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Comment about how our Rect class works. Note: the SAGA engine currently does use the alternate approach to rects! Hence we can't currently use all those nice and nifty helper methods from Common::Rect in SAGA.

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svn-id: r13626
This commit is contained in:
Max Horn 2004-04-25 16:16:21 +00:00
parent abc8dca073
commit 795a735a31
1 changed files with 14 additions and 1 deletions
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15
common/rect.h
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@ -46,7 +46,20 @@ struct Point {
/*! @brief simple class for handling a rectangular zone.
This small class is an helper for rectangles.
It is mostly used by the blitter class.
Note: This implementation is built around the assumption that (top,left) is
part of the rectangle, but (bottom,right) is not! This is reflected in
various methods, including contains(), intersects() and others.
Another very wide spread approach to rectangle classes treats (bottom,right)
also as a part of the rectangle.
Coneptually, both are sound, but the approach we use saves many intermediate
computations (like computing the height in our case is done by doing this:
height = bottom - top;
while in the alternate system, it would be
height = bottom - top + 1;
When writing code using our Rect class, always keep this principle in mind!
*/
struct Rect {
int16 top, left; //!< The point at the top left of the rectangle (part of the rect).