I am using the framework of route-me for working with locations. In this code the path between two markers(points) will be drawn as a line.
My Question: "What code should I add if I want to add an arrow in the middle(or top) of the line, so that it points the direction"
Thanks
- (void)drawInContext:(CGContextRef)theContext
{
renderedScale = [contents metersPerPixel];
float scale = 1.0f / [contents metersPerPixel];
float scaledLineWidth = lineWidth;
if(!scaleLineWidth) {
scaledLineWidth *= renderedScale;
}
//NSLog(@"line width = %f, content scale = %f", scaledLineWidth, renderedScale);
CGContextScaleCTM(theContext, scale, scale);
CGContextBeginPath(theContext);
CGContextAddPath(theContext, path);
CGContextSetLineWidth(theContext, scaledLineWidth);
CGContextSetStrokeColorWithColor(theContext, [lineColor CGColor]);
CGContextSetFillColorWithColor(theContext, [fillColor CGColor]);
// according to Apple's documentation, DrawPath closes the path if it's a filled style, so a call to ClosePath isn't necessary
CGContextDrawPath(theContext, drawingMode);
}
- (void) drawLine: (CGContextRef) context from: (CGPoint) from to: (CGPoint) to
{
double slopy, cosy, siny;
// Arrow size
double length = 10.0;
double width = 5.0;
slopy = atan2((from.y - to.y), (from.x - to.x));
cosy = cos(slopy);
siny = sin(slopy);
//draw a line between the 2 endpoint
CGContextMoveToPoint(context, from.x - length * cosy, from.y - length * siny );
CGContextAddLineToPoint(context, to.x + length * cosy, to.y + length * siny);
//paints a line along the current path
CGContextStrokePath(context);
//here is the tough part - actually drawing the arrows
//a total of 6 lines drawn to make the arrow shape
CGContextMoveToPoint(context, from.x, from.y);
CGContextAddLineToPoint(context,
from.x + ( - length * cosy - ( width / 2.0 * siny )),
from.y + ( - length * siny + ( width / 2.0 * cosy )));
CGContextAddLineToPoint(context,
from.x + (- length * cosy + ( width / 2.0 * siny )),
from.y - (width / 2.0 * cosy + length * siny ) );
CGContextClosePath(context);
CGContextStrokePath(context);
/*/-------------similarly the the other end-------------/*/
CGContextMoveToPoint(context, to.x, to.y);
CGContextAddLineToPoint(context,
to.x + (length * cosy - ( width / 2.0 * siny )),
to.y + (length * siny + ( width / 2.0 * cosy )) );
CGContextAddLineToPoint(context,
to.x + (length * cosy + width / 2.0 * siny),
to.y - (width / 2.0 * cosy - length * siny) );
CGContextClosePath(context);
CGContextStrokePath(context);
}