Package ej.mwt.render

Class RenderPolicy

java.lang.Object

ej.mwt.render.RenderPolicy

Direct Known Subclasses:

DefaultRenderPolicy

public abstract class RenderPolicy
extends java.lang.Object

A render policy is responsible of rendering the widgets of a desktop on the display.

A render policy is associated to a single desktop.

A render policy provides a method to render the desktop on the display. This method is used by the desktop in order to perform the initial rendering of the complete widget hierarchy.

A render policy also provides a method to handle render requests targeting specific widgets of the desktop. The goal of this method is to render only a part of the widget hierarchy considering that an old representation of the desktop is already visible on the display. The most naive implementation would be to render the whole hierarchy of the desktop.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	RenderPolicy.RenderListener	Listener for render events (when it is requested and when it is actually executed).

Field Summary

Fields

Modifier and Type	Field	Description
protected static java.lang.String	DEBUG_RENDER_ENABLED_CONSTANT	BON boolean constant to enable/disable the render debug.
protected static java.lang.String	DEBUG_RENDER_MONITOR_CONSTANT	BON Class constant to set the render monitor.
protected static RenderPolicy.RenderListener	MONITOR	RenderPolicy.RenderListener instance to be used by all RenderPolicy implementations.

Constructor Summary

Constructors

Constructor	Description
RenderPolicy(Desktop desktop)	Creates a render policy.

Method Summary

Modifier and Type	Method	Description
Desktop	getDesktop()	Returns the desktop managed by this render policy.
abstract void	renderDesktop()	Renders the desktop on the display.
protected void	renderWidget(ej.microui.display.GraphicsContext g, Widget widget)	Performs the increment render of the widget.
abstract void	requestRender(Widget widget, int x, int y, int width, int height)	Requests a rendering of the given widget on the display.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEBUG_RENDER_ENABLED_CONSTANT

protected static final java.lang.String DEBUG_RENDER_ENABLED_CONSTANT

BON boolean constant to enable/disable the render debug.

If enabled, "ej.mwt.debug.render.monitor" must also be set.

See Also:

Constant Field Values

DEBUG_RENDER_MONITOR_CONSTANT

protected static final java.lang.String DEBUG_RENDER_MONITOR_CONSTANT

BON Class constant to set the render monitor.

Set it to the FQN of an implementation of RenderPolicy.RenderListener to monitor rendering.

See Also:

Constant Field Values

MONITOR

@Nullable
protected static final RenderPolicy.RenderListener MONITOR

RenderPolicy.RenderListener instance to be used by all RenderPolicy implementations.

It is null iff "ej.mwt.debug.render.enabled" is false.

Constructor Detail

RenderPolicy

public RenderPolicy(Desktop desktop)

Creates a render policy.

Parameters:

desktop - the desktop to render.

Method Detail

getDesktop

public Desktop getDesktop()

Returns the desktop managed by this render policy.

Returns:

the desktop managed by this render policy.

renderDesktop

public abstract void renderDesktop()

Renders the desktop on the display. This method is used by the desktop in order to perform the initial rendering of the complete widget hierarchy.

This method should be called in the MicroUI thread as the rendering of the widget is performed synchronously.

requestRender

public abstract void requestRender(Widget widget,
                                   int x,
                                   int y,
                                   int width,
                                   int height)

Requests a rendering of the given widget on the display. The goal of this method is to render only a part of the widget hierarchy considering that an old representation of the desktop is already visible on the display.

This method returns immediately and the rendering of the widget is performed asynchronously in the MicroUI thread.

The given bounds are relative to the widget.

Parameters:

widget - the widget to render.

x - the x coordinate of the area to render.

y - the y coordinate of the area to render.

width - the width of the area to render.

height - the height of the area to render.

renderWidget

protected void renderWidget(ej.microui.display.GraphicsContext g,
                            Widget widget)

Performs the increment render of the widget.

Parameters:

g - the graphics context.

widget - the widget to render.