CGContextSetRGBStrokeColor won't draw borders
I am trying to create a pie chart. Each pie should be with different color and have it's border. So I made my own class PieChart.m:
#import "PieChart.h"
@implementation PieChart
@synthesize startDeg, endDeg, isSelected, colorNumber;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
// Only override drawRect: if you perform开发者_开发知识库 custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
int centerX = 120;
int centerY = 160;
int radius = 94;
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSetRGBStrokeColor(ctx, 255.0/255.0, 255.0/255.0, 255.0/255.0, 1.0);
CGContextSetLineWidth(ctx, 2.0);
CGContextSetRGBFillColor(ctx, [self getColorFor:1]/255.0, [self getColorFor:2]/255.0, [self getColorFor:3]/255.0, 1.0);
CGContextMoveToPoint(ctx, centerX, centerY);
CGContextAddArc(ctx, centerX, centerY, radius, (startDeg)*M_PI/180.0, (endDeg)*M_PI/180.0, 0);
CGContextClosePath(ctx);
CGContextFillPath(ctx);
}
- (void)dealloc
{
[super dealloc];
}
-(float)getColorFor:(int)rgb {
if (colorNumber == 1) {
switch (rgb) {
case 1:
return 232.0;
break;
case 2:
return 96.0;
break;
case 3:
return 104.0;
break;
default:
return 255.0;
break;
}
}
if (colorNumber == 2) {
switch (rgb) {
case 1:
return 248.0;
break;
case 2:
return 198.0;
break;
case 3:
return 6.0;
break;
default:
return 255.0;
break;
}
}
return 255.0;
}
@end
The problem is that the borders would never draw. Or if I manage to draw the border the fill wouldn't be there! Any suggestions how this should be achieved?
Here is how I use the class in my viewcontroller:
- (void)viewDidLoad
{
[super viewDidLoad];
PieChart *pie1 = [[PieChart alloc] initWithFrame:CGRectMake(10, 10, 300, 400)];
pie1.startDeg = 0;
pie1.endDeg = 127;
pie1.colorNumber = 1;
pie1.backgroundColor = [UIColor clearColor];
PieChart *pie2 = [[PieChart alloc] initWithFrame:CGRectMake(10, 10, 300, 400)];
pie2.startDeg = 127;
pie2.endDeg = 360;
pie2.colorNumber = 2;
pie2.backgroundColor = [UIColor clearColor];
[self.view addSubview:pie1];
[self.view addSubview:pie2];
}
The problem with your code is that you only fill your path, not stroking it - so naturally border is now drawn. You need to replace CGContextFillPath call with
CGContextDrawPath (ctx, kCGPathFillStroke);
Stroking or filling the path clears the current path. That's why one works but not the other (whichever one you try first).
You can fix this by re-adding your path before stroking, or using CGContextDrawPath
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