Java:维护JPanel背景图像的纵横比
我有一个Java:维护JPanel背景图像的纵横比,java,swing,jpanel,background-image,aspect-ratio,Java,Swing,Jpanel,Background Image,Aspect Ratio,我有一个JPanel,它有一个绘制的背景图像和一个布局管理器,其中包含其他较小的图像,所有这些都在JFrame中。背景图像非常大,我希望它能够保持其纵横比,无论是在大屏幕还是小屏幕上 最后,我希望能够将我的LayoutManager及其单元格中的较小图像“粘贴”到背景图片上 我四处寻找资源,似乎许多示例都使用了缓冲图像,但我没有;这会造成问题吗?我将在下面发布我的代码来绘制图像,如果我缺少任何信息,请让我知道 public class MonitorPanel extends JPanel {
JPanel
,它有一个绘制的背景图像和一个布局管理器,其中包含其他较小的图像,所有这些都在JFrame
中。背景图像非常大,我希望它能够保持其纵横比,无论是在大屏幕还是小屏幕上
最后,我希望能够将我的LayoutManager
及其单元格中的较小图像“粘贴”到背景图片上
我四处寻找资源,似乎许多示例都使用了缓冲图像
,但我没有;这会造成问题吗?我将在下面发布我的代码来绘制图像,如果我缺少任何信息,请让我知道
public class MonitorPanel extends JPanel {
Image img;
public MonitorPanel() throws MalformedURLException {
//add components
try {
img = ImageIO.read(new File("src/customer_vlans.jpg"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
protected void paintComponent(Graphics g)
{
//paint background image
super.paintComponent(g);
//g.drawImage(img, 0, 0, getWidth(), getHeight(), this);
g.drawImage(img, 0, 0, this);
}
}
编辑:我应该提到,我知道纵横比公式: 原始高度/原始宽度x新宽度=新高度
但是,我不知道如何正确地使用它来为我带来好处。试试这样的方法:
import java.awt.*;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class SG2B2 {
JFrame frame;
public static void main(String[] args) {
SG2B2 gui = new SG2B2();
gui.createUI();
}
public void createUI() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyDrawPanel drawPanel = new MyDrawPanel();
frame.getContentPane().add(BorderLayout.CENTER, drawPanel);
frame.setSize(300, 400);
frame.setVisible(true);
}
class MyDrawPanel extends JPanel {
Image image;
private final String pic = "Logo.jpg";
public MyDrawPanel() {
image = new ImageIcon(pic).getImage();
image = scaleImage(image);
}
@Override
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.drawImage(image, 0, 0, this);
}
private Image scaleImage(Image rawImage) {
Image scaledImage = null;
System.out.println("Scaling");
try {
int rawImageWidth = rawImage.getWidth(this);
int rawImageHeight = rawImage.getHeight(this);
int paneWidth = (int) getWidth();
int paneHeight = (int) getHeight();
System.out.println("Image W = " + rawImageWidth
+ ", H = " + rawImageHeight
+ "; Pane W = " + paneWidth
+ ", H = " + paneHeight);
// preserve the original ratio
float widthRatio = (float) rawImageWidth / (float) paneWidth;
float heightRatio = (float) rawImageHeight / (float) paneHeight;
int widthFactor = -1;
int heightFactor = -1;
if ((widthRatio > heightRatio) && (widthRatio > 1.0)) {
widthFactor = paneWidth;
} else if ((heightRatio > widthRatio) && (heightRatio > 1.0)) {
heightFactor = paneHeight;
}
System.out.println("widthRatio = "
+ String.format("%.3f", widthRatio)
+ ", heightRatio = "
+ String.format("%.3f", heightRatio));
System.out.println("widthFactor = " + widthFactor
+ ", heightFactor = " + heightFactor);
if ((widthFactor < 0) && (heightFactor < 0)) {
scaledImage = rawImage;
} else {
scaledImage = rawImage.getScaledInstance(widthFactor, heightFactor,
Image.SCALE_SMOOTH);
// load the new image, 'getScaledInstance' loads asynchronously
MediaTracker tracker = new MediaTracker(this);
tracker.addImage(scaledImage, 0);
tracker.waitForID(0);
}
} catch (InterruptedException ie) {
System.err.println("load interrupt: " + ie.getMessage());
} catch (Exception e) {
e.printStackTrace();
}
return (scaledImage);
}
}
}
import java.awt.*;
导入javax.swing.ImageIcon;
导入javax.swing.JFrame;
导入javax.swing.JPanel;
公共级SG2B2{
JFrame框架;
公共静态void main(字符串[]args){
SG2B2 gui=新的SG2B2();
createUI();
}
public void createUI(){
frame=新的JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyDrawPanel drawPanel=新建MyDrawPanel();
frame.getContentPane().add(BorderLayout.CENTER,drawPanel);
框架。设置尺寸(300400);
frame.setVisible(true);
}
类MyDrawPanel扩展了JPanel{
图像;
私有最终字符串pic=“Logo.jpg”;
公共事务委员会(){
image=newimageicon(pic).getImage();
图像=缩放图像(图像);
}
@凌驾
公共组件(图形g){
图形2d g2=(图形2d)g;
g2.drawImage(图像,0,0,this);
}
专用图像缩放图像(图像rawImage){
图像缩放图像=空;
System.out.println(“缩放”);
试一试{
int rawImageWidth=rawImage.getWidth(这个);
int rawImageHeight=rawImage.getHeight(此值);
int paneWidth=(int)getWidth();
int paneHeight=(int)getHeight();
System.out.println(“图像W=“+rawImageWidth
+“,H=“+rawImageHeight
+“窗格W=“+窗格宽度”
+“,H=“+paneHeight);
//保持原来的比例
浮动宽度比率=(浮动)RAWMAGEEWITH/(浮动)窗格宽度;
浮动高度比率=(浮动)原始图像高度/(浮动)窗格高度;
整数宽度因子=-1;
整数高度因子=-1;
如果((宽度比>高度比)和&(宽度比>1.0)){
宽度系数=平面宽度;
}否则如果((高度比>宽度比)和&(高度比>1.0)){
高度系数=面板高度;
}
System.out.println(“宽度比=”
+字符串格式(“%.3f”,宽度比)
+,高度比=
+格式(“%.3f”,高度比));
System.out.println(“widthFactor=“+widthFactor
+“,heightFactor=“+heightFactor”);
如果((宽度系数<0)和(&(高度系数<0)){
缩放图像=原始图像;
}否则{
ScaleImage=rawImage.getScaledInstance(宽度因子、高度因子、,
图像。缩放(平滑);
//加载新映像,“GetScaleInstance”异步加载
MediaTracker=新的MediaTracker(此);
tracker.addImage(scaledImage,0);
tracker.waitForID(0);
}
}捕获(中断异常ie){
System.err.println(“加载中断:+ie.getMessage());
}捕获(例外e){
e、 printStackTrace();
}
返回(缩放图像);
}
}
}
通过使用
getScaledInstance(int-width,int-height,ImageObserver io)
最终将图像缩放到JPanel
的大小
g.drawImage(img.getScaledInstance(newWidth, -1, Image. SCALE_SMOOTH), x, y, this);
如果您想知道负数,java文档会说:
如果宽度或高度为负数,则值为
替换以保持原始图像的纵横比
尺寸。如果宽度和高度均为负值,则原始
使用图像尺寸
更新
作为旁注(我的谷歌正在播放)
getScaledInstance
既不是最快的方法,也不是最高质量的方法,但却是最简单的方法
通读一遍,了解更多的想法
更新
缩放图像以适应某个区域比简单地缩放纵横比稍微复杂一些。您必须选择是否希望图像“适合”该区域(可能在其周围留下空白区域)或“填充”该区域(使其最小尺寸适合该区域的最大尺寸)
装填
基本上,我使用比例因子
这将返回特定大小的比例因子。我用它来根据我需要的算法来决定我想要使用哪种因素
public static double getScaleFactor(int iMasterSize, int iTargetSize) {
double dScale = 1;
if (iMasterSize > iTargetSize) {
dScale = (double) iTargetSize / (double) iMasterSize;
} else {
dScale = (double) iTargetSize / (double) iMasterSize;
}
return dScale;
}
这两种方法都使用它。它们只需要两个维度
s。原作和目标
public static double getScaleFactorToFit(Dimension original, Dimension toFit) {
double dScale = 1d;
if (original != null && toFit != null) {
double dScaleWidth = getScaleFactor(original.width, toFit.width);
double dScaleHeight = getScaleFactor(original.height, toFit.height);
dScale = Math.min(dScaleHeight, dScaleWidth);
}
return dScale;
}
public static double getScaleFactorToFill(Dimension masterSize, Dimension targetSize) {
double dScaleWidth = getScaleFactor(masterSize.width, targetSize.width);
double dScaleHeight = getScaleFactor(masterSize.height, targetSize.height);
double dScale = Math.max(dScaleHeight, dScaleWidth);
return dScale;
}
将图像传递到中(直接或通过支持方法)相对简单。例如,您可以在paint
方法中调用它
double factor getScaledFactorToFit(new Dimension(image.getWidth(), image.getHeight()), getSize());
int scaledWidth = image.getWidth() * scale;
int scaledHeight *= image.getWidth() * scale;
这将自动为您考虑纵横比;)
<
public double getScaleFactor(int iMasterSize, int iTargetSize) {
double dScale = 1;
if (iMasterSize > iTargetSize) {
dScale = (double) iTargetSize / (double) iMasterSize;
} else {
dScale = (double) iTargetSize / (double) iMasterSize;
}
return dScale;
}
public double getScaleFactorToFit(Dimension original, Dimension toFit) {
double dScale = 1d;
if (original != null && toFit != null) {
double dScaleWidth = getScaleFactor(original.width, toFit.width);
double dScaleHeight = getScaleFactor(original.height, toFit.height);
dScale = Math.min(dScaleHeight, dScaleWidth);
}
return dScale;
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
double scaleFactor = Math.min(1d, getScaleFactorToFit(new Dimension(image.getWidth(), image.getHeight()), getSize()));
int scaleWidth = (int) Math.round(image.getWidth() * scaleFactor);
int scaleHeight = (int) Math.round(image.getHeight() * scaleFactor);
Image scaled = image.getScaledInstance(scaleWidth, scaleHeight, Image.SCALE_SMOOTH);
int width = getWidth() - 1;
int height = getHeight() - 1;
int x = (width - scaled.getWidth(this)) / 2;
int y = (height - scaled.getHeight(this)) / 2;
g.drawImage(scaled, x, y, this);
}
@Override
protected void paintComponent(Graphics g) {
Graphics2D g2d = (Graphics2D) g;
super.paintComponent(g);
double scaleFactor = Math.min(1d, getScaleFactorToFit(new Dimension(image.getWidth(), image.getHeight()), getSize()));
int scaleWidth = (int) Math.round(image.getWidth() * scaleFactor);
int scaleHeight = (int) Math.round(image.getHeight() * scaleFactor);
//Image scaled = image.getScaledInstance(scaleWidth, scaleHeight, Image.SCALE_SMOOTH);
int width = getWidth() - 1;
int height = getHeight() - 1;
int x = (width - scaleWidth) / 2;
int y = (height - scaleHeight) / 2;
g2d.drawImage(image, x, y, scaleWidth, scaleHeight, this);
}
public class ImageLabel extends JPanel {
private Image image = null;
public void setImage(Image img) {
image = img;
repaint();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image != null) {
int imgWidth, imgHeight;
double contRatio = (double) getWidth() / (double) getHeight();
double imgRatio = (double) image.getWidth(this) / (double) image.getHeight(this);
//width limited
if(contRatio < imgRatio){
imgWidth = getWidth();
imgHeight = (int) (getWidth() / imgRatio);
//height limited
}else{
imgWidth = (int) (getHeight() * imgRatio);
imgHeight = getHeight();
}
//to center
int x = (int) (((double) getWidth() / 2) - ((double) imgWidth / 2));
int y = (int) (((double) getHeight()/ 2) - ((double) imgHeight / 2));
g.drawImage(image, x, y, imgWidth, imgHeight, this);
}
}
}