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<p class="MsoNormal"><span lang="EN-US">Hello,<br>
<br>
I’m trying to write a frame-grabber software for my display which is using the wayland-ivi-extension (</span><a href="https://github.com/GENIVI/wayland-ivi-extension"><span lang="EN-US">https://github.com/GENIVI/wayland-ivi-extension</span></a><span lang="EN-US">).
The frame-grabber software is used for a test-automation to check if the display render the pictures correctly.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I always want to take a screenshot, if something changed on my surface. Actually, my problem is to detect changes on my surface.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">After I looked up in the ivi-layermanagement-api I have noticed that a surface has particular properties (“<span class="pl-en">ilmSurfaceProperties”). One of these is the property “frameCounter”, which shows the
</span><span class="pl-c">already rendered frames of a surface. So if the Counter
</span></span><span class="tlid-translation"><span lang="EN">increases by one, something changed on the surface.</span></span><span lang="EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">One idea was to use the function “<span class="pl-c1">ilm_surfaceAddNotification” to get a callback if the property
</span><span class="pl-en">“frameCounter” changed. However, the callback function was not invoked, after my display rendered. It looks like the property is not observed for notification.<o:p></o:p></span></span></p>
<p class="MsoNormal"><span class="pl-en"><span lang="EN-US">Is there an elegant way to detect
</span></span><span lang="EN-US">changes on my surface by callback without polling the property by myself? Maybe some kernel-events or other API callbacks.</span><o:p></o:p></p>
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