Re: [Lazarus] "Defeating" a screen saver
zeljko wrote: Health warning: http://lists.lazarus.freepascal.org/pipermail/lazarus/2008-August/037407.ht ml suggests following a handle in TForm to arrive at a window ID, but that appears to depend on the combination of widget set and window manager: as a particular example, it's unreliable with gtk2 on top of KDE. Without delving into the raw X API, the only reliable way of doing this appears to be to run xwininfo and parse the output. The window ID from that is compatible with xdg-screensaver. What's problem with gtk2 and KDE ? You already have helper functions for X11 in gtk2widgetset.inc, so there you can see howto get XWindow handle and do whatever with it with direct calls. Go on then: how do I temporarily defeat the screensaver? -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
Mark Morgan Lloyd wrote: Mark Morgan Lloyd wrote: Mark Morgan Lloyd wrote: Graeme Geldenhuys wrote: On 2012-09-25 17:57, Mark Morgan Lloyd wrote: suggestion of looking at the VLC sources I see they use it which has to be a recommendation. Interesting... I was wondering what they did. :) I'll see what I can work in, but particularly allowing that xdg-screensaver can take several seconds to run it's more suited to being run at the start and end of a program session than "on the fly" Needs a window ID. I think I can get that from a shell variable if there's a shell, but not if started directly from the desktop: anybody got any thoughts? Health warning: http://lists.lazarus.freepascal.org/pipermail/lazarus/2008-August/037407.html suggests following a handle in TForm to arrive at a window ID, but that appears to depend on the combination of widget set and window manager: as a particular example, it's unreliable with gtk2 on top of KDE. Without delving into the raw X API, the only reliable way of doing this appears to be to run xwininfo and parse the output. The window ID from that is compatible with xdg-screensaver. Just a little warning that seems related to this topic... In my Delphi communication programs I used PostMessage *very* much. I used to pass the main form's handle down into my threads so they could post to that handle. But a form's handle is not guaranteed to remain the same. Therefore I now pass a TForm reference down so the handle can be obtained when needed. A month ago some of my code that still passed just the handle failed under Win7. Seems that Win7 was doing something to an *invisible* form and changing the form's handle so my messages went nowhere. Passing the TForm reference fixed the bug. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
> Health warning: > http://lists.lazarus.freepascal.org/pipermail/lazarus/2008-August/037407.ht > ml suggests following a handle in TForm to arrive at a window ID, but that > appears to depend on the combination of widget set and window manager: as > a particular example, it's unreliable with gtk2 on top of KDE. > > Without delving into the raw X API, the only reliable way of doing this > appears to be to run xwininfo and parse the output. The window ID from > that is compatible with xdg-screensaver. What's problem with gtk2 and KDE ? You already have helper functions for X11 in gtk2widgetset.inc, so there you can see howto get XWindow handle and do whatever with it with direct calls. zeljko -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
Mark Morgan Lloyd wrote: Mark Morgan Lloyd wrote: Graeme Geldenhuys wrote: On 2012-09-25 17:57, Mark Morgan Lloyd wrote: suggestion of looking at the VLC sources I see they use it which has to be a recommendation. Interesting... I was wondering what they did. :) I'll see what I can work in, but particularly allowing that xdg-screensaver can take several seconds to run it's more suited to being run at the start and end of a program session than "on the fly" Needs a window ID. I think I can get that from a shell variable if there's a shell, but not if started directly from the desktop: anybody got any thoughts? Health warning: http://lists.lazarus.freepascal.org/pipermail/lazarus/2008-August/037407.html suggests following a handle in TForm to arrive at a window ID, but that appears to depend on the combination of widget set and window manager: as a particular example, it's unreliable with gtk2 on top of KDE. Without delving into the raw X API, the only reliable way of doing this appears to be to run xwininfo and parse the output. The window ID from that is compatible with xdg-screensaver. -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
Mark Morgan Lloyd wrote: Graeme Geldenhuys wrote: On 2012-09-25 17:57, Mark Morgan Lloyd wrote: suggestion of looking at the VLC sources I see they use it which has to be a recommendation. Interesting... I was wondering what they did. :) I'll see what I can work in, but particularly allowing that xdg-screensaver can take several seconds to run it's more suited to being run at the start and end of a program session than "on the fly" Why not simply execute the command in a background thread. Your main thread then continues pulling in data or whatever it does. I've already got a thread moving data around, and I know that when data's actively moving that the user isn't fiddling with keyboard or mouse (odds are he's got his hands on a MIDI device). I can also assume that he used the GUI shortly before data started arriving, so in practice I can use a 30 secs foreground timer (which already looks for and loads an updated backend .so) to fire an enable/disable command when the rate of flow changes. Needs a window ID. I think I can get that from a shell variable if there's a shell, but not if started directly from the desktop: anybody got any thoughts? -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
Graeme Geldenhuys wrote: On 2012-09-25 17:57, Mark Morgan Lloyd wrote: suggestion of looking at the VLC sources I see they use it which has to be a recommendation. Interesting... I was wondering what they did. :) I'll see what I can work in, but particularly allowing that xdg-screensaver can take several seconds to run it's more suited to being run at the start and end of a program session than "on the fly" Why not simply execute the command in a background thread. Your main thread then continues pulling in data or whatever it does. I've already got a thread moving data around, and I know that when data's actively moving that the user isn't fiddling with keyboard or mouse (odds are he's got his hands on a MIDI device). I can also assume that he used the GUI shortly before data started arriving, so in practice I can use a 30 secs foreground timer (which already looks for and loads an updated backend .so) to fire an enable/disable command when the rate of flow changes. -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
On 2012-09-25 17:57, Mark Morgan Lloyd wrote: suggestion of looking at the VLC sources I see they use it which has to be a recommendation. Interesting... I was wondering what they did. :) I'll see what I can work in, but particularly allowing that xdg-screensaver can take several seconds to run it's more suited to being run at the start and end of a program session than "on the fly" Why not simply execute the command in a background thread. Your main thread then continues pulling in data or whatever it does. Regards, - Graeme - -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
Henry Vermaak wrote: On 25/09/12 11:01, Mark Morgan Lloyd wrote: I appreciate that there might be no guaranteed portable answer to this one, and FWIW I'm primarily interested in the Linux+X+KDE combination. If a program knows that something's going on that it might later need to tell the user about, e.g. that there's serial comms going on in the background even if the GUI's not being updated, is it possible to do anything that the LCL and lower levels will interpret similarly to keyboard and mouse activity in order to prevent a screen saver from kicking in? xdg-screensaver is a script that you can use to control the screensaver (seems to support all the ones I know). It's in the xdg-utils package on my system. I don't know of a nicer way to do this and cover all the bases, except to use dbus with org.freedesktop.ScreenSaver, most desktop environments should work with that, I think. I try to use the xdg utilities when I can, and pursuing Graeme's suggestion of looking at the VLC sources I see they use it which has to be a recommendation. I'll see what I can work in, but particularly allowing that xdg-screensaver can take several seconds to run it's more suited to being run at the start and end of a program session than "on the fly" when data is seen coming through. The only alternative I can see is doing something at the kernel level to push a keyboard or mouse event through to X. -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
Graeme Geldenhuys wrote: On 2012-09-25 11:55, Mark Morgan Lloyd wrote: stringgrid with an updating field on the screen, I've not yet tried e.g. simulating a shiftkey event. Another option. From the 'man xscreensaver-command' output. - -deactivate This tells xscreensaver to pretend that there has just been user activity. This means that if the screensaver is active (the screen is blanked), then this command will cause the screen to un-blank as if there had been keyboard or mouse activity. If the screen is locked, then the password dialog will pop up first, as usual. If the screen is not blanked, then this simulated user activity will re-start the countdown (so, issuing the -deactivate command periodically is one way to prevent the screen from blanking.) - But then I don't know if this applies to kde-screensaver and gnome-screensaver too, even though they are forks of xscreensaver. Thanks for that, interesting. I've certainly had problems getting screensaver+powerdown to work properly in the past, which I tracked down to different configuration requirements for the X and KDE implementations (specifically, IIRC, the X server had to be told not to do various things to give KDE a chance). -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
On 2012-09-25 11:55, Henry Vermaak wrote: xdg-screensaver is a script that you can use to control the screensaver (seems to support all the ones I know). Cool, I didn't know about that one. At least I can confirm that OpenSUSE 12.2 does have xdg-screensaver functionality. Regards, - Graeme - -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
On 2012-09-25 11:55, Mark Morgan Lloyd wrote: stringgrid with an updating field on the screen, I've not yet tried e.g. simulating a shiftkey event. Another option. From the 'man xscreensaver-command' output. - -deactivate This tells xscreensaver to pretend that there has just been user activity. This means that if the screensaver is active (the screen is blanked), then this command will cause the screen to un-blank as if there had been keyboard or mouse activity. If the screen is locked, then the password dialog will pop up first, as usual. If the screen is not blanked, then this simulated user activity will re-start the countdown (so, issuing the -deactivate command periodically is one way to prevent the screen from blanking.) - But then I don't know if this applies to kde-screensaver and gnome-screensaver too, even though they are forks of xscreensaver. Regards, - Graeme - -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
On 25/09/12 11:01, Mark Morgan Lloyd wrote: > I appreciate that there might be no guaranteed portable answer to this > one, and FWIW I'm primarily interested in the Linux+X+KDE combination. > > If a program knows that something's going on that it might later need to > tell the user about, e.g. that there's serial comms going on in the > background even if the GUI's not being updated, is it possible to do > anything that the LCL and lower levels will interpret similarly to > keyboard and mouse activity in order to prevent a screen saver from > kicking in? xdg-screensaver is a script that you can use to control the screensaver (seems to support all the ones I know). It's in the xdg-utils package on my system. I don't know of a nicer way to do this and cover all the bases, except to use dbus with org.freedesktop.ScreenSaver, most desktop environments should work with that, I think. Henry -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
Graeme Geldenhuys wrote: On 2012-09-25 11:01, Mark Morgan Lloyd wrote: interpret similarly to keyboard and mouse activity in order to prevent a screen saver from kicking in? Maybe download the VLC Player source code, and see what they do to disable the screensaver while a video is playing. I know VLC works well in that context. I don't know of other X11 applications that temporarily disable the screensaver while working, but I am sure there must be some. Thanks, that's a good idea. I've already tried making sure there's a stringgrid with an updating field on the screen, I've not yet tried e.g. simulating a shiftkey event. -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "Defeating" a screen saver
On 2012-09-25 11:01, Mark Morgan Lloyd wrote: interpret similarly to keyboard and mouse activity in order to prevent a screen saver from kicking in? Maybe download the VLC Player source code, and see what they do to disable the screensaver while a video is playing. I know VLC works well in that context. I don't know of other X11 applications that temporarily disable the screensaver while working, but I am sure there must be some. Sorry I can't be or more help. Regards, - Graeme - -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
