cartesian coordinate

[Aisin Geuru]

Hi,

anybody know how to convert a pc coordinate system(0,0 at top left corner)
to cartesian coordinate which 0,0 at center and ++ at upper right
-- at lower left.

how about some example in gfxtools 2.0?

regards


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[Eric Pearson]

Aisin --

> how about some example in gfxtools 2.0?

There's no need to perform the conversion yourself... Graphics Tools 2.0 allows the creation of any integer-based coordinate system that you need. See the GfxWorld function in the help file. Also see the sample programs that start with "World" (i.e. world*.bas).

-- Eric Pearson, Perfect Sync Software

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Perfect Sync Development Tools
Perfect Sync Web Site
Contact Us: mailto:[email protected][email protected]</A>

[This message has been edited by Eric Pearson (edited October 06, 2004).]

[Emil Menzel]

Aisin:
Here's another way, if you don't have gfxtools. There are still
easier ways, but this might be useful in more problems other
than the one you mention

Emil Menzel

===========================================================
'Adapted from an Applesoft program
'(in BASIC Computer programs in science & engineering, by J. H. Gilder,1980)
'by Emil W. Menzel, Jr
'Purpose: Convert a Cartesian X,Y from one frame of reference to another
'Language: almost any BASIC


'demo (in PB3.5)
Xno=320: Yno=240 'new origin... e.g.center of a 640x480 VGA screen
'NOTE!: old origin is assumed to be 0,0

DegreesRotation =0


INPUT "X,Y (on old scale) ",X,Y
CALL NewCoordinates(Xno, Yno, DegreesRotation, X, Y)
PRINT X, Y; " (on new scale)"
'end demo

SUB NewCoordinates(Xno, Yno, DegreesRotation, X, Y)
D=DegreesRotation * 3.14159 / 180
X = (X-Xno) * COS(D) + (Y-Yno) * SIN(D)
Y = - (X-Xno) * SIN(D) + (Y-Yno) * COS(D)
END SUB



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