We design most of our themes and custom slides 'offline' from the projection location, etiher on a single-screen machine, or with a second monitor of differnt resolution and proportions to the target device. We may also want to use the same slide designs on different projection environments, and we need to ensure that the layout works the same regardless of what it's projected on / through.
One thing to that causes issues is that the physical size of a screen and the resolution do not scale linearly. Just because we have 1440x960 avaialble now, 1024x768 tomorrow, and 800600 the next time, does not mean we have a larger display or that the viewing distance is larger or smaller. And if designing on a 1920x1280 or suchlike laptop, it's even worse when those slides are used in a low resolution target environment. Note the screen resolution of the control/design environemnet will normally be much greater than
Note that we may not have any prior access or knowledge of the exact projection details before we set up. So we do not get the option to work this out.
At present, OpenLP directly maps 'pixels' to 'font height', which means that if I move display, a slide will likely (a) have much smaller fonts in physical height on higher resolution systems than it will have on low resolution ones and (b) lay out can change radically. This makes effective theme design almost impossible across all display platforms, and means some of our people really don't want to move fully into OpenLP.
So, how do I force the effective font height (not the 'number of pixels' but the 'physical projected height' or 'proportion of screen height' ) constant regardless of output resolution, and especially when designing offline from the target environoment? I understand that the system defaults to variable screen resolution and constant pixel size, but we need to force the actual 'proportion of screen taken' to be constant across target display environments.