For projectors, I think it would be best if the dimensions could be configured.
On Wed, 4 May 2016 11:12:38 -0700 "Jasper St. Pierre" <[email protected]> wrote: > What are the dimensions of a projector, whose > pixels-per-inch or dots-per-inch value is a distance of > how far away the projector is for the wall, or, in a > keystoned case, isn't even constant across the display? > > For limited scenarios, you can make it work (with > caution, see [0]). But we cannot calculate a sensible DPI > value in the general case. > > [0] > https://lists.fedoraproject.org/pipermail/devel/2011-October/157671.html > > On Wed, May 4, 2016 at 10:45 AM, Mattias Andrée > <[email protected]> wrote: > > On Wed, 4 May 2016 19:01:09 +0200 > > Alberto Salvia Novella <[email protected]> wrote: > > > >> Mattias Andrée: > >> > What's wrong with dots per inch? > >> > >> How can an application reliably know which is the > >> current pixel density of the desktop? > >> > >> > > > > Well, you cannot know anything reliably. The EDID > > does contain all information you need for DPI, however > > with limited precision. X.org reports a bogus DPI. But > > if pretend that all monitors' dimensions are in whole > > centimetres, than the number of pixels per centimetre > > can be calculated > > > > ppc_x = output_width_px(monitor) / > > output_width_cm(monitor); ppc_y = > > output_height_px(monitor) / output_height_cm(monitor); > > > > Notice that this is easier to calculate than the pixels > > per inch. > > > > ppi_x = output_width_px(monitor) / > > output_width_cm(monitor) * 2.540; ppi_y = > > output_height_px(monitor) / output_height_cm(monitor) * > > 2.540; > > > > But why is pixels preferred over dots? > > > > _______________________________________________ > > xdg mailing list > > [email protected] > > https://lists.freedesktop.org/mailman/listinfo/xdg > > > > >
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