250 lines
8.6 KiB
C
250 lines
8.6 KiB
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);
|
||
}
|
||
|
||
/* 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;
|
||
}
|