Commit message: Fix #72696: imagefilltoborder stackoverflow on truecolor images

We must not allow negative color values be passed to
gdImageFillToBorder(), because that can lead to infinite recursion
since the recursion termination condition will not necessarily be met.
CVE: CVE-2016-9933
CWE: CWE-119
Vulnerability description: Stack consumption vulnerability in the gdImageFillToBorder function in gd.c in the GD Graphics Library (aka libgd) before 2.2.2, as used in PHP before 5.6.28 and 7.x before 7.0.13, allows remote attackers to cause a denial of service (segmentation violation) via a crafted imagefilltoborder call that triggers use of a negative color value.

Project: php-src

static void _gdImageFilledHRectangle (gdImagePtr im, int x1, int y1, int x2, int y2, int color)
{
	int x, y;

	if (x1 == x2 && y1 == y2) {
		gdImageSetPixel(im, x1, y1, color);
		return;
	}

	if (x1 > x2) {
		x = x1;
		x1 = x2;
		x2 = x;
	}

	if (y1 > y2) {
		y = y1;
		y1 = y2;
		y2 = y;
	}

	if (x1 < 0) {
		x1 = 0;
	}

	if (x2 >= gdImageSX(im)) {
		x2 = gdImageSX(im) - 1;
	}

	if (y1 < 0) {
		y1 = 0;
	}

	if (y2 >= gdImageSY(im)) {
		y2 = gdImageSY(im) - 1;
	}

	for (x = x1; (x <= x2); x++) {
		for (y = y1; (y <= y2); y++) {
			gdImageSetPixel (im, x, y, color);
		}
	}
}

Project: php-src

static void _gdImageFilledVRectangle (gdImagePtr im, int x1, int y1, int x2, int y2, int color)
{
	int x, y;

	if (x1 == x2 && y1 == y2) {
		gdImageSetPixel(im, x1, y1, color);
		return;
	}

	if (x1 > x2) {
		x = x1;
		x1 = x2;
		x2 = x;
	}

	if (y1 > y2) {
		y = y1;
		y1 = y2;
		y2 = y;
	}

	if (x1 < 0) {
		x1 = 0;
	}

	if (x2 >= gdImageSX(im)) {
		x2 = gdImageSX(im) - 1;
	}

	if (y1 < 0) {
		y1 = 0;
	}

	if (y2 >= gdImageSY(im)) {
		y2 = gdImageSY(im) - 1;
	}

	for (y = y1; (y <= y2); y++) {
		for (x = x1; (x <= x2); x++) {
			gdImageSetPixel (im, x, y, color);
		}
	}
}

Project: php-src

void gdImageAALine (gdImagePtr im, int x1, int y1, int x2, int y2, int col)
{
	/* keep them as 32bits */
	long x, y, inc, frac;
	long dx, dy,tmp;

	/* 2.0.10: Nick Atty: clip to edges of drawing rectangle, return if no points need to be drawn */
	if (!clip_1d(&x1,&y1,&x2,&y2,gdImageSX(im)-1) || !clip_1d(&y1,&x1,&y2,&x2,gdImageSY(im)-1)) {
		return;
	}

	dx = x2 - x1;
	dy = y2 - y1;

	if (dx == 0 && dy == 0) {
		return;
	}
	if (abs(dx) > abs(dy)) {
		if (dx < 0) {
			tmp = x1;
			x1 = x2;
			x2 = tmp;
			tmp = y1;
			y1 = y2;
			y2 = tmp;
			dx = x2 - x1;
			dy = y2 - y1;
		}
		y = y1;
		inc = (dy * 65536) / dx;
		frac = 0;
		for (x = x1; x <= x2; x++) {
			gdImageSetAAPixelColor(im, x, y, col, (frac >> 8) & 0xFF);
			if (y + 1 < im->sy) {
				gdImageSetAAPixelColor(im, x, y + 1, col, (~frac >> 8) & 0xFF);
			}
			frac += inc;
			if (frac >= 65536) {
				frac -= 65536;
				y++;
			} else if (frac < 0) {
				frac += 65536;
				y--;
			}
		}
	} else {
		if (dy < 0) {
			tmp = x1;
			x1 = x2;
			x2 = tmp;
			tmp = y1;
			y1 = y2;
			y2 = tmp;
			dx = x2 - x1;
			dy = y2 - y1;
		}
		x = x1;
		inc = (dx * 65536) / dy;
		frac = 0;
		for (y = y1; y <= y2; y++) {
			gdImageSetAAPixelColor(im, x, y, col, (frac >> 8) & 0xFF);
			if (x + 1 < im->sx) {
				gdImageSetAAPixelColor(im, x + 1, y, col, (~frac >> 8) & 0xFF);
			}
			frac += inc;
			if (frac >= 65536) {
				frac -= 65536;
				x++;
			} else if (frac < 0) {
				frac += 65536;
				x--;
			}
		}
	}
}

Project: php-src

void gdImageArc (gdImagePtr im, int cx, int cy, int w, int h, int s, int e, int color)
{
	gdImageFilledArc(im, cx, cy, w, h, s, e, color, gdNoFill);
}

Project: php-src

void gdImageColorTransparent (gdImagePtr im, int color)
{
	if (color < 0) {
		return;
	}
	if (!im->trueColor) {
		if((color >= im->colorsTotal)) {
			return;
		}
		/* Make the old transparent color opaque again */
		if (im->transparent != -1) {
			im->alpha[im->transparent] = gdAlphaOpaque;
		}
		im->alpha[color] = gdAlphaTransparent;
	}
	im->transparent = color;
}

Project: php-src

void gdImageCopy (gdImagePtr dst, gdImagePtr src, int dstX, int dstY, int srcX, int srcY, int w, int h)
{
	int c;
	int x, y;
	int tox, toy;
	int i;
	int colorMap[gdMaxColors];

	if (dst->trueColor) {
		/* 2.0: much easier when the destination is truecolor. */
		/* 2.0.10: needs a transparent-index check that is still valid if
		 * the source is not truecolor. Thanks to Frank Warmerdam.
		 */

		if (src->trueColor) {
			for (y = 0; (y < h); y++) {
				for (x = 0; (x < w); x++) {
					int c = gdImageGetTrueColorPixel (src, srcX + x, srcY + y);
					if (c != src->transparent) {
						gdImageSetPixel (dst, dstX + x, dstY + y, c);
					}
				}
			}
		} else {
			/* source is palette based */
			for (y = 0; (y < h); y++) {
				for (x = 0; (x < w); x++) {
					int c = gdImageGetPixel (src, srcX + x, srcY + y);
					if (c != src->transparent) {
						gdImageSetPixel(dst, dstX + x, dstY + y, gdTrueColorAlpha(src->red[c], src->green[c], src->blue[c], src->alpha[c]));
					}
				}
			}
		}
		return;
	}

	/* Palette based to palette based */
	for (i = 0; i < gdMaxColors; i++) {
		colorMap[i] = (-1);
	}
	toy = dstY;
	for (y = srcY; y < (srcY + h); y++) {
		tox = dstX;
		for (x = srcX; x < (srcX + w); x++) {
			int nc;
			int mapTo;
			c = gdImageGetPixel (src, x, y);
			/* Added 7/24/95: support transparent copies */
			if (gdImageGetTransparent (src) == c) {
				tox++;
				continue;
			}
			/* Have we established a mapping for this color? */
			if (src->trueColor) {
				/* 2.05: remap to the palette available in the destination image. This is slow and
				 * works badly, but it beats crashing! Thanks to Padhrig McCarthy.
				 */
				mapTo = gdImageColorResolveAlpha (dst, gdTrueColorGetRed (c), gdTrueColorGetGreen (c), gdTrueColorGetBlue (c), gdTrueColorGetAlpha (c));
			} else if (colorMap[c] == (-1)) {
				/* If it's the same image, mapping is trivial */
				if (dst == src) {
					nc = c;
				} else {
					/* Get best match possible. This function never returns error. */
					nc = gdImageColorResolveAlpha (dst, src->red[c], src->green[c], src->blue[c], src->alpha[c]);
				}
				colorMap[c] = nc;
				mapTo = colorMap[c];
			} else {
				mapTo = colorMap[c];
			}
			gdImageSetPixel (dst, tox, toy, mapTo);
			tox++;
		}
		toy++;
	}
}

Project: php-src
File: gd.c

gdImagePtr gdImageCreate (int sx, int sy)
{
	int i;
	gdImagePtr im;

	if (overflow2(sx, sy)) {
		return NULL;
	}

	if (overflow2(sizeof(unsigned char *), sy)) {
		return NULL;
	}

	if (overflow2(sizeof(unsigned char *), sx)) {
		return NULL;
	}

	im = (gdImage *) gdCalloc(1, sizeof(gdImage));

	/* Row-major ever since gd 1.3 */
	im->pixels = (unsigned char **) gdMalloc(sizeof(unsigned char *) * sy);
	im->AA_opacity = (unsigned char **) gdMalloc(sizeof(unsigned char *) * sy);
	im->polyInts = 0;
	im->polyAllocated = 0;
	im->brush = 0;
	im->tile = 0;
	im->style = 0;
	for (i = 0; i < sy; i++) {
		/* Row-major ever since gd 1.3 */
		im->pixels[i] = (unsigned char *) gdCalloc(sx, sizeof(unsigned char));
		im->AA_opacity[i] = (unsigned char *) gdCalloc(sx, sizeof(unsigned char));
	}
	im->sx = sx;
	im->sy = sy;
	im->colorsTotal = 0;
	im->transparent = (-1);
	im->interlace = 0;
	im->thick = 1;
	im->AA = 0;
	im->AA_polygon = 0;
	for (i = 0; i < gdMaxColors; i++) {
		im->open[i] = 1;
		im->red[i] = 0;
		im->green[i] = 0;
		im->blue[i] = 0;
	}
	im->trueColor = 0;
	im->tpixels = 0;
	im->cx1 = 0;
	im->cy1 = 0;
	im->cx2 = im->sx - 1;
	im->cy2 = im->sy - 1;
	im->interpolation = NULL;
	im->interpolation_id = GD_BILINEAR_FIXED;
	return im;
}

Project: php-src

gdImagePtr gdImageCreateTrueColor (int sx, int sy)
{
	int i;
	gdImagePtr im;

	if (overflow2(sx, sy)) {
		return NULL;
	}

	if (overflow2(sizeof(unsigned char *), sy)) {
		return NULL;
	}

	if (overflow2(sizeof(int *), sx)) {
		return NULL;
	}

	im = (gdImage *) gdMalloc(sizeof(gdImage));
	memset(im, 0, sizeof(gdImage));
	im->tpixels = (int **) gdMalloc(sizeof(int *) * sy);
	im->AA_opacity = (unsigned char **) gdMalloc(sizeof(unsigned char *) * sy);
	im->polyInts = 0;
	im->polyAllocated = 0;
	im->brush = 0;
	im->tile = 0;
	im->style = 0;
	for (i = 0; i < sy; i++) {
		im->tpixels[i] = (int *) gdCalloc(sx, sizeof(int));
		im->AA_opacity[i] = (unsigned char *) gdCalloc(sx, sizeof(unsigned char));
	}
	im->sx = sx;
	im->sy = sy;
	im->transparent = (-1);
	im->interlace = 0;
	im->trueColor = 1;
	/* 2.0.2: alpha blending is now on by default, and saving of alpha is
	 * off by default. This allows font antialiasing to work as expected
	 * on the first try in JPEGs -- quite important -- and also allows
	 * for smaller PNGs when saving of alpha channel is not really
	 * desired, which it usually isn't!
	 */
	im->saveAlphaFlag = 0;
	im->alphaBlendingFlag = 1;
	im->thick = 1;
	im->AA = 0;
	im->AA_polygon = 0;
	im->cx1 = 0;
	im->cy1 = 0;
	im->cx2 = im->sx - 1;
	im->cy2 = im->sy - 1;
	im->interpolation = NULL;
	im->interpolation_id = GD_BILINEAR_FIXED;
	return im;
}

Project: php-src

void gdImageFilledArc (gdImagePtr im, int cx, int cy, int w, int h, int s, int e, int color, int style)
{
	gdPoint pts[363];
	int i, pti;
	int lx = 0, ly = 0;
	int fx = 0, fy = 0;


    if ((s % 360)  == (e % 360)) {
		s = 0; e = 360;
	} else {
		if (s > 360) {
			s = s % 360;
		}

		if (e > 360) {
			e = e % 360;
		}

		while (s < 0) {
			s += 360;
		}

		while (e < s) {
			e += 360;
		}
		if (s == e) {
			s = 0; e = 360;
		}
	}

	for (i = s, pti = 1; i <= e; i++, pti++) {
		int x, y;
		x = ((long) gdCosT[i % 360] * (long) w / (2 * 1024)) + cx;
		y = ((long) gdSinT[i % 360] * (long) h / (2 * 1024)) + cy;
		if (i != s) {
			if (!(style & gdChord)) {
				if (style & gdNoFill) {
					gdImageLine(im, lx, ly, x, y, color);
				} else {
					if (y == ly) {
						pti--; /* don't add this point */
						if (((i > 270 || i < 90) && x > lx) || ((i >  90 && i < 270) && x < lx)) {
							/* replace the old x coord, if increasing on the
							   right side or decreasing on the left side */
							pts[pti].x = x;
						}
					} else {
						pts[pti].x = x;
						pts[pti].y = y;
					}
  				}
			}
		} else {
			fx = x;
			fy = y;
			if (!(style & (gdChord | gdNoFill))) {
				pts[0].x = cx;
				pts[0].y = cy;
				pts[pti].x = x;
				pts[pti].y = y;
			}
		}
		lx = x;
		ly = y;
	}
	if (style & gdChord) {
		if (style & gdNoFill) {
			if (style & gdEdged) {
				gdImageLine(im, cx, cy, lx, ly, color);
				gdImageLine(im, cx, cy, fx, fy, color);
			}
			gdImageLine(im, fx, fy, lx, ly, color);
		} else {
			pts[0].x = fx;
			pts[0].y = fy;
			pts[1].x = lx;
			pts[1].y = ly;
			pts[2].x = cx;
			pts[2].y = cy;
			gdImageFilledPolygon(im, pts, 3, color);
		}
	} else {
		if (style & gdNoFill) {
			if (style & gdEdged) {
				gdImageLine(im, cx, cy, lx, ly, color);
				gdImageLine(im, cx, cy, fx, fy, color);
			}
		} else {
			pts[pti].x = cx;
			pts[pti].y = cy;
			gdImageFilledPolygon(im, pts, pti+1, color);
		}
	}
}

Project: php-src

void gdImageFilledPolygon (gdImagePtr im, gdPointPtr p, int n, int c)
{
	int i;
	int y;
	int miny, maxy, pmaxy;
	int x1, y1;
	int x2, y2;
	int ind1, ind2;
	int ints;
	int fill_color;

	if (n <= 0) {
		return;
	}

	if (overflow2(sizeof(int), n)) {
		return;
	}

	if (c == gdAntiAliased) {
		fill_color = im->AA_color;
	} else {
		fill_color = c;
	}

	if (!im->polyAllocated) {
		im->polyInts = (int *) gdMalloc(sizeof(int) * n);
		im->polyAllocated = n;
	}
	if (im->polyAllocated < n) {
		while (im->polyAllocated < n) {
			im->polyAllocated *= 2;
		}
		if (overflow2(sizeof(int), im->polyAllocated)) {
			return;
		}
		im->polyInts = (int *) gdRealloc(im->polyInts, sizeof(int) * im->polyAllocated);
	}
	miny = p[0].y;
	maxy = p[0].y;
	for (i = 1; i < n; i++) {
		if (p[i].y < miny) {
			miny = p[i].y;
		}
		if (p[i].y > maxy) {
			maxy = p[i].y;
		}
	}
	/* necessary special case: horizontal line */
	if (n > 1 && miny == maxy) {
		x1 = x2 = p[0].x;
		for (i = 1; (i < n); i++) {
			if (p[i].x < x1) {
				x1 = p[i].x;
			} else if (p[i].x > x2) {
				x2 = p[i].x;
			}
		}
		gdImageLine(im, x1, miny, x2, miny, c);
		return;
	}
	pmaxy = maxy;
	/* 2.0.16: Optimization by Ilia Chipitsine -- don't waste time offscreen */
	if (miny < 0) {
		miny = 0;
	}
	if (maxy >= gdImageSY(im)) {
		maxy = gdImageSY(im) - 1;
	}

	/* Fix in 1.3: count a vertex only once */
	for (y = miny; y <= maxy; y++) {
		/*1.4           int interLast = 0; */
		/*              int dirLast = 0; */
		/*              int interFirst = 1; */
		ints = 0;
		for (i = 0; i < n; i++) {
			if (!i) {
				ind1 = n - 1;
				ind2 = 0;
			} else {
				ind1 = i - 1;
				ind2 = i;
			}
			y1 = p[ind1].y;
			y2 = p[ind2].y;
			if (y1 < y2) {
				x1 = p[ind1].x;
				x2 = p[ind2].x;
			} else if (y1 > y2) {
				y2 = p[ind1].y;
				y1 = p[ind2].y;
				x2 = p[ind1].x;
				x1 = p[ind2].x;
			} else {
				continue;
			}
			/* Do the following math as float intermediately, and round to ensure
			 * that Polygon and FilledPolygon for the same set of points have the
			 * same footprint.
			 */
			if (y >= y1 && y < y2) {
				im->polyInts[ints++] = (float) ((y - y1) * (x2 - x1)) / (float) (y2 - y1) + 0.5 + x1;
			} else if (y == pmaxy && y == y2) {
				im->polyInts[ints++] = x2;
			}
		}
		qsort(im->polyInts, ints, sizeof(int), gdCompareInt);

		for (i = 0; i < ints - 1; i += 2) {
			gdImageLine(im, im->polyInts[i], y, im->polyInts[i + 1], y, fill_color);
		}
	}

	/* If we are drawing this AA, then redraw the border with AA lines. */
	if (c == gdAntiAliased) {
		gdImagePolygon(im, p, n, c);
	}
}

Project: php-src

void gdImageFilledRectangle (gdImagePtr im, int x1, int y1, int x2, int y2, int color)
{
	_gdImageFilledVRectangle(im, x1, y1, x2, y2, color);
}

Project: php-src

static void gdImageHLine(gdImagePtr im, int y, int x1, int x2, int col)
{
	if (im->thick > 1) {
		int thickhalf = im->thick >> 1;
		_gdImageFilledHRectangle(im, x1, y - thickhalf, x2, y + im->thick - thickhalf - 1, col);
	} else {
		if (x2 < x1) {
			int t = x2;
			x2 = x1;
			x1 = t;
		}

		for (;x1 <= x2; x1++) {
			gdImageSetPixel(im, x1, y, col);
		}
	}
	return;
}

Project: php-src

void gdImageLine (gdImagePtr im, int x1, int y1, int x2, int y2, int color)
{
	int dx, dy, incr1, incr2, d, x, y, xend, yend, xdirflag, ydirflag;
	int wid;
	int w, wstart;
	int thick = im->thick;

	if (color == gdAntiAliased) {
		/*
		   gdAntiAliased passed as color: use the much faster, much cheaper
		   and equally attractive gdImageAALine implementation. That
		   clips too, so don't clip twice.
		   */
		gdImageAALine(im, x1, y1, x2, y2, im->AA_color);
		return;
	}

	/* 2.0.10: Nick Atty: clip to edges of drawing rectangle, return if no points need to be drawn */
	if (!clip_1d(&x1,&y1,&x2,&y2,gdImageSX(im)-1) || !clip_1d(&y1,&x1,&y2,&x2,gdImageSY(im)-1)) {
		return;
	}

	dx = abs (x2 - x1);
	dy = abs (y2 - y1);

	if (dx == 0) {
		gdImageVLine(im, x1, y1, y2, color);
		return;
	} else if (dy == 0) {
		gdImageHLine(im, y1, x1, x2, color);
		return;
	}

	if (dy <= dx) {
		/* More-or-less horizontal. use wid for vertical stroke */
		/* Doug Claar: watch out for NaN in atan2 (2.0.5) */
		if ((dx == 0) && (dy == 0)) {
			wid = 1;
		} else {
			/* 2.0.12: Michael Schwartz: divide rather than multiply;
TBB: but watch out for /0! */
			double ac = cos (atan2 (dy, dx));
			if (ac != 0) {
				wid = thick / ac;
			} else {
				wid = 1;
			}
			if (wid == 0) {
				wid = 1;
			}
		}
		d = 2 * dy - dx;
		incr1 = 2 * dy;
		incr2 = 2 * (dy - dx);
		if (x1 > x2) {
			x = x2;
			y = y2;
			ydirflag = (-1);
			xend = x1;
		} else {
			x = x1;
			y = y1;
			ydirflag = 1;
			xend = x2;
		}

		/* Set up line thickness */
		wstart = y - wid / 2;
		for (w = wstart; w < wstart + wid; w++) {
			gdImageSetPixel(im, x, w, color);
		}

		if (((y2 - y1) * ydirflag) > 0) {
			while (x < xend) {
				x++;
				if (d < 0) {
					d += incr1;
				} else {
					y++;
					d += incr2;
				}
				wstart = y - wid / 2;
				for (w = wstart; w < wstart + wid; w++) {
					gdImageSetPixel (im, x, w, color);
				}
			}
		} else {
			while (x < xend) {
				x++;
				if (d < 0) {
					d += incr1;
				} else {
					y--;
					d += incr2;
				}
				wstart = y - wid / 2;
				for (w = wstart; w < wstart + wid; w++) {
					gdImageSetPixel (im, x, w, color);
				}
			}
		}
	} else {
		/* More-or-less vertical. use wid for horizontal stroke */
		/* 2.0.12: Michael Schwartz: divide rather than multiply;
		   TBB: but watch out for /0! */
		double as = sin (atan2 (dy, dx));
		if (as != 0) {
			wid = thick / as;
		} else {
			wid = 1;
		}
		if (wid == 0) {
			wid = 1;
		}

		d = 2 * dx - dy;
		incr1 = 2 * dx;
		incr2 = 2 * (dx - dy);
		if (y1 > y2) {
			y = y2;
			x = x2;
			yend = y1;
			xdirflag = (-1);
		} else {
			y = y1;
			x = x1;
			yend = y2;
			xdirflag = 1;
		}

		/* Set up line thickness */
		wstart = x - wid / 2;
		for (w = wstart; w < wstart + wid; w++) {
			gdImageSetPixel (im, w, y, color);
		}

		if (((x2 - x1) * xdirflag) > 0) {
			while (y < yend) {
				y++;
				if (d < 0) {
					d += incr1;
				} else {
					x++;
					d += incr2;
				}
				wstart = x - wid / 2;
				for (w = wstart; w < wstart + wid; w++) {
					gdImageSetPixel (im, w, y, color);
				}
			}
		} else {
			while (y < yend) {
				y++;
				if (d < 0) {
					d += incr1;
				} else {
					x--;
					d += incr2;
				}
				wstart = x - wid / 2;
				for (w = wstart; w < wstart + wid; w++) {
					gdImageSetPixel (im, w, y, color);
				}
			}
		}
	}
}

Project: php-src

void gdImageRectangle (gdImagePtr im, int x1, int y1, int x2, int y2, int color)
{
	int x1h = x1, x1v = x1, y1h = y1, y1v = y1, x2h = x2, x2v = x2, y2h = y2, y2v = y2;
	int thick = im->thick;
	int t;

	if (x1 == x2 && y1 == y2 && thick == 1) {
		gdImageSetPixel(im, x1, y1, color);
		return;
	}

	if (y2 < y1) {
		t=y1;
		y1 = y2;
		y2 = t;
	}
	
	if (x2 < x1) {
		t = x1;
		x1 = x2;
		x2 = t;
	}

	x1h = x1; x1v = x1; y1h = y1; y1v = y1; x2h = x2; x2v = x2; y2h = y2; y2v = y2;
	if (thick > 1) {
		int cx, cy, x1ul, y1ul, x2lr, y2lr;
		int half = thick >> 1;

		x1ul = x1 - half;
		y1ul = y1 - half;

		x2lr = x2 + half;
		y2lr = y2 + half;

		cy = y1ul + thick;
		while (cy-- > y1ul) {
			cx = x1ul - 1;
			while (cx++ < x2lr) {
				gdImageSetPixel(im, cx, cy, color);
			}
		}

		cy = y2lr - thick;
		while (cy++ < y2lr) {
			cx = x1ul - 1;
			while (cx++ < x2lr) {
				gdImageSetPixel(im, cx, cy, color);
			}
		}

		cy = y1ul + thick - 1;
		while (cy++ < y2lr -thick) {
			cx = x1ul - 1;
			while (cx++ < x1ul + thick) {
				gdImageSetPixel(im, cx, cy, color);
			}
		}

		cy = y1ul + thick - 1;
		while (cy++ < y2lr -thick) {
			cx = x2lr - thick - 1;
			while (cx++ < x2lr) {
				gdImageSetPixel(im, cx, cy, color);
			}
		}

		return;
	} else {
		if (x1 == x2 || y1 == y2) {
			gdImageLine(im, x1, y1, x2, y2, color);
		} else {
			y1v = y1h + 1;
			y2v = y2h - 1;
			gdImageLine(im, x1h, y1h, x2h, y1h, color);
			gdImageLine(im, x1h, y2h, x2h, y2h, color);
			gdImageLine(im, x1v, y1v, x1v, y2v, color);
			gdImageLine(im, x2v, y1v, x2v, y2v, color);
		}
	}
}