QGVCore.h

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/***************************************************************
QGVCore
Copyright (c) 2014, Bergont Nicolas, All rights reserved.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3.0 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library.
***************************************************************/

#ifndef QGVCORE_H
#define QGVCORE_H

#include <QPointF>
#include <QPolygonF>
#include <QPainterPath>
#include <QColor>

// GraphViz headers
#include <gvc.h>
#include <cgraph.h>

const qreal DotDefaultDPI = 72.0;

class QGVCore
{
  public:
    static qreal graphHeight(Agraph_t *graph);
    static QPointF toPoint(pointf p, qreal gheight);
    static QPointF toPoint(point p, qreal gheight);
    static QPointF centerToOrigin(const QPointF &p, qreal width, qreal height);
    static QPolygonF toPolygon(const polygon_t* poly, qreal width,
        qreal height);

    static QPainterPath toPath(const char *type, const polygon_t *poly,
        qreal width, qreal height);
    static QPainterPath toPath(const splines* spl, qreal gheight);

    static Qt::BrushStyle toBrushStyle(const QString &style);
    static Qt::PenStyle toPenStyle(const QString &style);
    static QColor toColor(const QString &color);

    typedef struct {
      const char *data;
      int len;
      int cur;
    } rdr_t;

    static int memiofread(void *chan, char *buf, int bufsize)
    {
      const char *ptr;
      char *optr;
      char c;
      int l;
      rdr_t *s;

      if (bufsize == 0) return 0;
      s = static_cast<rdr_t *>(chan);
      if (s->cur >= s->len)
          return 0;
      l = 0;
      ptr = s->data + s->cur;
      optr = buf;
      do {
          *optr++ = c = *ptr++;
          l++;
      } while (c && (c != '\n') && (l < bufsize));
      s->cur += l;
      return l;
    }

    static Agraph_t *agmemread2(const char *cp)
    {
      Agraph_t* g;
      rdr_t rdr;
      Agdisc_t disc;
      Agiodisc_t memIoDisc;

      memIoDisc.afread = memiofread;
      memIoDisc.putstr = AgIoDisc.putstr;
      memIoDisc.flush = AgIoDisc.flush;
      rdr.data = cp;
      rdr.len = strlen(cp);
      rdr.cur = 0;

      disc.mem = &AgMemDisc;
      disc.id = &AgIdDisc;
      disc.io = &memIoDisc;
      g = agread(&rdr, &disc);
      return g;
    }
};

#endif