| PaintEvent |
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typedict |
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A
PaintEvent
is a high level event that tells a component it should repaint itself,
perhaps after first painting its background.
There are no official
PaintEvent
event handlers, but many components support a Yoix
paint
function, so sending a
PaintEvent
to a component using
postEvent
eventually results in a call of the component's
paint
function.
The fields in a
PaintEvent
are:
| id |
A
String
that should only be
"paint"
or
"update".
A
PaintEvent
identified as an update always starts by repainting the component's background.
| | updaterect |
A
Rectangle
that describes the rectangle that needs to be repainted.
Coordinates are in a coordinate system that has its origin
in the component's upper left corner, positive x to the right,
positive y down, and a resolution of 72 dots per inch.
A
NULL
rectangle means repaint the entire component.
|
A
PaintEvent
can be sent to any component, but there are no official event handlers
(i.e., Yoix functions that actually get the event),
because much of the work is handled behind the scenes by the Java Virtual Machine.
Many Yoix components support a
paint
function that is called whenever the component is painted, so sending a
PaintEvent
to a component using
postEvent
eventually results in a call of the component's
paint
function, however you should not count on a one to one correspondence between
PaintEvents
and
paint
calls.
| |
| Event Handlers: |
none
| | |
| Example: |
The program,
import yoix.*.*;
double factor = 1.0;
Frame f = {
Color background = Color.white;
int visible = TRUE;
paint(Rectangle rect) {
graphics {
gsave();
rectclip(rect);
moveto(72, 72);
rlineto(288, 0);
rlineto(0, 72);
rlineto(-288, 0);
setrgbcolor(1.0 - factor, factor, 0);
fill();
grestore();
rectstroke(rect);
}
}
};
PaintEvent pe = {
String id = "paint";
Rectangle updaterect = {
double x = 72;
double y = 72;
double width = 288;
double height = 72;
};
};
while (pe.updaterect.width > 18) {
sleep(.5);
factor *= .8;
pe.updaterect.width = 288*factor;
postEvent(pe, f);
}
sleep(1);
exit(0);
sends a series of
PaintEvents
to a frame that defines a
paint
function that lets you observe the events as they arrive.
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| See Also: |
ActionEvent,
AdjustmentEvent,
CaretEvent,
ChangeEvent,
ComponentEvent,
DragGestureEvent,
DragSourceEvent,
DropTargetEvent,
Event,
FocusEvent,
HyperlinkEvent,
InvocationEvent,
invokeLater,
isDispatchThread,
ItemEvent,
KeyEvent,
ListSelectionEvent,
MouseEvent,
MouseWheelEvent,
postEvent,
TextEvent,
TreeSelectionEvent,
WindowEvent
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Yoix is a registered trademark of AT&T Intellectual Property.
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