rdkit/Code/GraphMol/MolDrawing/DrawingToCairo.h

// $Id$
//
//  Copyright (C) 2012 Greg Landrum
//
//   @@ All Rights Reserved @@
//  This file is part of the RDKit.
//  The contents are covered by the terms of the BSD license
//  which is included in the file license.txt, found at the root
//  of the RDKit source tree.
//

/*
  To use include this in your CPPFLAGS:
      $(shell pkg-config --cflags cairo)
  and this in your LDFLAGS:
      $(shell pkg-config --libs cairo)
*/

#ifndef _RD_DRAWING_TO_CAIRO_H_
#define _RD_DRAWING_TO_CAIRO_H_

#include <GraphMol/MolDrawing/MolDrawing.h>
#include <cairo.h>

namespace RDKit {
namespace Drawing {
namespace {
void setColorCairo(int atNum, cairo_t *cr) {
  PRECONDITION(cr, "no context");
  switch (atNum) {
    case 7:
      cairo_set_source_rgb(cr, 0.0, 0.0, 1.0);
      break;
    case 8:
      cairo_set_source_rgb(cr, 1.0, 0.0, 0.0);
      break;
    case 9:
      cairo_set_source_rgb(cr, 0.2, 0.8, 0.8);
      break;
    case 15:
      cairo_set_source_rgb(cr, 1.0, 0.5, 0.0);
      break;
    case 16:
      cairo_set_source_rgb(cr, 0.8, 0.8, 0.0);
      break;
    case 17:
      cairo_set_source_rgb(cr, 0.0, 0.8, 0.0);
      break;
    case 35:
      cairo_set_source_rgb(cr, 0.5, 0.3, 0.1);
      break;
    case 0:
      cairo_set_source_rgb(cr, 0.5, 0.5, 0.5);
      break;
    default:
      cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
  }
}
void drawLineCairo(std::vector<int>::const_iterator &pos, cairo_t *cr) {
  PRECONDITION(cr, "no context");
  int width = *pos++;
  cairo_set_line_width(cr, width * 10);
  int dashed = *pos++;
  double dashes[2];
  switch (dashed) {
    case 0:
      cairo_set_dash(cr, 0, 0, 0);
      break;
    case 2:
      dashes[0] = 5.0;
      dashes[1] = 20.0;
      cairo_set_dash(cr, dashes, sizeof(dashes) / sizeof(dashes[0]), 0);
      break;
    default:
      dashes[0] = 20.0;
      dashes[1] = 20.0;
      cairo_set_dash(cr, dashes, sizeof(dashes) / sizeof(dashes[0]), 0);
  }
  int an1 = *pos++;
  int an2 = *pos++;
  int xp1 = *pos++;
  int yp1 = *pos++;
  int xp2 = *pos++;
  int yp2 = *pos++;
  if (an1 == an2) {
    setColorCairo(an1, cr);
    cairo_move_to(cr, xp1, yp1);
    cairo_line_to(cr, xp2, yp2);
    cairo_stroke(cr);
  } else {
    int mx = xp1 + (xp2 - xp1) / 2;
    int my = yp1 + (yp2 - yp1) / 2;

    setColorCairo(an1, cr);
    cairo_move_to(cr, xp1, yp1);
    cairo_line_to(cr, mx, my);
    cairo_stroke(cr);
    setColorCairo(an2, cr);
    cairo_move_to(cr, mx, my);
    cairo_line_to(cr, xp2, yp2);
    cairo_stroke(cr);
  }
}
void drawAtomCairo(std::vector<int>::const_iterator &pos, cairo_t *cr) {
  PRECONDITION(cr, "no context");
  int fontSz = 50;
  int atNum = *pos++;
  double xp = static_cast<double>(*pos++);
  double yp = static_cast<double>(*pos++);
  int slen = *pos++;
  std::string label = "";
  for (unsigned int i = 0; i < slen; ++i) {
    label += (char)*pos++;
  }
  RDKit::Drawing::OrientType orient =
      static_cast<RDKit::Drawing::OrientType>(*pos++);
  if (label.length()) {
    cairo_text_extents_t extents;
    cairo_text_extents(cr, label.c_str(), &extents);
    double twidth = extents.width, theight = extents.height;

    switch (orient) {
      case RDKit::Drawing::W:
        xp -= twidth;
        yp += theight / 2;
        break;
      case RDKit::Drawing::E:
        yp += theight / 2;
        break;
      case RDKit::Drawing::S:
        xp -= twidth / 2;
        yp += theight;
        break;
      case RDKit::Drawing::N:
        xp -= twidth / 2;
        yp -= theight / 2;
        break;
      default:
        xp -= twidth / 2;
        yp += theight / 2;
    }
    cairo_set_source_rgb(cr, 1.0, 1., 1.);
    cairo_rectangle(cr, xp - 10, yp - theight - 10, twidth + 20, theight + 20);
    cairo_fill(cr);

    cairo_move_to(cr, xp, yp);
    setColorCairo(atNum, cr);
    cairo_show_text(cr, label.c_str());
    cairo_stroke(cr);
  }
}
}  // end of anonymous namespace

void DrawingToCairo(const std::vector<int> &drawing, cairo_t *cr, int width,
                    int height, int fontSize = 12,
                    int maxDotsPerAngstrom = 60) {
  PRECONDITION(cr, "no context");
  PRECONDITION(width > 0 && height > 0, "bad dimensions");

  cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
  cairo_rectangle(cr, 0, 0, width, height);
  cairo_fill(cr);

  cairo_select_font_face(cr, "sans", CAIRO_FONT_SLANT_NORMAL,
                         CAIRO_FONT_WEIGHT_NORMAL);

  std::vector<int>::const_iterator pos = drawing.begin();
  int resolution = 0;
  if (*pos != Drawing::RESOLUTION) {
    std::cerr << "no RESOLUTION token found" << std::endl;
    return;
  }
  resolution = *(pos + 1);
  PRECONDITION(resolution > 0, "bad resolution");
  pos += 2;
  if (*pos != Drawing::BOUNDS) {
    std::cerr << "no bounds token found" << std::endl;
    return;
  }
  pos += 3;
  int dwidth, dheight;
  dwidth = *pos++;
  dheight = *pos++;
  PRECONDITION(dwidth > 0 && dheight > 0, "bad dimensions");

  // size of the image in angstroms:
  double xSize, ySize;
  xSize = static_cast<double>(dwidth) / resolution;
  ySize = static_cast<double>(dheight) / resolution;
  double scale = 1.0;

  if (dwidth > width || dheight > height) {
    if (static_cast<double>(dwidth) / width >
        static_cast<double>(dheight) / height) {
      scale = static_cast<double>(width) / dwidth;
    } else {
      scale = static_cast<double>(height) / dheight;
    }
  } else {
    if (width / xSize > height / ySize) {
      if (width / xSize > maxDotsPerAngstrom) {
        scale = maxDotsPerAngstrom * xSize / width;
      }
    } else {
      if (height / ySize > maxDotsPerAngstrom) {
        scale = maxDotsPerAngstrom * ySize / height;
      }
    }
  }

  scale *= 0.80;
  cairo_translate(cr, .5 * (width - dwidth * scale),
                  .5 * (height - dheight * scale));
  cairo_scale(cr, scale, scale);

  // scaling factors here are empirically determined
  double dFontSize = 1.5 * maxDotsPerAngstrom * fontSize / 14;
  cairo_set_font_size(cr, dFontSize);

  while (pos != drawing.end()) {
    int token = *pos++;
    switch (token) {
      case Drawing::LINE:
        drawLineCairo(pos, cr);
        break;
      case Drawing::ATOM:
        drawAtomCairo(pos, cr);
        break;
      default:
        std::cerr << "unrecognized token: " << token << std::endl;
    }
  }
}
}  // end of namespace Drawing
}  // end of namespace RDKit
#endif