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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-24039DCE-B5C4-46CB-9E02-AB421C64FB87" xml:lang="en"><title>Relationship |
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13 between window controls</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>When a control draws in the window of another control, the position |
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15 is relative to that window. If a control owns a window that is a child of |
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16 another window, that control's position is relative to the parent window; |
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17 however, if that control is a compound control, its child control's coordinates |
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18 are relative to its own parent control window position. Top-level window-owning |
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19 controls are displayed using a position relative to the display. In other |
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20 words, it uses the physical coordinates of the display.</p> |
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21 <p>The following figure illustrates this relationship.</p> |
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22 <fig id="GUID-9D373EB7-096D-4C84-8060-577F33D462EE"><title>Relative positions of three controls where the top-level parent owns |
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23 the window</title><image href="GUID-61C340D0-9058-45C2-9A90-4AB8E0612872_d0e42756_href.png"/></fig> |
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24 <p>Consider three controls, <b>A</b>, <b>B</b>, and <b>C</b> (shown in |
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25 the figure above):</p> |
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26 <ul> |
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27 <li><p><b>A</b> is a top-level control and owns a window</p> |
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28 </li> |
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29 <li><p>Child controls <b>B</b> and <b>C</b> do not create their |
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30 own windows in this example.</p></li> |
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31 <li><p><b>B</b>, a child control of <b>A</b>, does not create a |
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32 window, and it has a child control, <b>C</b>. </p> |
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33 <itemgroup> |
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34 <p><b>B</b>'s window is set calling the <parmname>CCoeControl::SetContainerWindowL(A)</parmname> method |
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35 and <b>C</b>'s window is set with <parmname>CCoeControl::SetContainerWindowL(B)</parmname>. |
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36 Then <b>C</b>'s position (p) is relative to <b>A</b>, since it is the actual |
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37 window owner. <b>A</b>'s position (m) is relative to the display position.</p> |
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38 </itemgroup> |
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39 </li> |
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40 </ul> |
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41 <p>However, if <b>B</b> is a child control of <b>A</b> but also has a window |
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42 of its own, it is a child window of <b>A</b>'s window (as shown in the following |
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43 figure). Then if <b>C</b> is a child of <b>B</b> and sets its window by calling <parmname>CCoeControl::SetContainerWindowL(B)</parmname>, |
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44 the position of <b>C</b> (p') is relative to <b>B</b>'s window.</p> |
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45 <fig id="GUID-5884BDB6-6ED0-4EF6-A64F-3EEAAAEE2FF0"><title>Relative positions of three controls where a child owns a window</title><image href="GUID-3A506E2A-2999-458B-BBA2-DCC4D2EA5492_d0e42859_href.png"/></fig> |
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46 <p>As the example illustrates, a control position depends on the window |
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47 in which it is drawn. Therefore, you need to know the drawing window for each |
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48 control. It is an important issue when designing a UI layout. There are some |
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49 common controls that optionally may have their own window, such as menus, |
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50 dialogs, and scroll bars. The application framework handles drawing these |
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51 controls, as long as the appropriate resources and flags have been set. The <xref href="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/reference/reference-cpp/Control_Environment/CCoeControlClass.html#%3a%3aCCoeControl%3a%3aOwnsWindow%28%29const" format="application/java-archive"><parmname>CCoeControl::OwnsWindow</parmname></xref> call can be used |
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52 to detect whether a control owns a window or not.</p> |
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53 </conbody></concept> |