- x -= dx;
- y -= dy;
- width += 2*dx;
- height += 2*dy;
-
- // check that we didn't make the rectangle invalid by accident (you almost
- // never want to have negative coords and never want negative size)
- if ( x < 0 )
- x = 0;
- if ( y < 0 )
- y = 0;
-
- // what else can we do?
- if ( width < 0 )
- width = 0;
- if ( height < 0 )
- height = 0;
+ if (-2*dx>width)
+ {
+ // Don't allow deflate to eat more width than we have,
+ // a well-defined rectangle cannot have negative width.
+ x+=width/2;
+ width=0;
+ }
+ else
+ {
+ // The inflate is valid.
+ x-=dx;
+ width+=2*dx;
+ }
+
+ if (-2*dy>height)
+ {
+ // Don't allow deflate to eat more height than we have,
+ // a well-defined rectangle cannot have negative height.
+ y+=height/2;
+ height=0;
+ }
+ else
+ {
+ // The inflate is valid.
+ y-=dy;
+ height+=2*dy;
+ }