尝试仅从活动的浏览器/窗口捕获屏幕截图时，任务栏上会显示屏幕底部的其他窗口或其他打开的应用程序（最小化）。
那么如何只从主动/光标聚焦的浏览器中捕获并忽略屏幕截图中任务底部的其他窗口
以下是我到目前为止所编写的用于捕获屏幕截图的代码，但它仍然捕获了屏幕截图中的其他打开的应用程序。
Dimension d = new Dimension(Toolkit.getDefaultToolkit().getScreenSize());
int width = (int) d.getWidth();
int height = (int) d.getHeight();
Image image = robot.createScreenCapture(new Rectangle(0, 0, width,
height));
BufferedImage bi = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = bi.createGraphics();
g.drawImage(image, 0, 0, width, height, null);
String fileNameToSaveTo = "D:/Pictures/" + PictureName + "_"
+ createTimeStampStr() + ".PNG";
writeImage(bi, fileNameToSaveTo, "PNG");
System.out.println("Screen Captured Successfully and Saved to:\n"+fileNameToSaveTo);
答案 0 :(得分：2)
解决方案是不捕获整个屏幕，而只捕获保存您感兴趣的窗口的矩形。要获得此窗口，您需要超越Java，例如使用第三方实用程序，或通过JNI或JNA。我已经使用JNA成功完成了这项工作。我发布了我的代码，但它是在超过100个类的大型项目中。
我可以展示我使用的一些特定的类和接口，但它们都是旧的而不是“专业品质”：
User32.java
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.platform.win32.BaseTSD.LONG_PTR;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinDef.RECT;
import com.sun.jna.win32.StdCallLibrary;
public interface User32 extends StdCallLibrary {
User32 INSTANCE = (User32) Native.loadLibrary("user32", User32.class);
interface WNDENUMPROC extends StdCallCallback {
boolean callback(Pointer hWnd, Pointer arg);
}
public static final int GW_OWNER = 4; // used with GetWindow to get win owner
public static final int GW_HWNDNEXT = 2; // used with GetNextWindow
public static final int GA_ROOT = 2; // used with GetAncestor
public static final int GWL_EXSTYLE = -20; // used with GetWindowLong
public static final long WS_EX_APPWINDOW = 0x00040000L;
public static final Pointer HWND_TOP = new Pointer(0L); // used with
// SetWindowPos
boolean EnumWindows(WNDENUMPROC lpEnumFunc, Pointer userData);
int GetWindowTextA(Pointer hWnd, byte[] lpString, int nMaxCount);
int SetForegroundWindow(Pointer hWnd);
Pointer GetForegroundWindow();
boolean GetWindowRect(Pointer hWnd, RECT rect);
boolean SetWindowPos(Pointer hWnd, Pointer hWndInsertAfter, int x, int y,
int cx, int cy, int uFlags);
boolean MoveWindow(Pointer hWnd, int x, int y, int nWidth, int nHeight, boolean bRepaint);
boolean IsWindow(Pointer hWnd);
Pointer GetWindow(Pointer hWnd, int uCmd);
LONG_PTR GetWindowLongPtr(HWND hWnd, int nIndex);
Pointer GetParent(Pointer hWnd);
Pointer GetAncestor(Pointer hWnd, int gaFlags);
boolean IsWindowVisible(Pointer hWnd);
}
JnaUtilException.java
public class JnaUtilException extends Exception {
private static final long serialVersionUID = 1L;
public JnaUtilException(String text) {
super(text);
}
}
JnaUtil.java
import java.awt.AWTException;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
import com.sun.jna.platform.win32.BaseTSD.LONG_PTR;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinDef.RECT;
/**
* static methods to allow Java to call Windows code. user32.dll code is as
* specified in the JNA interface User32.java
*
* @author Pete S
*
*/
public class JnaUtil {
private static final User32 user32 = User32.INSTANCE;
private static Pointer callBackHwnd;
public static boolean windowExists(final String startOfWindowName) {
return !user32.EnumWindows(new User32.WNDENUMPROC() {
@Override
public boolean callback(Pointer hWnd, Pointer userData) {
byte[] windowText = new byte[512];
user32.GetWindowTextA(hWnd, windowText, 512);
String wText = Native.toString(windowText).trim();
if (!wText.isEmpty() && wText.startsWith(startOfWindowName)) {
return false;
}
return true;
}
}, null);
}
public static List<String> getAllWindowNames() {
final List<String> windowNames = new ArrayList<String>();
user32.EnumWindows(new User32.WNDENUMPROC() {
@Override
public boolean callback(Pointer hWnd, Pointer arg) {
byte[] windowText = new byte[512];
user32.GetWindowTextA(hWnd, windowText, 512);
String wText = Native.toString(windowText).trim();
if (!wText.isEmpty()) {
windowNames.add(wText);
}
return true;
}
}, null);
return windowNames;
}
public static boolean windowExists(Pointer hWnd) {
return user32.IsWindow(hWnd);
}
public static Pointer getWinHwnd(final String startOfWindowName) {
callBackHwnd = null;
user32.EnumWindows(new User32.WNDENUMPROC() {
@Override
public boolean callback(Pointer hWnd, Pointer userData) {
byte[] windowText = new byte[512];
user32.GetWindowTextA(hWnd, windowText, 512);
String wText = Native.toString(windowText).trim();
if (!wText.isEmpty() && wText.startsWith(startOfWindowName)) {
callBackHwnd = hWnd;
return false;
}
return true;
}
}, null);
return callBackHwnd;
}
public static boolean setForegroundWindow(Pointer hWnd) {
return user32.SetForegroundWindow(hWnd) != 0;
}
public static Pointer getForegroundWindow() {
return user32.GetForegroundWindow();
}
public static String getForegroundWindowText() {
Pointer hWnd = getForegroundWindow();
int nMaxCount = 512;
byte[] lpString = new byte[nMaxCount];
int getWindowTextResult = user32
.GetWindowTextA(hWnd, lpString, nMaxCount);
if (getWindowTextResult == 0) {
return "";
}
return Native.toString(lpString);
}
public static boolean isForegroundWindow(Pointer hWnd) {
return user32.GetForegroundWindow().equals(hWnd);
}
public static boolean setForegroundWindow(String startOfWindowName) {
Pointer hWnd = getWinHwnd(startOfWindowName);
return user32.SetForegroundWindow(hWnd) != 0;
}
public static Rectangle getWindowRect(Pointer hWnd) throws JnaUtilException {
if (hWnd == null) {
throw new JnaUtilException(
"Failed to getWindowRect since Pointer hWnd is null");
}
Rectangle result = null;
RECT rect = new RECT();
boolean rectOK = user32.GetWindowRect(hWnd, rect);
if (rectOK) {
int x = rect.left;
int y = rect.top;
int width = rect.right - rect.left;
int height = rect.bottom - rect.top;
result = new Rectangle(x, y, width, height);
}
return result;
}
/**
* set window at x and y position with w and h width. Set on top of z-order
*
* @param hWnd
* @param x
* @param y
* @param w
* @param h
* @return boolean -- did it work?
*/
public static boolean setWindowPos(Pointer hWnd, int x, int y, int w, int h) {
int uFlags = 0;
return user32.SetWindowPos(hWnd, User32.HWND_TOP, x, y, w, h, uFlags);
}
public static boolean moveWindow(Pointer hWnd, int x, int y, int nWidth,
int nHeight) {
boolean bRepaint = true;
return user32.MoveWindow(hWnd, x, y, nWidth, nHeight, bRepaint );
}
public static Rectangle getWindowRect(String startOfWindowName)
throws JnaUtilException {
Pointer hWnd = getWinHwnd(startOfWindowName);
if (hWnd != null) {
return getWindowRect(hWnd);
} else {
throw new JnaUtilException("Failed to getWindowRect for \""
+ startOfWindowName + "\"");
}
}
public static Pointer getWindow(Pointer hWnd, int uCmd) {
return user32.GetWindow(hWnd, uCmd);
}
public static String getWindowText(Pointer hWnd) {
int nMaxCount = 512;
byte[] lpString = new byte[nMaxCount];
int result = user32.GetWindowTextA(hWnd, lpString, nMaxCount);
if (result == 0) {
return "";
}
return Native.toString(lpString);
}
public static Pointer getOwnerWindow(Pointer hWnd) {
return user32.GetWindow(hWnd, User32.GW_OWNER);
}
public static String getOwnerWindow(String childTitle) {
Pointer hWnd = getWinHwnd(childTitle);
Pointer parentHWnd = getOwnerWindow(hWnd);
if (parentHWnd == null) {
return "";
}
return getWindowText(parentHWnd);
}
public static Pointer getNextWindow(Pointer hWnd) {
if (hWnd == null) {
return null;
}
return user32.GetWindow(hWnd, User32.GW_HWNDNEXT);
}
public static boolean isWindowVisible(Pointer hWnd) {
return user32.IsWindowVisible(hWnd);
}
public static Pointer getParent(Pointer hWnd) {
return user32.GetParent(hWnd);
}
public static Pointer getRoot(Pointer hWnd) {
return user32.GetAncestor(hWnd, User32.GA_ROOT);
}
public static LONG_PTR getWindowLongPtr(Pointer hWndP, int nIndex) {
HWND hwnd = new HWND(hWndP);
return user32.GetWindowLongPtr(hwnd, nIndex);
}
public static void main(String[] args) throws InterruptedException {
List<String> winNameList = getAllWindowNames();
for (String winName : winNameList) {
System.out.println(winName);
}
String[] testStrs = { "Untitled-Notepad", "Untitled - Notepad",
"Untitled - Notepad", "Java-Epic", "Java - Epic", "Fubars rule!",
"The First Night", "New Tab", "Citrix X", "EHR PROD - SVC" };
for (String testStr : testStrs) {
Pointer hWnd = getWinHwnd(testStr);
boolean isWindow = windowExists(hWnd);
System.out.printf("%-22s %5b %16s %b%n", testStr,
windowExists(testStr), hWnd, isWindow);
}
String ehrProd = "EHR PROD - SVC";
Pointer hWnd = getWinHwnd(ehrProd);
System.out
.println("is it foreground window? " + isForegroundWindow(hWnd));
boolean foo = setForegroundWindow(ehrProd);
System.out.println("foregroundwindow: " + foo);
Thread.sleep(400);
System.out
.println("is it foreground window? " + isForegroundWindow(hWnd));
Thread.sleep(1000);
System.out.println("here A");
try {
Rectangle rect = getWindowRect(ehrProd);
System.out.println("rect: " + rect);
Robot robot = new Robot();
System.out.println("here B");
BufferedImage img = robot.createScreenCapture(rect);
System.out.println("here C, img is " + img);
Thread.sleep(500);
ImageIcon icon = new ImageIcon(img);
System.out.println("here D. icon is null? " + icon);
Thread.sleep(500);
final JLabel label = new JLabel(icon);
System.out.println("here E. label is null? " + label);
Thread.sleep(500);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
System.out.println("here F");
JOptionPane.showMessageDialog(null, label);
System.out.println("here G");
}
});
} catch (AWTException e) {
e.printStackTrace();
} catch (JnaUtilException e) {
e.printStackTrace();
}
}
}
方法JnaUtil.getWindowRect(hWnd);获取矩形并按如下方式使用：
new SwingWorker<Void, ImageIcon>() {
protected Void doInBackground() throws Exception {
Pointer hWnd = JnaUtil.getWinHwnd(winText);
if (hWnd == null) {
String errTxt = "Application Window \"" + winText
+ "\" not open. Try again";
JOptionPane.showMessageDialog(pollingGui.getMainPanel(), errTxt,
"App Not Found", JOptionPane.ERROR_MESSAGE);
return null;
}
try {
rect = JnaUtil.getWindowRect(hWnd);
fullWindowText = JnaUtil.getWindowText(hWnd);