ej.mwt.render

Class DefaultRenderPolicy

java.lang.Object

ej.mwt.render.RenderPolicy

ej.mwt.render.DefaultRenderPolicy

Direct Known Subclasses:

OverlapRenderPolicy

public class DefaultRenderPolicy
extends RenderPolicy

This render policy renders the requested widget or its parent if transparent.

When a widget is asked to be rendered:

• if the widget is transparent, its parent is asked to be rendered (and recursively),
• otherwise, the widget is rendered asynchronously.

When one widget is asked to be rendered, a flush is requested to the display. When several widgets are asked to be rendered in a row, only one flush is done at the end.

See Also:

Widget.isTransparent(), Display.requestFlush()

Constructor Summary

Constructors

Constructor and Description
DefaultRenderPolicy(Desktop desktop) Creates a default render policy.

Method Summary

Modifier and Type	Method and Description
void	renderDesktop() Renders the desktop on the display.
protected void	renderWidget(Widget widget, int x, int y, int width, int height) This method performs the increment render of the widget.
void	requestRender(Widget widget, int x, int y, int width, int height) Requests a rendering of the given widget on the display.
protected void	setParentClip(Widget widget, ej.microui.display.GraphicsContext g) Clips and translates a graphics context to the absolute bounds of the parent of a widget.

Methods inherited from class ej.mwt.render.RenderPolicy

getDesktop

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultRenderPolicy

public DefaultRenderPolicy(Desktop desktop)

Creates a default render policy.

Parameters:

desktop - the desktop.

Method Detail

renderDesktop

public 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.

The graphics context is translated to the position of the parent of the widget. The clipping area is set to the intersection of the parent's bounds and the given bounds.

Specified by:

renderDesktop in class RenderPolicy

requestRender

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

Description copied from class: RenderPolicy

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.

Specified by:

requestRender in class RenderPolicy

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(Widget widget,
                            int x,
                            int y,
                            int width,
                            int height)

This method performs the increment render of the widget. Its implementation only renders the widget and not its siblings, but this behavior may be changed by overriding this method.

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.

setParentClip

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

Clips and translates a graphics context to the absolute bounds of the parent of a widget.

It applies recursively a translation to each parent's coordinates, and a clip to its content size.

Parameters:

widget - the widget to clip from.

g - the graphics context to clip on.