| MouseWheelEvent |
|
typedict |
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A
MouseWheelEvent
indicates that a mouse equipped with a wheel is being used
and the wheel was rotated.
The fields in a
MouseWheelEvent
are:
| clickcount |
An
int
that is the number of mouse clicks associated with the event.
The value stored in this field currently is system dependent,
which means it should not be used for scrolling calculations.
| | coordinates |
A
Point
that indicates where the pointer was at the time of the event.
The
coordinates
and
location
fields may or may not match, but
coordinates
should only be used by event handlers that are defined in drawable objects
(i.e., components that define a
graphics
field).
In that case
coordinates
will be the location of the pointer in the coordinate system described by
the drawable object's
graphics.CTM
at the time the event arrived, otherwise
coordinates
and
location
will match.
coordinates
is ignored when a
MouseWheelEvent
is sent to another component using
postEvent.
| | id |
An
Object
that must be an
int
or
String,
that identifies the type of this event.
A value that is a
String
must be the name of an event handler that can process this event.
A value that is an
int
must be a number that the
yoix.event.HandlerID
dictionary associates with an event handler that can process this event.
In practice,
id
is only used when you build an event that gets handed to
postEvent,
and in that case the value assigned to
id
is almost always a
String.
| | location |
A
Point
that indicates where the pointer was at the time of the event.
The point always describes a location in the component that
requested the event in a coordinate system that has its origin
at that component's upper left corner, positive x to the right,
positive y down, and a resolution of 72 dots per inch.
| | modifiers |
An
int
that is a bitmask that tries to record the state of the mouse buttons
and keyboard modifiers at the time of the event.
Unfortunately, mouse button and keyboard modifier flags overlap
(e.g.,
BUTTON2_MASK
and
ALT_MASK
match), so
modifiers
can not record the state of all mouse buttons and keyboard modifiers,
however reliable information about them is available in
modifiersdown.
modifiers
and
modifiersdown
use disjoint sets of bits as flags, so make sure you test
modifiers
using some combination of
BUTTON1_MASK,
BUTTON2_MASK,
BUTTON3_MASK,
SHIFT_MASK,
CTRL_MASK,
ALT_MASK,
META_MASK,
and
ALT_GRAPH_MASK,
which are defined in
yoix.awt
and
yoix.swing.
Also available are
BUTTON_MASK
and
KEY_MASK,
which are convenient combinations that can be used to test for
any mouse button or any keyboard modifier.
| | modifiersdown |
An
int
that is a bitmask that represents the state of all keyboard modifiers
and mouse buttons when the event occurred.
modifiersdown
and
modifiers
use disjoint sets of bits as flags, so make sure you test
modifiersdown
using some combination of
BUTTON1_DOWN_MASK,
BUTTON2_DOWN_MASK,
BUTTON3_DOWN_MASK,
SHIFT_DOWN_MASK,
CTRL_DOWN_MASK,
ALT_DOWN_MASK,
META_DOWN_MASK,
and
ALT_GRAPH_DOWN_MASK,
which are defined in
yoix.awt
and
yoix.swing.
Also available are
BUTTON_DOWN_MASK
and
KEY_DOWN_MASK,
which are convenient combinations that can be used to test for
any mouse button or any keyboard modifier.
| | popuptrigger |
An
int
that is
1
if the event represents the system dependent popup trigger, and
0
otherwise.
| | pressed |
An
int
that counts the number of mouse buttons that are pressed immediately
after the event occurred.
| | scrollamount |
A platform dependent
int
that represents the number of units to scroll for each mouse wheel click
recorded in
wheelrotation
when
scrolltype
is
WHEEL_UNIT_SCROLL.
| | scrolltype |
A platform dependent
int
that represents the kind of scrolling that should take place in response
to this event.
The value should be
WHEEL_UNIT_SCROLL
or
WHEEL_BLOCK_SCROLL,
which are defined in
yoix.awt
and
yoix.swing.
| | wheelrotation |
An
int
that records the number of mouse wheel clicks and the direction that
the mouse wheel was rotated.
A postive
wheelrotation
means the mouse wheel was rotated in one direction,
a negative
wheelrotation
means it was rotated in the opposite direction,
and the magnitude of
wheelrotation
is the number of mouse wheel clicks recorded by this event.
When
scrolltype
is
WHEEL_UNIT_SCROLL
wheelrotation
and
scrollamount
should be multiplied to determine how far to scroll.
| | when |
A
double
that is a timestamp that represents when the event occurred.
|
Most components can receive
MouseWheelEvents,
but they only arrive if the component has defined a
mouseWheelMoved
event handler.
| |
| Example: |
The program,
import yoix.*.*;
VM.exitmodel = 0; // so main thread does not exit
JFrame frame = {
mouseWheelMoved(Event e) {
printf("mouseWheelMoved: %.2O\n", e);
if (e.modifiers & SHIFT_MASK)
exit(0);
}
};
frame.visible = TRUE;
MouseWheelEvent event = {
String id = "mouseWheelMoved";
int modifiers = BUTTON1_MASK;
int scrollamount = 3;
int wheelrotation = -5;
};
printf("Posting %s\n", event.id);
postEvent(event, frame);
prints
Posting mouseWheelMoved
mouseWheelMoved: Event[11:0]
clickcount=0
coordinates=Point[2:0]
>x=0.0
y=0.0
>id=507
location=Point[2:0]
>x=0.0
y=0.0
modifiers=16
popuptrigger=0
pressed=1
scrollamount=3
scrolltype=0
wheelrotation=-5
when=0.0
on standard output and then dumps all real
mouseWheelMoved
events until the shift key is held down while the mouse wheel is rotated.
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| See Also: |
ActionEvent,
AdjustmentEvent,
CaretEvent,
ChangeEvent,
ComponentEvent,
DragGestureEvent,
DragSourceEvent,
DropTargetEvent,
Event,
FocusEvent,
HyperlinkEvent,
InvocationEvent,
invokeLater,
isDispatchThread,
ItemEvent,
KeyEvent,
ListSelectionEvent,
MouseEvent,
PaintEvent,
postEvent,
TextEvent,
TreeSelectionEvent,
WindowEvent
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