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<concept id="GUID-27018D94-5273-5AC3-98E5-D2924776740C" xml:lang="en"><title>BackedUp:

backed-up windows</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<section><title>Description</title> <p>This example demonstrates how to implement

a backed up window. </p> <p>It implements freehand drawing in a similar way

to the <filepath>PtBuffer</filepath> example, using the pointer move buffer.

However, in this example, the window which may be drawn to is an <codeph>RBackedUpWindow</codeph> rather

than an <codeph>RWindow</codeph>. This means that any drawing is redrawn automatically

if it becomes covered up and then uncovered: the backed-up window receives

no redraw events. The example includes a small window which can be dragged

around the screen to illustrate this. </p> </section>

<section id="GUID-2CC58218-AABD-52F8-B8D1-303185C6F6BA"><title>Download</title> <p>Click

on the following link to download the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-8e5125ad-7e58-429a-8936-35b0b0c3c999.zip" scope="external">BackedUp.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-8e5125ad-7e58-429a-8936-35b0b0c3c999.html" scope="peer">browse</xref> to view the example code. </p> </section>

<section><title>Running on the emulator</title> <p>Drag the mouse with left

mouse button down for freehand drawing. You do not need to press the <userinput>Shift</userinput> key. </p> </section>

<section><title>Running on the target phone</title> <p>Draw using the pointer.

You do not need to press the <userinput>Shift</userinput> key. </p> </section>

<section><title>Class Summary</title><p>For Backedup Window: </p><p><xref href="GUID-27A95595-F74D-32B2-A960-0CA290C8A3B3.dita"><apiname>RBackedUpWindow</apiname></xref></p><p>For

Screen Device: </p><p><xref href="GUID-30479BE3-296E-3B4D-914D-B080ABD733E4.dita"><apiname>CWsScreenDevice</apiname></xref></p></section>