Drawing text in a pieChart drawRect method? - ios

Question

okie i am using a PieChart i got from github Astrokin Piechart
But in this piechart label has not been added to different slices and i want something as shown below
I have looked up on stackoverflow already and am trying to draw text in draw rect but doesnt seem to work. code is below
for (int i = 0; i < slicesCount; i++)
{
double value = [self.datasource pieChartView:self valueForSliceAtIndex:i];
NSString *title = [self.datasource pieChartView:self titleForSliceAtIndex:i];
endAngle = startAngle + M_PI*2*value/sum;
/*CGFloat x = centerX + (radius+10) * (cos((startAngle-90)*M_PI/180.0) + cos((endAngle-90)*M_PI/180.0)) / 2;
CGFloat y = centerY + (radius+10) * (sin((startAngle-90)*M_PI/180.0) + sin((endAngle-90)*M_PI/180.0)) / 2;
[title drawAtPoint:CGPointMake(x, y) withFont:[UIFont fontWithName:FONT_HELVETICA size:12.0]];*/
CGFloat x = centerX + ((radius + 10) * cos(startAngle));
CGFloat y = centerY + ((radius + 10) * sin(endAngle));
// NSLog(#"X Y: %f %f %f", x, y, degree);
NSString *text = #"Test";
[text drawInRect:CGRectMake(x, y, 50, 44) withFont:[UIFont systemFontOfSize:14.0f]];
CGContextAddArc(context, centerX, centerY, radius, startAngle, endAngle, false);
UIColor *drawColor = [self.datasource pieChartView:self colorForSliceAtIndex:i];
CGContextSetStrokeColorWithColor(context, drawColor.CGColor);
CGContextSetLineWidth(context, lineWidth);
CGContextStrokePath(context);
startAngle += M_PI*2*value/sum;
}
right now it looks like this
What am i possibly doing wrong?

Answer 1

You draw text with
[text drawInRect:CGRectMake(x, y, 50, 44) withFont:[UIFont systemFontOfSize:14.0f]];
That makes your text's top left corner to appear at point (x,y). As I can see, you want text's center to appear at point (x,y). What you need to do is to subtract half of the text's width from x and the same for y, so that it becomes:
CGFloat height = 50.0;
CGFloat width = 44.0;
[text drawInRect:CGRectMake(x - width / 2.0, y - height / 2.0, width, height) withFont:[UIFont systemFontOfSize:14.0f]];
Also you'll need to dynamically get text's width based on the string you have, "95%" is wider than "5%", yeah? So you'll need something like:
UIFont *font = [UIFont systemFontOfSize:14.0f];
CGSize textSize = [text sizeWithFont:font]; // -sizeWithFont is deprecated in iOS7, you'll need something else
CGFloat height = textSize.height;
CGFloat width = textSize.width;
[text drawInRect:CGRectMake(x - width / 2.0, y - height / 2.0, width, height) withFont:font];