Re: [AL] Width and height of rotated bitmap

[Sven S. <sv...@it...>]

MC Gnoyek wrote:
> Is there any better way to resolve width and height of rotated
> bitmap?

It's probably safer to use the exact same function as Allegro: since 
your code uses another algorithm (e.g., the inaccurate fixsin/fixcos 
rather than math.h's sin/cos), it is likely that it differs by a pixel 
or so from what is actually being drawn. The function you are looking 
for is called _rotate_scale_flip_coordinates() and is defined in 
allegro/src/rotate.c. It computes the coordinates in the destination 
bitmap of the sprite's corners as fixed point values, so to get the 
bounding box you should take the min and max x and y coordinates among 
these, and round them towards the closest integer (eg., using fixtoi()). 
This does not take clipping in the destination bitmap into account. It's 
considered an internal function, so you need to
#include <allegro/aintern.h>.

-- 
Sven