CGAffineTransform help, flipping a label

I basically have a pie chart where I have lines coming out of each segment of the pie chart. So in the case where the line comes out of the circle to the left, when I draw my text, it is reversed. "100%" would look like => "%001" (Note, the 1 and % sign are actually drawn in reverse to, like if a mirror. So t开发者_StackOverflowhe little overhang on top of the 1 points to the right, rather than the left.)

I tried reading through Apple's docs for the AffineTransform, but it doesn't make complete sense to me. I tried making this transformation matrix to start:

CGAffineTransform transform1 = CGAffineTransformMake(-1, 0, 0, 1, 0, 0);

This does flip the text around its x-axis so the text now looks correct on the left side of the circle. However, the text is now on the line, rather than at the end of the line like it originally was. So I thought I could translate it by moving the text in the x-axis direction by changing the tx value in the matrix. So instead of using the above matrix, I used this:

CGAffineTransform transform1 = CGAffineTransformMake(-1, 0, 0, 1, -strlen(t1AsChar), 0);

However, the text just stays where it's at. What am I doing wrong? Thanks.

strlen() doesn't give you the size of the rendered text box, it just gives you the length of the string itself (how many characters that string has). If you're using a UITextField you can use textField.frame.size.width instead.