/**
*@author blovedr
* Function: java drawing principle ------ draw one or more pictures on the window interface (or panel) problem solution
* Date: April 28, 2018 16:20
* Note: The little records of learning java, welcome all the great gods to criticize, guide and communicate.
*/
package com.test1;
import javax.swing.*;
import java.awt.*;
public class Demo_1 extends JFrame{
MyPanel mp = null; //Self Note: Define MyPanel
public static void main(String[] args) {
// TODO Auto-generated method stub
Demo_1 demo_1 = new Demo_1();
}
public Demo_1()
{
mp = new MyPanel(); //Self note: Create an object of MyPanel class mp
this.add(mp); //Self note: Add mp to this(JFrame)
this.setSize(400, 300);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Self note: To prevent memory leaks, set the default operation of the window close button (exit the process when you click close)
this.setVisible(true); //Self note: set the form to be visible
}
}
//Define a MyPanel (my own panel, which is the area for drawing and displaying drawing)
class MyPanel extends JPanel
{
//Override the paint method of JPanel
//Graphics is an important class for drawing, you can understand it as a brush
public void paint(Graphics g)
{
//1. Call the parent class function to complete the initialization (task)
//This sentence, can not be less
super.paint(g);
System.out.println("paint is called");
// first draw a circle
//g.drawOval(10, 10, 30, 30);
// draw a straight line
//g.drawLine(10, 10, 40, 40);
// draw a rectangle border
//g.drawRect(10, 10, 40, 60); //Self note: g.drawRect(x, y, width, height); ---x and y represent the coordinates of the upper left corner of the rectangle
// fill rectangle
//set color
// g.setColor(Color.blue);
// g.fillRect(10, 10, 40, 60);
// g.setColor(Color.red);
// g.fillRect(70, 70, 40, 60);
// draw the picture on the panel --- problem
//Image im = Toolkit.getDefaultToolkit().getImage(Panel.class.getResource("/hua.jpg")); //error
//Self note: Toolkit is a class, it has a static method called getDefaultToolkit() (to get the set of its tools), and then it has a getImage
// Panel.class.getResource() ---Use the getResource() method in the Panel class to load the image into the object m.
// Solution: Image im = Toolkit.getDefaultToolkit().getImage(Panel.class.getResource("/hua.jpg"));--- put " Panel.class.getResource("/hua.jpg")" Replace it with the path of the image , // as in the following method 1_ example, you can draw one or more images on the panel .
// Draw a picture on the panel Problem solution 1_Example 1---Three flowers belong to different paths (hua, hua2, hua3 belong to a single picture in different folders)
//Image im = Toolkit.getDefaultToolkit().getImage("D:\\picture\\hua\\hua.jpg"); //正确 2018.4.28 11:29
//Draw a picture on the panel Problem solution 1_Example 2---hua2 and hua belong to different paths
Image im2 = Toolkit.getDefaultToolkit().getImage("D:\\picture\\hua2\\hua2.jpg"); //正确 2018.4.28 15:18
//Draw a picture on the panel Problem solution 1_Example 3---hua3 and (hua and hua2) belong to different paths
//Image im3 = Toolkit.getDefaultToolkit().getImage("D:\\picture\\hua3\\hua3.jpg"); //正确 2018.4.28 15:29
// Draw a picture on the panel Problem solution 2_Example---Three flowers belong to the same folder (hua, hua2, hua3 belong to a single picture in the same folder)
//Image im = Toolkit.getDefaultToolkit().getImage("D:\\picture\\hua\\hua.jpg");
//Image im2 = Toolkit.getDefaultToolkit().getImage("D:\\picture\\hua\\hua2.jpg"); //error Self Note: If the three flowers belong to the same file, the program is in this program The picture alone cannot be displayed properly.
//Image im3 = Toolkit.getDefaultToolkit().getImage("D:\\picture\\hua\\hua3.jpg");
//show
//g.drawImage(im, 90, 90, 100, 50, this); //Example 1 //Correct 2018.4.28 11:29
g.drawImage(im2, 90, 90, 100, 50, this); //Example 2 //Correct 2018.4.28 15:18
//g.drawImage(im3, 90, 90, 100, 50, this); //Example 3 //Correct 2018.4.28 15:29
//自注： g.drawImage(im, dx1, dy1, dx2, dy2, sx1, sy1, sx2, sy2, observer)
// dx1, dy1 represent the upper left corner of the picture you draw, dx2, dy2 represent the width and height of the picture you use (dx2, dy2 --- width, height), this represents the JPanel itself.
}
}