如何在 Swing 中调整图像大小？
How to Resize an Image in Swing?
我已经学习了很多次如何在 Javax swing 中添加图像。
我用过容器和所有图像图标，但问题是我的照片太大，放不下。它们的尺寸超过 1800*1700 像素，屏幕显然无法容纳它们。
我会请你们提出一种缩小图像的方法。仅供参考，我已经尝试了其中的大部分方法，例如使用 awt Image、setBounds、SCALE_DEFAULT 等。
出于某种原因，我的 IDE，BlueJ 似乎无法使用建议的许多方法，但我仍然会请求您帮助我。
这是代码：
import javax.swing.*;
import java.awt.*;
class JLabelDemo
{
public JLabelDemo()
{
JFrame jfrm=new JFrame("Image from book");
jfrm.setLayout(new FlowLayout());
jfrm.setDefaultCloseOperation(jfrm.EXIT_ON_CLOSE);
jfrm.setSize(500,700);
ImageIcon ii=new ImageIcon("D:\Dhruv Rana\UNATIS Mandarmoni Trip\Sunrise.jpg");
JLabel jl=new JLabel("Background",ii,JLabel.CENTER);
jfrm.add(jl);
jfrm.setVisible(true);
}
public static void main(String [] args)
{
SwingUtilities.invokeLater(
new Runnable()
{
public void run()
{
new JLabelDemo();
}
}
);
}
}
将其放入缓冲图像
Graphics2D grph = image.createGraphics();
grph.scale(2.0, 2.0);
grph.dispose();
或者看看How to scale a BufferedImage
我想这取决于您是否要维护加载到 JLabel 中的图像的 Aspect Ratio。
无论如何，下面是一个考虑了宽高比的可运行文件，这样图像在显示时看起来就不会失真（拉长等）。 JFrame window 会根据图像纵横比自动调整大小，以便根据要显示的图像在纵向或横向中保持所需的窗体大小。如果图像是纵向格式，那么 JFrame window 也是。如果图像是横向格式，那么将 JFrame window.
两种有趣的方法是 resizeImageIcon() 和 getAspectRatioDimension() 方法。请务必阅读代码中的注释。
代码如下：
import java.awt.*;
import javax.swing.*;
public class JLabelDemo {
public JLabelDemo() {
int figNum = 1; // Image figure number (optional)
// Load in the Image
ImageIcon ii = new ImageIcon("D:\Dhruv Rana\UNATIS Mandarmoni Trip\Sunrise.jpg");
/* Get the Aspect Ratio of the image in relation to the
desired size of JFrame form (500 x 700) */
java.awt.Dimension aspectDimensions = getAspectRatioDimension(
ii.getIconWidth(), ii.getIconHeight(), 500, 700);
// Create the Window
JFrame jfrm = new JFrame("Image from book");
jfrm.setLayout(new FlowLayout());
jfrm.setAlwaysOnTop(true); // Form will always be on top of other wondows.
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
/* Set the form's size in accordance to the Aspect Ratio.
40 is added to the hieght so as to accommodate for the
JLabel text. */
jfrm.setSize(aspectDimensions.width, aspectDimensions.height + 40);
jfrm.setResizable(false); // Make form non-sizable
/* Resise the image in accordance to the Aspect Ratio
less 30 so as not to hug the edge of Window. */
ii = resizeImageIcon(ii, aspectDimensions.width - 30, aspectDimensions.height - 30);
// Create the JLabel and apply the image
JLabel jl = new JLabel("", ii, JLabel.CENTER);
// Un-comment if you want a border on the JLabel.
//jl.setBorder(BorderFactory.createLineBorder(Color.blue, 1));
// Set the JLabel text below the Image and at center.
jl.setVerticalTextPosition(JLabel.BOTTOM);
jl.setHorizontalTextPosition(JLabel.CENTER);
// Provide the JLabel text (basic HTML is used here to add a little pizaze)
jl.setText("<html><font size='2' color=gray><i>Figure " + figNum + ": Background</i></font></html>");
jfrm.add(jl);
jfrm.pack();
jfrm.setLocationRelativeTo(null); // Set window to center Screen.
jfrm.setVisible(true); // Display Window
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new JLabelDemo();
}
});
}
public static javax.swing.ImageIcon resizeImageIcon(javax.swing.ImageIcon icon, int resizedWidth, int resizedHeight) {
java.awt.Image img = icon.getImage();
java.awt.Image resizedImage = img.getScaledInstance(resizedWidth, resizedHeight, java.awt.Image.SCALE_SMOOTH);
return new javax.swing.ImageIcon(resizedImage);
}
/**
* This method will retrieve the required dimensions in order to maintain
* the aspect ratio between the original dimensions and the desired
* dimensions.<br><br>
* <p>
* <b>Example Usage:</b><pre>
*
* Dimension dim = getAspectRatioDimension(500, 300, 200, 200);
* System.out.println("Width = " + dim.width + " --- Height = " + dim.height);
* // Output will be: Width = 200 --- Height = 120</pre>
*
* @param currentWidth (Integer) The width of current dimension to convert
* from.
* @param currentHeight (Integer) The height of current dimension to convert
* from.
* @param desiredWidth (Integer) The width we want to convert to.
* @param desiredHeight (Integer) The height we want to convert to.
*
* @return (Dimension) The actual width & height dimensions we need to
* maintain the Aspect Ratio from the original current dimensions.
*/
public java.awt.Dimension getAspectRatioDimension(final int currentWidth,
final int currentHeight, final int desiredWidth, final int desiredHeight) {
int original_width = currentWidth;
int original_height = currentHeight;
int bound_width = desiredWidth;
int bound_height = desiredHeight;
int new_width = original_width;
int new_height = original_height;
// first check if we need to scale width
if (original_width > bound_width) {
//scale width to fit
new_width = bound_width;
//scale height to maintain aspect ratio
new_height = (new_width * original_height) / original_width;
}
// then check if we need to scale even with the new height
if (new_height > bound_height) {
//scale height to fit instead
new_height = bound_height;
//scale width to maintain aspect ratio
new_width = (new_height * original_width) / original_height;
}
return new java.awt.Dimension(new_width, new_height);
}
}
我已经学习了很多次如何在 Javax swing 中添加图像。 我用过容器和所有图像图标，但问题是我的照片太大，放不下。它们的尺寸超过 1800*1700 像素，屏幕显然无法容纳它们。 我会请你们提出一种缩小图像的方法。仅供参考，我已经尝试了其中的大部分方法，例如使用 awt Image、setBounds、SCALE_DEFAULT 等。 出于某种原因，我的 IDE，BlueJ 似乎无法使用建议的许多方法，但我仍然会请求您帮助我。 这是代码：
import javax.swing.*;
import java.awt.*;
class JLabelDemo
{
public JLabelDemo()
{
JFrame jfrm=new JFrame("Image from book");
jfrm.setLayout(new FlowLayout());
jfrm.setDefaultCloseOperation(jfrm.EXIT_ON_CLOSE);
jfrm.setSize(500,700);
ImageIcon ii=new ImageIcon("D:\Dhruv Rana\UNATIS Mandarmoni Trip\Sunrise.jpg");
JLabel jl=new JLabel("Background",ii,JLabel.CENTER);
jfrm.add(jl);
jfrm.setVisible(true);
}
public static void main(String [] args)
{
SwingUtilities.invokeLater(
new Runnable()
{
public void run()
{
new JLabelDemo();
}
}
);
}
}
将其放入缓冲图像
Graphics2D grph = image.createGraphics();
grph.scale(2.0, 2.0);
grph.dispose();
或者看看How to scale a BufferedImage
我想这取决于您是否要维护加载到 JLabel 中的图像的 Aspect Ratio。
无论如何，下面是一个考虑了宽高比的可运行文件，这样图像在显示时看起来就不会失真（拉长等）。 JFrame window 会根据图像纵横比自动调整大小，以便根据要显示的图像在纵向或横向中保持所需的窗体大小。如果图像是纵向格式，那么 JFrame window 也是。如果图像是横向格式，那么将 JFrame window.
两种有趣的方法是 resizeImageIcon() 和 getAspectRatioDimension() 方法。请务必阅读代码中的注释。
代码如下：
import java.awt.*;
import javax.swing.*;
public class JLabelDemo {
public JLabelDemo() {
int figNum = 1; // Image figure number (optional)
// Load in the Image
ImageIcon ii = new ImageIcon("D:\Dhruv Rana\UNATIS Mandarmoni Trip\Sunrise.jpg");
/* Get the Aspect Ratio of the image in relation to the
desired size of JFrame form (500 x 700) */
java.awt.Dimension aspectDimensions = getAspectRatioDimension(
ii.getIconWidth(), ii.getIconHeight(), 500, 700);
// Create the Window
JFrame jfrm = new JFrame("Image from book");
jfrm.setLayout(new FlowLayout());
jfrm.setAlwaysOnTop(true); // Form will always be on top of other wondows.
jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
/* Set the form's size in accordance to the Aspect Ratio.
40 is added to the hieght so as to accommodate for the
JLabel text. */
jfrm.setSize(aspectDimensions.width, aspectDimensions.height + 40);
jfrm.setResizable(false); // Make form non-sizable
/* Resise the image in accordance to the Aspect Ratio
less 30 so as not to hug the edge of Window. */
ii = resizeImageIcon(ii, aspectDimensions.width - 30, aspectDimensions.height - 30);
// Create the JLabel and apply the image
JLabel jl = new JLabel("", ii, JLabel.CENTER);
// Un-comment if you want a border on the JLabel.
//jl.setBorder(BorderFactory.createLineBorder(Color.blue, 1));
// Set the JLabel text below the Image and at center.
jl.setVerticalTextPosition(JLabel.BOTTOM);
jl.setHorizontalTextPosition(JLabel.CENTER);
// Provide the JLabel text (basic HTML is used here to add a little pizaze)
jl.setText("<html><font size='2' color=gray><i>Figure " + figNum + ": Background</i></font></html>");
jfrm.add(jl);
jfrm.pack();
jfrm.setLocationRelativeTo(null); // Set window to center Screen.
jfrm.setVisible(true); // Display Window
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new JLabelDemo();
}
});
}
public static javax.swing.ImageIcon resizeImageIcon(javax.swing.ImageIcon icon, int resizedWidth, int resizedHeight) {
java.awt.Image img = icon.getImage();
java.awt.Image resizedImage = img.getScaledInstance(resizedWidth, resizedHeight, java.awt.Image.SCALE_SMOOTH);
return new javax.swing.ImageIcon(resizedImage);
}
/**
* This method will retrieve the required dimensions in order to maintain
* the aspect ratio between the original dimensions and the desired
* dimensions.<br><br>
* <p>
* <b>Example Usage:</b><pre>
*
* Dimension dim = getAspectRatioDimension(500, 300, 200, 200);
* System.out.println("Width = " + dim.width + " --- Height = " + dim.height);
* // Output will be: Width = 200 --- Height = 120</pre>
*
* @param currentWidth (Integer) The width of current dimension to convert
* from.
* @param currentHeight (Integer) The height of current dimension to convert
* from.
* @param desiredWidth (Integer) The width we want to convert to.
* @param desiredHeight (Integer) The height we want to convert to.
*
* @return (Dimension) The actual width & height dimensions we need to
* maintain the Aspect Ratio from the original current dimensions.
*/
public java.awt.Dimension getAspectRatioDimension(final int currentWidth,
final int currentHeight, final int desiredWidth, final int desiredHeight) {
int original_width = currentWidth;
int original_height = currentHeight;
int bound_width = desiredWidth;
int bound_height = desiredHeight;
int new_width = original_width;
int new_height = original_height;
// first check if we need to scale width
if (original_width > bound_width) {
//scale width to fit
new_width = bound_width;
//scale height to maintain aspect ratio
new_height = (new_width * original_height) / original_width;
}
// then check if we need to scale even with the new height
if (new_height > bound_height) {
//scale height to fit instead
new_height = bound_height;
//scale width to maintain aspect ratio
new_width = (new_height * original_width) / original_height;
}
return new java.awt.Dimension(new_width, new_height);
}
}