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/* $Id: plwind.c,v 1.2 2007/05/08 09:09:37 rice Exp $
Routines for setting up world coordinates of the current viewport.
Copyright (C) 2004 Alan W. Irwin
This file is part of PLplot.
PLplot is free software; you can redistribute it and/or modify
it under the terms of the GNU General Library Public License as published
by the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
PLplot is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with PLplot; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "plplotP.h"
#define dtr 0.01745329252
/*--------------------------------------------------------------------------*\
* void plwind()
*
* Set up world coordinates of the viewport boundaries (2d plots).
\*--------------------------------------------------------------------------*/
void
c_plwind(PLFLT xmin, PLFLT xmax, PLFLT ymin, PLFLT ymax)
{
PLFLT dx, dy, mmxmi, mmxma, mmymi, mmyma;
PLWindow w;
if (plsc->level < 2) {
plabort("plwind: Please set up viewport first");
return;
}
/* Best to just warn and recover on bounds errors */
if (xmin == xmax) {
plwarn("plwind: Invalid window limits in x.");
xmin--; xmax++;
}
if (ymin == ymax) {
plwarn("plwind: Invalid window limits in y.");
ymin--; ymax++;
}
dx = (xmax - xmin) * 1.0e-5;
dy = (ymax - ymin) * 1.0e-5;
/* The true plot window is made slightly larger than requested so that */
/* the end limits will be on the graph */
plsc->vpwxmi = xmin - dx;
plsc->vpwxma = xmax + dx;
plsc->vpwymi = ymin - dy;
plsc->vpwyma = ymax + dy;
/* Compute the scaling between coordinate systems */
dx = plsc->vpwxma - plsc->vpwxmi;
dy = plsc->vpwyma - plsc->vpwymi;
plsc->wpxscl = (plsc->vppxma - plsc->vppxmi) / dx;
plsc->wpxoff = (xmax * plsc->vppxmi - xmin * plsc->vppxma) / dx;
plsc->wpyscl = (plsc->vppyma - plsc->vppymi) / dy;
plsc->wpyoff = (ymax * plsc->vppymi - ymin * plsc->vppyma) / dy;
mmxmi = plP_dcmmx(plsc->vpdxmi);
mmxma = plP_dcmmx(plsc->vpdxma);
mmymi = plP_dcmmy(plsc->vpdymi);
mmyma = plP_dcmmy(plsc->vpdyma);
/* Set transformation variables for world coordinates to mm */
plsc->wmxscl = (mmxma - mmxmi) / dx;
plsc->wmxoff = (xmax * mmxmi - xmin * mmxma) / dx;
plsc->wmyscl = (mmyma - mmymi) / dy;
plsc->wmyoff = (ymax * mmymi - ymin * mmyma) / dy;
/* Set transformation variables for world coordinates to device coords */
plsc->wdxscl = plsc->wmxscl * plsc->xpmm / (plsc->phyxma - plsc->phyxmi);
plsc->wdxoff = plsc->wmxoff * plsc->xpmm / (plsc->phyxma - plsc->phyxmi);
plsc->wdyscl = plsc->wmyscl * plsc->ypmm / (plsc->phyyma - plsc->phyymi);
plsc->wdyoff = plsc->wmyoff * plsc->ypmm / (plsc->phyyma - plsc->phyymi);
/* Register plot window attributes */
w.dxmi = plsc->vpdxmi;
w.dxma = plsc->vpdxma;
w.dymi = plsc->vpdymi;
w.dyma = plsc->vpdyma;
w.wxmi = plsc->vpwxmi;
w.wxma = plsc->vpwxma;
w.wymi = plsc->vpwymi;
w.wyma = plsc->vpwyma;
plP_swin(&w);
/* Go to level 3 */
plsc->level = 3;
}
/*--------------------------------------------------------------------------*\
* void plw3d()
*
* Set up a window for three-dimensional plotting. The data are mapped
* into a box with world coordinate size "basex" by "basey" by "height",
* with the base being symmetrically positioned about zero. Thus
* the mapping between data 3-d and world 3-d coordinates is given by:
*
* x = xmin => wx = -0.5*basex
* x = xmax => wx = 0.5*basex
* y = ymin => wy = -0.5*basey
* y = ymax => wy = 0.5*basey
* z = zmin => wz = 0.0
* z = zmax => wz = height
*
* The world coordinate box is then viewed from position "alt"-"az",
* measured in degrees. For proper operation, 0 <= alt <= 90 degrees,
* but az can be any value.
\*--------------------------------------------------------------------------*/
void
c_plw3d(PLFLT basex, PLFLT basey, PLFLT height, PLFLT xmin0,
PLFLT xmax0, PLFLT ymin0, PLFLT ymax0, PLFLT zmin0,
PLFLT zmax0, PLFLT alt, PLFLT az)
{
PLFLT xmin, xmax, ymin, ymax, zmin, zmax, d;
PLFLT cx, cy, saz, caz, salt, calt, zscale;
if (plsc->level < 3) {
plabort("plw3d: Please set up 2-d window first");
return;
}
if (basex <= 0.0 || basey <= 0.0 || height <= 0.0) {
plabort("plw3d: Invalid world coordinate boxsize");
return;
}
if (xmin0 == xmax0 || ymin0 == ymax0 || zmin0 == zmax0) {
plabort("plw3d: Invalid axis range");
return;
}
if (alt < 0.0 || alt > 90.0) {
plabort("plw3d: Altitude must be between 0 and 90 degrees");
return;
}
d = 1.0e-5 * (xmax0 - xmin0);
xmax = xmax0 + d;
xmin = xmin0 - d;
d = 1.0e-5 * (ymax0 - ymin0);
ymax = ymax0 + d;
ymin = ymin0 - d;
d = 1.0e-5 * (zmax0 - zmin0);
zmax = zmax0 + d;
zmin = zmin0 - d;
cx = basex / (xmax - xmin);
cy = basey / (ymax - ymin);
zscale = height / (zmax - zmin);
saz = sin(dtr * az);
caz = cos(dtr * az);
salt = sin(dtr * alt);
calt = cos(dtr * alt);
plsc->domxmi = xmin;
plsc->domxma = xmax;
plsc->domymi = ymin;
plsc->domyma = ymax;
plsc->zzscl = zscale;
plsc->ranmi = zmin;
plsc->ranma = zmax;
plsc->base3x = basex;
plsc->base3y = basey;
plsc->basecx = 0.5 * (xmin + xmax);
plsc->basecy = 0.5 * (ymin + ymax);
/* Mathematical explanation of the 3 transformations of coordinates:
* (I) Scaling:
* x' = cx*(x-x_mid) = cx*(x-plsc->basecx)
* y' = cy*(y-y_mid) = cy*(y-plsc->basecy)
* z' = zscale*(z-zmin) = zscale*(z-plsc->ranmi)
* (II) Rotation about z' axis clockwise by the angle of the azimut when
* looking from the top in a right-handed coordinate system.
* x'' x'
* y'' = M_1 * y'
* z'' z'
* where the rotation matrix M_1 (see any mathematical physics book such
* as Mathematical Methods in the Physical Sciences by Boas) is
* caz -saz 0
* saz caz 0
* 0 0 1
* (III) Rotation about x'' axis by 90 deg - alt to bring z''' axis
* coincident with line of sight and x''' and y''' corresponding to
* x and y coordinates in the 2D plane of the plot.
* x''' x''
* y''' = M_2 * y''
* z''' z''
* where the rotation matrix M_2 is
* 1 0 0
* 0 salt calt
* 0 -calt salt
* Note
* x''' x'
* y''' = M * y'
* z''' z'
* where M = M_2*M_1 is given by
* caz -saz 0
* salt*saz salt*caz calt
* -calt*saz -calt*caz salt
* plP_w3wcx and plP_w3wcy take the combination of the plsc->basecx,
* plsc->basecy, plsc->ranmi, plsc->cxx, plsc->cxy, plsc->cyx, plsc->cyy, and
* plsc->cyz data stored here to implement the combination of the 3
* transformations to determine x''' and y''' from x, y, and z.
*/
plsc->cxx = cx * caz;
plsc->cxy = -cy * saz;
plsc->cyx = cx * saz * salt;
plsc->cyy = cy * caz * salt;
plsc->cyz = zscale * calt;
}
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