Is weston_view.geomtery are the global coordinates?

[Sichem Zhou]

Hi all,

I am working on a Wayland compositor thanks to amazing` libweston` projects
to provide the backend. I am at the point where I need to implement tiling
window management algorithm. After reading through the `compositor.c`, I
had a few confusions that I hope to get the correct understanding about
Weston rendering pipeline.

- it seems that the geometry struct in the Weston view applies to the
global compositor coordinates. As I cannot find any code relates to
translate `weston_view.geometry` with output.geometry.

- However libweston draws every frame for every output through
`weston_output_repaint`. Where it build view_list and calls renderer to
draw them. So renderer is drawn on every plane where every output has its
own framebuffer (for example a OpenGL framebuffer).

- After looking into the function, I found that the `view_list` is built up
globally and damages are accumulated globally then clips against the output
region. So I guess these two operations will repeated several times for
every output? The frame callback list is filtered with the output as well.

Weston is a huge project and so far the only resources are the codebase
itself. I tried to figure out myself but maybe my understanding is
inaccurate.

Thanks for your help.

Regards,
Sichem
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