void
c_plvpas(PLFLT xmin, PLFLT xmax, PLFLT ymin, PLFLT ymax, PLFLT aspect)
{
PLFLT vpxmi, vpxma, vpymi, vpyma;
PLFLT vpxmid, vpymid, vpxlen, vpylen, w_aspect, ratio;
if (plsc->level < 1) {
plabort("plvpas: Please call plinit first");
return;
}
if ((xmin >= xmax) || (ymin >= ymax)) {
plabort("plvpas: Invalid limits");
return;
}
if (aspect <= 0.0) {
c_plvpor(xmin, xmax, ymin, ymax);
return;
}
vpxmi = plP_dcmmx(xmin);
vpxma = plP_dcmmx(xmax);
vpymi = plP_dcmmy(ymin);
vpyma = plP_dcmmy(ymax);
vpxmid = (vpxmi + vpxma) / 2.;
vpymid = (vpymi + vpyma) / 2.;
vpxlen = vpxma - vpxmi;
vpylen = vpyma - vpymi;
w_aspect = vpylen / vpxlen;
ratio = aspect / w_aspect;
/*
* If ratio < 1, you are requesting an aspect ratio (y/x) less than the natural
* aspect ratio of the specified window, and you will need to reduce the length
* in y correspondingly. Similarly, for ratio > 1, x length must be reduced.
*/
if (ratio <= 0.) {
plabort("plvpas: Error in aspect ratio setting");
return;
}
else if (ratio < 1.)
vpylen = vpylen * ratio;
else
vpxlen = vpxlen / ratio;
vpxmi = vpxmid - vpxlen / 2.;
vpxma = vpxmid + vpxlen / 2.;
vpymi = vpymid - vpylen / 2.;
vpyma = vpymid + vpylen / 2.;
plsvpa(vpxmi, vpxma, vpymi, vpyma);
}
void WINAPI
plvpor(PLFLT xmin, PLFLT xmax, PLFLT ymin, PLFLT ymax) {
c_plvpor(xmin,xmax,ymin,ymax);
}
