From: Dave Shapiro <daves@cfxc.com>
Subject: Re: Why is y upside down?
Date: 05 Aug 1999 00:00:00 GMT
Message-ID: <37AA0934.C015A4B1@cfxc.com>
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You're not stuck with upside-down y axes. GDI's viewport and origin
routines can make the y axis go the "correct" way:


  // Alter's Canvas's viewport and origin so that (0,0) is the lower-
  // left corner, with positive x going right, and positive y going up.
var
  H: HDC;
begin
  H := Canvas.Handle;
  SetMapMode(H, MM_ISOTROPIC);

  SetWindowOrgEx(H, 0, 0, nil);
  SetViewportOrgEx(H, 0, ClientHeight, nil);
  SetWindowExtEx(H, 1, 1, nil);
  SetViewportExtEx(H, 1, -1, nil);

  Windows.MoveToEx(H, 0, 0, nil);
  Windows.LineTo(H, 100, 100);
end;