Final transformation before the projection to the 2.0 version
In our church due the limitation of our projector the projected picture is larger than the screen.
It would be great if it could be possible to transform the picture just before the projection. This final transformation could corrigate some other geometrical distorsions too (for example horizontal keystone correction). It could be easy to set up the transformation matrix if we would make a setup screen where the user could distort a rectandle (by moving the vertexes) puting the projected corners of the rectangle to the corners of the phisical screen.
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Re: Final transformation before the projection to the 2.0 ...
In v2.0 it will be possible to specify margins for where the song text will go on the slide, so this will get around the problem of not being able to move the projector closer to the screen!
Most projectors, even budget ones, come with keystone correction and attempting to do this in software would take developers away from providing features the wider community will find beneficial. Attempting to do realtime transformations of videos would be difficult, and doing the same with powerpoint would be next to impossible since openlp does not control the output.
Re: Final transformation before the projection to the 2.0 ...
The projectors can do budget projectors can do vertical keystone correction, but it is not common to provide horizontal keystone correction too.
It is not uncommon to project from the balcony of the church. If the distance is longer than supported by the projector the picture will be too large. If you try from the side there is a serious keystone distorsion. The realtime video transformation is a processor intensive task. We can do it offline before the presentation.
The powerpoint is an other problem. If we would like to make the openlp 2.0 real platform independent free and open we have to decide not to use microsoft powerpoint to controll the presentation. It could be possible to use openoffice.org impress instead and control the presentation by the python-uno bridge. It could be a little CPU and memory hungry. An alternative solution - convert the powerpoint presentation to a series of images or to flash. The conversion is offline and it is possible to transfor during the conversion.