Class Robot

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public class Robot

extends java.lang.Object

Comparing jdk-20-ga and jdk-21+35

public class Robot extends Object

This class is used to generate native system input events for the purposes of test automation, self-running demos, and other applications where control of the mouse and keyboard is needed. The primary purpose of Robot is to facilitate automated testing of Java platform implementations.

Using the class to generate input events differs from posting events to the AWT event queue or AWT components in that the events are generated in the platform's native input queue. For example, Robot.mouseMove will actually move the mouse cursor instead of just generating mouse move events.

Note that some platforms require special privileges or extensions to access low-level input control. If the current platform configuration does not allow input control, an AWTException will be thrown when trying to construct Robot objects. For example, X-Window systems will throw the exception if the XTEST 2.2 standard extension is not supported (or not enabled) by the X server.

Applications that use Robot for purposes other than self-testing should handle these error conditions gracefully.

Platforms and desktop environments may impose restrictions or limitations on the access required to implement all functionality in the Robot class. For example:

preventing access to the contents of any part of a desktop or Window on the desktop that is not owned by the running application.
treating window decorations as non-owned content.
ignoring or limiting specific requests to manipulate windows.
ignoring or limiting specific requests for Robot generated (synthesized) events related to keyboard and mouse etc.
requiring specific or global permissions to any access to window contents, even application owned content,or to perform even limited synthesizing of events.

The Robot API specification requires that approvals for these be granted for full operation. If they are not granted, the API will be degraded as discussed here. Relevant specific API methods may document more specific limitations and requirements. Depending on the policies of the desktop environment, the approvals mentioned above may:

be required every time
or persistent for the lifetime of an application,
or persistent across multiple user desktop sessions
be fine-grained permissions
be associated with a specific binary application, or a class of binary applications.

When such approvals need to given interactively, it may impede the normal operation of the application until approved, and if approval is denied or not possible, or cannot be made persistent then it will degrade the functionality of this class and in turn any part of the operation of the application which is dependent on it.

Since:: 1.3

Constructors

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public Robot() throws java.awt.AWTException
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public Robot(java.awt.GraphicsDevice arg0) throws java.awt.AWTException

Methods

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public java.awt.image.MultiResolutionImage createMultiResolutionScreenCapture(java.awt.Rectangle arg0)
Comparing jdk-20-ga and jdk-21+35
createMultiResolutionScreenCapture

public MultiResolutionImage createMultiResolutionScreenCapture (Rectangle screenRect)

Creates an image containing pixels read from the screen. This image does not include the mouse cursor. This method can be used in case there is a scaling transform from user space to screen (device) space. Typically this means that the display is a high resolution screen, although strictly it means any case in which there is such a transform. Returns a MultiResolutionImage .
For a non-scaled display, the MultiResolutionImage will have one image variant:
Base Image with user specified size.

For a high resolution display where there is a scaling transform, the MultiResolutionImage will have two image variants:
Base Image with user specified size. This is scaled from the screen.
Native device resolution image with device size pixels.

Example:
Image nativeResImage; MultiResolutionImage mrImage = robot.createMultiResolutionScreenCapture(frame.getBounds()); List<Image> resolutionVariants = mrImage.getResolutionVariants(); if (resolutionVariants.size() > 1) { nativeResImage = resolutionVariants.get(1); } else { nativeResImage = resolutionVariants.get(0); }

Parameters:

screenRect - Rect to capture in screen coordinates

Returns:

The captured image

Throws:

IllegalArgumentException - if screenRect width and height are not greater than zero

SecurityException - if readDisplayPixels permission is not granted, or access to the screen is denied by the desktop environment

Since:

9

See Also:

SecurityManager.checkPermission(java.security.Permission)
AWTPermission
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public java.awt.image.BufferedImage createScreenCapture(java.awt.Rectangle arg0)
Comparing jdk-20-ga and jdk-21+35
createScreenCapture

public BufferedImage createScreenCapture (Rectangle screenRect)

Creates an image containing pixels read from the screen. This image does not include the mouse cursor.
If the desktop environment requires that permissions be granted to capture screen content, and the required permissions are not granted, then a SecurityException may be thrown, or the contents of the returned BufferedImage are undefined.

API Note:

It is recommended to avoid calling this method on the AWT Event Dispatch Thread since screen capture may be a lengthy operation, particularly if acquiring permissions is needed and involves user interaction.

Parameters:

screenRect - Rect to capture in screen coordinates

Returns:

The captured image

Throws:

IllegalArgumentException - if screenRect width and height are not greater than zero

SecurityException - if readDisplayPixels permission is not granted, or access to the screen is denied by the desktop environment

See Also:

SecurityManager.checkPermission(java.security.Permission)
AWTPermission
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public void delay(int arg0)
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public int getAutoDelay()
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public java.awt.Color getPixelColor(int arg0, int arg1)

Comparing jdk-20-ga and jdk-21+35

getPixelColor

public Color getPixelColor (int x, int y)

Returns the color of a pixel at the given screen coordinates.
Moved to a paragraph. If the desktop environment requires that permissions be granted to capture screen content, and the required permissions are not granted, then a SecurityException may be thrown, or the content of the returned Color is undefined.

API Note:

It is recommended to avoid calling this method on the AWT Event Dispatch Thread since screen capture may be a lengthy operation, particularly if acquiring permissions is needed and involves user interaction.

Parameters:

x - X position of pixel

y - Y position of pixel

Returns:

Color of the pixel

Throws:

SecurityException - if readDisplayPixels permission is not granted, or access to the screen is denied by the desktop environment
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public boolean isAutoWaitForIdle()
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public void keyPress(int arg0)
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public void keyRelease(int arg0)
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public void mouseMove(int arg0, int arg1)
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public void mousePress(int arg0)
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public void mouseRelease(int arg0)
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public void mouseWheel(int arg0)
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public void setAutoDelay(int arg0)
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public void setAutoWaitForIdle(boolean arg0)
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public java.lang.String toString()
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public void waitForIdle()

Summary

Differences
	Added	Added	Added	Changed	Removed	Total
	Elements	Comments	Descriptions			Total
Robot			3			3
createMultiResolutionScreenCapture(Rectangle)			2		1	3
createScreenCapture(Rectangle)			1		1	2
getPixelColor(int,int)			4	1		5
Total			10	1	2	13

Class Robot

Constructors

Methods

createMultiResolutionScreenCapture

createScreenCapture

getPixelColor

Summary