Use of drawing tools in the drawing board

Redrawing refers to the drawing of the picture to save, redraw divided into three kinds: remember coordinates, points, notes steps.

We are here to focus on the method of the coordinates of the workshop;

If we want to draw a straight line, the main thing is to record its two coordinates, so we should create an array to record the two coordinates.

The code is as follows:

public class Shape {

int x1,y1,x2,y2;

String name;

Color color;

public Shape (int x1, int y1, int x2, int y2) {

this.x1 = x1;

This.y1 = y1;

this.x2 = x2;

This.y2 = y2;

}

}

There is a need to re-build a class to hold the coordinates. This step should be the first step, you should first create a class

public class Drawframe extends JPanel {

Shape[] shape = new SHAPE[20];

This creates a shape array, and extends to rewrite the method in the JPanel;

Layout on the left side of the design

JPanel JP2 = new JPanel ();

This.setpreferredsize (New Dimension (850, 700));

This.setbackground (Color.White);

Jf.add (this);

/***********/

This.addmouselistener (LG);

This.addmousemotionlistener (LG);

Here this refers to our panel, we have to rewrite the method of the drawing of the JPanel to use this method.

public void Paint (Graphics g) {

Super.paint (g);

for (int i = 0; i < shape.length; i++) {

if (shape[i]! = null) {

if ("line". Equals (Shape[i].name)) {

G.setcolor (Shape[i].color);

G.drawline (shape[i].x1, Shape[i].y1, SHAPE[I].X2,

SHAPE[I].Y2);

}

if ("Round". Equals (Shape[i].name)) {

G.setcolor (Shape[i].color);

G.drawoval (Math.min (shape[i].x1, shape[i].x2), Math.min (Shape[i].y1, Shape[i].y2), Math.Abs (Shape[i].x1-shape[i]. x2),

Math.Abs (Shape[i].y1-shape[i].y2));

}

if ("Square". Equals (Shape[i].name)) {

G.setcolor (Shape[i].color);

G.drawrect (Math.min (SHAPE[I].X1,SHAPE[I].X2), Math.min (Shape[i].y1, Shape[i].y2), Math.Abs (Shape[i].x1-shape[i]. x2),

Math.Abs (Shape[i].y1-shape[i].y2));

}

}

}

}

Here is the most important step to rewrite, is to override the method in JPanel, the Paint method is automatically called in the JPanel. So do not intentionally add.

Private shape[] Shape;

private int index;

public void Setshape (shape[] Shape) {

This.shape = shape;

}

Here's how to add a method to the listener class, which is the class that passes shape to the listening mechanism.

Shape line = new shape (x1, y1, X4, y4);

Line.name = "Straight line";

Line.color = CO;

Shape[index] = line;

index++;

The next is to add that array to each method to hold the coordinates.

This rewrite is complete, thank you!

Use of paint tools in the drawing board