Re: Release critical or not? [was Re: strange box-offset]

[Daniel J S. <dan...@ie...>]

Ethan A Merritt wrote:
> On Saturday 15 July 2006 01:04 am, Timoth=C3=A9e Lecomte wrote:
>=20
>>this one comes from graphics.c:3408 :
>>
>>x =3D xl;
>>y =3D yb;
>>w =3D xr - xl + 1;
>>h =3D yt - yb + 1;
>>(*t->fillbox) (style, x, y, w, h);
>>(*t->move) (xl, yb);
>>(*t->vector) (xl, yt);
>>(*t->vector) (xr, yt);
>>(*t->vector) (xr, yb);
>>(*t->vector) (xl, yb);
>>
>>I think these "+1" should be removed for consistency with the other use=
s.
>=20
>=20
> I'm not so sure.
> The length in pixels of a line that starts at pixel x1 and ends at pixe=
l x2
> is (x2-x1)+1.   So this code looks correct to me.  It may well be that =
some
> terminals interpret w and h incorrectly, but that would be an error in =
the
> individual terminal driver, not the core code.=20
>=20
> I guess the fundamental question is whether "width" should be interpret=
ed
> as "number of horizontal pixels" or "x_right - x_left".  These are not
> the same number.  The former makes sense if you are thinking in terms o=
f
> terminal coords (pixels); the latter makes sense if you are thinking in=
=20
> terms of a continuous variable (plot x coordinate).

My initial preference would be to think along the lines of "plot x coordi=
nate", perhaps for the simple reason of however this thread got started. =
 If you plot a series of rectangles to "cover" a range staying with x_rig=
ht - x_left avoids there being an overlap of one pixel.

E.g., series of incremented ranges:

0-9
10-19
20-29
etc.

For histograms or whatever.  Saying that the width of the rectangle shoul=
d be 11 instead of 10 would mean that there is going to be one rectangle =
of the bunch that is 9 pixels and one which is 11 pixels.

Dan