How to draw a “speech bubble” on an iPhone?

Question

I\'m trying to get a \"speech bubble\" effect similar to the one in Mac OS X when you right click on something in the dock. Here\'s what I have now:

Answer 1

See the triangle on the pop up menu in the image below, thats drawn with Core Graphics funcs and is completely scalable.

Done like this to do an equilateral triangle (old-school function names, sorry):

#define triH(v) (v * 0.866)    

func(CGContextRef inContext, CGRect arrowRect, CustomPushButtonData* controlData) {
// Draw the triangle
float   arrowXstart, arrowYstart;
float   arrowXpos, arrowYpos, arrowHpos; 

if (controlData->controlEnabled && controlData->controlActive) {

    CGContextSetRGBFillColor(inContext, 0., 0., 0., 1.);

} else {

    CGContextSetRGBFillColor(inContext, 0., 0., 0., 0.5);

}

arrowHpos = triH(arrowRect.size.height);

// Point C

CGContextBeginPath(inContext);

arrowXstart = arrowXpos = (arrowRect.origin.x + ((float)(arrowRect.size.width / 2.) - (arrowSize / 2.)));

arrowYstart = arrowYpos = (arrowRect.origin.y + (float)((arrowRect.size.height / 2.) - (float)(arrowHpos / 2.)));

CGContextMoveToPoint(inContext, arrowXpos, arrowYpos);

// Point A

arrowXpos += arrowSize;

CGContextAddLineToPoint(inContext, arrowXpos, arrowYpos);

// Point B

arrowYpos += arrowHpos;

arrowXpos -= (float)(arrowSize / 2.0);

CGContextAddLineToPoint(inContext, arrowXpos, arrowYpos);

// Point C
CGContextAddLineToPoint(inContext, arrowXstart, arrowYstart);

CGContextClosePath(inContext);

CGContextFillPath(inContext);

}

Note that the triH(x) func is an optimized formula for calculating the height of an equitlateral triangle e.g. h = 1/2 * sqrt(3) * x . Since 1/2 * sqrt(3) never changes, I optimized it into that define.