/****************************************************************************
* Copyright (C) 2009-2015 EPAM Systems
*
* This file is part of Indigo toolkit.
*
* This file may be distributed and/or modified under the terms of the
* GNU General Public License version 3 as published by the Free Software
* Foundation and appearing in the file LICENSE.GPL included in the
* packaging of this file.
*
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
***************************************************************************/

#include "base_cpp/array.h"
#include "base_cpp/obj_array.h"
#include "base_cpp/output.h"
#include "molecule/molecule.h"
#include "reaction/reaction.h"
#include "render_context.h"

#include <limits.h>

using namespace indigo;

RenderContext::TextLock RenderContext::_tlock;

IMPL_ERROR(RenderContext, "render context");

#ifdef _WIN32

#define NOMINMAX
#include <windows.h>
#include "cairo-win32.h"

cairo_surface_t* RenderContext::createWin32PrintingSurfaceForHDC ()
{
   cairo_surface_t* surface = cairo_win32_printing_surface_create((HDC)opt.hdc);
   cairoCheckStatus();
   return surface;
}

cairo_surface_t* RenderContext::createWin32Surface ()
{
   cairo_surface_t* surface = cairo_win32_surface_create((HDC)opt.hdc);
   cairoCheckStatus();
   return surface;
}

static void _init_language_pack ()
{
    typedef BOOL (WINAPI *gdi_init_lang_pack_func_t)(int);
    gdi_init_lang_pack_func_t gdi_init_lang_pack;
    HMODULE module;

    if (GetModuleHandleA ("LPK.DLL"))
	return;

    module = GetModuleHandleA ("GDI32.DLL");
    if (module) {
	gdi_init_lang_pack = (gdi_init_lang_pack_func_t)
	    GetProcAddress (module, "GdiInitializeLanguagePack");
	if (gdi_init_lang_pack)
	    gdi_init_lang_pack (0);
    }
}

cairo_surface_t* RenderContext::createWin32PrintingSurfaceForMetafile (bool& isLarge)
{
   HDC dc = GetDC(NULL);
   int hr = GetDeviceCaps(dc, HORZRES);
   int hs = GetDeviceCaps(dc, HORZSIZE);
   int vr = GetDeviceCaps(dc, VERTRES);
   int vs = GetDeviceCaps(dc, VERTSIZE);
   // physical display size in millimeters, divided over the resolution and
   //    multiplied by 100, as metafile dimensions are specified in 0.01mm units
   float cfx = hs * 100.0f / hr;
   float cfy = vs * 100.0f / vr; // it may differ for x and y
   int w = (int)(_width * cfx);
   int h = (int)(_height * cfy);
   RECT rc = {0, 0, w, h}, crc;
   _init_language_pack();
   GetClipBox(dc, &crc);
   isLarge = (_width >= crc.right || _height >= crc.bottom);
   _meta_hdc = CreateEnhMetaFileA(dc, 0, &rc, "Indigo Render2D\0\0");
   ReleaseDC(NULL, dc);
   cairo_surface_t* s = cairo_win32_printing_surface_create((HDC)_meta_hdc);
   cairoCheckStatus();
   StartPage((HDC)_meta_hdc);
   return s;
}

void RenderContext::storeAndDestroyMetafile (bool discard)
{
   cairo_surface_show_page(_surface);
   cairoCheckStatus();
   EndPage((HDC)_meta_hdc);
   cairo_surface_destroy(_surface);
   cairoCheckStatus();
   _surface = NULL;
   HENHMETAFILE hemf = CloseEnhMetaFile((HDC)_meta_hdc);
   if (!discard) {
      int size = GetEnhMetaFileBits(hemf, 0, NULL);
      Array<char> buf;
      buf.resize(size);
      GetEnhMetaFileBits(hemf, size, (BYTE*)(buf.ptr()));
      opt.output->writeArray(buf);
   }
   DeleteEnhMetaFile(hemf);
}

#endif

CP_DEF(RenderContext);

RenderContext::RenderContext (const RenderOptions& ropt, float sf, float lwf): CP_INIT, TL_CP_GET(_fontfamily), TL_CP_GET(transforms),
metafileFontsToCurves(false), _cr(NULL), _surface(NULL), _meta_hdc(NULL), opt(ropt), _pattern(NULL)
{
   _settings.init(sf, lwf);
   bprintf(_fontfamily, "Arial");
   bbmin.x = bbmin.y = 1;
   bbmax.x = bbmax.y = -1;
   _defaultScale = 0.0f;
}

void RenderContext::bbIncludePoint (const Vec2f& v)
{
   double x = v.x, y = v.y;
   cairo_user_to_device(_cr, &x, &y);
   Vec2f u((float)x, (float)y);
   if (bbmin.x > bbmax.x) { // init
      bbmin.x = bbmax.x = u.x;
      bbmin.y = bbmax.y = u.y;
   } else {
      bbmin.min(u);
      bbmax.max(u);
   }
}

void RenderContext::_bbVecToUser (Vec2f& d, const Vec2f& s)
{
   double x = s.x, y = s.y;
   cairo_device_to_user(_cr, &x, &y);
   d.set((float)x, (float)y);
}

void RenderContext::bbGetMin (Vec2f& v)
{
   _bbVecToUser(v, bbmin);
}

void RenderContext::bbGetMax (Vec2f& v)
{
   _bbVecToUser(v, bbmax);
}

void RenderContext::bbIncludePoint (double x, double y)
{
   Vec2f v((float)x, (float)y);
   bbIncludePoint(v);
}

void RenderContext::bbIncludePath (bool stroke)
{
   double x1, x2, y1, y2;
   if (stroke)
      cairo_stroke_extents(_cr, &x1, &y1, &x2, &y2);
   else
      cairo_path_extents(_cr, &x1, &y1, &x2, &y2);
   bbIncludePoint(x1, y1);
   bbIncludePoint(x2, y2);
}

void RenderContext::setDefaultScale (float scale)
{
   _defaultScale = scale;
}

void RenderContext::setFontFamily (const char* ff)
{
   bprintf(_fontfamily, "%s", ff);
}

int RenderContext::getMaxPageSize () const
{
   if (opt.mode == MODE_PDF)
      return 14400;
   return INT_MAX;
}

cairo_status_t RenderContext::writer (void *closure, const unsigned char *data, unsigned int length)
{
   try {
      ((Output*)closure)->write(data, length);
   }
   catch (Output::Error &)
   {
      return CAIRO_STATUS_WRITE_ERROR;
   }
   return CAIRO_STATUS_SUCCESS;
}

void RenderContext::createSurface(cairo_write_func_t writer, Output* output, int width, int height)
{
   int mode = opt.mode;
   if (writer == NULL && (mode == MODE_HDC || mode == MODE_PRN))
      mode = MODE_PDF;
   switch (mode)
   {
   case MODE_NONE:
      throw Error("mode not set");
   case MODE_PDF:
      _surface = cairo_pdf_surface_create_for_stream(writer, opt.output, _width, _height);
      cairoCheckStatus();
      break;
   case MODE_SVG:
      _surface = cairo_svg_surface_create_for_stream(writer, opt.output, _width, _height);
      cairoCheckStatus();
      break;
   case MODE_PNG:
      _surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, _width, _height);
      cairoCheckStatus();
      break;
   case MODE_HDC:
#ifdef _WIN32
      _surface = createWin32Surface();
#else
      throw Error("mode \"HDC\" is not supported on this platform");
#endif
      break;
   case MODE_PRN:
#ifdef _WIN32
      _surface = createWin32PrintingSurfaceForHDC();
#else
      throw Error("mode \"PRN\" is not supported on this platform");
#endif
      break;
   case MODE_EMF:
#ifdef _WIN32
      bool isLarge;
      _surface = createWin32PrintingSurfaceForMetafile(isLarge);
      if (isLarge)
         metafileFontsToCurves = true;
#else
      throw Error("mode \"EMF\" is not supported on this platform");
#endif
      break;
   default:
      throw Error("unknown mode: %d", mode);
   }
}

void RenderContext::init()
{
   fontsInit();

   cairo_text_extents_t te;
   cairo_select_font_face(_cr, _fontfamily.ptr(), CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
   cairoCheckStatus();
   cairo_set_font_size(_cr, _settings.fzz[FONT_SIZE_ATTR]);
   cairoCheckStatus();
   _tlock.lock();
   cairo_text_extents(_cr, "N", &te);
   _tlock.unlock();
   cairoCheckStatus();

   cairo_set_antialias(_cr, CAIRO_ANTIALIAS_GRAY);
   cairoCheckStatus();

   _currentLineWidth = _settings.bondLineWidth;
}

void RenderContext::fillBackground()
{
   cairo_set_source_rgb(_cr, opt.backgroundColor.x, opt.backgroundColor.y, opt.backgroundColor.z);
   cairoCheckStatus();
   cairo_paint(_cr);
   cairoCheckStatus();
}

void RenderContext::initNullContext ()
{
   _width = 10;
   _height = 10;
   if (_surface != NULL || _cr != NULL)
      throw Error("context is already open (or invalid)");
   createSurface(NULL, NULL, 1, 1);
   cairoCheckStatus();
   _cr = cairo_create(_surface);
   scale(_defaultScale);
}

void RenderContext::initContext (int width, int height)
{
   _width = width;
   _height = height;
   if (opt.mode != MODE_HDC && opt.mode != MODE_PRN && opt.output == NULL)
      throw Error("output not set");
   if (_surface != NULL || _cr != NULL)
      throw Error("context is already open (or invalid)");

   createSurface(writer, opt.output, _width, _height);
   _cr = cairo_create(_surface);
   if (opt.backgroundColor.x >= 0 && opt.backgroundColor.y >= 0 && opt.backgroundColor.z >= 0)
      fillBackground();
}

void RenderContext::closeContext (bool discard)
{
   if (_cr != NULL)
   {
      cairo_destroy (_cr);
      _cr = NULL;
   }

   switch (opt.mode)
   {
   case MODE_NONE:
      throw Error("mode not set");
   case MODE_PNG:
	   if (!discard)
		   cairo_surface_write_to_png_stream(_surface, writer, opt.output);
      break;
   case MODE_PDF:
   case MODE_SVG:
   case MODE_HDC:
   case MODE_PRN:
      break;
   case MODE_EMF:
#ifdef _WIN32
      storeAndDestroyMetafile(discard);
#endif
      break;
   default:
      throw Error("unknown mode: %d", opt.mode);
   }

   if (_surface != NULL)
   {
      cairo_surface_destroy (_surface);
      _surface = NULL;
   }

   bbmin.x = bbmin.y = 1;
   bbmax.x = bbmax.y = -1;

   fontsDispose();
}

void RenderContext::translate (float dx, float dy)
{
   cairo_translate(_cr, dx, dy);
   cairoCheckStatus();
}

void RenderContext::scale (float s)
{
   cairo_scale(_cr, s, s);
   cairoCheckStatus();
}

void RenderContext::storeTransform ()
{
   cairo_matrix_t& t = transforms.push();
   cairo_get_matrix(_cr, &t);
   cairoCheckStatus();
}
void RenderContext::restoreTransform ()
{
   cairo_matrix_t& t = transforms.top();
   cairo_set_matrix(_cr, &t);
   cairoCheckStatus();
}
void RenderContext::removeStoredTransform ()
{
   transforms.pop();
}

void RenderContext::resetTransform ()
{
   cairo_matrix_t t;
   cairo_matrix_init_identity(&t);
   cairo_set_matrix(_cr, &t);
   cairoCheckStatus();
}

void RenderContext::setLineWidth (double width)
{
   _currentLineWidth = (float)width;
   cairo_set_line_width(_cr, width);
   cairoCheckStatus();
}

void RenderContext::drawRectangle (const Vec2f& p, const Vec2f& sz)
{
   cairo_rectangle(_cr, p.x, p.y, sz.x, sz.y);
   cairoCheckStatus();
   checkPathNonEmpty();
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::drawItemBackground (const RenderItem& item)
{
   cairo_rectangle(_cr, item.bbp.x, item.bbp.y, item.bbsz.x, item.bbsz.y);
   cairoCheckStatus();
   if (opt.backgroundColor.x >= 0 && opt.backgroundColor.y >= 0 && opt.backgroundColor.z >= 0)
      setSingleSource(opt.backgroundColor);
   else
      setSingleSource(CWC_WHITE);

   checkPathNonEmpty();
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::drawTextItemText (const TextItem& ti)
{
   Vec3f color;
   if (ti.ritype == RenderItem::RIT_AAM)
      color.copy(opt.aamColor);
   else if (ti.ritype == RenderItem::RIT_DATASGROUP)
      color.copy(opt.dataGroupColor);
   else if (ti.ritype == RenderItem::RIT_COMMENT)
      color.copy(opt.commentColor);
   else if (ti.ritype == RenderItem::RIT_TITLE)
      color.copy(opt.titleColor);
   else
   {
      getColorVec(color, ti.color);
      if (ti.highlighted && opt.highlightColorEnable)
         color.copy(opt.highlightColor);
   }
   drawTextItemText (ti, color);
}

void RenderContext::drawTextItemText (const TextItem& ti, const Vec3f& color)
{
   bool bold = ti.highlighted && opt.highlightThicknessEnable;
   drawTextItemText (ti, color, bold);
}

void RenderContext::drawTextItemText (const TextItem& ti, const Vec3f& color, bool bold)
{
   fontsSetFont(_cr, ti.fontsize, bold);
   fontsDrawText(ti, color, bold);
}

void RenderContext::drawLine (const Vec2f& v0, const Vec2f& v1)
{
   moveTo(v0);
   lineTo(v1);
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::drawPoly (const Array<Vec2f>& v)
{
   moveTo(v[0]);
   for (int i = 1; i < v.size(); ++i)
      lineTo(v[i]);
   lineTo(v[0]);
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::checkPathNonEmpty () const
{
#ifdef DEBUG
   cairo_path_t* p = cairo_copy_path(_cr);
   cairoCheckStatus();
   if (p->num_data == 0)
      throw Error("Empty path");
   cairo_path_destroy(p);
   cairoCheckStatus();
#endif
}

void RenderContext::fillQuad (const Vec2f& v0, const Vec2f& v1, const Vec2f& v2, const Vec2f& v3)
{
   moveTo(v0);
   lineTo(v1);
   lineTo(v2);
   lineTo(v3);
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::fillHex (const Vec2f& v0, const Vec2f& v1, const Vec2f& v2, const Vec2f& v3, const Vec2f& v4, const Vec2f& v5)
{
   moveTo(v0);
   lineTo(v1);
   lineTo(v2);
   lineTo(v3);
   lineTo(v4);
   lineTo(v5);
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::fillQuadStripes (const Vec2f& v0r, const Vec2f& v0l, const Vec2f& v1r, const Vec2f& v1l, int cnt)
{
   Vec2f r(v0r), dr;
   Vec2f l(v0l), dl;
   dr.diff(v1r, v0r); dr.scale(1.0f/cnt);
   dl.diff(v1l, v0l); dl.scale(1.0f/cnt);

   if (cnt < 3)
      cnt = 3;
   for (int i = 0; i < cnt; ++i)
   {
      r.add(dr);
      l.add(dl);
      moveTo(r);
      lineTo(l);
   }
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::fillPentagon (const Vec2f& v0, const Vec2f& v1, const Vec2f& v2, const Vec2f& v3, const Vec2f& v4)
{
   moveTo(v0);
   lineTo(v1);
   lineTo(v2);
   lineTo(v3);
   lineTo(v4);
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::drawQuad (const Vec2f& v0, const Vec2f& v1, const Vec2f& v2, const Vec2f& v3)
{
   moveTo(v0);
   lineTo(v1);
   lineTo(v2);
   lineTo(v3);
   cairo_close_path(_cr);
   cairoCheckStatus();
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::drawTriangleZigzag (const Vec2f& v0, const Vec2f& v1, const Vec2f& v2, int cnt)
{
   Vec2f r(v0), dr;
   Vec2f l(v0), dl;
   dr.diff(v1, v0); dr.scale(1.0f/cnt);
   dl.diff(v2, v0); dl.scale(1.0f/cnt);

   cairo_set_line_join(_cr, CAIRO_LINE_JOIN_MITER);
   cairoCheckStatus();

   moveTo(v0);
   if (cnt < 3)
      cnt = 3;
   for (int i = 0; i < cnt; ++i)
   {
      r.add(dr);
      l.add(dl);
      if (i & 1)
         lineTo(l);
      else
         lineTo(r);
   }
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
   cairo_set_line_join(_cr, CAIRO_LINE_JOIN_BEVEL);
   cairoCheckStatus();
}

void RenderContext::drawCircle (const Vec2f& center, const float r)
{
   cairo_new_path(_cr);
   cairo_arc(_cr, center.x, center.y, r, 0, 2 * PI);
   cairoCheckStatus();
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
   cairo_new_path(_cr);
}

void RenderContext::fillCircle (const Vec2f& center, const float r)
{
   cairo_arc(_cr, center.x, center.y, r, 0, 2 * PI);
   cairoCheckStatus();
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::drawArc (const Vec2f& center, const float r, const float a0, const float a1)
{
   cairo_new_path(_cr);
   cairoCheckStatus();
   cairo_arc(_cr, center.x, center.y, r, a0, a1);
   cairoCheckStatus();
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::setFontSize (double fontSize)
{
   cairo_set_font_size(_cr, fontSize);
   cairoCheckStatus();
}

void RenderContext::setTextItemSize (TextItem& ti)
{
   bool bold = ti.highlighted && opt.highlightThicknessEnable;

   fontsSetFont(_cr, ti.fontsize, bold);
   fontsGetTextExtents(_cr, ti.text.ptr(), ti.fontsize, ti.bbsz.x, ti.bbsz.y, ti.relpos.x, ti.relpos.y);
}

void RenderContext::setTextItemSize (TextItem& ti, const Vec2f& c)
{
   setTextItemSize(ti);

   cairo_font_extents_t fe;
   cairo_font_extents (_cr, &fe);
   ti.bbp.x = c.x - ti.bbsz.x / 2;
   ti.bbp.y = c.y - ti.bbsz.y / 2;
}

void RenderContext::setGraphItemSizeDot (GraphItem& gi)
{
   gi.type = GraphItem::DOT;
   gi.bbsz.set(2 * _settings.graphItemDotRadius, 2 * _settings.graphItemDotRadius);
   gi.relpos.set(_settings.graphItemDotRadius, _settings.graphItemDotRadius);
}

void RenderContext::setGraphItemSizeCap (GraphItem& gi)
{
   gi.type = GraphItem::CAP;
   gi.bbsz.set(2 * _settings.graphItemCapWidth, _settings.graphItemCapWidth * _settings.graphItemCapSlope);
   gi.relpos.set(0, _settings.graphItemCapWidth * _settings.graphItemCapSlope);
}

void RenderContext::setGraphItemSizeSign (GraphItem& gi, GraphItem::TYPE type)
{
   gi.type = type;
   gi.bbsz.set(_settings.graphItemDigitWidth, _settings.graphItemDigitHeight);
   gi.relpos.set(0, 0);
}

void RenderContext::drawAttachmentPoint (RenderItemAttachmentPoint& ri)
{
   setSingleSource(ri.color);
   if (ri.highlighted && opt.highlightColorEnable)
      setSingleSource(opt.highlightColor);
   setLineWidth(_settings.unit);
   moveTo(ri.p0);
   lineTo(ri.p1);
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_stroke(_cr);
   cairoCheckStatus();

   Vec2f n;
   n.copy(ri.dir);
   n.rotateL(1, 0);
   Vec2f p, q, r;
   int waveCnt = 10;
   float waveLength = 0.5f;
   float waveWidth = waveLength / waveCnt;
   float slopeFactor = 0.2f;
   p.lineCombin(ri.p1, n, -0.5f * waveLength);
   moveTo(p);
   float step = waveLength / waveCnt;
   for (int i = 0; i < waveCnt; ++i) {
      int turn = ((i & 1) ? 1 : -1);
      q.lineCombin(p, ri.dir, waveWidth * turn);
      q.addScaled(n, waveWidth * slopeFactor);
      p.addScaled(n, step);
      r.lineCombin(p, ri.dir, waveWidth * turn);
      r.addScaled(n, -waveWidth * slopeFactor);
      cairo_curve_to(_cr, q.x, q.y, r.x, r.y, p.x, p.y);
   }
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_stroke(_cr);
   cairoCheckStatus();

   QS_DEF(TextItem, ti);
   ti.clear();
   if (ri.number > 0) {
      bprintf(ti.text, "%d", ri.number);
      ti.fontsize = FONT_SIZE_ATTACHMENT_POINT_INDEX;
      setTextItemSize(ti, ri.p1);
      float sz = ti.bbsz.length();
      ti.bbp.addScaled(n, -(sz/2 + _settings.unit));
      ti.bbp.addScaled(ri.dir, -(sz/2 + waveWidth + _settings.unit));
      drawTextItemText(ti);
   }
}

void RenderContext::drawRSiteAttachmentIndex (RenderItemRSiteAttachmentIndex& ri)
{
   setSingleSource(ri.color);
   setLineWidth(_settings.unit/2);
   drawCircle(ri.bbp, ri.radius);
}

void RenderContext::drawGraphItem (GraphItem& gi)
{
   setSingleSource(gi.color);
   if (gi.highlighted && opt.highlightColorEnable)
      setSingleSource(opt.highlightColor);
   _drawGraphItem(gi);
}

void RenderContext::drawGraphItem (GraphItem& gi, const Vec3f& color)
{
   setSingleSource(color);
   _drawGraphItem(gi);
}

void RenderContext::_drawGraphItem (GraphItem& gi)
{
   Vec2f v0;
   v0.sum(gi.bbp, gi.relpos);
   switch (gi.type)
   {
   case GraphItem::CAP:
      moveTo(v0);
      lineToRel(_settings.graphItemCapWidth, _settings.graphItemCapSlope * -_settings.graphItemCapWidth);
      lineToRel(_settings.graphItemCapWidth, _settings.graphItemCapSlope * _settings.graphItemCapWidth);
      lineToRel(-_settings.graphItemCapBase, 0);
      lineToRel(_settings.graphItemCapBase - _settings.graphItemCapWidth,
         _settings.graphItemCapSlope * (_settings.graphItemCapBase - _settings.graphItemCapWidth));
      lineToRel(_settings.graphItemCapBase - _settings.graphItemCapWidth,
         _settings.graphItemCapSlope * (_settings.graphItemCapWidth - _settings.graphItemCapBase));
      break;
   case GraphItem::DOT:
      moveTo(v0);
      cairo_arc(_cr, v0.x, v0.y, _settings.graphItemDotRadius, 0, 2 * M_PI);
      cairoCheckStatus();
      break;
   case GraphItem::PLUS:
      moveTo(v0);
      moveToRel(0, (_settings.graphItemDigitHeight - _settings.graphItemSignLineWidth) / 2);
      lineToRel(_settings.graphItemPlusEdge, 0);
      lineToRel(0, -_settings.graphItemPlusEdge);
      lineToRel(_settings.graphItemSignLineWidth, 0);
      lineToRel(0, _settings.graphItemPlusEdge);
      lineToRel(_settings.graphItemPlusEdge, 0);
      lineToRel(0, _settings.graphItemSignLineWidth);
      lineToRel(-_settings.graphItemPlusEdge, 0);
      lineToRel(0, _settings.graphItemPlusEdge);
      lineToRel(-_settings.graphItemSignLineWidth, 0);
      lineToRel(0, -_settings.graphItemPlusEdge);
      lineToRel(-_settings.graphItemPlusEdge, 0);
      break;
   case GraphItem::MINUS:
      moveTo(v0);
      moveToRel(0, (_settings.graphItemDigitHeight - _settings.graphItemSignLineWidth) / 2);
      lineToRel(_settings.graphItemDigitWidth, 0);
      lineToRel(0, _settings.graphItemSignLineWidth);
      lineToRel(-_settings.graphItemDigitWidth, 0);
      break;
   }
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::drawBracket (RenderItemBracket& bracket)
{
   setSingleSource(bracket.color);
   setLineWidth(_settings.unit);

   Vec2f p;
   moveTo(bracket.q0);
   lineTo(bracket.p0);
   lineTo(bracket.p1);
   lineTo(bracket.q1);

   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::fillRect (double x, double y, double w, double h)
{
   cairo_rectangle(_cr, x, y, w, h);
   cairoCheckStatus();
   checkPathNonEmpty();
   cairo_fill(_cr);
   cairoCheckStatus();
}

void RenderContext::drawEquality (const Vec2f& pos, const float linewidth, const float size, const float interval)
{
   moveTo(pos);
   moveToRel(0, -interval/2);
   lineToRel(size, 0);
   moveTo(pos);
   moveToRel(0, interval/2);
   lineToRel(size, 0);
   setLineWidth(linewidth);
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::drawPlus (const Vec2f& pos, const float linewidth, const float size)
{
   float hsz = size / 2;
   moveTo(pos);

   moveToRel(-hsz, 0);
   lineToRel(2 * hsz, 0);
   moveToRel(-hsz, -hsz);
   lineToRel(0, 2 * hsz);
   setLineWidth(linewidth);
   checkPathNonEmpty();
   bbIncludePath(true);
   cairo_stroke(_cr);
   cairoCheckStatus();
}

void RenderContext::drawArrow (const Vec2f& p1, const Vec2f& p2, const float width, const float headwidth, const float headsize)
{
   Vec2f d, n, p(p1);
   d.diff(p2, p1);
   float len = d.length();
   d.normalize();
   n.copy(d);
   n.rotate(1, 0);

   p.addScaled(n, width / 2);
   moveTo(p);
   p.addScaled(d, len - headsize);
   lineTo(p);
   p.addScaled(n, (headwidth - width) / 2);
   lineTo(p);
   p.addScaled(n, -headwidth / 2);
   p.addScaled(d, headsize);
   lineTo(p);
   p.addScaled(n, -headwidth / 2);
   p.addScaled(d, -headsize);
   lineTo(p);
   p.addScaled(n, (headwidth - width) / 2);
   lineTo(p);
   p.addScaled(d, -len + headsize);
   lineTo(p);
   checkPathNonEmpty();
   bbIncludePath(false);
   cairo_fill(_cr);
   cairoCheckStatus();
}

float RenderContext::highlightedBondLineWidth () const
{
   return _settings.bondLineWidth * (opt.highlightThicknessEnable ? opt.highlightThicknessFactor : 1.0f);
}

float RenderContext::currentLineWidth () const
{
   return _currentLineWidth;
}

void RenderContext::setHighlight()
{
   if (opt.highlightColorEnable)
      setSingleSource(opt.highlightColor);
   if (opt.highlightThicknessEnable)
      setLineWidth(opt.highlightThicknessFactor * _settings.bondLineWidth);
}

void RenderContext::resetHighlightThickness()
{
   setLineWidth(_settings.bondLineWidth);
}

void RenderContext::resetHighlight()
{
   setSingleSource(CWC_BASE);
   resetHighlightThickness();
}

void RenderContext::getColorVec (Vec3f& v, int color)
{
   getColor(v.x, v.y, v.z, color);
   float y, ymax = 0.5f;
   if (color >= CWC_COUNT)
   {
      y = 0.299f * v.x + 0.587f * v.y + 0.114f * v.z;
      if (y > ymax)
         v.scale(ymax / y);
   }
}

void RenderContext::setSingleSource (int color)
{
   Vec3f v;
   getColorVec(v, color);
   cairo_set_source_rgb(_cr, v.x, v.y, v.z);
   cairoCheckStatus();
}

void RenderContext::setSingleSource (const Vec3f& color)
{
   cairo_set_source_rgb(_cr, color.x, color.y, color.z);
   cairoCheckStatus();
}

void RenderContext::setGradientSource (const Vec3f& color1, const Vec3f& color2, const Vec2f& pos1, const Vec2f& pos2)
{
   if (_pattern != NULL) {
      throw new Error("Pattern already initialized");
   }

   _pattern = cairo_pattern_create_linear (pos1.x, pos1.y, pos2.x, pos2.y);
   cairo_pattern_add_color_stop_rgb (_pattern, 0, color1.x, color1.y, color1.z);
   cairo_pattern_add_color_stop_rgb (_pattern, 1, color2.x, color2.y, color2.z);
   cairo_set_source (_cr, _pattern);

   cairoCheckStatus();
}

void RenderContext::clearPattern ()
{
   if (_pattern != NULL) {
      cairo_pattern_destroy (_pattern);
      _pattern = NULL;
      cairoCheckStatus();
   }
}

float RenderContext::_getDashedLineAlignmentOffset (float length)
{
   float offset = 0;
   float delta = length - floorf(length / _settings.dashUnit);
   if (delta > 0.5)
      offset = 1-delta - _settings.eps * _settings.dashUnit;
   else
      offset = -delta - _settings.eps * _settings.dashUnit;
   return offset;
}

void RenderContext::setDash (const Array<double>& dash, float length)
{
   cairo_set_dash(_cr, dash.ptr(), dash.size(), _getDashedLineAlignmentOffset(length));
   cairoCheckStatus();
}

void RenderContext::resetDash ()
{
   cairo_set_dash(_cr, NULL, 0, 0);
   cairoCheckStatus();
}

void RenderContext::lineTo (const Vec2f& v)
{
   cairo_line_to(_cr, v.x, v.y);
   cairoCheckStatus();
}

void RenderContext::lineToRel (float x, float y)
{
   cairo_rel_line_to(_cr, x, y);
   cairoCheckStatus();
}

void RenderContext::lineToRel (const Vec2f& v)
{
   cairo_rel_line_to(_cr, v.x, v.y);
   cairoCheckStatus();
}

void RenderContext::moveTo (const Vec2f& v)
{
   cairo_move_to(_cr, v.x, v.y);
   cairoCheckStatus();
}

void RenderContext::moveToRel (float x, float y)
{
   cairo_rel_move_to(_cr, x, y);
   cairoCheckStatus();
}

void RenderContext::moveToRel (const Vec2f& v)
{
   cairo_rel_move_to(_cr, v.x, v.y);
   cairoCheckStatus();
}


int RenderContext::getElementColor (int label)
{
   return label - ELEM_H + CWC_COUNT;
}

void RenderContext::getColor (float& r, float& g, float& b, int c)
{
   static double colors[][3] = {
      {1.0f, 1.0f, 1.0f}, // WHITE
      {0.0f, 0.0f, 0.0f}, // BLACK
      {1.0f, 0.0f, 0.0f}, // RED
      {0.0f, 0.8f, 0.0f}, // GREEN
      {0.0f, 0.0f, 1.0f}, // BLUE
      {0.0f, 0.5f, 0.0f}, // DARKGREEN

      {0.0, 0.0, 0.0}, // ELEM_H
      {0.85, 1.0, 1.0}, // ....
      {0.80, 0.50, 1.0},
      {0.76, 1.0, 0},
      {1.0, 0.71, 0.71},
      {0.0, 0.0, 0.0},
      {0.19, 0.31, 0.97},
      {1.0, 0.051, 0.051},
      {0.56, 0.88, 0.31},
      {0.70, 0.89, 0.96},
      {0.67, 0.36, 0.95},
      {0.54, 1.0, 0},
      {0.75, 0.65, 0.65},
      {0.94, 0.78, 0.63},
      {1.0, 0.50, 0},
      {0.85, 0.65, 0.10},
      {0.12, 0.94, 0.12},
      {0.50, 0.82, 0.89},
      {0.56, 0.25, 0.83},
      {0.24, 1.0, 0},
      {0.90, 0.90, 0.90},
      {0.75, 0.76, 0.78},
      {0.65, 0.65, 0.67},
      {0.54, 0.60, 0.78},
      {0.61, 0.48, 0.78},
      {0.88, 0.40, 0.20},
      {0.94, 0.56, 0.63},
      {0.31, 0.82, 0.31},
      {0.78, 0.50, 0.20},
      {0.49, 0.50, 0.69},
      {0.76, 0.56, 0.56},
      {0.40, 0.56, 0.56},
      {0.74, 0.50, 0.89},
      {1.0, 0.63, 0},
      {0.65, 0.16, 0.16},
      {0.36, 0.72, 0.82},
      {0.44, 0.18, 0.69},
      {0, 1.0, 0},
      {0.58, 1.0, 1.0},
      {0.58, 0.88, 0.88},
      {0.45, 0.76, 0.79},
      {0.33, 0.71, 0.71},
      {0.23, 0.62, 0.62},
      {0.14, 0.56, 0.56},
      {0.039, 0.49, 0.55},
      {0, 0.41, 0.52},
      {0.75, 0.75, 0.75},
      {1.0, 0.85, 0.56},
      {0.65, 0.46, 0.45},
      {0.40, 0.50, 0.50},
      {0.62, 0.39, 0.71},
      {0.83, 0.48, 0},
      {0.58, 0, 0.58},
      {0.26, 0.62, 0.69},
      {0.34, 0.090, 0.56},
      {0, 0.79, 0},
      {0.44, 0.83, 1.0},
      {1.0, 1.0, 0.78},
      {0.85, 1.0, 0.78},
      {0.78, 1.0, 0.78},
      {0.64, 1.0, 0.78},
      {0.56, 1.0, 0.78},
      {0.38, 1.0, 0.78},
      {0.27, 1.0, 0.78},
      {0.19, 1.0, 0.78},
      {0.12, 1.0, 0.78},
      {0, 1.0, 0.61},
      {0, 0.90, 0.46},
      {0, 0.83, 0.32},
      {0, 0.75, 0.22},
      {0, 0.67, 0.14},
      {0.30, 0.76, 1.0},
      {0.30, 0.65, 1.0},
      {0.13, 0.58, 0.84},
      {0.15, 0.49, 0.67},
      {0.15, 0.40, 0.59},
      {0.090, 0.33, 0.53},
      {0.82, 0.82, 0.88},
      {1.0, 0.82, 0.14},
      {0.72, 0.72, 0.82},
      {0.65, 0.33, 0.30},
      {0.34, 0.35, 0.38},
      {0.62, 0.31, 0.71},
      {0.67, 0.36, 0},
      {0.46, 0.31, 0.27},
      {0.26, 0.51, 0.59},
      {0.26, 0, 0.40},
      {0, 0.49, 0},
      {0.44, 0.67, 0.98},
      {0, 0.73, 1.0},
      {0, 0.63, 1.0},
      {0, 0.56, 1.0},
      {0, 0.50, 1.0},
      {0, 0.42, 1.0},
      {0.33, 0.36, 0.95},
      {0.47, 0.36, 0.89},
      {0.54, 0.31, 0.89},
      {0.63, 0.21, 0.83},
      {0.70, 0.12, 0.83},
      {0.70, 0.22, 0.83},
      {0.60, 0.12, 0.83},
      {0.50, 0.12, 0.83},
      {0.70, 0.12, 0.63},
      {0.70, 0.12, 0.83},
      {0.70, 0.32, 0.83},
      {0.60, 0.12, 0.83},
      {0.70, 0.12, 0.43}
   };

   if (c == CWC_BASE)
   {
      r = (float)opt.baseColor.x;
      g = (float)opt.baseColor.y;
      b = (float)opt.baseColor.z;
      return;
   }

   if (c < 0 || c >= NELEM(colors))
      throw Error("unknown color: %d", c);

   r = (float)colors[c][0];
   g = (float)colors[c][1];
   b = (float)colors[c][2];
}