Re: [Pipmak-Users] File IO with Pipmak and image manipulation.

[Christian W. <cwa...@gm...>]

Andrea Viarengo wrote:
> I need to write and to read info from external file, I tried standard Lue IO lib
> without success:
> 
>   for line in io.lines(filename) do ... end
> 
> and
> 
>   for line in file:lines() do ... end
> 
> How I can do that?

The Lua IO library (along with the OS library) has deliberately been 
left out of Pipmak - it's considered a feature that Pipmak projects are 
not able to mess around with a user's files. Can you explain what 
exactly you want to do? We might find a solution that meets both goals.

Also, you always have the option of compiling your own version of Pipmak 
that includes the IO library.

If the file you want to read lives inside the project and can be brought 
into Lua form, you could also use pipmak.dofile().

> Second one:
> It would be difficult implement in pipmak a method to distort a patch in a
> perspective manner?
> That is, a function which deform a rectangular patch in a
> trapezial one,
> passing 4 arbitrary points that lie on the surface of a cubic face.

That should be quite easy, given that Pipmak uses OpenGL. Well, 
perspective distortion would only work on panoramic nodes because on 
flat nodes the camera is orthographic - you'd have to live with linear 
distortion there.

> Another useful method would be a function to crop a patch.

That shouldn't be too difficult either. It might get a bit messy 
together with the support of rigid margins/stretchable center for 
patches on flat nodes that's already in SVN, but it should be manageable.

What are you trying to do with that? Maybe it could already be done 
using two overlapping patches, one covering the portions of the other 
that you want cropped away?

  -Christian