org.eclipse.swt.widgets.Event Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2000, 2022 IBM Corporation and others.
*
* This program and the accompanying materials
* are made available under the terms of the Eclipse Public License 2.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-2.0/
*
* SPDX-License-Identifier: EPL-2.0
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.widgets;
import org.eclipse.swt.graphics.*;
/**
* Instances of this class provide a description of a particular
* event which occurred within SWT. The SWT untyped listener
* API uses these instances for all event dispatching.
*
* Note: For a given event, only the fields which are appropriate
* will be filled in. The contents of the fields which are not used
* by the event are unspecified.
*
*
* @see Listener
* @see org.eclipse.swt.events.TypedEvent
* @see SWT Example: ControlExample, Listeners
* @see Sample code and further information
*/
public class Event {
/**
* the display where the event occurred
*
* @since 2.0
*/
public Display display;
/**
* the widget that issued the event
*/
public Widget widget;
/**
* the type of event, as defined by the event type constants
* in class SWT
*
* @see org.eclipse.swt.SWT
*/
public int type;
/**
* the event specific detail field, as defined by the detail constants
* in class SWT
*
* @see org.eclipse.swt.SWT
*/
public int detail;
/**
* the item that the event occurred in (can be null)
*/
public Widget item;
/**
* the index of the item where the event occurred
*
* @since 3.2
*/
public int index;
/**
* the graphics context to use when painting
* that is configured to use the colors, font and
* damaged region of the control. It is valid
* only during the paint and must not be disposed
*/
public GC gc;
/**
* depending on the event type, the x offset of the bounding
* rectangle of the region that requires painting or the
* widget-relative, x coordinate of the pointer at the
* time the mouse button was pressed or released
*/
public int x;
/**
* depending on the event type, the y offset of the bounding
* rectangle of the region that requires painting or the
* widget-relative, y coordinate of the pointer at the
* time the mouse button was pressed or released
*/
public int y;
/**
* the width of the bounding rectangle of the
* region that requires painting
*/
public int width;
/**
* the height of the bounding rectangle of the
* region that requires painting
*/
public int height;
/**
* depending on the event type, the number of following
* paint events that are pending which may always be zero
* on some platforms, or the number of lines or pages to
* scroll using the mouse wheel, or the number of times the
* mouse has been clicked
*/
public int count;
/**
* the time that the event occurred.
*
* NOTE: This field is an unsigned integer and should
* be AND'ed with 0xFFFFFFFFL so that it can be treated
* as a signed long.
*/
public int time;
/**
* the button that was pressed or released; 1 for the
* first button, 2 for the second button, and 3 for the
* third button, etc.
*/
public int button;
/**
* depending on the event, the character represented by the key
* that was typed. This is the final character that results
* after all modifiers have been applied. For example, when the
* user types Ctrl+A, the character value is 0x01 (ASCII SOH).
* It is important that applications do not attempt to modify the
* character value based on a stateMask (such as SWT.CTRL) or the
* resulting character will not be correct.
*/
public char character;
/**
* character that is good for keyboard shortcut comparison. Unlike
* {@link #character}, this tries to ignore modifier keys and deal
* with non-latin keyboard layouts.
* Examples:
*
* Layout US key label character keyCode Windows English US C 'c' 'c' Windows English US Shift+C 'C' 'c' Windows English US Ctrl+C 0x03 'c' Windows English Dvorak I 'c' 'c' Windows Bulgarian Ъ 'ъ' 'c' Windows French 2 'é' '2' Windows French Shift+2 '2' '2'
*
* How it is done differs per platform, and on many platforms,
* SWT resorts to various magic. To understand the problem,
* consider the following questions about the well known
* Ctrl+C shortcut:
*
* - Which key invokes Ctrl+C in English? Well, that's easy, key
* C does it.
* - Dvorak is basically an English layout, but with keys
* shuffled around. Where English has C, Dvorak has J. Where
* English has I, Dvorak has C. Which key invokes Ctrl+C in
* English-Dvorak? Well, both answers are kind of correct.
* There's a heated debate on the internet which answer is better:
* some argue that they like English shortcuts they learned
* before they decided to try Dvorak. Others argue that key
* labels shall match invoked shortcuts. The usually preferred
* answer is that if a key types C in Dvorak, then it shall
* invoke Ctrl+C. That is, the key that is labeled I in English.
* - Which key invokes Ctrl+C in non-latin keyboard layouts?
* That's where it gets hard. Consider Hebrew, Cyrillic,
* Japanese. These layouts simply don't have latin C anywhere!
*
* Approaching all 3 questions at once is non-trivial, and each OS
* does it in a different way. In very simple words:
*
* - Windows keyboard layouts have an additional invisible
* mapping of keys to keyboard shortcuts, completely independent
* from characters typed by these keys. Layouts also have the
* regular mapping of keys to produced characters. Both are
* edited in keyboard layout editors.
* - macOS keyboard layouts have hidden Latin sub-layouts and
* switch to them when a modifier such as Cmd is pressed. This
* is easy to see in builtin on-screen keyboard. It's a lot more
* complicated with modifiers other than Cmd and Ctrl.
* - Linux is worst. It lacks the information to map shortcuts
* on non-latin keyboards and resorts to inspecting other
* installed layouts to find something latin.
*
*
* For detailed information, see {@link Widget#setKeyState} per
* platform.
*
*
* @see org.eclipse.swt.SWT
*/
/*
* For debugging, see
*
* - Unit tests Test_org_eclipse_swt_events_KeyEvent
* - Files with names containing 'Issue0351_EventKeyCode'
*
*/
public int keyCode;
/**
* depending on the event, the location of key specified by the
* keyCode or character. The possible values for this field are
* SWT.LEFT, SWT.RIGHT, SWT.KEYPAD,
* or SWT.NONE representing the main keyboard area.
*
* The location field can be used to differentiate key events that have
* the same key code and character but are generated by different keys
* in the keyboard. For example, a key down event with the key code equals
* to SWT.SHIFT can be generated by the left and the right shift keys in the
* keyboard. The location field can only be used to determine the location
* of the key code or character in the current event. It does not
* include information about the location of modifiers in state
* mask.
*
*
* @see org.eclipse.swt.SWT#LEFT
* @see org.eclipse.swt.SWT#RIGHT
* @see org.eclipse.swt.SWT#KEYPAD
*
* @since 3.6
*/
public int keyLocation;
/**
* depending on the event, the state of the keyboard modifier
* keys and mouse masks at the time the event was generated.
*
* @see org.eclipse.swt.SWT#MODIFIER_MASK
* @see org.eclipse.swt.SWT#BUTTON_MASK
*/
public int stateMask;
/**
* depending on the event, the range of text being modified.
* Setting these fields only has effect during ImeComposition
* events.
*/
public int start, end;
/**
* depending on the event, the new text that will be inserted.
* Setting this field will change the text that is about to
* be inserted or deleted.
*/
public String text;
/**
* Bidi segment offsets
* @since 3.8
*/
public int[] segments;
/**
* Characters to be applied on the segment boundaries
* @since 3.8
*/
public char[] segmentsChars;
/**
* depending on the event, a flag indicating whether the operation
* should be allowed. Setting this field to false will cancel the
* operation.
*/
public boolean doit = true;
/**
* a field for application use
*/
public Object data;
/**
* An array of the touch states for the current touch event.
*
* @since 3.7
*/
public Touch[] touches;
/**
* If nonzero, a positive value indicates a swipe to the right,
* and a negative value indicates a swipe to the left.
*
* @since 3.7
*/
public int xDirection;
/**
* If nonzero, a positive value indicates a swipe in the up direction,
* and a negative value indicates a swipe in the down direction.
*
* @since 3.7
*/
public int yDirection;
/**
* The change in magnification. This value should be added to the current
* scaling of an item to get the new scale factor.
*
* @since 3.7
*/
public double magnification;
/**
* The number of degrees rotated on the track pad.
*
* @since 3.7
*/
public double rotation;
/**
* Gets the bounds.
*
* @return a rectangle that is the bounds.
*/
public Rectangle getBounds () {
return new Rectangle (x, y, width, height);
}
Point getLocation () {
return new Point (x, y);
}
/**
* Sets the bounds.
*
* @param rect the new rectangle
*/
public void setBounds (Rectangle rect) {
this.x = rect.x;
this.y = rect.y;
this.width = rect.width;
this.height = rect.height;
}
void setLocation (int x, int y) {
this.x = x;
this.y = y;
}
/**
* Returns a string containing a concise, human-readable
* description of the receiver.
*
* @return a string representation of the event
*/
@Override
public String toString () {
return "Event {type=" + type + " " + widget + " time=" + time + " data=" + data + " x=" + x + " y=" + y + " width=" + width + " height=" + height + " detail=" + detail + "}"; //$NON-NLS-1$//$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$ //$NON-NLS-6$ //$NON-NLS-7$
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy