plugin-examples/avtk/dial.h

/*
 * Author: Harry van Haaren 2013
 *         harryhaaren@gmail.com
 * 
 * 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.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 * 
 */


#ifndef AVTK_DIAL_H
#define AVTK_DIAL_H

#include <FL/Fl_Dial.H>
#include <FL/Fl_Slider.H>

namespace Avtk
{

class Dial : public Fl_Slider
{
  public:
    Dial(int _x, int _y, int _w, int _h, const char* _label=0):
        Fl_Slider(_x, _y, _w, _h, _label)
    {
      x = _x;
      y = _y;
      w = _w;
      h = _h;
      
      // * 0.9 for line width to remain inside redraw area
      if ( w > h )
        radius = (h / 2.f)*0.9;
      else
        radius = (w / 2.f)*0.9;
      
      lineWidth = 1.4 + radius / 12.f;
      
      mouseClickedY = 0;
      mouseClicked = false;
      
      highlight = false;
      label = _label;
    }
    
    bool highlight;
    int x, y, w, h;
    const char* label;
    bool drawLab;
    void drawLabel(bool b){drawLab = b; redraw();}
    
    float radius;
    float lineWidth;
    
    int mouseClickedY;
    bool mouseClicked;
    
    void draw()
    {
      if (damage() & FL_DAMAGE_ALL)
      {
        cairo_t *cr = Fl::cairo_cc();
        
        cairo_save( cr );
        
        // label behind value
        draw_label();
        
        cairo_set_line_join(cr, CAIRO_LINE_JOIN_ROUND);
        cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
        
        cairo_set_line_width(cr, lineWidth-0.2);
        cairo_move_to( cr, x+w/2,y+h/2);
        cairo_line_to( cr, x+w/2,y+h/2);
        cairo_set_source_rgba(cr, 0.5, 0.5, 0.5, 0.4 );
        
        // draw dash guide
        double dashes[2];
        cairo_set_line_width(cr, 1.7);
        dashes[0] = 3.0;
        dashes[1] = 3.0;
        cairo_set_dash ( cr, dashes, 2, 0.0);
        cairo_stroke(cr);
        
        cairo_arc(cr, x+w/2,y+h/2, radius, 2.46, 0.75 );
        //cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 0.4 );
        cairo_stroke(cr);
        cairo_set_dash ( cr, dashes, 0, 0.0);
        
        float angle = 2.46 + ( 4.54 * value() );
        cairo_set_line_width(cr, lineWidth);
        cairo_arc(cr, x+w/2,y+h/2, radius, 2.46, angle );
        cairo_line_to(cr, x+w/2,y+h/2);
        cairo_set_source_rgba(cr, 1.0, 0.48,   0, 1.0);
        cairo_stroke(cr);
        
        cairo_restore( cr );
        
        if ( drawLab )
        {
          //draw_label();
        }
        
      }
    }
    
    void resize(int X, int Y, int W, int H)
    {
      Fl_Slider::resize(X,Y,W,H);
      x = X;
      y = Y;
      w = W;
      h = H;
      redraw();
    }
    
    int handle(int event)
    {
      //cout << "handle event type = " << event << " value = " << value() << endl;
      
      //Fl_Slider::handle( event );
      
      switch(event) {
        case FL_PUSH:
          highlight = 1;
          redraw();
          return 1;
        case FL_DRAG:
          {
            if ( Fl::event_state(FL_BUTTON1) )
            {
              if ( mouseClicked == false ) // catch the "click" event
              {
                mouseClickedY = Fl::event_y();
                mouseClicked = true;
              }
              
              float deltaY = mouseClickedY - Fl::event_y();
              
              float val = value();
              val += deltaY / 100.f;
              
              if ( val > 1.0 ) val = 1.0;
              if ( val < 0.0 ) val = 0.0;
              
              set_value( val );
              
              mouseClickedY = Fl::event_y();
              redraw();
              do_callback(); // makes FLTK call "extra" code entered in FLUID
            }
          }
          return 1;
        case FL_RELEASE:
          if (highlight) {
            highlight = 0;
            redraw();
            // never do anything after a callback, as the callback
            // may delete the widget!
          }
          mouseClicked = false;
          return 1;
        default:
          return Fl_Widget::handle(event);
      }
    }
};

} // Avtk

#endif // AVTK_DIAL_H