docs/tech/tn0014.txt

   1                       XRC resources format specification
   2                       ==================================
   3
   4                          !!!!! NOT YET FINISHED !!!!!
   5
   6 0. Introduction
   7 ===============
   8
   9 This note describes the file format used for storing XRC resources that are
  10 used by wxXmlResource class. It is probably only useful for those implementing
  11 dialog editors with XRC support.
  12
  13 If you only want to use the resources, you can choose from a number of editors:
  14   a) wxDesigner (http://www.roebling.de)
  15   b) XRCed (wxPython/tools)
  16   c) wxWorkshop (http://wxworkshop.sf.net)
  17   b) wxrcedit (contrib/utils/wxrcedit)
  18
  19 The XRC format is based on XML 1.0 (please consult W3C's specification). There
  20 is no DTD available since it is not possible to fully describe the format with
  21 the limited expressive power of DTDs.
  22
  23
  24 Note: see also http://ldaptool.sourceforge.net/XRCGuide/XRCGuideSingle/
  25
  26
  27
  28 1. Terminology
  29 ==============
  30
  31 The usual XML terminology applies. In particular, we shall use the terms
  32 NODE, PROPERTY and VALUE in the XML sense:
  33
  34     <node property1="value1" property2="value2">...</node>
  35
  36 The term ATTRIBUTE is specific to XRC and refers to a subnode
  37 of an <object> or <object_ref> node that is itself not <object> or <object_ref>.
  38 In the example bellow, <pos>, <label> and <style> are attributes, while neither
  39 <resource> nor either of <object>s is:
  40
  41     <?xml version="1.0" encoding="utf-8">
  42     <resource xmlns="http://www.wxwidgets.org/wxxrc" version="2.3.0.1">
  43         <object class="wxPanel">
  44             <style>wxSUNKEN_BORDER</style>             <!-- attr -->
  45             <object class="wxStaticText">
  46                 <label>A label</label>                 <!-- attr -->
  47                 <pos>10,10</pos>                       <!-- attr -->
  48             </object>
  49         </object>
  50     </resource>
  51
  52 ATTRIBUTE VALUE is the content of all text elements within attribute tag. In the
  53 above example, "wxSUNKEN_BORDER", "A label" and "10,10" are attribute values.
  54 ATTRIBUTE TYPE defines what attribute values are valid for given attribute (you
  55 can think of it as attribute value syntax definition).
  56
  57
  58
  59 2. Elementary description
  60 =========================
  61
  62 XRC resource file is a well-formed XML 1.0 document. All elements of XRC file
  63 are from the http://www.wxwidgets.org/wxxrc namespace.
  64
  65 The root node of XRC document must be <resource>. The <resource> node has
  66 optional "version" property. Default version  (in absence of the version
  67 property) is "0.0.0.0". The version consists of four integers separated by
  68 periods. Version of XRC format changes only if there was an incompatible
  69 change introduced (i.e. either the library cannot understand old resource
  70 files or older versions of the library wouldn't understand the new format).
  71 The first three integers are major, minor and release number of the wxWidgets
  72 release when the change was introduced, the last one is revision number and
  73 is 0 for the first incompatible change in given wxWidgets release, 1 for
  74 the second etc.
  75
  76 Differences between versions are described within this document in paragraphs
  77 entitled "Version Note".
  78
  79 The <resource> node contains namespace declaration, too:
  80
  81     <resource xmlns="http://www.wxwidgets.org/wxxrc" version="2.3.0.1">
  82
  83 The <resource> node is only allowed to have <object> and <object_ref>
  84 subnodes, all of which must have the "name" property.
  85
  86 The <object> node represents a single object (GUI element) and it usually maps
  87 directly to a wxWidgets class instance. It three properties: "name", "class"
  88 and "subclass". "class" must always be present, it tells XRC what wxWidgets
  89 object should be created in this place. The other two are optional.  "name" is
  90 ID used to identify the object. It is the value passed to the XRCID() macro and
  91 is also used to construct wxWindow's id and name attributes and must be unique
  92 among all children of the neareset container object (wxDialog, wxFrame,
  93 wxPanel, wxNotebook) upside from the object in XML nodes hiearchy (two distinct
  94 containers may contain objects with same "name", though). "subclass" is
  95 optional name of class whose constructor will be called instead of the
  96 constructor for "class". Subclass must be available in the program that loads
  97 the resource, must be derived from "class" and must be registered within
  98 wxWidgets' RTTI system.
  99
 100 Example:
 101
 102     <object name="MyList1" class="wxListCtrl" subclass="MyListCtrlClass">
 103         ...
 104     </object>
 105
 106 <object> node may have arbitrary child nodes. What child nodes and their
 107 semantics are class-dependent and are defined later in this document. The user
 108 is allowed to register new object handlers within XRC and extend it to accept
 109 new <object> classes (and therefore different <object>'s child nodes).
 110
 111 <object_ref> node is identical to <object>, except that it does _not_ have
 112 "class" property and has additonal required property "ref". It's concept is
 113 similar to Unix symlinks: value of the "ref" property is equal to the value of
 114 "name" property of some existing node (called referred node) in the resources
 115 (not neccessary top-level).  Referred node's "class" property and all subnodes
 116 are copied in place of the referee <object_ref> node which is then processed as
 117 regular <object> node. If the <object_ref> node itself has child nodes, then
 118 these nodes _override_ any nodes from the referred node.
 119
 120 Example:
 121
 122     <object name="foo" class="wxTextCtrl">
 123         <value>hello</value>
 124         <size>100,-1d</size>
 125     </object>
 126     <object_ref name="bar" ref="foo">
 127         <value>bar</value>               <!-- override! -->
 128     </object_ref>
 129
 130 is identical to:
 131
 132     <object name="foo" class="wxTextCtrl">
 133         <value>hello</value>
 134         <size>100,-1d</size>
 135     </object>
 136     <object name="bar" class="wxTextCtrl">
 137         <value>bar</value>
 138         <size>100,-1d</size>
 139     </object>
 140
 141
 142
 143 3. Common attribute types
 144 =========================
 145
 146 There are several attribute types (see section 1. Terminology) that are common
 147 to many attributes of different classes:
 148
 149 String
 150 ------
 151 Any text. Some characters have special interpretation and are translated
 152 by XRC parser according to this table:
 153     "_"    -> "&"  ('&' is used to underline e.g. menu items in wxWidgets)
 154     "__"   -> "_"
 155     "\n"   -> line break (C character '\n')
 156     "\r"   -> carriage return (C character '\r')
 157     "\t"   -> tabelator (C character '\t')
 158
 159 Version Note:
 160     '$' was used instead of '_' prior to version 2.3.0.1.
 161
 162
 163 I18nString
 164 ----------
 165 Like String, but the value is translated to native language using wxLocale
 166 at runtime (unless it was disabled by not passing wxXRC_USE_LOCALE flag to
 167 wxXmlResource constructor). Used for strings that are "visible" in the GUI.
 168
 169
 170 UnsignedInteger
 171 ---------------
 172 This is obvious. Only digits 0-9 may be present and there must be at least
 173 one digit.
 174
 175
 176 Integer
 177 -------
 178 Like UnsignedInteger but may be prefixed with '-' (ints less than zero).
 179
 180
 181 Position
 182 --------
 183 Specifies (window's) position in 2D space. Syntax is <integer>,<integer>[d]
 184 where <integer> is valid value of Integer type.
 185
 186
 187 Size
 188 ----
 189 Syntax is same as Position's syntax, but the values are interpreted as window
 190 size (wxSize type) and not position (wxPosition type).
 191
 192
 193 Style[wxSomeClass]
 194 ------------------
 195 List of style flags that can be passed to wxSomeClass' constructor. Flags are
 196 written in same way as in C++ code (e.g. "wxSUNKEN_BORDER",
 197 "wxHW_SCROLLBAR_NEVER") and are delimined with any combination of whitespaces
 198 and '|'. Possible flags are class-dependent and are not described in this
 199 technote. Please refer to wxWidgets manual for all styles that given class can
 200 accept; if XRC does not accept a flag listed in wxWidgets documentation, it is
 201 a bug.
 202
 203
 204 Bitmap
 205 ------
 206 Attribute value is interpreted as filename (either absolute or relative to
 207 the location of XRC resource file). In addition, attribute node may have
 208 "stock_id" and "stock_client" properties. Their values may be any of wxArtID (or
 209 wxArtClient respectively) values as used by wxArtProvider (because the user may
 210 define own constants, efectively any string is legal here). Examples are
 211 "wxART_FILE_OPEN" (id) or "wxART_MENU" (client).
 212
 213 Any of "stock_id" or "stock_client" properties or the filename may be omitted.
 214 XRC determines the bitmap to use according to this algorithm:
 215   1. If there is non-empty "stock_id" property, query wxArtProvider for the
 216      bitmap (if there is no "stock_client", use default one, which is usually
 217      wxART_OTHER; exceptions are noted in class-specific sections bellow). If
 218      the query fails, continue to 2.
 219   2. Load the bitmap from the file in attribute value.
 220
 221
 222 Boolean
 223 -------
 224 Boolean value, either "0" (false) or "1" (true).
 225
 226
 227
 228 4. Supported classes
 229 ====================
 230
 231 Attributes are listed in tables in the following format:
 232 attribute name             attribute type          default value, if any
 233                            [(optional remarks....................
 234                            ...................................)]
 235
 236 wxBitmap
 237 --------
 238 This is a special case, because it does not create a wxWindow instance but
 239 creates wxBitmap instead. Another exceptional thing is that it does not have
 240 any attributes. Instead, the node itself is interpreted as if it were attribute
 241 of type Bitmap.
 242
 243 Example: <object class="wxBitmap">bitmaps/foo.gif</object>
 244
 245
 246 wxIcon
 247 ------
 248 Identical to wxBitmap class, except that it creates wxIcon instead of wxBitmap.
 249
 250
 251 wxButton
 252 --------
 253 position                   Position                -1,-1
 254 size                       Size                    -1,-1
 255 style                      Style[wxButton]
 256
 257 label                      I18nString
 258 default                    Boolean                 false
 259                            (Is the button default button?)
 260
 261
 262 wxCalendarCtrl
 263 --------------
 264 position                   Position                -1,-1
 265 size                       Size                    -1,-1
 266 style                      Style[wxCalendarCtrl]
 267
 268
 269 wxCheckBox
 270 ----------
 271 position                   Position                -1,-1
 272 size                       Size                    -1,-1
 273 style                      Style[wxCheckBox]
 274 checked                    Boolean                 false
 275
 276
 277 wxCheckList
 278 -----------
 279 position                   Position                -1,-1
 280 size                       Size                    -1,-1
 281 style                      Style[wxCheckList]
 282 content                    (see bellow)            (empty)
 283
 284 Optional "content" attribute does not have attribute value. Instead,
 285 arbitrary number of <item> nodes may be rooted under it (the control
 286 is filled with strings contained in these nodes). Each <item>
 287 node must contain I18nString value and may have "checked" property
 288 with possible values "0" or "1" indicating the the item is initially
 289 checked.
 290
 291 Example:
 292 <object class="wxCheckList">
 293     <content>
 294       <item>One</item>
 295       <item checked="1">Two</item>
 296       <item checked="1">Three</item>
 297       <item>Four</item>
 298     </content>
 299 </object>
 300
 301
 302 wxScrolledWindow
 303 ----------------
 304 position                   Position                -1,-1
 305 size                       Size                    -1,-1
 306 style                      Style[wxScrolledWindow] wxHSCROLL | wxVSCROLL
 307
 308
 309 wxSplitterWindow
 310 ----------------
 311 position                   Position                -1,-1
 312 size                       Size                    -1,-1
 313 style                      Style[wxSplitterWindow] wxSP_3D
 314 sashpos                    Integer                 0
 315                            (Initial sash position)
 316 minsize                    Integer                 -1
 317                            (Minimal panel size)
 318 orientation                "horizontal"|"vertical" horizontal
 319
 320 wxSplitterWindow must have at least one and at most two children objects.
 321 If there's only one child object, it is passed to wxSplitterWindow::Initialize
 322 and the splitter is created unsplitted. If there are two children, the
 323 splitter is created splitted, either horizontally or vertically depending
 324 on the value of "orientation" attribute.
 325
 326 wxStatusBar
 327 -----------
 328 fields                     Integer number of fields
 329 widths                     Width1, Width2, Width3, ...
 330
 331 wxToolBar
 332 ---------
 333 position                   Position                -1,-1
 334 size                       Size                    -1,-1
 335 style                      Style[wxToolBar]        wxNO_BORDER|wxTB_HORIZONTAL
 336 bitmapsize                 Size                    -1,-1
 337                            (Size of contained bitmaps)
 338 margins                    Size                    -1,-1
 339 packing                    Integer                 -1
 340 separation                 Integer                 -1
 341
 342 wxToolBar node may have children <object> and <object_ref> nodes. Their class
 343 may be either "tool", "separator" or any wxWidgets class derived from
 344 wxControl. "tool" and "separator" are special pseudo-classes that may only
 345 appear within wxToolBar node. Their attributes are as follows:
 346
 347     separator
 348     ---------
 349     (doesn't have any attributes)
 350
 351     tool
 352     ----
 353     bitmap                 Bitmap
 354     bitmap2                Bitmap                  wxNullBitmap
 355     toggle                 Boolean                 0
 356     radio                  Boolean                 0
 357     label                  I18nString              ""
 358     tooltip                I18nString              ""
 359     longhelp               I18nString              ""
 360     position               Position                -1,-1
 361
 362     Constraints:
 363       At most one of "toggle" and "radio" attributes may be 1.
 364       Attribute "position" may not appear if "label" or "radio" attributes
 365       are used or if parent wxToolBar's style contains wxTB_TEXT.
 366
 367     Note:
 368       Use of "position" attribute is strongly discouraged, it is deprecated
 369       usage of wxToolBar and it is not supported by MSW and GTK
 370       implementations.
 371
 372 Children objects are added to the toolbar using AddTool for "tool" class,
 373 AddSeparator for "separator" and AddControl for other classes.
 374
 375
 376
 377 5. More features
 378 ================
 379
 380 FIXME -- "platform" property handling
 381
 382
 383 === EOF ===
 384
 385 Version: $Id$