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chartdrawing.cpp

/***************************************************************************
                          chartdrawing.cpp
    description          :
    begin                : 
    copyright            : (C) 2002 by Michael Otto
    email                : Michael.Otto@saskathex.de
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#define SIZE_X 300
#define SIZE_Y 300
#define LINES 10 
#define DAYS 30
#define OFFSET_X 40
#define OFFSET_Y 7
#define VALUE_COLUMN_SIZE 60
#define VALUE_ROW_SIZE 30

#include "chartdrawing.h"

#include "stock.h"
#include "config.h"

ChartDrawing::ChartDrawing(const Stock * const stock) {
  ChartDrawing::stock = stock;
  values = stock->getValuesVector();
  
  stepX = SIZE_X / DAYS;
  stepY = SIZE_Y / LINES;

  set_size_request (SIZE_X-stepX+1+OFFSET_X+VALUE_COLUMN_SIZE, SIZE_Y+1+OFFSET_Y+VALUE_ROW_SIZE);
  set_events (Gdk::EXPOSURE_MASK);
  gdk_rgb_init();
}


ChartDrawing::~ChartDrawing() {
}



bool ChartDrawing::on_expose_event(GdkEventExpose *event) {

  Glib::RefPtr<Gdk::GC> some_gc;
  some_gc = Gdk::GC::create(get_window());
  Glib::RefPtr<Pango::Layout> layout = Pango::Layout::create(Gtk::Widget::create_pango_context());

  // find max
  float max = 0;
  float step;
  for (int i = 0; i < values.size(); i++) {
    if (values[i] > max) max = values[i];
  }
  if (stock->getCurrentMarketPrice() > max) max = stock->getCurrentMarketPrice();
#ifdef DEBUG
  cout << "maximum is " << max << endl;
#endif
  max += 0.05 * max;
  step = max / 10;
#ifdef DEBUG
  cout << "stepping is " << step << endl;
#endif
  // vertical lines = No. of Days
  for (int i = 0; i < DAYS; i++) {
    get_window()->draw_line(this->get_style()->get_white_gc(), i*stepX + OFFSET_X, 0 + OFFSET_Y, i*stepX + OFFSET_X, LINES*stepY + OFFSET_Y);
  }

  // horizontal lines, day value of the stock
  for (int i = 0; i <= LINES; i++) {
    get_window()->draw_line(this->get_style()->get_white_gc(), 0 + OFFSET_X, i*stepY + OFFSET_Y, (DAYS-1)*stepX + OFFSET_X, i*stepY + OFFSET_Y);
  }    

  // Draw values on the y axis
  char c[8];
  for (int i = 0; i < LINES; i++) {
    sprintf(c,"%.2f", (LINES-i)*step);
    layout->set_text(c);
    get_window()->draw_layout(this->get_style()->get_black_gc(), SIZE_X+OFFSET_X+3, i*stepY, layout);
  }
  // Draw day values on the x axis
  for (int i = 0; i <= DAYS; i++) {
    if ((i % 5) == 0) {
      if (i == 0) sprintf(c,"%d", i);
      else sprintf(c,"%d", -i);
      layout->set_text(c);
      get_window()->draw_layout(this->get_style()->get_black_gc(), (DAYS-i)*stepX + OFFSET_X-12, LINES*stepY + OFFSET_Y+5, layout);
    }
  }
  //layout->set_text("days");
  //get_window()->draw_layout(this->get_style()->get_black_gc(), (DAYS)*stepX + OFFSET_X + 15, LINES*stepY + OFFSET_Y+10, layout);
    
  
  int value, valueBefore;
  int x = DAYS - 2;
  for (int i = values.size()-1; i >= 0; i--) {
    if (x > 0) {
      // getting & scaling the values
      value = (int) ((values[i] / max) * SIZE_Y);
      valueBefore = (int) ((values[i-1] / max) * SIZE_Y);
      // drawing the values
      get_window()->draw_point(some_gc, x*stepX + OFFSET_X, SIZE_Y - value + OFFSET_Y);
      if (i != 0) get_window()->draw_line(some_gc, (x-1)*stepX + OFFSET_X, SIZE_Y-valueBefore + OFFSET_Y, x*stepX + OFFSET_X, SIZE_Y-value + OFFSET_Y);
      x--;
    }
    else {
#ifdef DEBUG
      cout << "more than 30 days stored!" << endl;
#endif
      break;
    }
  }

  value = (int) ((stock->getCurrentMarketPrice() / max) * SIZE_Y);
  valueBefore = (int) ((stock->getCurrentMarketPriceDayBefore() / max) * SIZE_Y);
  get_window()->draw_point(some_gc, (DAYS-1)*stepX + OFFSET_X, SIZE_Y - value + OFFSET_Y);
  get_window()->draw_line(some_gc, (DAYS-2)*stepX + OFFSET_X, SIZE_Y-valueBefore + OFFSET_Y, (DAYS-1)*stepX + OFFSET_X, SIZE_Y-value + OFFSET_Y);
  
  return true;
}

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