122 lines
2.7 KiB
Java
122 lines
2.7 KiB
Java
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import java.awt.*;
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import java.awt.event.*;
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import java.util.*;
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//
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//
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// ScribbleCanvas-
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// This class manages all the events generated on the canvas.
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// The class draws the lines on the canvas, creates a Stroke object for each stroke, and notifies the registered
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// listeners about it.
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// A stoke is a line that is drawn while the the left mouse button is held down.
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// The class keeps a list of all strokes drawn (for repaint) in a vector (strokes).
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//
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//
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public class ScribbleC extends Canvas
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{
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protected Vector strokes = new Vector(5,5);
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private Stroke currentStroke = null;
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private Point currentPoint = null;
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private Vector listeners = new Vector(5,5);
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public ScribbleC()
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{
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// Turns on mouse motion and clicks
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enableEvents(AWTEvent.MOUSE_MOTION_EVENT_MASK | AWTEvent.MOUSE_EVENT_MASK);
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}
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public void processMouseEvent(MouseEvent e)
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{
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// Handle clicks
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if(e.getID() == e.MOUSE_PRESSED)
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{
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currentStroke = new Stroke();
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currentPoint = e.getPoint();
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currentStroke.addElement(currentPoint);
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}
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else if(e.getID() == e.MOUSE_RELEASED)
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{
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currentStroke.addElement(e.getPoint());
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strokes.addElement(currentStroke);
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for(Enumeration enum = listeners.elements(); enum.hasMoreElements(); )
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{
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ScribbleL sl = (ScribbleL)enum.nextElement();
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sl.strokeCreated(currentStroke);
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}
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currentStroke = null;
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currentPoint = null;
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}
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}
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public void processMouseMotionEvent(MouseEvent e)
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{
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// Handle motion
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if(e.getID() == e.MOUSE_DRAGGED)
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{
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if(currentStroke != null)
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{
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Point newPoint = e.getPoint();
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Graphics g = getGraphics();
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g.drawLine(currentPoint.x, currentPoint.y, newPoint.x, newPoint.y);
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currentPoint = newPoint;
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currentStroke.addElement(newPoint);
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}
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}
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}
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public void paint(Graphics g)
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{
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// Enumerate through strokes and paint them.
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for(Enumeration e = strokes.elements(); e.hasMoreElements(); )
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{
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Stroke stroke = (Stroke)e.nextElement();
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drawStroke(g, stroke);
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}
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}
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public void drawStroke(Graphics g, Stroke stroke)
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{
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Enumeration points = stroke.elements();
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if(points.hasMoreElements())
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{
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for(Point currPoint = (Point)points.nextElement() ; points.hasMoreElements(); )
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{
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Point tempPoint = (Point)points.nextElement();
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g.drawLine(currPoint.x, currPoint.y, tempPoint.x, tempPoint.y);
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currPoint = tempPoint;
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}
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}
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}
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public void addScribbleListener(ScribbleL l)
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{
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listeners.addElement(l);
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}
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public void removeScribbleListener(ScribbleL l)
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{
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listeners.removeElement(l);
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}
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public void addStroke(Stroke stroke)
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{
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strokes.addElement(stroke);
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Graphics g = getGraphics();
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drawStroke(g, stroke);
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}
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public void clear()
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{
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strokes = new Vector(5,5);
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repaint();
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}
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}
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