"Aaron Ardiri" <[EMAIL PROTECTED]> ??? news:[EMAIL PROTECTED] ???... > > > > does anyone know how to draw text with different slope/angles > > > > (e.g. 30, 45, 90 degrees) ? > > > > thx! > > > > > > implement your own rotation algorithm... or, wait until PalmOS > > > catches up to every other platform with providing graphic context > > > support (and, stuff like this), in Palm OS6 :) > > > > many map programs display/draw street names according to the slope of their > > street lines, but I have no idea how to do that > > google for rotation transformation matrix. > > http://kwon3d.com/theory/transform/transform.html > http://kwon3d.com/theory/transform/rot.html > > draw it to an offscreen window - then, apply a rotation. then > overlay onto the 'final' display :) done. doesn't take much to > code up :) to save you doing a lot of digging/math - here is the > basic algorithm > > void > rotate(x,y,*_x,*_y,angle) > { > *x = ( cos(angle) * x) + (sin(angle) * y); > *y = (-sin(angle) * x) + (cos(angle) * y); > }
I don't really understand the above algorithm x & y are the original coordinates ? so what do *_x & *_y mean? why they are not included in : *x = ( cos(angle) * x) + (sin(angle) * y); *y = (-sin(angle) * x) + (cos(angle) * y); ? and *x & *y are the new coordinates ? I'm quite confused > > basic trigonometry :) piece of cake - now, to make it fast > you can use integer math instead of using 'cos' and 'sin' > functions (= slow). Mathlib can help there if needed. > > --- > Aaron Ardiri > [EMAIL PROTECTED] > http://www.mobilewizardry.com/members/aaron_ardiri.php [profile] > -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
