Re: opengl and images (was: Re: fltk backend fix & mouse wheel scroll factor)

[Michael Goffioul]

A better - more generic - solution would be to implement
images::properties::update_[x|y]data() correctly. Basically,
an image always extend beyond xdata and ydata, by half
a pixel width (here, I mean an image pixel, no a screen pixel).
This must be taken into account by the algorithm that is
computing the axes limits. That's the purpose of the xlim
and ylim hidden properties of the image object.

For a complete fix, you would also need to implement the
"axis image" mode.

Michael.


On Thu, Oct 1, 2009 at 9:13 PM, Shai Ayal <address@hidden> wrote:
> I can confirm this behavior.
> I know what causes the first problem, of the image disappearing.
> OpenGL will only draw the image if the origin of the image is within
> the window (viewport in OpenGL teminology). When you change the axis,
> it moves the image origin out of the viewport.
> I will try and fix this by drawing only the part of the image which is
> inside the viewport if the origin is outside the viewport
>
> I have no idea about the second problem -- the strange axes aspect
> ration which is corrected by a screen redraw.
>
> Shai
>
> Shai
>
>