调整java applet中查看图像所需的大小 [英] resize required to view images in java applet
本文介绍了调整java applet中查看图像所需的大小的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我第一次使用java图像，并且在applet加载时遇到问题。如果我调整窗口大小，它们显示正常。我觉得这是一个常见的第一次定时器错误。有人遇到过这种情况么？知道修复可能是什么吗？下面列出了我认为是代码的相关部分。感谢您对此的任何和所有帮助......
I'm working with java images for the first time and having a problem viewing them when the applet loads. If I resize the window they display fine. I feel like this is a common first-timer error. Has anyone else encountered this? Any idea what the fix could be? What I believe to be the pertinent parts of the code are listed below. Thanks for any and all help with this...
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
import java.util.*;
public class example extends JApplet implements Runnable
{
boolean updating;
Thread thread;
private int width, height;
Table aTable; //used to create and store values
private AudioClip[] sounds = new AudioClip[4]; //array to hold audio clips
private int counter = 0; //counter for audio clip array
private Image GameImage;
private Graphics GameGraphics;
public example() //set up applet gui
{
this.resize(new Dimension(600, 500));
//setup table
aTable = new Table(50, 50, 50, 50, 16, 16, getImage("images/FLY.gif", Color.white),
getImage("images/FlySwatter.gif", Color.white)); //Table must be square or flyswatter wont move straight
//add cordTxtFlds to bottom of screen
//this.add(cordTxtFlds, BorderLayout.SOUTH);
super.resize(800, 600);
repaint();
}
public void init()
{
width = getSize().width;
height = getSize().height;
GameImage = createImage(width, height);
GameGraphics = GameImage.getGraphics();
// Automatic in some systems, not in others
GameGraphics.setColor(Color.black);
repaint();
validate();
//show the greeting
ImageIcon icon = new ImageIcon("images/FLY.gif",
"a fly");
repaint();
validate();
}
/** Description of paint(Graphics g)
*
* Function draws table and sets the table color
* @param g graphics object used to draw table
* @return void
*/
public void paint(Graphics g)
{
GameGraphics.clearRect(0, 0, getWidth(), getHeight());
aTable.draw(GameGraphics);
g.drawImage(GameImage, 0, 0, this);
}
public void update(Graphics g)
{
paint(g);
validate();
}
public void start()
{
thread = new Thread(this);
thread.start();
}
public void stop()
{
updating = false;
}
public void run()
{
while(updating)
{
aTable.update();
}
}
//returns a transparent image.
//color is made transparent
private Image getImage(String imgPath, final Color color)
{
Image img = Toolkit.getDefaultToolkit().getImage(imgPath);
ImageFilter filter = new RGBImageFilter() {
// the color we are looking for... Alpha bits are set to opaque
public int markerRGB = color.getRGB() | 0xFFFFFF;
public final int filterRGB(int x, int y, int rgb) {
if ( ( rgb | 0xFF000000 ) == markerRGB ) {
// Mark the alpha bits as zero - transparent
return 0x00FFFFFF & rgb;
}
else {
// nothing to do
return rgb;
}
}
};
ImageProducer ip = new FilteredImageSource(img.getSource(), filter);
img = Toolkit.getDefaultToolkit().createImage(ip);
return img;
}
}
和班级它处理绘图（在drawValues（）中）
and the class which handles the drawing (in drawValues())
import java.awt.*;
import java.util.Random;
public class Table extends Panel
{
private char[][]values = new char[10][10]; //probably better to use array of integer values(0 or 1)
private Point[]coordLoc;// = new Point[100]; //stores the x & y coordinates of points on the grid
private boolean[]itemMarker; //stores the truth value of wether or not an item
// is located at the coresponding point in cordLoc array
private int [][]coords;// = new int [100][2];
Image itemImg; // stores the item image
private int Rows; // stores number of rows
private int Columns; // stores number of columns
private int BoxWidth ; // stores the width of a box
private int BoxHeight; // stores the height of a box
public Point Pos = new Point(); // creates a new point to draw from
private int tableHeight; // stores the height of the table
private int tableWidth; // stores the width of the table
private int numOfGridLocs;
/** Description of public Table( x, y, width, height, col, rows, X, O)
*
* Constructor function
* @param x contains an x-coordinate of the table
* @param y contains a y-coordinate of the table
* @param width contains the width of a box in the table
* @param height contains the height of a box in the table
* @param col contains the number of columns in the table
* @param rows contains the number of rows in the table
* @param itemImg contains the "target" image ie: ant, fly, ... unicorn
* @return none
*/
public Table(int x, int y, int width, int height, int col, int rows, Image itemImg, Image swatterImg)
{
/*set values*/
numOfGridLocs = (col - 1) * (rows - 1);
//initialize arrays
coordLoc = new Point[numOfGridLocs];
for(int i = 0; i < numOfGridLocs; i++)
coordLoc[i] = new Point();
Rows = rows;
Columns = col;
BoxWidth = width;
BoxHeight = height;
Pos.x = x;
Pos.y = y;
this.itemImg = itemImg;
tableHeight = Rows*BoxHeight;
tableWidth = Columns*BoxWidth;
itemMarker = new boolean[numOfGridLocs];
coords = new int [numOfGridLocs][2];
this.setValues();
mapGrid();
}
/** Description of draw(Graphics g)
*
* Function draws the lines used in the table
* @param g object used to draw the table
* @return none
*/
public void draw(Graphics g)
{
Graphics2D g2=(Graphics2D)g;
//draw flyswatter
drawValues(g2); //draw values
//draw vertical table lines
for (int i = 0 ; i <= Columns ; i++)
{
//make center line thicker
if(i == Rows/2)
g2.setStroke(new BasicStroke(2));
else
g2.setStroke(new BasicStroke(1));
g2.drawLine(i*BoxWidth + Pos.x, Pos.y, i*BoxWidth + Pos.x, tableHeight+Pos.y);
}
//draw horizontal table line
for(int i = 0 ; i <= Rows ; i++)
{
//make center line thicker
if(i == Rows/2)
g2.setStroke(new BasicStroke(2));
else
g2.setStroke(new BasicStroke(1));
g2.drawLine(Pos.x, i*BoxHeight + Pos.y, tableWidth+Pos.x, i*BoxHeight + Pos.y);
}
drawLables(g);
}
/** Description of drawLables(Graphics g)
*
* Function draws the Lables of the Table
* @param g object used to draw the table
* @return none
*/
private void drawLables(Graphics g)
{
String Lable;
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
Font font = new Font("Serif", Font.PLAIN, 10);
g2.setFont(font);
int xLabel = this.Columns/2 * -1;
int yLabel = this.Rows/2;
//draw Row lables
for (int i = 0 ; i <= Rows ; i++)
{
Lable = "" + yLabel;
g2.drawString(Lable, Pos.x - 25, Pos.y + BoxHeight*i);
yLabel--;
}
//draw Column lables
for (int i = 0 ; i <= Columns ; i++)
{
Lable = "" + xLabel;
g2.drawString(Lable, Pos.x + BoxWidth*i - 5, Pos.y - 20 );
xLabel++;
}
}
/** Description of randomChangeFunc()
*
* Function randomly determines which table value to change
* @param none
* @return void
*/
public int getX(int XCordinate)
{
int x = XCordinate+Columns/2;
if(x < 0) x *= -1; //x must be positive
x *= BoxWidth;
x += Pos.x;
return x-BoxWidth/2;
}
//returns Position of Y-cordinate
public int getY(int YCordinate)
{
int y = YCordinate -Rows/2;
if (y < 0) y *= -1; //y must be positive
y *= BoxHeight;
y += Pos.y;
return y-BoxHeight/2;
}
/** Description of getValue( col, row )
*
* Function draws the lines used in the table
* @param col contains a column coordinate
* @param row contains a row coordinate
* @return returns table coordinates
*/
public char getValue(int col, int row)
{
return values[row][col];
}
/** Description of isDrawable( x, y )
*
* Function returns true if (x,y) is a point in the table
* @param x contains a table column
* @param y contains a table row
* @return boolean if (x,y) is a point in the table
*/
public boolean isDrawable(int x, int y)
{
if((this.getRow(y)!=-1)||(this.getColumn(x)!=-1))
return true;
else
return false;
}
private void drawValues(Graphics g)
{
for(int i = 0; i < numOfGridLocs; i++)
if(itemMarker[i])
g.drawImage(itemImg,coordLoc[i].x+1, coordLoc[i].y+1, BoxWidth-1, BoxHeight-1, null);
g.setColor(Color.black); // set color of table to black
}
//sets the randomized boolean values in itemMarker array
private void setValues()
{
double probOfItem = .25;
for(int count = 0; count < numOfGridLocs; count++){
itemMarker[count] = randomBool(probOfItem);
if(itemMarker[count])
System.out.println("true");
else
System.out.println("false");
}
}
//returns random boolean value, p is prob of 'true'
private boolean randomBool(double p)
{
return (Math.random() < p);
}
public int getColumn(int x)
{
x += (BoxWidth/2); //aTable.getX/Y returns in the middle of squares not at upper left point
int offsetx=0;
for (int i = 0 ; i < Columns*2 ; i++)
{
offsetx = i*BoxWidth;
if((x>=Pos.x+offsetx)&& (x<Pos.x+offsetx+BoxWidth))
return i-Columns;
}
return -100;
}
public int getRow(int y)
{
int offsety=0;
y += (BoxHeight/2); //aTable.getX/Y returns in the middle of squares not at upper left point
for (int i = 0 ; i < Rows*2 ; i++) {
offsety = i * BoxHeight;
if((y >= (offsety+Pos.y))&& (y < (offsety+BoxHeight+Pos.y)))
{
return ((i)*-1)+Rows;
}
}
return -100;
}
public boolean isValidGuess(int x, int y)
{
if ((x > Columns/2) || (x < Columns/2*-1) || (y > Rows/2) || (y < Rows/2*-1))
return false;
return true;
}
/** Description of randomChangeFunc()
*
* Function randomly determines which table value to change
* @param none
* @return void
*/
public void randomChangeFunc()
{
//get random row and column
Random rand=new Random();
int randRow = rand.nextInt(Rows); // gets and holds a random column
int randCol = rand.nextInt(Columns); // gets and holds a random column
System.out.println("randRow = " + randRow + " randCol = " + randCol);
if(values[randRow][randCol] == 'X')
values[randRow][randCol] = 'O';
else if(values[randRow][randCol] == 'O')
values[randRow][randCol] = 'X';
else
System.out.println("ERROR SWAPPING SQUARE VALUE"); // error message
}
private void mapGrid() //set values for coordLoc array
{
//set counter variables
int count = 0;
int index = 0;
//loop through all points, assigning them to the coordLoc array
for (int r=0; r < Rows-1; r++)
for (int c=0; c < Columns-1; c++) {
//the width/height / 2 places the points on grid line intersections, not the boxes they create
coordLoc[count].x = Pos.x + (BoxWidth) * c + (BoxWidth/2); // record x-point
coordLoc[count].y = Pos.y + (BoxHeight) * r + (BoxHeight/2); // record y-point
System.out.println(coordLoc[count].getX() + ", " + coordLoc[count].getY());
count++;
} //end inner for
//set positive x coord values for coords array
int y_axisBeginingIndex = (Rows - 2)/2;
for(int greaterIndex = 0; greaterIndex < ((Rows) / 2); greaterIndex++){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = y_axisBeginingIndex + greaterIndex + ((Rows - 1) * minorIndex);
coords[index][0] = greaterIndex;
}
}
//set negative x coord values for coords array
for(int greaterIndex = -1; greaterIndex > (0-((Rows) / 2)); greaterIndex--){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = y_axisBeginingIndex + greaterIndex + ((Rows - 1) * minorIndex);
coords[index][0] = greaterIndex;
}
}
//set positive y values for coords array
int x_axisBeginingIndex = (Rows - 1) * ((Rows / 2) - 1);
for(int greaterIndex = 0; greaterIndex < ((Rows) / 2); greaterIndex++){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = x_axisBeginingIndex + minorIndex;
coords[index][1] = greaterIndex;
}
x_axisBeginingIndex -= (Rows - 1);
}
//set negative y values for coords array
x_axisBeginingIndex = (Rows - 1) * ((Rows / 2) - 1) + (Rows - 1);
for(int greaterIndex = -1; greaterIndex > (0-((Rows) / 2)); greaterIndex--){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = x_axisBeginingIndex + minorIndex;
coords[index][1] = greaterIndex;
}
x_axisBeginingIndex += (Rows - 1);
}
//print out the x and y coords
for(int i = 0; i < numOfGridLocs; i++){
System.out.println("[" + i + "] -> x = " + coords[i][0] + " y = " + coords[i][1]);
}
}
public boolean thereIsAnItemAt(int index){
return itemMarker[index];
}
public boolean bugsLeft(){
boolean thereAreBugsLeft = false;
for(int i = 0; i < numOfGridLocs; i++)
if(itemMarker[i])
thereAreBugsLeft = true;
return thereAreBugsLeft;
}
void update()
{
this.repaint();
}
}
被困了好几个星期。再次感谢...
Been stumped on this for weeks. Thanks again...
推荐答案
答案是更改将JPanel扩展为paintComponent（）的类中的draw（）方法将drawImage（）调用中的最后一个参数切换为'this'而不是'null'。立即完美工作！
The answer is changing the draw() method in the class that extends JPanel to paintComponent() and switching the last parameter in the call to drawImage() to 'this' instead of 'null'. Worked instantly and perfectly!
这篇关于调整java applet中查看图像所需的大小的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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