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Jeff Lacki wrote:
John McClurkin wrote:
The upper left origin is standard in QNX, Windows, and Linux, probably
in Mac OSX as well. OpenGL is the only API that I know of that uses a
lower left origin. What I do to plot data "right side up" is
windowY = windowHeight * (dataY - dataMax) / -dataRange;
Thanks John. After I played with this a while I wondered why not just
multiply all the Y values
by -1 to 'flip' the image. The only issue I found was that I needed to
subtract the height of
each object. Maybe others needed the 'flip' to line up within the
viewport, but for me, since
Im initializing data as I startup the Scene, I dont really care where
its at on the Y scale, just
as long as it comes up right side up. I replied mostly just find out if
Im missing something
that will bite me later.
Well, the data I plot are all positive values. If I just multiply by -1,
the data will be shifted out of the view port. Second, I want the data
to fit entirely within the view port. Therefore, subtracting dataMax
from dataY gives a negative value. Dividing by the negative of the data
range flips the data value and scales it to the range. Multiplying by
the windowHeight squeezes the data into the window.
Thanks again for all the help,
Jeff
You are welcome
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