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Diffstat (limited to 'Build/source/libs/potrace/potrace-src/src/render.c')
-rw-r--r-- | Build/source/libs/potrace/potrace-src/src/render.c | 245 |
1 files changed, 0 insertions, 245 deletions
diff --git a/Build/source/libs/potrace/potrace-src/src/render.c b/Build/source/libs/potrace/potrace-src/src/render.c deleted file mode 100644 index ff66b0f4f56..00000000000 --- a/Build/source/libs/potrace/potrace-src/src/render.c +++ /dev/null @@ -1,245 +0,0 @@ -/* Copyright (C) 2001-2017 Peter Selinger. - This file is part of Potrace. It is free software and it is covered - by the GNU General Public License. See the file COPYING for details. */ - -#ifdef HAVE_CONFIG_H -#include <config.h> -#endif - -#include <stdio.h> -#include <stdlib.h> -#include <math.h> -#include <string.h> - -#include "render.h" -#include "greymap.h" -#include "auxiliary.h" - -/* ---------------------------------------------------------------------- */ -/* routines for anti-aliased rendering of curves */ - -/* we use the following method. Given a point (x,y) (with real-valued - coordinates) in the plane, let (xi,yi) be the integer part of the - coordinates, i.e., xi=floor(x), yi=floor(y). Define a path from - (x,y) to infinity as follows: path(x,y) = - (x,y)--(xi+1,y)--(xi+1,yi)--(+infty,yi). Now as the point (x,y) - moves smoothly across the plane, the path path(x,y) sweeps - (non-smoothly) across a certain area. We proportionately blacken - the area as the path moves "downward", and we whiten the area as - the path moves "upward". This way, after the point has traversed a - closed curve, the interior of the curve has been darkened - (counterclockwise movement) or lightened (clockwise movement). (The - "grey shift" is actually proportional to the winding number). By - choosing the above path with mostly integer coordinates, we achieve - that only pixels close to (x,y) receive grey values and are subject - to round-off errors. The grey value of pixels far away from (x,y) - is always in "integer" (where 0=black, 1=white). As a special - trick, we keep an accumulator rm->a1, which holds a double value to - be added to the grey value to be added to the current pixel - (xi,yi). Only when changing "current" pixels, we convert this - double value to an integer. This way we avoid round-off errors at - the meeting points of line segments. Another speedup measure is - that we sometimes use the rm->incrow_buf array to postpone - incrementing or decrementing an entire row. If incrow_buf[y]=x+1!=0, - then all the pixels (x,y),(x+1,y),(x+2,y),... are scheduled to be - incremented/decremented (which one is the case will be clear from - context). This keeps the greymap operations reasonably local. */ - -/* allocate a new rendering state */ -render_t *render_new(greymap_t *gm) { - render_t *rm; - - rm = (render_t *) malloc(sizeof(render_t)); - if (!rm) { - return NULL; - } - memset(rm, 0, sizeof(render_t)); - rm->gm = gm; - rm->incrow_buf = (int *) calloc(gm->h, sizeof(int)); - if (!rm->incrow_buf) { - free(rm); - return NULL; - } - return rm; -} - -/* free a given rendering state. Note: this does not free the - underlying greymap. */ -void render_free(render_t *rm) { - free(rm->incrow_buf); - free(rm); -} - -/* close path */ -void render_close(render_t *rm) { - if (rm->x0 != rm->x1 || rm->y0 != rm->y1) { - render_lineto(rm, rm->x0, rm->y0); - } - GM_INC(rm->gm, rm->x0i, rm->y0i, (rm->a0+rm->a1)*255); - - /* assert (rm->x0i != rm->x1i || rm->y0i != rm->y1i); */ - - /* the persistent state is now undefined */ -} - -/* move point */ -void render_moveto(render_t *rm, double x, double y) { - /* close the previous path */ - render_close(rm); - - rm->x0 = rm->x1 = x; - rm->y0 = rm->y1 = y; - rm->x0i = (int)floor(rm->x0); - rm->x1i = (int)floor(rm->x1); - rm->y0i = (int)floor(rm->y0); - rm->y1i = (int)floor(rm->y1); - rm->a0 = rm->a1 = 0; -} - -/* add b to pixels (x,y) and all pixels to the right of it. However, - use rm->incrow_buf as a buffer to economize on multiple calls */ -static void incrow(render_t *rm, int x, int y, int b) { - int i, x0; - - if (y < 0 || y >= rm->gm->h) { - return; - } - - if (x < 0) { - x = 0; - } else if (x > rm->gm->w) { - x = rm->gm->w; - } - if (rm->incrow_buf[y] == 0) { - rm->incrow_buf[y] = x+1; /* store x+1 so that we can use 0 for "vacant" */ - return; - } - x0 = rm->incrow_buf[y]-1; - rm->incrow_buf[y] = 0; - if (x0 < x) { - for (i=x0; i<x; i++) { - GM_INC(rm->gm, i, y, -b); - } - } else { - for (i=x; i<x0; i++) { - GM_INC(rm->gm, i, y, b); - } - } -} - -/* render a straight line */ -void render_lineto(render_t *rm, double x2, double y2) { - int x2i, y2i; - double t0=2, s0=2; - int sn, tn; - double ss=2, ts=2; - double r0, r1; - int i, j; - int rxi, ryi; - int s; - - x2i = (int)floor(x2); - y2i = (int)floor(y2); - - sn = abs(x2i - rm->x1i); - tn = abs(y2i - rm->y1i); - - if (sn) { - s0 = ((x2>rm->x1 ? rm->x1i+1 : rm->x1i) - rm->x1)/(x2-rm->x1); - ss = fabs(1.0/(x2-rm->x1)); - } - if (tn) { - t0 = ((y2>rm->y1 ? rm->y1i+1 : rm->y1i) - rm->y1)/(y2-rm->y1); - ts = fabs(1.0/(y2-rm->y1)); - } - - r0 = 0; - - i = 0; - j = 0; - - rxi = rm->x1i; - ryi = rm->y1i; - - while (i<sn || j<tn) { - if (j>=tn || (i<sn && s0+i*ss < t0+j*ts)) { - r1 = s0+i*ss; - i++; - s = 1; - } else { - r1 = t0+j*ts; - j++; - s = 0; - } - /* render line from r0 to r1 segment of (rm->x1,rm->y1)..(x2,y2) */ - - /* move point to r1 */ - rm->a1 += (r1-r0)*(y2-rm->y1)*(rxi+1-((r0+r1)/2.0*(x2-rm->x1)+rm->x1)); - - /* move point across pixel boundary */ - if (s && x2>rm->x1) { - GM_INC(rm->gm, rxi, ryi, rm->a1*255); - rm->a1 = 0; - rxi++; - rm->a1 += rm->y1+r1*(y2-rm->y1)-ryi; - } else if (!s && y2>rm->y1) { - GM_INC(rm->gm, rxi, ryi, rm->a1*255); - rm->a1 = 0; - incrow(rm, rxi+1, ryi, 255); - ryi++; - } else if (s && x2<=rm->x1) { - rm->a1 -= rm->y1+r1*(y2-rm->y1)-ryi; - GM_INC(rm->gm, rxi, ryi, rm->a1*255); - rm->a1 = 0; - rxi--; - } else if (!s && y2<=rm->y1) { - GM_INC(rm->gm, rxi, ryi, rm->a1*255); - rm->a1 = 0; - ryi--; - incrow(rm, rxi+1, ryi, -255); - } - - r0 = r1; - } - - /* move point to (x2,y2) */ - - r1 = 1; - rm->a1 += (r1-r0)*(y2-rm->y1)*(rxi+1-((r0+r1)/2.0*(x2-rm->x1)+rm->x1)); - - rm->x1i = x2i; - rm->y1i = y2i; - rm->x1 = x2; - rm->y1 = y2; - - /* assert (rxi != rm->x1i || ryi != rm->y1i); */ -} - -/* render a Bezier curve. */ -void render_curveto(render_t *rm, double x2, double y2, double x3, double y3, double x4, double y4) { - double x1, y1, dd0, dd1, dd, delta, e2, epsilon, t; - - x1 = rm->x1; /* starting point */ - y1 = rm->y1; - - /* we approximate the curve by small line segments. The interval - size, epsilon, is determined on the fly so that the distance - between the true curve and its approximation does not exceed the - desired accuracy delta. */ - - delta = .1; /* desired accuracy, in pixels */ - - /* let dd = maximal value of 2nd derivative over curve - this must - occur at an endpoint. */ - dd0 = sq(x1-2*x2+x3) + sq(y1-2*y2+y3); - dd1 = sq(x2-2*x3+x4) + sq(y2-2*y3+y4); - dd = 6*sqrt(max(dd0, dd1)); - e2 = 8*delta <= dd ? 8*delta/dd : 1; - epsilon = sqrt(e2); /* necessary interval size */ - - for (t=epsilon; t<1; t+=epsilon) { - render_lineto(rm, x1*cu(1-t)+3*x2*sq(1-t)*t+3*x3*(1-t)*sq(t)+x4*cu(t), - y1*cu(1-t)+3*y2*sq(1-t)*t+3*y3*(1-t)*sq(t)+y4*cu(t)); - } - render_lineto(rm, x4, y4); -} |