transform.c

/*
 * transformed coordinate system objects for X
 */

# include	<X11/Xos.h>
# include	<stdlib.h>
# include	<X11/Xlib.h>
# include	"transform.h"

#if 0
static XPoint *
TranslatePoints (TPoint *points, int n_points, Transform *t, int mode)
{
	XPoint	*xpoints;
	int	i;
	double	xoff = 0.0, yoff = 0.0;

	xpoints = (XPoint *) malloc (n_points * sizeof (*xpoints));
	if (!xpoints)
		return NULL;
	for (i = 0; i < n_points; i++) {
		xpoints[i].x = Xx(points[i].x + xoff, points[i].y + yoff, t);
		xpoints[i].y = Xy(points[i].x + xoff, points[i].y + yoff, t);
		if (mode == CoordModePrevious) {
			xoff += points[i].x;
			yoff += points[i].y;
		}
	}
	return xpoints;
}

static void
TFillPolygon (
    Display	*dpy,
    Drawable	d,
    GC		gc,
    Transform	*t,
    TPoint	*points,
    int		n_points,
    int		shape,
    int		mode)
{
	XPoint	*xpoints;

	xpoints = TranslatePoints (points, n_points, t, mode);
	if (xpoints) {
		XFillPolygon (dpy, d, gc, xpoints, n_points, shape,
				CoordModeOrigin);
		free (xpoints);
	}
}

static void
TDrawArc (
    Display	*dpy,
    Drawable	d,
    GC		gc,
    Transform	*t,
    double	x,
    double	y,
    double	width,
    double	height,
    int		angle1,
    int		angle2)
{
	int	xx, xy, xw, xh;

	xx = Xx(x,y,t);
	xy = Xy(x,y,t);
	xw = Xwidth (width, height, t);
	xh = Xheight (width, height, t);
	if (xw < 0) {
		xx += xw;
		xw = -xw;
	}
	if (xh < 0) {
		xy += xh;
		xh = -xh;
	}
	XDrawArc (dpy, d, gc, xx, xy, xw, xh, angle1, angle2);
}
#endif

void
Trectangle(const Transform *t, const TRectangle *i, TRectangle *o)
{
    o->x = t->mx * i->x + t->bx;
    o->y = t->my * i->y + t->by;
    o->width = t->mx * i->width;
    o->height = t->my * i->height;
    if (o->width < 0) {
	o->x += o->width;
	o->width = -o->width;
    }
    if (o->height < 0) {
	o->y += o->height;
	o->height = -o->height;
    }
}

void
SetTransform (Transform *t,
	      int xx1, int xx2, int xy1, int xy2,
	      double tx1, double tx2, double ty1, double ty2)
{
	t->mx = ((double) xx2 - xx1) / (tx2 - tx1);
	t->bx = ((double) xx1) - t->mx * tx1;
	t->my = ((double) xy2 - xy1) / (ty2 - ty1);
	t->by = ((double) xy1) - t->my * ty1;
}