[deb_xorg-server.git] / mi / mifpolycon.c

/***********************************************************

Copyright 1987, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

******************************************************************/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <math.h>
#include <X11/X.h>
#include "gcstruct.h"
#include "windowstr.h"
#include "pixmapstr.h"
#include "mifpoly.h"

static int GetFPolyYBounds(SppPointPtr pts, int n, double yFtrans,
                           int *by, int *ty);

/*
 *	Written by Todd Newman; April. 1987.
 *
 *	Fill a convex polygon.  If the given polygon
 *	is not convex, then the result is undefined.
 *	The algorithm is to order the edges from smallest
 *	y to largest by partitioning the array into a left
 *	edge list and a right edge list.  The algorithm used
 *	to traverse each edge is digital differencing analyzer
 *	line algorithm with y as the major axis. There's some funny linear
 *	interpolation involved because of the subpixel postioning.
 */
void
miFillSppPoly(DrawablePtr dst, GCPtr pgc, int count,    /* number of points */
              SppPointPtr ptsIn,        /* the points */
              int xTrans, int yTrans,   /* Translate each point by this */
              double xFtrans, double yFtrans    /* translate before conversion
                                                   by this amount.  This provides
                                                   a mechanism to match rounding
                                                   errors with any shape that must
                                                   meet the polygon exactly.
                                                 */
    )
{
    double xl = 0.0, xr = 0.0,  /* x vals of left and right edges */
        ml = 0.0,               /* left edge slope */
        mr = 0.0,               /* right edge slope */
        dy,                     /* delta y */
        i;                      /* loop counter */
    int y,                      /* current scanline */
     j, imin,                   /* index of vertex with smallest y */
     ymin,                      /* y-extents of polygon */
     ymax, *width, *FirstWidth, /* output buffer */
    *Marked;                    /* set if this vertex has been used */
    int left, right,            /* indices to first endpoints */
     nextleft, nextright;       /* indices to second endpoints */
    DDXPointPtr ptsOut, FirstPoint;     /* output buffer */

    if (pgc->miTranslate) {
        xTrans += dst->x;
        yTrans += dst->y;
    }

    imin = GetFPolyYBounds(ptsIn, count, yFtrans, &ymin, &ymax);

    y = ymax - ymin + 1;
    if ((count < 3) || (y <= 0))
        return;
    ptsOut = FirstPoint = malloc(sizeof(DDXPointRec) * y);
    width = FirstWidth = malloc(sizeof(int) * y);
    Marked = malloc(sizeof(int) * count);

    if (!ptsOut || !width || !Marked) {
        free(Marked);
        free(width);
        free(ptsOut);
        return;
    }

    for (j = 0; j < count; j++)
        Marked[j] = 0;
    nextleft = nextright = imin;
    Marked[imin] = -1;
    y = ICEIL(ptsIn[nextleft].y + yFtrans);

    /*
     *  loop through all edges of the polygon
     */
    do {
        /* add a left edge if we need to */
        if ((y > (ptsIn[nextleft].y + yFtrans) ||
             ISEQUAL(y, ptsIn[nextleft].y + yFtrans)) &&
            Marked[nextleft] != 1) {
            Marked[nextleft]++;
            left = nextleft++;

            /* find the next edge, considering the end conditions */
            if (nextleft >= count)
                nextleft = 0;

            /* now compute the starting point and slope */
            dy = ptsIn[nextleft].y - ptsIn[left].y;
            if (dy != 0.0) {
                ml = (ptsIn[nextleft].x - ptsIn[left].x) / dy;
                dy = y - (ptsIn[left].y + yFtrans);
                xl = (ptsIn[left].x + xFtrans) + ml * max(dy, 0);
            }
        }

        /* add a right edge if we need to */
        if ((y > ptsIn[nextright].y + yFtrans) ||
            (ISEQUAL(y, ptsIn[nextright].y + yFtrans)
             && Marked[nextright] != 1)) {
            Marked[nextright]++;
            right = nextright--;

            /* find the next edge, considering the end conditions */
            if (nextright < 0)
                nextright = count - 1;

            /* now compute the starting point and slope */
            dy = ptsIn[nextright].y - ptsIn[right].y;
            if (dy != 0.0) {
                mr = (ptsIn[nextright].x - ptsIn[right].x) / dy;
                dy = y - (ptsIn[right].y + yFtrans);
                xr = (ptsIn[right].x + xFtrans) + mr * max(dy, 0);
            }
        }

        /*
         *  generate scans to fill while we still have
         *  a right edge as well as a left edge.
         */
        i = (min(ptsIn[nextleft].y, ptsIn[nextright].y) + yFtrans) - y;

        if (i < EPSILON) {
            if (Marked[nextleft] && Marked[nextright]) {
                /* Arrgh, we're trapped! (no more points) 
                 * Out, we've got to get out of here before this decadence saps
                 * our will completely! */
                break;
            }
            continue;
        }
        else {
            j = (int) i;
            if (!j)
                j++;
        }
        while (j > 0) {
            int cxl, cxr;

            ptsOut->y = (y) + yTrans;

            cxl = ICEIL(xl);
            cxr = ICEIL(xr);
            /* reverse the edges if necessary */
            if (xl < xr) {
                *(width++) = cxr - cxl;
                (ptsOut++)->x = cxl + xTrans;
            }
            else {
                *(width++) = cxl - cxr;
                (ptsOut++)->x = cxr + xTrans;
            }
            y++;

            /* increment down the edges */
            xl += ml;
            xr += mr;
            j--;
        }
    } while (y <= ymax);

    /* Finally, fill the spans we've collected */
    (*pgc->ops->FillSpans) (dst, pgc,
                            ptsOut - FirstPoint, FirstPoint, FirstWidth, 1);
    free(Marked);
    free(FirstWidth);
    free(FirstPoint);
}
\f
/* Find the index of the point with the smallest y.also return the
 * smallest and largest y */
static
    int
GetFPolyYBounds(SppPointPtr pts, int n, double yFtrans, int *by, int *ty)
{
    SppPointPtr ptMin;
    double ymin, ymax;
    SppPointPtr ptsStart = pts;

    ptMin = pts;
    ymin = ymax = (pts++)->y;

    while (--n > 0) {
        if (pts->y < ymin) {
            ptMin = pts;
            ymin = pts->y;
        }
        if (pts->y > ymax)
            ymax = pts->y;

        pts++;
    }

    *by = ICEIL(ymin + yFtrans);
    *ty = ICEIL(ymax + yFtrans - 1);
    return ptMin - ptsStart;
}
Commit	Line	Data
a09e091a JB	1	/***********************************************************
	2
	3	Copyright 1987, 1998 The Open Group
	4
	5	Permission to use, copy, modify, distribute, and sell this software and its
	6	documentation for any purpose is hereby granted without fee, provided that
	7	the above copyright notice appear in all copies and that both that
	8	copyright notice and this permission notice appear in supporting
	9	documentation.
	10
	11	The above copyright notice and this permission notice shall be included in
	12	all copies or substantial portions of the Software.
	13
	14	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	15	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	16	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	17	OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
	18	AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	19	CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	20
	21	Except as contained in this notice, the name of The Open Group shall not be
	22	used in advertising or otherwise to promote the sale, use or other dealings
	23	in this Software without prior written authorization from The Open Group.
	24
	25	Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
	26
	27	All Rights Reserved
	28
	29	Permission to use, copy, modify, and distribute this software and its
	30	documentation for any purpose and without fee is hereby granted,
	31	provided that the above copyright notice appear in all copies and that
	32	both that copyright notice and this permission notice appear in
	33	supporting documentation, and that the name of Digital not be
	34	used in advertising or publicity pertaining to distribution of the
	35	software without specific, written prior permission.
	36
	37	DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
	38	ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
	39	DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
	40	ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	41	WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
	42	ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
	43	SOFTWARE.
	44
	45	******************************************************************/
	46	#ifdef HAVE_DIX_CONFIG_H
	47	#include <dix-config.h>
	48	#endif
	49
	50	#include <math.h>
	51	#include <X11/X.h>
	52	#include "gcstruct.h"
	53	#include "windowstr.h"
	54	#include "pixmapstr.h"
	55	#include "mifpoly.h"
	56
	57	static int GetFPolyYBounds(SppPointPtr pts, int n, double yFtrans,
	58	int by, int ty);
	59
	60	/*
	61	* Written by Todd Newman; April. 1987.
	62	*
	63	* Fill a convex polygon. If the given polygon
	64	* is not convex, then the result is undefined.
65	* The algorithm is to order the edges from smallest
66	* y to largest by partitioning the array into a left
67	* edge list and a right edge list. The algorithm used
68	* to traverse each edge is digital differencing analyzer
69	* line algorithm with y as the major axis. There's some funny linear
70	* interpolation involved because of the subpixel postioning.
71	*/
72	void
73	miFillSppPoly(DrawablePtr dst, GCPtr pgc, int count, /* number of points */
74	SppPointPtr ptsIn, /* the points */
75	int xTrans, int yTrans, /* Translate each point by this */
76	double xFtrans, double yFtrans /* translate before conversion
77	by this amount. This provides
78	a mechanism to match rounding
79	errors with any shape that must
80	meet the polygon exactly.
81	*/
82	)
83	{
84	double xl = 0.0, xr = 0.0, /* x vals of left and right edges */
85	ml = 0.0, /* left edge slope */
86	mr = 0.0, /* right edge slope */
87	dy, /* delta y */
88	i; /* loop counter */
89	int y, /* current scanline */
90	j, imin, /* index of vertex with smallest y */
91	ymin, /* y-extents of polygon */
92	ymax, width, FirstWidth, /* output buffer */
93	Marked; / set if this vertex has been used */
94	int left, right, /* indices to first endpoints */
95	nextleft, nextright; /* indices to second endpoints */
96	DDXPointPtr ptsOut, FirstPoint; /* output buffer */
97
98	if (pgc->miTranslate) {
99	xTrans += dst->x;
100	yTrans += dst->y;
101	}
102
103	imin = GetFPolyYBounds(ptsIn, count, yFtrans, &ymin, &ymax);
104
105	y = ymax - ymin + 1;
106	if ((count < 3) \|\| (y <= 0))
107	return;
108	ptsOut = FirstPoint = malloc(sizeof(DDXPointRec) * y);
109	width = FirstWidth = malloc(sizeof(int) * y);
110	Marked = malloc(sizeof(int) * count);
111
112	if (!ptsOut \|\| !width \|\| !Marked) {
113	free(Marked);
114	free(width);
115	free(ptsOut);
116	return;
117	}
118
119	for (j = 0; j < count; j++)
120	Marked[j] = 0;
121	nextleft = nextright = imin;
122	Marked[imin] = -1;
123	y = ICEIL(ptsIn[nextleft].y + yFtrans);
124
125	/*
126	* loop through all edges of the polygon
127	*/
128	do {
129	/* add a left edge if we need to */
130	if ((y > (ptsIn[nextleft].y + yFtrans) \|\|
131	ISEQUAL(y, ptsIn[nextleft].y + yFtrans)) &&
132	Marked[nextleft] != 1) {
133	Marked[nextleft]++;
134	left = nextleft++;
135
136	/* find the next edge, considering the end conditions */
137	if (nextleft >= count)
138	nextleft = 0;
139
140	/* now compute the starting point and slope */
141	dy = ptsIn[nextleft].y - ptsIn[left].y;
142	if (dy != 0.0) {
143	ml = (ptsIn[nextleft].x - ptsIn[left].x) / dy;
144	dy = y - (ptsIn[left].y + yFtrans);
145	xl = (ptsIn[left].x + xFtrans) + ml * max(dy, 0);
146	}
147	}
148
149	/* add a right edge if we need to */
150	if ((y > ptsIn[nextright].y + yFtrans) \|\|
151	(ISEQUAL(y, ptsIn[nextright].y + yFtrans)
152	&& Marked[nextright] != 1)) {
153	Marked[nextright]++;
154	right = nextright--;
155
156	/* find the next edge, considering the end conditions */
157	if (nextright < 0)
158	nextright = count - 1;
159
160	/* now compute the starting point and slope */
161	dy = ptsIn[nextright].y - ptsIn[right].y;
162	if (dy != 0.0) {
163	mr = (ptsIn[nextright].x - ptsIn[right].x) / dy;
164	dy = y - (ptsIn[right].y + yFtrans);
165	xr = (ptsIn[right].x + xFtrans) + mr * max(dy, 0);
166	}
167	}
168
169	/*
170	* generate scans to fill while we still have
171	* a right edge as well as a left edge.
172	*/
173	i = (min(ptsIn[nextleft].y, ptsIn[nextright].y) + yFtrans) - y;
174
175	if (i < EPSILON) {
176	if (Marked[nextleft] && Marked[nextright]) {
177	/* Arrgh, we're trapped! (no more points)
178	* Out, we've got to get out of here before this decadence saps
179	* our will completely! */
180	break;
181	}
182	continue;
183	}
184	else {
185	j = (int) i;
186	if (!j)
187	j++;
188	}
189	while (j > 0) {
190	int cxl, cxr;
191
192	ptsOut->y = (y) + yTrans;
193
194	cxl = ICEIL(xl);
195	cxr = ICEIL(xr);
196	/* reverse the edges if necessary */
197	if (xl < xr) {
198	*(width++) = cxr - cxl;
199	(ptsOut++)->x = cxl + xTrans;
200	}
201	else {
202	*(width++) = cxl - cxr;
203	(ptsOut++)->x = cxr + xTrans;
204	}
205	y++;
206
207	/* increment down the edges */
208	xl += ml;
209	xr += mr;
210	j--;
211	}
212	} while (y <= ymax);
213
214	/* Finally, fill the spans we've collected */
215	(*pgc->ops->FillSpans) (dst, pgc,
216	ptsOut - FirstPoint, FirstPoint, FirstWidth, 1);
217	free(Marked);
218	free(FirstWidth);
219	free(FirstPoint);
220	}
221	\f
222	/* Find the index of the point with the smallest y.also return the
223	* smallest and largest y */
224	static
225	int
226	GetFPolyYBounds(SppPointPtr pts, int n, double yFtrans, int by, int ty)
227	{
228	SppPointPtr ptMin;
229	double ymin, ymax;
230	SppPointPtr ptsStart = pts;
231
232	ptMin = pts;
233	ymin = ymax = (pts++)->y;
234
235	while (--n > 0) {
236	if (pts->y < ymin) {
237	ptMin = pts;
238	ymin = pts->y;
239	}
240	if (pts->y > ymax)
241	ymax = pts->y;
242
243	pts++;
244	}
245
246	*by = ICEIL(ymin + yFtrans);
247	*ty = ICEIL(ymax + yFtrans - 1);
248	return ptMin - ptsStart;
249	}