/*
 *  Scribble
 *  --------
 *  This program lets the user scribble on a window
 *  with the mouse. It was adapted from the applet
 *  found on pages 10-12 of "Java in a Nutshell",
 *  2nd edition, by David Flanagan, as a comparison.
 */

#include <graphapp.h>

/** Scribble application variables: **/

  point last_position;      // Store the last mouse position.
  rgb current_colour;       // Store the current colour.
  button clear_button;      // Button to clear the window.
  listbox colour_choices;   // The colour dropdown list.

  char * colour_names[] = { "Black", "Red", "Yellow", "Green" };
  rgb    colours[] =      {  Black,   Red,   Yellow,   Green  };

/** This function is called when the user clicks the mouse
 ** to start scribbling. **/
void mouseDown(window w, int buttons, point p)
{
	last_position = p;
}

/** This function is called when the user drags the mouse. **/
void mouseDrag(window w, int buttons, point p)
{
	setcolour(current_colour);
	drawline(last_position, p);
	last_position = p;
}

/** This function is called when the user clicks on the
 ** clear button to clear the window. **/
void selectClear(button b)
{
	clear(parentwindow(b));
}

/** This function is called when the user selects a
 ** colour from the dropdown list. **/
void selectColour(listbox d, int i)
{
	current_colour = colours[i];
}

/** This function is called to initialise the Scribble
 ** application, from the main function. **/
void init(void)
{
	// Create the application window.
	window w = newwindow("Scribble", rect(50,50,480,400),
				StandardWindow);
	show(w);
	setmousedown(w, mouseDown);
	setmousedrag(w, mouseDrag);

	// Set the background colour.
	setbackground(w, White);

	// Create a button and add it to the window.
	clear_button = newbutton("Clear", rect(100,10,80,24),
				selectClear);

	// Create a dropdown list of colours and add it
	// to the window, with a label saying what it is.
	newlabel("Colour: ", rect(200,10,80,24), AlignCenter);
	colour_choices = newdroplist(colour_names,
				rect(300,10,80,24), selectColour);

	// Initialise current colour.
	setlistitem(colour_choices, 0);
}

/** The main function is the starting point for the
 ** application, and it is here that everything is
 ** initialised. **/
int main(int argc, char *argv[])
{
	init();
	mainloop();
	return 0;
}