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 below, <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="2.5.3.0">
  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="2.5.3.0">
  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 nearest container object (wxDialog, wxFrame,
  93 wxPanel, wxNotebook) upside from the object in XML nodes hierarchy (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 additional 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 necessary 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"   -> tab (C character '\t')
 158     "\\"   -> "\"
 159               (introduced in version 2.5.3.0, not done in earlier versions)
 160
 161 Version Note:
 162     '$' was used instead of '_' prior to version 2.3.0.1.
 163
 164
 165 I18nString
 166 ----------
 167 Like String, but the value is translated to native language using wxLocale
 168 at runtime (unless it was disabled by not passing wxXRC_USE_LOCALE flag to
 169 wxXmlResource constructor). Used for strings that are "visible" in the GUI.
 170
 171
 172 UnsignedInteger
 173 ---------------
 174 This is obvious. Only digits 0-9 may be present and there must be at least
 175 one digit.
 176
 177
 178 Integer
 179 -------
 180 Like UnsignedInteger but may be prefixed with '-' (ints less than zero).
 181
 182
 183 Position
 184 --------
 185 Specifies (window's) position in 2D space. Syntax is <integer>,<integer>[d]
 186 where <integer> is valid value of Integer type.
 187
 188
 189 Size
 190 ----
 191 Syntax is same as Position's syntax, but the values are interpreted as window
 192 size (wxSize type) and not position (wxPosition type).
 193
 194
 195 Style[wxSomeClass]
 196 ------------------
 197 List of style flags that can be passed to wxSomeClass' constructor. Flags are
 198 written in same way as in C++ code (e.g. "wxSUNKEN_BORDER",
 199 "wxHW_SCROLLBAR_NEVER") and are delimited with any combination of whitespaces
 200 and '|'. Possible flags are class-dependent and are not described in this
 201 technote. Please refer to wxWidgets manual for all styles that given class can
 202 accept; if XRC does not accept a flag listed in wxWidgets documentation, it is
 203 a bug.
 204
 205
 206 Bitmap
 207 ------
 208 Attribute value is interpreted as filename (either absolute or relative to
 209 the location of XRC resource file). In addition, attribute node may have
 210 "stock_id" and "stock_client" properties. Their values may be any of wxArtID (or
 211 wxArtClient respectively) values as used by wxArtProvider (because the user may
 212 define own constants, effectively any string is legal here). Examples are
 213 "wxART_FILE_OPEN" (id) or "wxART_MENU" (client).
 214
 215 Any of "stock_id" or "stock_client" properties or the filename may be omitted.
 216 XRC determines the bitmap to use according to this algorithm:
 217   1. If there is non-empty "stock_id" property, query wxArtProvider for the
 218      bitmap (if there is no "stock_client", use default one, which is usually
 219      wxART_OTHER; exceptions are noted in class-specific sections below). If
 220      the query fails, continue to 2.
 221   2. Load the bitmap from the file in attribute value.
 222
 223
 224 Boolean
 225 -------
 226 Boolean value, either "0" (false) or "1" (true).
 227
 228
 229 Font
 230 ----
 231 Font value. A font can be described either in terms of its elementary
 232 properties, or it can be derived from one of system fonts. The font node
 233 may contain following subnodes (the table lists subnode name on the left and
 234 variable type as per the definitions above on the right side):
 235
 236 size            UnsignedInteger
 237 style           normal | italic | slant
 238 weight          normal | bold | light
 239 family          roman | script | decorative | swiss | modern | teletype
 240 underlined      Boolean
 241 face            comma-separated list of faces
 242 encoding        charset of the font (meaningless in Unicode build), as string
 243 sysfont         symbolic name of system standard font
 244                 (one of wxSYS_*_FONT constants)
 245 relativesize    Float, font size relative to choosen system font's size;
 246                 can only be used when 'sysfont' is used and when 'size' is not
 247                 used
 248
 249 All of them are optional, if they are missing, wxFont default is used.
 250
 251 Examples:
 252
 253     <font>
 254         <face>arial,helvetica</face>
 255         <size>12</size>
 256     </font>
 257
 258     <font>
 259         <sysfont>wxSYS_DEFAULT_GUI_FONT</sysfont>
 260         <weight>bold</weight>
 261         <relativesize>1.5</relativesize>
 262     </font>
 263
 264
 265 Colour
 266 ------
 267 A colour value is either explicit RGB value in the standard #rrggbb format
 268 where rr, gg and bb are hexadecimal case-insensitive values in the 00..FF
 269 range, or a symbolic name. Symbolic names are wxSYS_COLOUR_* constants defined
 270 by wxWidgets, written as strings.
 271
 272 Example:
 273
 274     <bg>wxSYS_COLOUR_SCROLLBAR</bg>
 275     <fg>#FF0000</fg>
 276
 277
 278
 279 4. Supported classes
 280 ====================
 281
 282 Attributes are listed in tables in the following format:
 283 attribute name             attribute type          default value, if any
 284                            [(optional remarks....................
 285                            ...................................)]
 286
 287 wxBitmap
 288 --------
 289 This is a special case, because it does not create a wxWindow instance but
 290 creates wxBitmap instead. Another exceptional thing is that it does not have
 291 any attributes. Instead, the node itself is interpreted as if it were attribute
 292 of type Bitmap.
 293
 294 Example: <object class="wxBitmap">bitmaps/foo.gif</object>
 295
 296
 297 wxIcon
 298 ------
 299 Identical to wxBitmap class, except that it creates wxIcon instead of wxBitmap.
 300
 301
 302 wxButton
 303 --------
 304 pos                        Position                -1,-1
 305 size                       Size                    -1,-1
 306 style                      Style[wxButton]
 307
 308 label                      I18nString
 309 default                    Boolean                 false
 310                            (Is the button default button?)
 311
 312
 313 wxCalendarCtrl
 314 --------------
 315 pos                        Position                -1,-1
 316 size                       Size                    -1,-1
 317 style                      Style[wxCalendarCtrl]
 318
 319
 320 wxCheckBox
 321 ----------
 322 pos                        Position                -1,-1
 323 size                       Size                    -1,-1
 324 style                      Style[wxCheckBox]
 325 checked                    Boolean                 false
 326
 327
 328 wxCheckList
 329 -----------
 330 pos                        Position                -1,-1
 331 size                       Size                    -1,-1
 332 style                      Style[wxCheckList]
 333 content                    (see below)             (empty)
 334
 335 Optional "content" attribute does not have attribute value. Instead,
 336 arbitrary number of <item> nodes may be rooted under it (the control
 337 is filled with strings contained in these nodes). Each <item>
 338 node must contain I18nString value and may have "checked" property
 339 with possible values "0" or "1" indicating the the item is initially
 340 checked.
 341
 342 Example:
 343 <object class="wxCheckList">
 344     <content>
 345       <item>One</item>
 346       <item checked="1">Two</item>
 347       <item checked="1">Three</item>
 348       <item>Four</item>
 349     </content>
 350 </object>
 351
 352
 353 wxDatePickerCtrl
 354 ----------------
 355 pos                        Position                -1,-1
 356 size                       Size                    -1,-1
 357 style                      Style[wxDatePickerCtrl]
 358
 359
 360 wxDialog
 361 --------
 362 pos                        Position                -1,-1
 363 size                       Size                    -1,-1
 364 style                      Style[wxDialog]         wxDEFAULT_DIALOG_STYLE
 365 title                      I18nString              ""
 366 icon                       Bitmap                  (empty)
 367 centered                   Boolean                 false
 368
 369 wxDialog may have children objects.
 370
 371
 372 wxFrame
 373 --------
 374 pos                        Position                -1,-1
 375 size                       Size                    -1,-1
 376 style                      Style[wxDialog]         wxDEFAULT_FRAME_STYLE
 377 title                      I18nString              ""
 378 icon                       Bitmap                  (empty)
 379 centered                   Boolean                 false
 380
 381 wxFrame may have children objects. There can be at most one wxToolBar,
 382 wxMenuBar and wxStatusBar children; objects of these types are automatically
 383 set as frame's tool-, menu- and statusbar respectively.
 384
 385
 386 wxScrolledWindow
 387 ----------------
 388 pos                        Position                -1,-1
 389 size                       Size                    -1,-1
 390 style                      Style[wxScrolledWindow] wxHSCROLL | wxVSCROLL
 391
 392 wxScolledWindow may have children objects.
 393
 394
 395 wxSplitterWindow
 396 ----------------
 397 pos                        Position                -1,-1
 398 size                       Size                    -1,-1
 399 style                      Style[wxSplitterWindow] wxSP_3D
 400 sashpos                    Integer                 0
 401                            (Initial sash position)
 402 minsize                    Integer                 -1
 403                            (Minimal panel size)
 404 orientation                "horizontal"|"vertical" horizontal
 405
 406 wxSplitterWindow must have at least one and at most two children objects.
 407 If there's only one child object, it is passed to wxSplitterWindow::Initialize
 408 and the splitter is created unsplit. If there are two children, the
 409 splitter is created split, either horizontally or vertically depending
 410 on the value of "orientation" attribute.
 411
 412
 413 wxStatusBar
 414 -----------
 415 fields                     Integer number of fields
 416 widths                     Width1, Width2, Width3, ...
 417
 418
 419 wxToolBar
 420 ---------
 421 pos                        Position                -1,-1
 422 size                       Size                    -1,-1
 423 style                      Style[wxToolBar]        wxNO_BORDER|wxTB_HORIZONTAL
 424 bitmapsize                 Size                    -1,-1
 425                            (Size of contained bitmaps)
 426 margins                    Size                    -1,-1
 427 packing                    Integer                 -1
 428 separation                 Integer                 -1
 429
 430 wxToolBar node may have children <object> and <object_ref> nodes. Their class
 431 may be either "tool", "separator" or any wxWidgets class derived from
 432 wxControl. "tool" and "separator" are special pseudo-classes that may only
 433 appear within wxToolBar node. Their attributes are as follows:
 434
 435     separator
 436     ---------
 437     (doesn't have any attributes)
 438
 439     tool
 440     ----
 441     bitmap                 Bitmap
 442     bitmap2                Bitmap                  wxNullBitmap
 443     toggle                 Boolean                 0
 444     radio                  Boolean                 0
 445     label                  I18nString              ""
 446     tooltip                I18nString              ""
 447     longhelp               I18nString              ""
 448     pos                    Position                -1,-1
 449
 450     Constraints:
 451       At most one of "toggle" and "radio" attributes may be 1.
 452       Attribute "pos" may not appear if "label" or "radio" attributes
 453       are used or if parent wxToolBar's style contains wxTB_TEXT.
 454
 455     Note:
 456       Use of "pos" attribute is strongly discouraged, it is deprecated
 457       usage of wxToolBar and it is not supported by MSW and GTK
 458       implementations.
 459
 460 Children objects are added to the toolbar using AddTool for "tool" class,
 461 AddSeparator for "separator" and AddControl for other classes.
 462
 463
 464
 465 5. More features
 466 ================
 467
 468 FIXME -- "platform" property handling
 469
 470
 471 === EOF ===
 472
 473 Version: $Id$