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-rw-r--r--raster/pathstroke.c725
1 files changed, 725 insertions, 0 deletions
diff --git a/raster/pathstroke.c b/raster/pathstroke.c
new file mode 100644
index 00000000..2527e6ad
--- /dev/null
+++ b/raster/pathstroke.c
@@ -0,0 +1,725 @@
+#include <fitz.h>
+
+enum { BUTT = 0, ROUND = 1, SQUARE = 2, MITER = 0, BEVEL = 2 };
+
+struct sctx
+{
+ fz_gel *gel;
+ fz_matrix *ctm;
+ float flatness;
+
+ int linecap;
+ int linejoin;
+ float linewidth;
+ float miterlimit;
+ fz_point beg[2];
+ fz_point seg[2];
+ int sn, bn;
+ int dot;
+
+ fz_dash *dash;
+ int toggle;
+ int offset;
+ float phase;
+ fz_point cur;
+};
+
+static fz_error *
+line(struct sctx *s, float x0, float y0, float x1, float y1)
+{
+ float tx0 = s->ctm->a * x0 + s->ctm->c * y0 + s->ctm->e;
+ float ty0 = s->ctm->b * x0 + s->ctm->d * y0 + s->ctm->f;
+ float tx1 = s->ctm->a * x1 + s->ctm->c * y1 + s->ctm->e;
+ float ty1 = s->ctm->b * x1 + s->ctm->d * y1 + s->ctm->f;
+ return fz_insertgel(s->gel, tx0, ty0, tx1, ty1);
+}
+
+static fz_error *
+arc(struct sctx *s,
+ float xc, float yc,
+ float x0, float y0,
+ float x1, float y1)
+{
+ fz_error *error;
+ float th0, th1, r;
+ float theta;
+ float ox, oy, nx, ny;
+ int n, i;
+
+ r = fabs(s->linewidth);
+ theta = 2 * M_SQRT2 * sqrt(s->flatness / r);
+ th0 = atan2(y0, x0);
+ th1 = atan2(y1, x1);
+
+ if (r > 0)
+ {
+ if (th0 < th1)
+ th0 += M_PI * 2;
+ n = ceil((th0 - th1) / theta);
+ }
+ else
+ {
+ if (th1 < th0)
+ th1 += M_PI * 2;
+ n = ceil((th1 - th0) / theta);
+ }
+
+ ox = x0;
+ oy = y0;
+ for (i = 1; i < n; i++)
+ {
+ theta = th0 + (th1 - th0) * i / n;
+ nx = cos(theta) * r;
+ ny = sin(theta) * r;
+ error = line(s, xc + ox, yc + oy, xc + nx, yc + ny);
+ if (error) return error;
+ ox = nx;
+ oy = ny;
+ }
+
+ error = line(s, xc + ox, yc + oy, xc + x1, yc + y1);
+ if (error) return error;
+
+ return nil;
+}
+
+static fz_error *
+linestroke(struct sctx *s, fz_point a, fz_point b)
+{
+ fz_error *error;
+
+ float dx = b.x - a.x;
+ float dy = b.y - a.y;
+ float scale = s->linewidth / sqrt(dx * dx + dy * dy);
+ float dlx = dy * scale;
+ float dly = -dx * scale;
+
+ error = line(s, a.x - dlx, a.y - dly, b.x - dlx, b.y - dly);
+ if (error) return error;
+
+ error = line(s, b.x + dlx, b.y + dly, a.x + dlx, a.y + dly);
+ if (error) return error;
+
+ return nil;
+}
+
+static fz_error *
+linejoin(struct sctx *s, fz_point a, fz_point b, fz_point c)
+{
+ fz_error *error;
+ float miterlimit = s->miterlimit;
+ float linewidth = s->linewidth;
+ int linejoin = s->linejoin;
+ float dx0, dy0;
+ float dx1, dy1;
+ float dlx0, dly0;
+ float dlx1, dly1;
+ float dmx, dmy;
+ float dmr2;
+ float scale;
+ float cross;
+
+ dx0 = b.x - a.x;
+ dy0 = b.y - a.y;
+
+ dx1 = c.x - b.x;
+ dy1 = c.y - b.y;
+
+ if (dx0 * dx0 + dy0 * dy0 < FLT_EPSILON)
+ return nil;
+ if (dx1 * dx1 + dy1 * dy1 < FLT_EPSILON)
+ return nil;
+
+ scale = linewidth / sqrt(dx0 * dx0 + dy0 * dy0);
+ dlx0 = dy0 * scale;
+ dly0 = -dx0 * scale;
+
+ scale = linewidth / sqrt(dx1 * dx1 + dy1 * dy1);
+ dlx1 = dy1 * scale;
+ dly1 = -dx1 * scale;
+
+ cross = dx1 * dy0 - dx0 * dy1;
+
+ dmx = (dlx0 + dlx1) * 0.5;
+ dmy = (dly0 + dly1) * 0.5;
+ dmr2 = dmx * dmx + dmy * dmy;
+
+ if (cross * cross < FLT_EPSILON && dx0 * dx1 + dy0 * dy1 >= 0)
+ linejoin = BEVEL;
+
+ if (linejoin == MITER)
+ if (dmr2 * miterlimit * miterlimit < linewidth * linewidth)
+ linejoin = BEVEL;
+
+ if (linejoin == BEVEL)
+ {
+ error = line(s, b.x - dlx0, b.y - dly0, b.x - dlx1, b.y - dly1);
+ if (error) return error;
+ error = line(s, b.x + dlx1, b.y + dly1, b.x + dlx0, b.y + dly0);
+ if (error) return error;
+ }
+
+ if (linejoin == MITER)
+ {
+ scale = linewidth * linewidth / dmr2;
+ dmx *= scale;
+ dmy *= scale;
+
+ if (cross < 0)
+ {
+ error = line(s, b.x - dlx0, b.y - dly0, b.x - dlx1, b.y - dly1);
+ if (error) return error;
+ error = line(s, b.x + dlx1, b.y + dly1, b.x + dmx, b.y + dmy);
+ if (error) return error;
+ error = line(s, b.x + dmx, b.y + dmy, b.x + dlx0, b.y + dly0);
+ if (error) return error;
+ }
+ else
+ {
+ error = line(s, b.x + dlx1, b.y + dly1, b.x + dlx0, b.y + dly0);
+ if (error) return error;
+ error = line(s, b.x - dlx0, b.y - dly0, b.x - dmx, b.y - dmy);
+ if (error) return error;
+ error = line(s, b.x - dmx, b.y - dmy, b.x - dlx1, b.y - dly1);
+ if (error) return error;
+ }
+ }
+
+ if (linejoin == ROUND)
+ {
+ if (cross < 0)
+ {
+ error = line(s, b.x - dlx0, b.y - dly0, b.x - dlx1, b.y - dly1);
+ if (error) return error;
+ error = arc(s, b.x, b.y, dlx1, dly1, dlx0, dly0);
+ if (error) return error;
+ }
+ else
+ {
+ error = line(s, b.x + dlx1, b.y + dly1, b.x + dlx0, b.y + dly0);
+ if (error) return error;
+ error = arc(s, b.x, b.y, -dlx0, -dly0, -dlx1, -dly1);
+ if (error) return error;
+ }
+ }
+
+ return nil;
+}
+
+static fz_error *
+linecap(struct sctx *s, fz_point a, fz_point b)
+{
+ fz_error *error;
+ float flatness = s->flatness;
+ float linewidth = s->linewidth;
+ int linecap = s->linecap;
+
+ float dx = b.x - a.x;
+ float dy = b.y - a.y;
+
+ float scale = linewidth / sqrt(dx * dx + dy * dy);
+ float dlx = dy * scale;
+ float dly = -dx * scale;
+
+ if (linecap == BUTT)
+ return line(s, b.x - dlx, b.y - dly, b.x + dlx, b.y + dly);
+
+ if (linecap == ROUND)
+ {
+ int i;
+ int n = ceil(M_PI / (2.0 * M_SQRT2 * sqrt(flatness / linewidth)));
+ float ox = b.x - dlx;
+ float oy = b.y - dly;
+ for (i = 1; i < n; i++)
+ {
+ float theta = M_PI * i / n;
+ float cth = cos(theta);
+ float sth = sin(theta);
+ float nx = b.x - dlx * cth - dly * sth;
+ float ny = b.y - dly * cth + dlx * sth;
+ error = line(s, ox, oy, nx, ny);
+ if (error) return error;
+ ox = nx;
+ oy = ny;
+ }
+ error = line(s, ox, oy, b.x + dlx, b.y + dly);
+ if (error) return error;
+ }
+
+ if (linecap == SQUARE)
+ {
+ error = line(s, b.x - dlx, b.y - dly,
+ b.x - dlx - dly,
+ b.y - dly + dlx);
+ if (error) return error;
+ error = line(s, b.x - dlx - dly,
+ b.y - dly + dlx,
+ b.x + dlx - dly,
+ b.y + dly + dlx);
+ if (error) return error;
+ error = line(s, b.x + dlx - dly,
+ b.y + dly + dlx,
+ b.x + dlx, b.y + dly);
+ if (error) return error;
+ }
+
+ return nil;
+}
+
+static fz_error *
+linedot(struct sctx *s, fz_point a)
+{
+ fz_error *error;
+ float flatness = s->flatness;
+ float linewidth = s->linewidth;
+ int n = ceil(M_PI / (M_SQRT2 * sqrt(flatness / linewidth)));
+ float ox = a.x - linewidth;
+ float oy = a.y;
+ int i;
+ for (i = 1; i < n; i++)
+ {
+ float theta = M_PI * 2 * i / n;
+ float cth = cos(theta);
+ float sth = sin(theta);
+ float nx = a.x - cth * linewidth;
+ float ny = a.y + sth * linewidth;
+ error = line(s, ox, oy, nx, ny);
+ if (error) return error;
+ ox = nx;
+ oy = ny;
+ }
+ error = line(s, ox, oy, a.x - linewidth, a.y);
+ if (error) return error;
+ return nil;
+}
+
+static fz_error *
+strokeflush(struct sctx *s)
+{
+ fz_error *error;
+
+ if (s->sn == 2)
+ {
+ error = linecap(s, s->beg[1], s->beg[0]);
+ if (error) return error;
+ error = linecap(s, s->seg[0], s->seg[1]);
+ if (error) return error;
+ }
+ else if (s->dot)
+ {
+ error = linedot(s, s->beg[0]);
+ if (error) return error;
+ }
+
+ s->dot = 0;
+
+ return nil;
+}
+
+static fz_error *
+strokemoveto(struct sctx *s, fz_point cur)
+{
+ fz_error *error;
+
+ error = strokeflush(s);
+ if (error) return error;
+
+ s->seg[0] = cur;
+ s->beg[0] = cur;
+ s->sn = 1;
+ s->bn = 1;
+
+ return nil;
+}
+
+static fz_error *
+strokelineto(struct sctx *s, fz_point cur)
+{
+ fz_error *error;
+
+ float dx = cur.x - s->seg[s->sn-1].x;
+ float dy = cur.y - s->seg[s->sn-1].y;
+
+ if (dx * dx + dy * dy < s->flatness * s->flatness * 0.25)
+ {
+ s->dot = 1;
+ return nil;
+ }
+
+ error = linestroke(s, s->seg[s->sn-1], cur);
+ if (error) return error;
+
+ if (s->sn == 2)
+ {
+ error = linejoin(s, s->seg[0], s->seg[1], cur);
+ if (error) return error;
+
+ s->seg[0] = s->seg[1];
+ s->seg[1] = cur;
+ }
+
+ if (s->sn == 1)
+ s->seg[s->sn++] = cur;
+ if (s->bn == 1)
+ s->beg[s->bn++] = cur;
+
+ return nil;
+}
+
+static fz_error *
+strokeclosepath(struct sctx *s)
+{
+ fz_error *error;
+
+ if (s->sn == 2)
+ {
+ error = strokelineto(s, s->beg[0]);
+ if (error) return error;
+
+ if (s->seg[1].x == s->beg[0].x && s->seg[1].y == s->beg[0].y)
+ error = linejoin(s, s->seg[0], s->beg[0], s->beg[1]);
+ else
+ error = linejoin(s, s->seg[1], s->beg[0], s->beg[1]);
+ if (error) return error;
+ }
+
+ else if (s->dot)
+ {
+ error = linedot(s, s->beg[0]);
+ if (error) return error;
+ }
+
+ s->bn = 0;
+ s->sn = 0;
+ s->dot = 0;
+
+ return nil;
+}
+
+static fz_error *
+strokebezier(struct sctx *s,
+ float xa, float ya,
+ float xb, float yb,
+ float xc, float yc,
+ float xd, float yd)
+{
+ fz_error *error;
+ float dmax;
+ float xab, yab;
+ float xbc, ybc;
+ float xcd, ycd;
+ float xabc, yabc;
+ float xbcd, ybcd;
+ float xabcd, yabcd;
+
+ /* termination check */
+ dmax = ABS(xa - xb);
+ dmax = MAX(dmax, ABS(ya - yb));
+ dmax = MAX(dmax, ABS(xd - xc));
+ dmax = MAX(dmax, ABS(yd - yc));
+ if (dmax < s->flatness) {
+ fz_point p;
+ p.x = xd;
+ p.y = yd;
+ return strokelineto(s, p);
+ }
+
+ xab = xa + xb;
+ yab = ya + yb;
+ xbc = xb + xc;
+ ybc = yb + yc;
+ xcd = xc + xd;
+ ycd = yc + yd;
+
+ xabc = xab + xbc;
+ yabc = yab + ybc;
+ xbcd = xbc + xcd;
+ ybcd = ybc + ycd;
+
+ xabcd = xabc + xbcd;
+ yabcd = yabc + ybcd;
+
+ xab *= 0.5f; yab *= 0.5f;
+ xbc *= 0.5f; ybc *= 0.5f;
+ xcd *= 0.5f; ycd *= 0.5f;
+
+ xabc *= 0.25f; yabc *= 0.25f;
+ xbcd *= 0.25f; ybcd *= 0.25f;
+
+ xabcd *= 0.125f; yabcd *= 0.125f;
+
+ error = strokebezier(s, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd);
+ if (error)
+ return error;
+
+ return strokebezier(s, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd);
+}
+
+fz_error *
+fz_strokepath(fz_gel *gel, fz_pathnode *path, fz_matrix ctm, float flatness)
+{
+ fz_error *error;
+ struct sctx s;
+ fz_point p0, p1, p2, p3;
+ int i;
+
+ s.gel = gel;
+ s.ctm = &ctm;
+ s.flatness = flatness;
+
+ s.linecap = path->linecap;
+ s.linejoin = path->linejoin;
+ s.linewidth = path->linewidth * 0.5;
+ s.miterlimit = path->miterlimit;
+ s.sn = 0;
+ s.bn = 0;
+ s.dot = 0;
+
+ i = 0;
+
+ while (i < path->len)
+ {
+ switch (path->els[i++].k)
+ {
+ case FZ_MOVETO:
+ p1.x = path->els[i++].v;
+ p1.y = path->els[i++].v;
+ error = strokemoveto(&s, p1);
+ if (error)
+ return error;
+ p0 = p1;
+ break;
+
+ case FZ_LINETO:
+ p1.x = path->els[i++].v;
+ p1.y = path->els[i++].v;
+ error = strokelineto(&s, p1);
+ if (error)
+ return error;
+ p0 = p1;
+ break;
+
+ case FZ_CURVETO:
+ p1.x = path->els[i++].v;
+ p1.y = path->els[i++].v;
+ p2.x = path->els[i++].v;
+ p2.y = path->els[i++].v;
+ p3.x = path->els[i++].v;
+ p3.y = path->els[i++].v;
+ error = strokebezier(&s, p0.x, p0.y, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+ if (error)
+ return error;
+ p0 = p3;
+ break;
+
+ case FZ_CLOSEPATH:
+ error = strokeclosepath(&s);
+ if (error)
+ return error;
+ break;
+ }
+ }
+
+ return strokeflush(&s);
+}
+
+static fz_error *
+dashmoveto(struct sctx *s, fz_point a)
+{
+ s->toggle = 1;
+ s->offset = 0;
+ s->phase = s->dash->phase;
+
+ while (s->phase >= s->dash->array[s->offset])
+ {
+ s->toggle = !s->toggle;
+ s->phase -= s->dash->array[s->offset];
+ s->offset ++;
+ if (s->offset == s->dash->len)
+ s->offset = 0;
+ }
+
+ s->cur = a;
+
+ if (s->toggle)
+ return strokemoveto(s, a);
+
+ return nil;
+}
+
+static fz_error *
+dashlineto(struct sctx *s, fz_point b)
+{
+ fz_error *error;
+ float dx, dy;
+ float total, used, ratio;
+ fz_point a;
+ fz_point m;
+
+ a = s->cur;
+ dx = b.x - a.x;
+ dy = b.y - a.y;
+ total = sqrt(dx * dx + dy * dy);
+ used = 0;
+
+ while (total - used > s->dash->array[s->offset] - s->phase)
+ {
+ used += s->dash->array[s->offset] - s->phase;
+ ratio = used / total;
+ m.x = a.x + ratio * dx;
+ m.y = a.y + ratio * dy;
+
+ if (s->toggle)
+ error = strokelineto(s, m);
+ else
+ error = strokemoveto(s, m);
+ if (error)
+ return error;
+
+ s->toggle = !s->toggle;
+ s->phase = 0;
+ s->offset ++;
+ if (s->offset == s->dash->len)
+ s->offset = 0;
+ }
+
+ s->phase += total - used;
+
+ s->cur = b;
+
+ if (s->toggle)
+ return strokelineto(s, b);
+
+ return nil;
+}
+
+static fz_error *
+dashbezier(struct sctx *s,
+ float xa, float ya,
+ float xb, float yb,
+ float xc, float yc,
+ float xd, float yd)
+{
+ fz_error *error;
+ float dmax;
+ float xab, yab;
+ float xbc, ybc;
+ float xcd, ycd;
+ float xabc, yabc;
+ float xbcd, ybcd;
+ float xabcd, yabcd;
+
+ /* termination check */
+ dmax = ABS(xa - xb);
+ dmax = MAX(dmax, ABS(ya - yb));
+ dmax = MAX(dmax, ABS(xd - xc));
+ dmax = MAX(dmax, ABS(yd - yc));
+ if (dmax < s->flatness) {
+ fz_point p;
+ p.x = xd;
+ p.y = yd;
+ return dashlineto(s, p);
+ }
+
+ xab = xa + xb;
+ yab = ya + yb;
+ xbc = xb + xc;
+ ybc = yb + yc;
+ xcd = xc + xd;
+ ycd = yc + yd;
+
+ xabc = xab + xbc;
+ yabc = yab + ybc;
+ xbcd = xbc + xcd;
+ ybcd = ybc + ycd;
+
+ xabcd = xabc + xbcd;
+ yabcd = yabc + ybcd;
+
+ xab *= 0.5f; yab *= 0.5f;
+ xbc *= 0.5f; ybc *= 0.5f;
+ xcd *= 0.5f; ycd *= 0.5f;
+
+ xabc *= 0.25f; yabc *= 0.25f;
+ xbcd *= 0.25f; ybcd *= 0.25f;
+
+ xabcd *= 0.125f; yabcd *= 0.125f;
+
+ error = dashbezier(s, xa, ya, xab, yab, xabc, yabc, xabcd, yabcd);
+ if (error) return error;
+ return dashbezier(s, xabcd, yabcd, xbcd, ybcd, xcd, ycd, xd, yd);
+}
+
+fz_error *
+fz_dashpath(fz_gel *gel, fz_pathnode *path, fz_matrix ctm, float flatness)
+{
+ fz_error *error;
+ struct sctx s;
+ fz_point p0, p1, p2, p3, beg;
+ int i;
+
+ s.gel = gel;
+ s.ctm = &ctm;
+ s.flatness = flatness;
+
+ s.linecap = path->linecap;
+ s.linejoin = path->linejoin;
+ s.linewidth = path->linewidth * 0.5;
+ s.miterlimit = path->miterlimit;
+ s.sn = 0;
+ s.bn = 0;
+ s.dot = 0;
+
+ s.dash = path->dash;
+ s.toggle = 0;
+ s.offset = 0;
+ s.phase = 0;
+
+ i = 0;
+
+ while (i < path->len)
+ {
+ switch (path->els[i++].k)
+ {
+ case FZ_MOVETO:
+ p1.x = path->els[i++].v;
+ p1.y = path->els[i++].v;
+ error = dashmoveto(&s, p1);
+ if (error)
+ return error;
+ beg = p0 = p1;
+ break;
+
+ case FZ_LINETO:
+ p1.x = path->els[i++].v;
+ p1.y = path->els[i++].v;
+ error = dashlineto(&s, p1);
+ if (error)
+ return error;
+ p0 = p1;
+ break;
+
+ case FZ_CURVETO:
+ p1.x = path->els[i++].v;
+ p1.y = path->els[i++].v;
+ p2.x = path->els[i++].v;
+ p2.y = path->els[i++].v;
+ p3.x = path->els[i++].v;
+ p3.y = path->els[i++].v;
+ error = dashbezier(&s, p0.x, p0.y, p1.x, p1.y, p2.x, p2.y, p3.x, p3.y);
+ if (error)
+ return error;
+ p0 = p3;
+ break;
+
+ case FZ_CLOSEPATH:
+ error = dashlineto(&s, beg);
+ if (error)
+ return error;
+ break;
+ }
+ }
+
+ return strokeflush(&s);
+}
+
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