| [9] | 1 | <?xml version='1.0' encoding='UTF-8'?>
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| 2 | <?xml-stylesheet type="text/css"
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| 3 | href="eclipseos2-xxe.css"
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| 4 | ?>
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| 5 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
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| 6 | "xhtml1-strict.dtd">
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| 7 | <html>
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| 8 | <head>
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| 9 | <link type="text/css"
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| 10 | href="eclipseos2.css"
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| 11 | rel="stylesheet" />
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| 12 |
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| 13 | <title>Eclipse for OS/2 Transitional Project Notes</title>
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| 14 | </head>
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| 15 |
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| 16 | <body>
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| 17 | <h1>SWT Step 4. Layout basics</h1>
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| 18 |
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| 19 | <h2>Objective</h2>
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| 20 |
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| 21 | <p>Implement the basics of the layout management. The testcase example
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| 22 | shoud be able to create a top shell containing a simple button.</p>
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| 23 |
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| 24 | <h2>Task notes</h2>
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| 25 |
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| 26 | <h3>Default Shell size and position</h3>
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| 27 |
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| 28 | <p>In SWT, it's assumed that the <code>o.e.swt.widgets.Shell</code> is
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| 29 | created with the default size and position assigned by the system.</p>
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| 30 |
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| 31 | <p>Since OS/2 handles the <code>FS_SHELLPOSITION</code> flag in a very
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| 32 | strange manner (the size/position of the frame after creation remains zero
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| 33 | until the frame is shown for the first time, and there's no way
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| 34 | neither to get the size/position the system is going to assign nor to
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| 35 | change them before the frame is shown) the workaround is made using
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| 36 | <code>WinQueryTaskSizePos()</code> (it seems to return the same values the
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| 37 | system uses when <code>FS_SHELLPOSITION</code> is specified). This means,
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| 38 | that the <code>Shell.getBounds()</code> method will return system assigned
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| 39 | values (but not zero as it would be in the case of <code>FS_SHELLPOSITION</code>)
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| 40 | after <code>Shell</code> creation and before opening (showing) it and
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| 41 | it's also possible to change them -- the same behavior is shown in
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| 42 | Windows.</p>
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| 43 |
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| 44 | <h3>Notification messages</h3>
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| 45 |
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| 46 | <p>In OS/2 control notification messages (<code>WM_CONTROL</code>,
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| 47 | <code>WM_COMMAND</code>) do not necessarily contain the control window
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| 48 | handle in their parameters, only the identity is guaranteed to present in
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| 49 | most cases. Therefore, in order to send the message back to the widget
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| 50 | (this is an SWT logic and it is quite handy) the only way to determine its
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| 51 | handle, which we need to obtain a reference to the widget, is to use its
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| 52 | window ID. This, in turn, requires an algorithm to generate IDs during
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| 53 | window creation, that are unique within the owner window context. The
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| 54 | window handle could be such unique identifier, but the problem is that the
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| 55 | window ID is a 16-bit value. However, at the present, we still use it for
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| 56 | that purpose taking its low 16 bits, which is based on the assumption that
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| 57 | handles in OS/2 always have a form of <code>0x8000nnnn</code>. But this
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| 58 | assumtion is possibly erroneous, so in the future this algorithm should be
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| 59 | replaced with another one.</p>
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| 60 |
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| 61 | <h3><a name="WidgetHeight">Widget height</a></h3>
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| 62 |
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| 63 | <p>As mentioned in task notes of the <a
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| 64 | href="swt002.html#ScreenCoordinates">SWT002</a> step about screen
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| 65 | coordinates, we need an easy way to obtain the height of a widget as well
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| 66 | as the height of its parent to do necessary calculations related to the
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| 67 | coordinate space flipping. The package method <code>Control.getHeight()</code>
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| 68 | can still be used to get the height of the widget itself (respecting the
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| 69 | situation when the widget is the <code>Decorations</code> instance and it
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| 70 | is minimized). The height of the widget's parent can be obtained by
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| 71 | the <code>Control.getParentHeight()</code> call (which, for the
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| 72 | <code>Shell</code> class, returns the value of the <code>Shell.display.getHeight()</code>
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| 73 | method, rather then <code>parent.getHeight()</code>, if the parent is
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| 74 | <code>null</code>). The situation for non-<code>Shell</code> windows when
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| 75 | the parent is <code>null</code> is inapplicable, so the exception is
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| 76 | thrown in this case. The <code>Control.getBounds(SWP)</code> package
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| 77 | method returns the height of the parent just as it returned by the
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| 78 | <code>getParentHeight()</code> method.</p>
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| 79 |
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| 80 | <h2>Step checklist</h2>
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| 81 |
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| 82 | <table>
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| 83 | <col width="40%" />
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| 84 |
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| 85 | <col />
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| 86 |
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| 87 | <col width="50%" />
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| 88 |
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| 89 | <thead>
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| 90 | <tr>
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| 91 | <th>Operation</th>
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| 92 |
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| 93 | <th>Status</th>
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| 94 |
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| 95 | <th>Remarks</th>
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| 96 | </tr>
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| 97 | </thead>
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| 98 |
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| 99 | <tr>
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| 100 | <td>Make the size and position methods of widgets to work correcty
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| 101 | (add <code>OS.SWP</code> structre, <code>OS.WinQueryTaskSizePos()</code>,
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| 102 | <code>WinQueryWindowPos()</code>); implement <code>Display.getBounds()</code></td>
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| 103 |
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| 104 | <td>Done [dmik]</td>
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| 105 |
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| 106 | <td>Size and position relative methods are completely rewritten: now
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| 107 | they use the package helper method <code>getBounds(SWP)</code> which
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| 108 | uses <code>WinQueryWindowPos()</code> instead of <code>WinQueryWindowRect()</code>.</td>
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| 109 | </tr>
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| 110 |
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| 111 | <tr>
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| 112 | <td>Implement <code>Decorations.{get|set}{Minimized|Maximized}()</code>
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| 113 | methods</td>
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| 114 |
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| 115 | <td>Done [dmik]</td>
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| 116 |
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| 117 | <td></td>
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| 118 | </tr>
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| 119 |
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| 120 | <tr>
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| 121 | <td>Add <code>OS.objcpy (int, SWP)</code>, <code>objcpy(SWP, int)</code>;
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| 122 | <code>WM_WINDOWPOSCHANGED</code>, <code>WM_ADJUSTWINDOWPOS</code>
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| 123 | message handling and <code>AWP_*</code> constants; implement
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| 124 | <code>SWT.Resize</code>, <code>SWT.Move</code>, <code>SWT.Iconify</code>,
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| 125 | <code>SWT.Deiconify</code> events... Activate?</td>
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| 126 |
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| 127 | <td>Done [dmik]</td>
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| 128 |
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| 129 | <td></td>
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| 130 | </tr>
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| 131 |
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| 132 | <tr>
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| 133 | <td>Add <code>OS.WinGetSysBitmap()</code> and <code>SBMP_*</code>
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| 134 | constants, <code>GpiQueryBitmapInfoHeader()</code> and <code>BITMAPINFOHEADER2</code>
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| 135 | class, <code>GpiDeleteBitmap()</code></td>
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| 136 |
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| 137 | <td>Done [dmik]</td>
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| 138 |
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| 139 | <td>Currently used to detect dimensions of the check box</td>
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| 140 | </tr>
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| 141 |
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| 142 | <tr>
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| 143 | <td>Add <code>OS.WinSetPresParam()</code> and <code>PP_*</code>
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| 144 | constants, implement two helper methods (<code>Control.setPres{Foreground|Background}()</code>)</td>
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| 145 |
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| 146 | <td>Done [dmik]</td>
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| 147 |
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| 148 | <td>Used to set the background and foreground colors of standard
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| 149 | controls drawn by the system</td>
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| 150 | </tr>
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| 151 |
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| 152 | <tr>
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| 153 | <td>add <code>BS_*</code>, <code>BM_*</code>, <code>BN_*</code>,
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| 154 | <code>BDS_*</code> constants</td>
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| 155 |
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| 156 | <td>Done [dmik]</td>
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| 157 |
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| 158 | <td></td>
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| 159 | </tr>
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| 160 |
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| 161 | <tr>
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| 162 | <td>Add <code>malloc()</code>, <code>free()</code>, <code>memcpy()</code>,
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| 163 | <code>memset()</code>; add 3 static helper methods to <code>Control</code>:
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| 164 | <code>beginDeferWindowPos()</code>, <code>endDeferWindowPos()</code>
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| 165 | and <code>deferWindowPos()</code>; add <code>OS.WinSetMultWindowPos()</code>,
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| 166 | <code>WinIsWindow()</code></td>
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| 167 |
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| 168 | <td>Done [dmik]</td>
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| 169 |
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| 170 | <td>We use standard C memory management functions because there's
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| 171 | no advantage to organize a heap on the Java level. Without the heap,
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| 172 | direct calls to <code>DosAllocMem()</code> to allocate small amounts
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| 173 | waste memory since they always allocate it by blocks of 4KB.<br /><br /><code>OS.WinSetMultWindowPos()</code>
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| 174 | is used to improve the performance of sizing/moving operations.</td>
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| 175 | </tr>
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| 176 |
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| 177 | <tr>
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| 178 | <td>Add handlers for <code>WM_CONTROL</code>, <code>WM_COMMAND</code>
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| 179 | messages, <code>CMDSRC_*</code> constants; Add and partially implement
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| 180 | the <code>Button</code> class (basic OS/2 buttons, <code>setSelection()</code>,
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| 181 | <code>getSelection()</code>, <code>SWT.Selection</code> event)</td>
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| 182 |
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| 183 | <td>Done [dmik]</td>
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| 184 |
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| 185 | <td>Only OS/2 basic button styles are now implemented (excluding
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| 186 | imaged ones)</td>
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| 187 | </tr>
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| 188 |
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| 189 | <tr>
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| 190 | <td>Add <code>OS.WinCalcFrameRect()</code>, Implement <code>Composite.setLayout()</code>,
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| 191 | <code>getLayout()</code>, <code>layout()</code>, <code>Control.computeSize()</code>,
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| 192 | <code>Scrollable.computeTrim()</code></td>
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| 193 |
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| 194 | <td>Done [dmik]</td>
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| 195 |
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| 196 | <td>Currently scrollbars are not taken into account when calculating
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| 197 | the widget's preferred size</td>
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| 198 | </tr>
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| 199 |
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| 200 | <tr>
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| 201 | <td>Replace the <code>SWT004</code> testcase with <code>SWT004_01</code>
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| 202 | and <code>SWT004_02</code> ones</td>
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| 203 |
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| 204 | <td>Done [dmik]</td>
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| 205 |
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| 206 | <td></td>
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| 207 | </tr>
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| 208 |
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| 209 | <tr>
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| 210 | <td>Make <code>Control.getBorderWidth()</code> to return values
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| 211 | applicable for individual widgets</td>
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| 212 |
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| 213 | <td>Will be done on next steps</td>
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| 214 |
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| 215 | <td>Now it always returns the value of <code>SV_CXBORDER</code>, which
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| 216 | is not the case for many widgets</td>
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| 217 | </tr>
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| 218 | </table>
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| 219 | </body>
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| 220 | </html>
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