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Registered User
Join Date: Mar 2004
Posts: 7
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drawing shapes in any diagonal direction in applet
i have a simple paint applet, which only allows drawing shapes form the top left to the bottom right, you cant drag it from the bottom right to the top left etc.
how would i go about changing this to allow any direction to be used
this is my applet so far
Code:
// import required modules
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import javax.swing.*;
public class Drawing extends Applet
{
// declare required objects
Panel palette, tools, bgcolour;
Button line, rect, oval, arc;
Checkbox filled;
Button black, cyan, red, blue, green, yellow, pink, white,
bgblack, bgred, bgblue, bggreen, bgyellow, bgwhite;
MyCanvas drawarea;
TextField startText, sweepText;
Label startLabel = new Label("Arc starting angle");
Label sweepLabel = new Label("Arc sweep angle");
Label linesLabel = new Label("Line Style");
Label bgColourLabel = new Label("Background Colours");
Label shapesLabel = new Label("Shapes");
private JComboBox lineComboBox;
// declare and initialise some variables
int mx = 0; int my = 0; int mx1 = 0; int my1 = 0;
int currentTool = 0;
Color currentColor = new Color(0,0,0);
boolean wipe = false;
private String message = "Waiting for events...";
public void init()
{
setLayout(new BorderLayout()); // Define a new layout for the applet
lineComboBox = new JComboBox();
lineComboBox.setMaximumRowCount(3);
lineComboBox.addItem("Any Direction");
lineComboBox.addItem("Horizontal");
lineComboBox.addItem("Vertical");
lineComboBox.addItemListener(
new ItemListener() { // anonymous inner class
// handle JComboBox event
public void itemStateChanged( ItemEvent event )
{
// determine whether it is selected
if ( event.getStateChange() == ItemEvent.SELECTED )
lineComboBox.getSelectedIndex();
}
} // end anonymous inner class
); // end call to addItemListener
// Define and position the palette at the bottom of the screen
palette = new Panel();
palette.setLayout(new GridLayout(2,4,5,5));
//set up palette buttons
black = new Button();
black.setBackground(Color.black);
cyan = new Button();
cyan.setBackground(Color.cyan);
red = new Button();
red.setBackground(Color.red);
blue = new Button();
blue.setBackground(Color.blue);
green = new Button();
green.setBackground(Color.green);
yellow = new Button();
yellow.setBackground(Color.yellow);
pink = new Button();
pink.setBackground(Color.pink);
white = new Button();
white.setBackground(Color.white);
// add palette buttons
palette.add(black);
palette.add(cyan);
palette.add(red);
palette.add(blue);
palette.add(green);
palette.add(yellow);
palette.add(pink);
palette.add(white);
add(palette,"South");
// Define the position of the bg colour toolbar at the right of the screen
bgcolour = new Panel();
bgcolour.setLayout( new GridLayout( 7, 1, 4, 4 ));
// set up background colour buttons
bgblack = new Button();
bgblack.setBackground(Color.black);
bgred = new Button();
bgred.setBackground(Color.red);
bgblue = new Button();
bgblue.setBackground(Color.blue);
bggreen = new Button();
bggreen.setBackground(Color.green);
bgyellow = new Button();
bgyellow.setBackground(Color.yellow);
bgwhite = new Button();
bgwhite.setBackground(Color.white);
bgcolour.add(bgColourLabel);
// add background colour buttons
bgcolour.add(bgblack);
bgcolour.add(bgred);
bgcolour.add(bgblue);
bgcolour.add(bggreen);
bgcolour.add(bgyellow);
bgcolour.add(bgwhite);
add(bgcolour,"East");
// Define and position the tool bar at the left of the screen
tools = new Panel();
tools.setLayout(new GridLayout(12,1,5,5));
line = new Button("Line");
rect = new Button("Rectangle");
oval = new Button("Oval");
arc = new Button("Arc");
filled = new Checkbox("Filled",false);
startText = new TextField(10);
sweepText = new TextField(10);
startText.setText("0");
sweepText.setText("270");
tools.add(shapesLabel);
tools.add(line);
tools.add(rect);
tools.add(oval);
tools.add(arc);
tools.add(filled);
tools.add(startLabel);
tools.add(startText);
tools.add(sweepLabel);
tools.add(sweepText);
tools.add(linesLabel);
tools.add(lineComboBox);
add(tools,"West");
drawarea = new MyCanvas();
add(drawarea,"Center"); // add drawing canvas to the middle of the screen
validate();
}// end method init
// If the user clicks a button on the toolbar, then change the value of "currentTool" and call "filled.setEnable" appropriately
public boolean action(Event evt, Object obj) // define event handler
{
if (evt.target == line)
{
currentTool = 0;
filled.setEnabled(false);
}
else if (evt.target == rect)
{
currentTool = 1;
filled.setEnabled(true);
}
else if (evt.target == oval)
{
currentTool = 2;
filled.setEnabled(true);
}
else if (evt.target == arc)
{
currentTool = 3;
filled.setEnabled(true);
}
// Change the value of currentColor to the appropraite color clicked by user
else if (evt.target == black) currentColor = new Color(0,0,0);
else if (evt.target == cyan) currentColor = new Color(0,255,255);
else if (evt.target == red) currentColor = new Color(255,0,0);
else if (evt.target == blue) currentColor = new Color(0,0,255);
else if (evt.target == green) currentColor = new Color(0,255,0);
else if (evt.target == yellow) currentColor = new Color(255,255,0);
else if (evt.target == pink) currentColor = new Color(255,175,175);
else if (evt.target == white) currentColor = new Color(255,255,255);
// change the colour of the canvas according to which buttont he user clicks
else if (evt.target == bgblack) drawarea.setBackground(Color.black);
else if (evt.target == bgred) drawarea.setBackground(Color.red);
else if (evt.target == bgblue) drawarea.setBackground(Color.blue);
else if (evt.target == bggreen) drawarea.setBackground(Color.green);
else if (evt.target == bgyellow) drawarea.setBackground(Color.yellow);
else if (evt.target == bgwhite) drawarea.setBackground(Color.white);
return (true);
}
// Create a new class called "MyCanvas" which extends the standard class Canvas
class MyCanvas extends Canvas implements MouseListener
{
// the classes constructor
public MyCanvas()
{
addMouseListener(this);
}
// These actions are performed when the user is pressing the left mouse button
public void mousePressed(MouseEvent e)
{
mx = e.getX();
my = e.getY();
mx1 = e.getX();
my1 = e.getY();
// return (true);
}// end method mousePressed
// These actions are performed when the user is dragging the mouse
public void mouseReleased(MouseEvent e)
{
mx1 = e.getX();
my1 = e.getY();
repaint();
}// end method mouseReleased
public void mouseClicked(MouseEvent e)
{
//empty method
}// end method mouseClicked
public void mouseEntered(MouseEvent e)
{
//empty method
}// end method mousePressed
public void mouseExited(MouseEvent e)
{
//empty method
}// end method mousePressed
public void update(Graphics g)
{
paint(g);
}// end method update
public void paint(Graphics g) // When the user paints on the canvcas, then do the following
{
// add header text
g.drawString( "S-ID: 12129103 - David McCabe", 0, 15 );
String s = startText.getText();
int start = Integer.parseInt(s);
s = sweepText.getText();
int sweep = Integer.parseInt(s);
g.setColor(currentColor); // Set the drawing color to that selected
// Determine shape selected and if it is to be filled with current colour
switch ( currentTool )
{
case 0: // line selected
g.drawLine( mx, my, mx1, my1 );
/*
if ( lineNum == 0 )
g.drawLine( mx, my, mx1, my1 );
else if ( lineNum == 1)
g.drawLine( mx, my, mx1, my );
else if ( lineNum == 2)
g.drawLine( mx, my, mx, my1);
*/
break; // done processing case
case 1: // rectangle selected
if ( filled.getState() == true )
g.fillRect( mx, my, mx1-mx, my1-my );
else g.drawRect( mx, my, mx1-mx, my1-my );
break; // done processing case
case 2: // oval selected
if (filled.getState() == true)
g.fillOval( mx, my, mx1-mx, my1-my );
else g.drawOval( mx, my, mx1-mx, my1-my );
break; // done processing case
case 3: // arc selected
if (filled.getState() == true)
g.fillArc( mx, my, mx1-mx, my1-my, start, sweep );
else g.drawArc( mx, my, mx1-mx, my1-my, start, sweep );
break; // done processing case
default:
} // end switch
}// end method paint
}// end class MyCanvas
}// end class Drawing
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