[Opengc-devel] OpenGC coordinate system

[Damion S. <dam...@ho...>]

Actually, I don't think I've mentioned the OpenGC coordinate system before,
so it's good that you bring this up.

Gauges and components are designed in units of millimeters. m_MonitorSize is
the size of your display in millimeters and there's a corresponding
m_MonitorResolution; together these are used to provide a rough calibration
from "design" millimeters to "physical" millimeters. So, presumably, if
things are calibrated right, a gauge component that is 80 millimeters tall
in the code will actually appear 80 mm tall on your monitor. Right now, this
is invariant of window size as well, so OpenGC will clip off any portion of
the gauge which would "physically" extend beyond window.

This is important for more than than just proper scaling, because knowing
the final "pixel" size of a gauge/component allows you to set up gl windows
so that gaugecomponents are clipped properly (very important to accomplish,
among many examples, the artificial horizon).

There's also the separate issue of how to allow zooming, but I'm still
trying to figure out how that fits into the calibrated framework.

-Damion-

> //-----------------Desktop Measurement--------------------
>
> m_MonitorSize.x = ___  and m_MonitorSize = _________
>
> You might try 400 and 300 respectively and note the results.
>
> Also note next line: units per pixel is determined by the value in the x
> direction.