	CGFloat baseWidth = self.lineWidth;
  CGFloat width = zoomScale < 0.01 ? baseWidth / 2 : baseWidth;

  // nice for debugging
//  CGContextSetRGBFillColor(context, (rand() % 255) / 255.0, 0, 0, 0.1);
//  CGContextFillRect(context, [self rectForMapRect:mapRect]);

	// draw the border. it's slightly wider than the specified line width.
	[self drawLine:self.borderColor.CGColor
					 width:width * self.borderMultiplier
		 allowDashes:NO
		forZoomScale:zoomScale
			 inContext:context];

	// a white background.
  if (self.backgroundColor) {
    [self drawLine:self.backgroundColor.CGColor
             width:width
       allowDashes:NO
      forZoomScale:zoomScale
         inContext:context];
  }

	// draw the actual line.
	[self drawLine:self.strokeColor.CGColor
					 width:width
		 allowDashes:YES
		forZoomScale:zoomScale
			 inContext:context];

}

- (void)constructPath
{
	// turn the polyline into a path
	BOOL pathIsEmpty = YES;

	for (int i = 0; i < self.polyline.pointCount; i++) {
		CGPoint point = [self pointForMapPoint:self.polyline.points[i]];

		if (pathIsEmpty) {
			CGPathMoveToPoint(_mutablePath, nil, point.x, point.y);
			pathIsEmpty = NO;
		} else {
			CGPathAddLineToPoint(_mutablePath, nil, point.x, point.y);
		}
	}
}

#pragma mark - Private helpers

- (void)drawLine:(CGColorRef)color
					 width:(CGFloat)width
		 allowDashes:(BOOL)allowDashes
		forZoomScale:(MKZoomScale)zoomScale
			 inContext:(CGContextRef)context
{
	CGContextAddPath(context, _mutablePath);

	// use the defaults which takes care of the dash pattern
	// and other things
	if (allowDashes) {
		[self applyStrokePropertiesToContext:context atZoomScale:zoomScale];
	} else {
		// some setting we still want to apply
		CGContextSetLineCap(context, self.lineCap);
		CGContextSetLineJoin(context, self.lineJoin);
		CGContextSetMiterLimit(context, self.miterLimit);
	}

	// now set the colour and width
	CGContextSetStrokeColorWithColor(context, color);
	CGContextSetLineWidth(context, width / zoomScale);

	CGContextStrokePath(context);
}

@end