Skunkware 5/Skunkware 5.iso/src/Tools/MotifApp/Extras/bounce/BouncingBall.C

C/C++ Source or Header | 1995-05-03 | 4.8 KB | 179 lines

///////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//         This example code is from the book:
//
//           Object-Oriented Programming with C++ and OSF/Motif
//         by
//           Douglas Young
//           Prentice Hall, 1992
//           ISBN 0-13-630252-1
//
//         Copyright 1991 by Prentice Hall
//         All Rights Reserved
//
//  Permission to use, copy, modify, and distribute this software for
//  any purpose except publication and without fee is hereby granted, provided
//  that the above copyright notice appear in all copies of the software.
///////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////


//////////////////////////////////////////////////////////
// BouncingBall.C
//////////////////////////////////////////////////////////
#include "Application.h"
#include "Stage.h"
#include "BouncingBall.h"
#include "ColorChooser.h"
#include "InfoDialogManager.h"
#include "libc.h"

#define SIZE 25

BouncingBall::BouncingBall ( Stage * stage,
                char *colorName ) : Actor ( stage )
{
    // Get an initial velocity at random

    _delta.x = (int) ( SIZE * drand48() );
    _delta.y = (int) ( SIZE * drand48() );

    // Initialize the current location and bounding box of the object

    _bounds.width = _bounds.height = SIZE;
    _bounds.x     = _bounds.width  + 1;
    _bounds.y     = _bounds.height + 1;

    _gc = NULL;

    // If a color name has been specified, try to allocate a color.
    // Otherwise use the ColorChooser to let the user pick a color.

    if ( colorName )
    {
    XGCValues  gcv;
    Display   *dpy  = theApplication->display();
    int        scr  = DefaultScreen ( dpy );
    Colormap   cmap = DefaultColormap ( dpy, scr );
    XColor     color, ignore;

    // If color allocation fails, use the default black pixel

    if ( XAllocNamedColor ( dpy,
                   cmap, colorName,
                   &color, &ignore ) )
        gcv.foreground = color.pixel;
    else
        gcv.foreground = BlackPixel ( dpy, scr );

    // Create a graphics context used to draw this object

    _gc = XtGetGC ( _stage->baseWidget(),
               GCForeground,
               &gcv );
    }
    else
    {
    ColorChooser *colorChooser =
        new ColorChooser ( theApplication->baseWidget(),
                  "colorChooser" );

    colorChooser->pickColor ( &BouncingBall::colorSelectedCallback,
                 &BouncingBall::canceledCallback,
                 (void *) this );
    }
}

void BouncingBall::nextFrame ( Drawable  d,
                   Dimension width,
                   Dimension height )
{
    if ( !_gc)   // Return if no color has been chosen yet
    return;

    // Update the current position

    _bounds.x += _delta.x;
    _bounds.y += _delta.y;

    // If we have hit the right wall, reposition and
    // reverse the x component of the  velocity

    if ( _bounds.x + _bounds.width >= width )
    {
    _bounds.x = width - _bounds.width;
    _delta.x  = -_delta.x;
    }
    else if ( _bounds.x <= 0 )  // Check for hitting the left wall
    {
    _bounds.x = 0;
    _delta.x  = -_delta.x;
    }

    // If we have hit the floor, reposition and
    // reverse the y component of the velocity

    if ( _bounds.y + _bounds.height >= height )
    {
    _bounds.y = height - _bounds.height;
    _delta.y  = -_delta.y;
    }
    else if ( _bounds.y <= 0 )  // Check for bouncing off the top
    {
    _bounds.y = 0;
    _delta.y  = -_delta.y;
    }

    draw ( d );
}


void BouncingBall::draw ( Drawable  d )
{
    //     Draw the object at the new location

    XFillArc ( theApplication->display(), d, _gc,
          _bounds.x,     _bounds.y,
          _bounds.width, _bounds.height,
          0, 360 * 64 );
}

void BouncingBall::colorSelectedCallback ( int   red,
                       int   green,
                       int   blue,
                       void *clientData )
{
    BouncingBall *obj = (BouncingBall *) clientData;

    obj->colorSelected ( red, green, blue );
}
void BouncingBall::colorSelected ( int red, int green, int blue )
{
    XGCValues  gcv;
    Display   *dpy  = theApplication->display();
    int        scr  = DefaultScreen ( dpy );
    Colormap   cmap = DefaultColormap ( dpy, scr );
    XColor     color;

    color.red   = red   * 256;
    color.green = green * 256;
    color.blue  = blue  * 256 ;

    if ( XAllocColor ( dpy,
              cmap, &color ) )
    gcv.foreground = color.pixel;
    else
    gcv.foreground = BlackPixel ( dpy, scr );

    _gc = XtGetGC ( _stage->baseWidget(),
           GCForeground,
           &gcv );
}
void BouncingBall::canceledCallback ( void *clientData )
{
    BouncingBall *obj = (BouncingBall *) clientData;

    theInfoDialogManager->post ( "Using Black as the default color" );
    obj->colorSelected ( 0, 0, 0 );
}