On Wed, Nov 5, 2008 at 11:47 AM, Leonard Ritter <[EMAIL PROTECTED]>wrote:
> On Wed, Nov 5, 2008 at 9:05 AM, Saul Lethbridge <[EMAIL PROTECTED] > > wrote: > >> Hi, >> >> Regarding your comments below on untransformed mouse coordinates - can you >> give me an example on how you've calculated the transformation? I'm having >> difficulty getting that to work in my app. >> > > assumed that your app uses a group to scale and translate everything else, > here is the code to translate world coordinates to local coordinates: > > px,py = group.get_position() > sx,sy = group.get_scale() > x = (event.x - px) / sx > y = (event.y - py) / sy > > and back: > > px,py = group.get_position() > sx,sy = group.get_scale() > x = (local_x * sx) + px > y = (local_y * sy) + py > > of course you have to work with floats for the calculations. >
