How can i draw on desktop？

[Keigo]

Hi guys：
I wanna know how can i draw a picture on the desktop of Linux.
thx!

[tbscope]

Define "on the desktop" please.

As in a wallpaper?

Anyway, if you want to do anything platform specific, you will need to look at the platform api's. In this case at least the KDE and GNOME api's

[squidge]

OS's are normally quite protective of there desktops. The easiest way to do what you want therefore is to create a frameless window and draw on that. There are platform specific APIs (as stated already) that allow you to grab a copy of the desktop, should you wish to make your window more transparent.

[Keigo]

OS's are normally quite protective of there desktops. The easiest way to do what you want therefore is to create a frameless window and draw on that. There are platform specific APIs (as stated already) that allow you to grab a copy of the desktop, should you wish to make your window more transparent.

thx for the advice, what i have been doing is to develop a screen recorder which is a project my teacher gave me, and i already did the part of recording. Now the problem is i wanna to draw a rect on the desktop or on the bottom layer of the desktop as the valid area. So i wander if it is possible.

[Keigo]

Define "on the desktop" please.

As in a wallpaper?

Anyway, if you want to do anything platform specific, you will need to look at the platform api's. In this case at least the KDE and GNOME api's

Now i am working on a screen recorder, so i want to draw a rect in a wallpaper or underneath the wallpaper as a valid recording area. Of cause, it should not interfere the Linux's event response (mouse event etc.).

[aamer4yu]

Now the problem is i wanna to draw a rect on the desktop or on the bottom layer of the desktop as the valid area. So i wander if it is possible.

If you draw a transparent widget with only solid opaque borders, it will appear like a rect on the desktop !! isnt it

[tbscope]

Now i am working on a screen recorder, so i want to draw a rect in a wallpaper or underneath the wallpaper as a valid recording area. Of cause, it should not interfere the Linux's event response (mouse event etc.).

You want it to be on top of everything else.

With "not interfere", do you mean not send or receive messages generated by or destined for your rectangle? That would be extremely difficult.

[Keigo]

With "not interfere", do you mean not send or receive messages generated by or destined for your rectangle? That would be extremely difficult

well, i would say no. what you just said ,there is no doubt, is also a mission impossible for me. But
what i really mean “not interfere” is not interfere users' operation. For instance, users can click or double click the icons on the desktop, drag window. Have you ever heard or used a screen recorder named "Camtasia Studio". If you do, you would know exactly what i am talking about.
Anyway, thanks again.

[squidge]

Right, so what you really want to do is record on-screen activity?

[Keigo]

Right, so what you really want to do is record on-screen activity?

yes, all i wanted is to record on-screen activity in a selected area.