Use-case for CTRC background color?

Ucan, Emre (ADITG/ESB) eucan at
Fri Nov 16 08:29:43 UTC 2018


Clients should not control a property of a wl_output directly. 

You can add a new property to the weston-config for output section, so that weston can enable a specific color for an output at startup.

Best regards

Emre Ucan
Engineering Software Base (ADITG/ESB)

Tel. +49 5121 49 6937

> -----Original Message-----
> From: wayland-devel <wayland-devel-bounces at> On
> Behalf Of Harish Krupo
> Sent: Freitag, 16. November 2018 04:57
> To: wayland-devel at
> Cc: pekka.paalanen at; daniels at
> Subject: Use-case for CTRC background color?
> Hi,
> This patch [1] introduces the background crtc color property. This
> property is available on some display controlers and allows setting a
> non-black colors for pixels not covered by any plane (or pixels covered
> by the transparent regions of higher planes). I would like to implement
> a userspace consumer of this propery in weston.
> The primary use case for this property is for compositors to set the
> background color. I am planning on implementing it as follows:
> * The desktop client would bind to the weston-desktop-shell protocol.
> * The weston-desktop-shell would have a wrapper for the wl_output
> object.
> * The client would create a wrapper for wl_output (maybe called
> weston_desktop_shell_output).
> * This output interface will have an event to advertise its capability
> to set the background color directly.
> * Once the capability is found and if the client wishes to set the
> background color, it would use the set_background_color request in the
> weston_desktop_shell_ouput interface to set the color by providing the
> r,g,b primaries.
> I have not completely thought this through, so I am sure this is
> incomplete and will require modification. I would like to know your
> comments and suggestions on the above method (or even if we could use
> this property differently) before I begin the implementation.
> Thank you
> Regards
> Harish Krupo
> [1]
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