gd.c

php-4.4.7学习linux时下载的源代码

		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) {
			if (!(wid = thick / as)) {
				wid = 1;
			}
		} else {
			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);
				}
			}
		}
	}

	/* If this is the only line we are drawing, go ahead and blend. */
	if (color == gdAntiAliased && !im->AA_polygon) {
		gdImageAABlend(im);
	}
}


/*
 * Added on 2003/12 by Pierre-Alain Joye ([e-mail])
 * */
#define BLEND_COLOR(a, nc, c, cc) \
nc = (cc) + (((((c) - (cc)) * (a)) + ((((c) - (cc)) * (a)) >> 8) + 0x80) >> 8);

inline static void gdImageSetAAPixelColor(gdImagePtr im, int x, int y, int color, int t)
{
	int dr,dg,db,p,r,g,b;
	dr = gdTrueColorGetRed(color);
	dg = gdTrueColorGetGreen(color);
	db = gdTrueColorGetBlue(color);

	p = gdImageGetPixel(im,x,y);
	r = gdTrueColorGetRed(p);
	g = gdTrueColorGetGreen(p);
	b = gdTrueColorGetBlue(p);

	BLEND_COLOR(t, dr, r, dr);
	BLEND_COLOR(t, dg, g, dg);
	BLEND_COLOR(t, db, b, db);
	im->tpixels[y][x]=gdTrueColorAlpha(dr, dg, db,  gdAlphaOpaque);
}  

/*
 * Added on 2003/12 by Pierre-Alain Joye ([e-mail])
 **/
void gdImageAALine (gdImagePtr im, int x1, int y1, int x2, int y2, int col)
{
	/* keep them as 32bits */
	long x, y, inc;
	long dx, dy,tmp;

	if (y1 < 0 && y2 < 0) {
		return;
	}
	if (y1 < 0) {
		x1 += (y1 * (x1 - x2)) / (y2 - y1);
		y1 = 0;
	}
	if (y2 < 0) {
		x2 += (y2 * (x1 - x2)) / (y2 - y1);
		y2 = 0;
	}

	/* bottom edge */
	if (y1 >= im->sy && y2 >= im->sy) {
		return;
	}
	if (y1 >= im->sy) {
		x1 -= ((im->sy - y1) * (x1 - x2)) / (y2 - y1);
		y1 = im->sy - 1;
	}
	if (y2 >= im->sy) {
		x2 -= ((im->sy - y2) * (x1 - x2)) / (y2 - y1);
		y2 = im->sy - 1;
	}

	/* left edge */
	if (x1 < 0 && x2 < 0) {
		return;
	}
	if (x1 < 0) {
		y1 += (x1 * (y1 - y2)) / (x2 - x1);
		x1 = 0;
	}
	if (x2 < 0) {
		y2 += (x2 * (y1 - y2)) / (x2 - x1);
		x2 = 0;
	}
	/* right edge */
	if (x1 >= im->sx && x2 >= im->sx) {
		return;
	}
	if (x1 >= im->sx) {
		y1 -= ((im->sx - x1) * (y1 - y2)) / (x2 - x1);
		x1 = im->sx - 1;
	}
	if (x2 >= im->sx) {
		y2 -= ((im->sx - x2) * (y1 - y2)) / (x2 - x1);
		x2 = im->sx - 1;
	}

	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;
		}
		x = x1 << 16;
		y = y1 << 16;
		inc = (dy * 65536) / dx;
		while ((x >> 16) < x2) {
			gdImageSetAAPixelColor(im, x >> 16, y >> 16, col, (y >> 8) & 0xFF);
			if ((y >> 16) + 1 < im->sy) {
				gdImageSetAAPixelColor(im, x >> 16, (y >> 16) + 1,col, (~y >> 8) & 0xFF);
			}
			x += (1 << 16);
			y += inc;
		}
	} else {
		if (dy < 0) {
			tmp = x1;
			x1 = x2;
			x2 = tmp;
			tmp = y1;
			y1 = y2;
			y2 = tmp;
			dx = x2 - x1;
			dy = y2 - y1;
		}
		x = x1 << 16;
		y = y1 << 16;
		inc = (dx * 65536) / dy;
		while ((y>>16) < y2) {
			gdImageSetAAPixelColor(im, x >> 16, y >> 16, col, (x >> 8) & 0xFF);
			if ((x >> 16) + 1 < im->sx) {
				gdImageSetAAPixelColor(im, (x >> 16) + 1, (y >> 16),col, (~x >> 8) & 0xFF);
			}
			x += inc;
			y += (1<<16);
		}
	}
}

static void dashedSet (gdImagePtr im, int x, int y, int color, int *onP, int *dashStepP, int wid, int vert);

void gdImageDashedLine (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 dashStep = 0;
	int on = 1;
	int wid;
	int vert;
	int thick = im->thick;

	dx = abs(x2 - x1);
	dy = abs(y2 - y1);
	if (dy <= dx) {
		/* More-or-less horizontal. use wid for vertical 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;
		}
		wid = (int)(thick * sin(atan2(dy, dx)));
		vert = 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;
		}
		dashedSet(im, x, y, color, &on, &dashStep, wid, vert);
		if (((y2 - y1) * ydirflag) > 0) {
			while (x < xend) {
				x++;
				if (d < 0) {
					d += incr1;
				} else {
					y++;
					d += incr2;
				}
				dashedSet(im, x, y, color, &on, &dashStep, wid, vert);
			}
		} else {
			while (x < xend) {
				x++;
				if (d < 0) {
					d += incr1;
				} else {
					y--;
					d += incr2;
				}
				dashedSet(im, x, y, color, &on, &dashStep, wid, vert);
			}
		}
	} else {
		/* 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;
		}
		vert = 0;

		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;
		}
		dashedSet(im, x, y, color, &on, &dashStep, wid, vert);
		if (((x2 - x1) * xdirflag) > 0) {
			while (y < yend) {
				y++;
				if (d < 0) {
					d += incr1;
				} else {
					x++;
					d += incr2;
				}
				dashedSet(im, x, y, color, &on, &dashStep, wid, vert);
			}
		} else {
			while (y < yend) {
				y++;
				if (d < 0) {
					d += incr1;
				} else {
					x--;
					d += incr2;
				}
				dashedSet(im, x, y, color, &on, &dashStep, wid, vert);
			}
		}
	}
}

static void dashedSet (gdImagePtr im, int x, int y, int color, int *onP, int *dashStepP, int wid, int vert)
{
	int dashStep = *dashStepP;
	int on = *onP;
	int w, wstart;

	dashStep++;
	if (dashStep == gdDashSize) {
		dashStep = 0;
		on = !on;
	}
	if (on) {
		if (vert) {
			wstart = y - wid / 2;
			for (w = wstart; w < wstart + wid; w++) {
				gdImageSetPixel(im, x, w, color);
			}
		} else {
			wstart = x - wid / 2;
			for (w = wstart; w < wstart + wid; w++) {
				gdImageSetPixel(im, w, y, color);
			}
		}
	}
	*dashStepP = dashStep;
	*onP = on;
}

void gdImageChar (gdImagePtr im, gdFontPtr f, int x, int y, int c, int color)
{
	int cx, cy;
	int px, py;
	int fline;
	cx = 0;
	cy = 0;
#ifdef CHARSET_EBCDIC
	c = ASC (c);
#endif /*CHARSET_EBCDIC */
	if ((c < f->offset) || (c >= (f->offset + f->nchars))) {
		return;
	}
	fline = (c - f->offset) * f->h * f->w;
	for (py = y; (py < (y + f->h)); py++) {
		for (px = x; (px < (x + f->w)); px++) {
			if (f->data[fline + cy * f->w + cx]) {
				gdImageSetPixel(im, px, py, color);
			}
			cx++;
		}
		cx = 0;
		cy++;
	}
}

void gdImageCharUp (gdImagePtr im, gdFontPtr f, int x, int y, int c, int color)
{
	int cx, cy;
	int px, py;
	int fline;
	cx = 0;
	cy = 0;
#ifdef CHARSET_EBCDIC
	c = ASC (c);
#endif /*CHARSET_EBCDIC */
	if ((c < f->offset) || (c >= (f->offset + f->nchars))) {
		return;
	}
	fline = (c - f->offset) * f->h * f->w;
	for (py = y; py > (y - f->w); py--) {
		for (px = x; px < (x + f->h); px++) {
			if (f->data[fline + cy * f->w + cx]) {
				gdImageSetPixel(im, px, py, color);
			}
			cy++;
		}
		cy = 0;
		cx++;
	}
}

void gdImageString (gdImagePtr im, gdFontPtr f, int x, int y, unsigned char *s, int color)
{
	int i;
	int l;
	l = strlen ((char *) s);
	for (i = 0; (i < l); i++) {
		gdImageChar(im, f, x, y, s[i], color);
		x += f->w;
	}
}

void gdImageStringUp (gdImagePtr im, gdFontPtr f, int x, int y, unsigned char *s, int color)
{
	int i;
	int l;
	l = strlen ((char *) s);
	for (i = 0; (i < l); i++) {
		gdImageCharUp(im, f, x, y, s[i], color);
		y -= f->w;
	}
}

static int strlen16 (unsigned short *s);

void gdImageString16 (gdImagePtr im, gdFontPtr f, int x, int y, unsigned short *s, int color)
{
	int i;
	int l;
	l = strlen16(s);
	for (i = 0; (i < l); i++) {
		gdImageChar(im, f, x, y, s[i], color);
		x += f->w;
	}
}

void gdImageStringUp16 (gdImagePtr im, gdFontPtr f, int x, int y, unsigned short *s, int color)
{
	int i;
	int l;
	l = strlen16(s);
	for (i = 0; i < l; i++) {
		gdImageCharUp(im, f, x, y, s[i], color);
		y -= f->w;
	}
}

static int strlen16 (unsigned short *s)
{
	int len = 0;
	while (*s) {
		s++;
		len++;
	}
	return len;
}

#ifndef HAVE_LSQRT
/* If you don't have a nice square root function for longs, you can use
   ** this hack
 */
long lsqrt (long n)
{
 	long result = (long) sqrt ((double) n);
	return result;
}
#endif

/* s and e are integers modulo 360 (degrees), with 0 degrees
   being the rightmost extreme and degrees changing clockwise.
   cx and cy are the center in pixels; w and h are the horizontal 
   and vertical diameter in pixels. Nice interface, but slow.
   See gd_arc_f_buggy.c for a better version that doesn't 
   seem to be bug-free yet. */

void gdImageArc (gdImagePtr im, int cx, int cy, int w, int h, int s, int e, int color)
{
	if ((s % 360) == (e % 360)) {
		gdImageEllipse(im, cx, cy, w, h, color);
	} else {
		gdImageFilledArc(im, cx, cy, w, h, s, e, color, gdNoFill);
	}
}

void gdImageFilledArc (gdImagePtr im, int cx, int cy, int w, int h, int s, int e, int color, int style)
{
	gdPoint pts[3];
	int i;
	int lx = 0, ly = 0;
	int fx = 0, fy = 0;

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

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

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

	while (e < s) {
		e += 360;