/**
* Set the canvas visibility and brings canvas to the front of screen when made visible. This
* method can also be used to bring an already visible canvas to the front of other windows.
*
* @param visible boolean value representing the desired visibility of the canvas (true or false)
*/
public void setVisible(boolean visible) {
if (graphic == null) {
// first time: instantiate the offscreen image and fill it with
// the background color
Dimension size = canvas.getSize();
canvasImage = canvas.createImage(size.width, size.height);
graphic = (Graphics2D) canvasImage.getGraphics();
graphic.setColor(backgroundColor);
graphic.fillRect(0, 0, size.width, size.height);
graphic.setColor(Color.black);
}
frame.setVisible(visible);
}
/** Erase the whole canvas. (Does not repaint.) */
private void erase() {
Color original = graphic.getColor();
graphic.setColor(backgroundColor);
Dimension size = canvas.getSize();
graphic.fill(new Rectangle(0, 0, size.width, size.height));
graphic.setColor(original);
}
/**
* Erases a String on the Canvas.
*
* @param text the String to be displayed
* @param x x co-ordinate for text placement
* @param y y co-ordinate for text placement
*/
public void eraseString(String text, int x, int y) {
Color original = graphic.getColor();
graphic.setColor(backgroundColour);
graphic.drawString(text, x, y);
graphic.setColor(original);
canvas.repaint();
}
/** Redraw ell shapes currently on the Canvas. */
private void redraw() {
erase();
for (Object shape : objects) {
shapes.get(shape).draw(graphic);
}
canvas.repaint();
}
/**
* Erases a given shape's outline on the screen.
*
* @param shape the shape object to be erased
*/
public void eraseOutline(Shape shape) {
Color original = graphic.getColor();
graphic.setColor(backgroundColour);
graphic.draw(shape); // erase by drawing background colour
graphic.setColor(original);
canvas.repaint();
}
/** Redraw ell shapes currently on the Canvas. */
private void redraw() {
erase();
for (Iterator i = objects.iterator(); i.hasNext(); ) {
shapes.get(i.next()).draw(graphic);
}
canvas.repaint();
}
/**
* Create a Canvas.
*
* @param title title to appear in Canvas Frame
* @param width the desired width for the canvas
* @param height the desired height for the canvas
* @param bgClour the desired background colour of the canvas
*/
private Canvas(String title, int width, int height, Color bgColour) {
frame = new JFrame();
canvas = new CanvasPane();
frame.setContentPane(canvas);
frame.setTitle(title);
canvas.setPreferredSize(new Dimension(width, height));
backgroundColour = bgColour;
frame.pack();
}
/**
* Create a Canvas.
*
* @param title title to appear in Canvas Frame
* @param width the desired width for the canvas
* @param height the desired height for the canvas
* @param bgClour the desired background colour of the canvas
*/
private Canvas(String title, int width, int height, Color bgColour) {
frame = new JFrame();
canvas = new CanvasPane();
frame.setContentPane(canvas);
frame.setTitle(title);
canvas.setPreferredSize(new Dimension(width, height));
backgroundColour = bgColour;
frame.pack();
objects = new ArrayList<Object>();
shapes = new HashMap<Object, ShapeDescription>();
}
/**
* Fills the internal dimensions of a given shape with the current foreground colour of the
* canvas.
*
* @param shape the shape object to be filled
*/
public void fill(Shape shape) {
graphic.fill(shape);
canvas.repaint();
}
/**
* Draws a given shape onto the canvas.
*
* @param shape the shape object to be drawn on the canvas
*/
public void draw(Shape shape) {
graphic.draw(shape);
canvas.repaint();
}
/**
* Returns the size of the canvas.
*
* @return The current dimension of the canvas
*/
public Dimension getSize() {
return canvas.getSize();
}
/**
* Sets the size of the canvas.
*
* @param width new width
* @param height new height
*/
public void setSize(int width, int height) {
canvas.setPreferredSize(new Dimension(width, height));
frame.pack();
}
/**
* Draws a line on the Canvas.
*
* @param x1 x co-ordinate of start of line
* @param y1 y co-ordinate of start of line
* @param x2 x co-ordinate of end of line
* @param y2 y co-ordinate of end of line
*/
public void drawLine(int x1, int y1, int x2, int y2) {
graphic.drawLine(x1, y1, x2, y2);
canvas.repaint();
}
/**
* Draws a String on the Canvas.
*
* @param text the String to be displayed
* @param x x co-ordinate for text placement
* @param y y co-ordinate for text placement
*/
public void drawString(String text, int x, int y) {
graphic.drawString(text, x, y);
canvas.repaint();
}
/**
* Draws an image onto the canvas.
*
* @param image the Image object to be displayed
* @param x x co-ordinate for Image placement
* @param y y co-ordinate for Image placement
* @return returns boolean value representing whether the image was completely loaded
*/
public boolean drawImage(Image image, int x, int y) {
boolean result = graphic.drawImage(image, x, y, null);
canvas.repaint();
return result;
}
