package first_shape_drawing;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Scanner;
import javax.swing.JFrame;
import javax.swing.Timer;
public class DrawingProgram extends JFrame {
private final static int DELAY = 10000;
Drawing drawing = new Drawing();
// INNER Class
class MyMouseHandler extends MouseAdapter
{
public void mousePressed(MouseEvent e)
{
drawing.mousePressed(e.getPoint());
repaint();
}
public void mouseReleased(MouseEvent e)
{
drawing.mouseReleased(e.getPoint());
repaint();
}
public void mouseDragged(MouseEvent e)
{
drawing.mouseDragged(e.getPoint());
repaint();
}
}
DrawingProgram()
{
super("My Drawing Program");
setSize(800, 400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
MyMouseHandler mmh = new MyMouseHandler();
addMouseListener(mmh);
addMouseMotionListener(mmh);
setVisible(true);
}
public void paint(Graphics g)
{
Dimension dimen = getSize();
Insets insets = getInsets();
int top = insets.top;
int left = insets.left;
g.setColor(Color.white);
g.fillRect(0, 0, dimen.width, dimen.height);
drawing.draw(g);
String str = drawing.toString();
System.out.println(str);
}
public static void main(String[] args) {
DrawingProgram dp = new DrawingProgram();
Scanner keyboard = new Scanner(System.in);
boolean continueFlag=true;
while(continueFlag)
{
System.out.println("Cmds: r,o,l,s,p,a,q,?,f,d,b,m,g");
String str = keyboard.next().toLowerCase();
if (str.length() == 0) continue;
switch(str.charAt(0))
{
case 'r':
dp.drawing.setDrawType(DrawType.rectangle);
break;
case 'o':
dp.drawing.setDrawType(DrawType.oval);
break;
case 'l':
dp.drawing.setDrawType(DrawType.line);
break;
case 's':
dp.drawing.setDrawType(DrawType.scribble);
break;
case 'p':
case 'a':
dp.drawing.setDrawType(DrawType.polygon);
break;
case 'q':
continueFlag = false;
break;
case 'f':
dp.drawing.setFilled(true);
break;
case 'd':
dp.drawing.setFilled(false);
break;
case 'b':
dp.drawing.setColor(Color.blue);
break;
case 'm':
dp.drawing.setColor(Color.magenta);
break;
case 'g':
dp.drawing.setColor(Color.green);
break;
default: // '?' comes here
System.out.println("r - drawType= Rectangle");
System.out.println("o - drawType= Oval");
System.out.println("l - drawType= Line");
System.out.println("s - drawType= Scribble");
System.out.println("p - drawType= Polygon");
System.out.println("a - another Polygon");
System.out.println("q - quit");
System.out.println("f - filled objects");
System.out.println("d - draw objects (not filled)");
System.out.println("b - Use Blue Color");
System.out.println("m - Use magenta Color");
System.out.println("g - Use Green Color");
break;
}
}
System.out.println("Exitting the Drawing Program");
dp.dispose();
keyboard.close();
}
}
我每次画画时如何防止这种情况发生闪烁？我已经检查了其他一些问题以及其他一些网站，但我无法确定如何实现我想要的内容。基本上，每当我去绘画时，面板都会闪烁。
如果这也是相关的，这里是Drawing.java
package first_shape_drawing;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Point;
import java.util.ArrayList;
enum DrawType {scribble, oval, rectangle, polygon, line};
class DrawingProperties
{
DrawType drawType;
boolean filled;
Color color;
DrawingProperties(DrawType drawType, Color color, boolean filled)
{
this.drawType = drawType;
this.color = color;
this.filled = filled;
}
public String toString()
{
return drawType + " color=" + color +" filled="+ filled;
}
}
public class Drawing {
DrawingProperties drawingProperties = new DrawingProperties(DrawType.rectangle, Color.blue, false);
ArrayList<Shape> shapeArr = new ArrayList<Shape>();
Shape inProgress = null;
public String toString()
{
return drawingProperties.toString();
}
public void draw(Graphics g)
{
for (int i=0; i < shapeArr.size(); i++)
{
Shape s = shapeArr.get(i);
s.draw(g);
}
if (inProgress != null)
inProgress.draw(g);
}
public void setColor(Color color)
{
drawingProperties.color = color;
}
public void setFilled(boolean filled)
{
drawingProperties.filled = filled;
}
public void setDrawType(DrawType drawType)
{
drawingProperties.drawType = drawType;
}
public void mousePressed(Point p)
{
switch(drawingProperties.drawType)
{
case rectangle:
inProgress = new Rectangle(drawingProperties.color, drawingProperties.filled);
break;
case oval:
inProgress = new Oval(drawingProperties.color, drawingProperties.filled);
break;
case line:
inProgress = new Line(drawingProperties.color);
break;
case scribble:
inProgress = new Scribble(drawingProperties.color);
break;
}
inProgress.firstPoint(p);
}
public void mouseDragged(Point p)
{
switch(drawingProperties.drawType)
{
case rectangle:
case oval:
case scribble:
case line:
inProgress.subsequentPoint(p);
break;
}
}
public void mouseReleased(Point p)
{
inProgress.subsequentPoint(p);
shapeArr.add(inProgress);
inProgress = null;
}
}
abstract class Shape
{
Color color;
Shape ( Color c)
{
color =c;
}
abstract void firstPoint(Point p);
abstract void draw(Graphics g);
abstract void subsequentPoint(Point p);
}
class Rectangle extends Shape
{
boolean filled=false;
Point start;
Point lastPoint;
Rectangle(Color c, boolean filled)
{
super(c);
lastPoint = start;
this.filled = filled;
}
@Override
void firstPoint(Point p) {
start =p;
lastPoint =p;
}
@Override
void draw(Graphics g) {
g.setColor(color);
int x = Math.min(start.x, lastPoint.x);
int y = Math.min(start.y, lastPoint.y);
int w = Math.abs(start.x - lastPoint.x);
int h = Math.abs(start.y - lastPoint.y);
if (filled)
g.fillRect(x, y, w, h);
else
g.drawRect(x, y, w, h);
}
@Override
void subsequentPoint(Point p) {
lastPoint =p;
}
}
class Scribble extends Shape
{
ArrayList<Point> points= new ArrayList<Point>();
Scribble(Color c)
{
super(c);
}
@Override
void firstPoint(Point p) {
points.add(p);
}
@Override
void draw(Graphics g) {
g.setColor(color);
for (int i=1; i < points.size(); i++)
{
Point first = points.get(i-1);
Point next = points.get(i);
g.drawLine(first.x, first.y, next.x, next.y);
}
}
@Override
void subsequentPoint(Point p) {
points.add(p);
}
}
class Oval extends Shape {
boolean filled=false;
Point start;
Point lastPoint;
Oval(Color c, boolean filled)
{
super(c);
lastPoint = start;
this.filled = filled;
}
@Override
void firstPoint(Point p) {
start =p;
lastPoint =p;
}
@Override
void draw(Graphics g) {
g.setColor(color);
//oval is int x, int y, int width, int height
int x = Math.min(start.x, lastPoint.x);
int y = Math.min(start.y, lastPoint.y);
int w = Math.abs(start.x - lastPoint.x);
int h = Math.abs(start.y - lastPoint.y);
if (filled)
g.fillOval(x, y, w, h);
else
g.drawOval(x, y, w, h);
}
@Override
void subsequentPoint(Point p) {
lastPoint =p;
}
}
class Line extends Shape
{
Point start;
Point lastPoint;
Line(Color c)
{
super(c);
}
@Override
void firstPoint(Point p) {
start =p;
lastPoint =p;
}
@Override
void draw(Graphics g) {
g.setColor(color);
g.drawLine(start.x, start.y, lastPoint.x, lastPoint.y);
}
@Override
void subsequentPoint(Point p) {
lastPoint =p;
}
}
答案 0 :(得分：0)
不确定正确的方法是什么，但问题出在哪里：
g.setColor(Color.white);
g.fillRect(0, 0, dimen.width, dimen.height);
您可以在任何绘图之前删除整个面板，即先将其全部涂成白色。这不是必要的。
删除这两行，你的闪烁就会停止。
结果可能会出现其他问题，但在绘图之前擦除整个面板几乎总是闪烁的。
答案 1 :(得分：0)
如果你想避免闪烁，你必须在图像上绘制所有内容并在paint（）中绘制该图像。
public void paint(Graphics g)
{
Dimension dimen = getSize();
Insets insets = getInsets();
int top = insets.top;
int left = insets.left;
if(im!=null) {
Graphics g2=im.getGraphics();
g2.setColor(Color.white);
g2.fillRect(0, 0, im.getWidth(null), im.getHeight(null));
drawing.draw(im);
g.drawImage(im, 0, 0, this);
}
String str = drawing.toString();
System.out.println(str);
}
您将图像定义为
Image im;
并在设置为visible后在构造函数中启动它：
setVisible(true);
im=createImage(getWidth(), getHeight());
然后你有另外一个这样的绘制功能
public void draw(Image im)
{
Graphics g=im.getGraphics();
for (int i=0; i < shapeArr.size(); i++)
{
Shape s = shapeArr.get(i);
s.draw(g);
}
if (inProgress != null)
inProgress.draw(g);
}