+++ /dev/null
-/* Libart_LGPL - library of basic graphic primitives
- * Copyright (C) 1999-2000 Raph Levien
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- */
-
-/* Apply a dash style to a vector path. */
-
-#include <math.h>
-#include <stdlib.h>
-
-#include "art_misc.h"
-
-#include "art_vpath.h"
-#include "art_vpath_dash.h"
-
-
-/* Return the length of the largest subpath within vpath */
-static int
-art_vpath_dash_max_subpath (const ArtVpath *vpath)
-{
- int max_subpath;
- int i;
- int start;
-
- max_subpath = 0;
- start = 0;
- for (i = 0; vpath[i].code != ART_END; i++)
- {
- if (vpath[i].code == ART_MOVETO || vpath[i].code == ART_MOVETO_OPEN)
- {
- if (i - start > max_subpath)
- max_subpath = i - start;
- start = i;
- }
- }
- if (i - start > max_subpath)
- max_subpath = i - start;
-
- return max_subpath;
-}
-
-/**
- * art_vpath_dash: Add dash style to vpath.
- * @vpath: Original vpath.
- * @dash: Dash style.
- *
- * Creates a new vpath that is the result of applying dash style @dash
- * to @vpath.
- *
- * This implementation has two known flaws:
- *
- * First, it adds a spurious break at the beginning of the vpath. The
- * only way I see to resolve this flaw is to run the state forward one
- * dash break at the beginning, and fix up by looping back to the
- * first dash break at the end. This is doable but of course adds some
- * complexity.
- *
- * Second, it does not suppress output points that are within epsilon
- * of each other.
- *
- * Return value: Newly created vpath.
- **/
-ArtVpath *
-art_vpath_dash (const ArtVpath *vpath, const ArtVpathDash *dash)
-{
- int max_subpath;
- double *dists;
- ArtVpath *result;
- int n_result, n_result_max;
- int start, end;
- int i;
- double total_dist;
-
- /* state while traversing dasharray - offset is offset of current dash
- value, toggle is 0 for "off" and 1 for "on", and phase is the distance
- in, >= 0, < dash->dash[offset]. */
- int offset, toggle;
- double phase;
-
- /* initial values */
- int offset_init, toggle_init;
- double phase_init;
-
- max_subpath = art_vpath_dash_max_subpath (vpath);
- dists = art_new (double, max_subpath);
-
- n_result = 0;
- n_result_max = 16;
- result = art_new (ArtVpath, n_result_max);
-
- /* determine initial values of dash state */
- toggle_init = 1;
- offset_init = 0;
- phase_init = dash->offset;
- while (phase_init >= dash->dash[offset_init])
- {
- toggle_init = !toggle_init;
- phase_init -= dash->dash[offset_init];
- offset_init++;
- if (offset_init == dash->n_dash)
- offset_init = 0;
- }
-
- for (start = 0; vpath[start].code != ART_END; start = end)
- {
- for (end = start + 1; vpath[end].code == ART_LINETO; end++);
- /* subpath is [start..end) */
- total_dist = 0;
- for (i = start; i < end - 1; i++)
- {
- double dx, dy;
-
- dx = vpath[i + 1].x - vpath[i].x;
- dy = vpath[i + 1].y - vpath[i].y;
- dists[i - start] = sqrt (dx * dx + dy * dy);
- total_dist += dists[i - start];
- }
- if (total_dist <= dash->dash[offset_init] - phase_init)
- {
- /* subpath fits entirely within first dash */
- if (toggle_init)
- {
- for (i = start; i < end; i++)
- art_vpath_add_point (&result, &n_result, &n_result_max,
- vpath[i].code, vpath[i].x, vpath[i].y);
- }
- }
- else
- {
- /* subpath is composed of at least one dash - thus all
- generated pieces are open */
- double dist;
-
- phase = phase_init;
- offset = offset_init;
- toggle = toggle_init;
- dist = 0;
- i = start;
- if (toggle)
- art_vpath_add_point (&result, &n_result, &n_result_max,
- ART_MOVETO_OPEN, vpath[i].x, vpath[i].y);
- while (i != end - 1)
- {
- if (dists[i - start] - dist > dash->dash[offset] - phase)
- {
- /* dash boundary is next */
- double a;
- double x, y;
-
- dist += dash->dash[offset] - phase;
- a = dist / dists[i - start];
- x = vpath[i].x + a * (vpath[i + 1].x - vpath[i].x);
- y = vpath[i].y + a * (vpath[i + 1].y - vpath[i].y);
- art_vpath_add_point (&result, &n_result, &n_result_max,
- toggle ? ART_LINETO : ART_MOVETO_OPEN,
- x, y);
- /* advance to next dash */
- toggle = !toggle;
- phase = 0;
- offset++;
- if (offset == dash->n_dash)
- offset = 0;
- }
- else
- {
- /* end of line in vpath is next */
- phase += dists[i - start] - dist;
- i++;
- dist = 0;
- if (toggle)
- art_vpath_add_point (&result, &n_result, &n_result_max,
- ART_LINETO, vpath[i].x, vpath[i].y);
- }
- }
- }
- }
-
- art_vpath_add_point (&result, &n_result, &n_result_max,
- ART_END, 0, 0);
-
- art_free (dists);
-
- return result;
-}
projects / rrdtool.git / blobdiff