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) DialogBlocks (wxPython/tools)
  17
  18 and others listed on the Resources section of the wxWidgets web
  19 site.
  20
  21 The XRC format is based on XML 1.0 (please consult W3C's specification). There
  22 is no DTD available since it is not possible to fully describe the format with
  23 the limited expressive power of DTDs.
  24
  25
  26 Note: see also http://ldaptool.sourceforge.net/XRCGuide/XRCGuideSingle/
  27
  28
  29
  30 1. Terminology
  31 ==============
  32
  33 The usual XML terminology applies. In particular, we shall use the terms
  34 NODE, PROPERTY and VALUE in the XML sense:
  35
  36     <node property1="value1" property2="value2">...</node>
  37
  38 The term ATTRIBUTE is specific to XRC and refers to a subnode
  39 of an <object> or <object_ref> node that is itself not <object> or <object_ref>.
  40 In the example below, <pos>, <label> and <style> are attributes, while neither
  41 <resource> nor either of <object>s is:
  42
  43     <?xml version="1.0" encoding="utf-8">
  44     <resource xmlns="http://www.wxwidgets.org/wxxrc" version="2.5.3.0">
  45         <object class="wxPanel">
  46             <style>wxSUNKEN_BORDER</style>             <!-- attr -->
  47             <object class="wxStaticText">
  48                 <label>A label</label>                 <!-- attr -->
  49                 <pos>10,10</pos>                       <!-- attr -->
  50             </object>
  51         </object>
  52     </resource>
  53
  54 ATTRIBUTE VALUE is the content of all text elements within attribute tag. In the
  55 above example, "wxSUNKEN_BORDER", "A label" and "10,10" are attribute values.
  56 ATTRIBUTE TYPE defines what attribute values are valid for given attribute (you
  57 can think of it as attribute value syntax definition).
  58
  59
  60
  61 2. Elementary description
  62 =========================
  63
  64 XRC resource file is a well-formed XML 1.0 document. All elements of XRC file
  65 are from the http://www.wxwidgets.org/wxxrc namespace.
  66
  67 The root node of XRC document must be <resource>. The <resource> node has
  68 optional "version" property. Default version  (in absence of the version
  69 property) is "0.0.0.0". The version consists of four integers separated by
  70 periods. Version of XRC format changes only if there was an incompatible
  71 change introduced (i.e. either the library cannot understand old resource
  72 files or older versions of the library wouldn't understand the new format).
  73 The first three integers are major, minor and release number of the wxWidgets
  74 release when the change was introduced, the last one is revision number and
  75 is 0 for the first incompatible change in given wxWidgets release, 1 for
  76 the second etc.
  77
  78 Differences between versions are described within this document in paragraphs
  79 entitled "Version Note".
  80
  81 The <resource> node contains namespace declaration, too:
  82
  83     <resource xmlns="http://www.wxwidgets.org/wxxrc" version="2.5.3.0">
  84
  85 The <resource> node is only allowed to have <object> and <object_ref>
  86 subnodes, all of which must have the "name" property.
  87
  88 The <object> node represents a single object (GUI element) and it usually maps
  89 directly to a wxWidgets class instance. It has the properties: "name", "class"
  90 and "subclass". "class" must always be present, it tells XRC what wxWidgets
  91 object should be created in this place. The other two are optional.  "name" is
  92 ID used to identify the object. It is the value passed to the XRCID() macro and
  93 is also used to construct wxWindow's id and name attributes and must be unique
  94 among all children of the nearest container object (wxDialog, wxFrame,
  95 wxPanel, wxNotebook) upside from the object in XML nodes hierarchy (two distinct
  96 containers may contain objects with same "name", though). "subclass" is
  97 optional name of class whose constructor will be called instead of the
  98 constructor for "class". Subclass must be available in the program that loads
  99 the resource, must be derived from "class" and must be registered within
 100 wxWidgets' RTTI system.
 101
 102 Finally, an optional "insert_at" property may be present. Currently only the
 103 values "begin" and "end" are supported, meaning to insert the object in the
 104 beginning of the parent node objects list or to append it at the end (which is
 105 the default if this property is absent).
 106
 107 Example:
 108
 109     <object name="MyList1" class="wxListCtrl" subclass="MyListCtrlClass">
 110         ...
 111     </object>
 112
 113 <object> node may have arbitrary child nodes. What child nodes and their
 114 semantics are class-dependent and are defined later in this document. The user
 115 is allowed to register new object handlers within XRC and extend it to accept
 116 new <object> classes (and therefore different <object>'s child nodes).
 117
 118 <object_ref> node is identical to <object>, except that it does _not_ have
 119 "class" property and has additional required property "ref". Its concept is
 120 similar to Unix symlinks: value of the "ref" property is equal to the value of
 121 "name" property of some existing node (called referred node) in the resources
 122 (not necessary top-level).  Referred node's "class" property and all subnodes
 123 are copied in place of the referee <object_ref> node which is then processed as
 124 regular <object> node. If the <object_ref> node itself has child nodes, then
 125 these nodes _override_ any nodes from the referred node.
 126
 127 Example:
 128
 129     <object name="foo" class="wxTextCtrl">
 130         <value>hello</value>
 131         <size>100,-1d</size>
 132     </object>
 133     <object_ref name="bar" ref="foo">
 134         <value>bar</value>               <!-- override! -->
 135     </object_ref>
 136
 137 is identical to:
 138
 139     <object name="foo" class="wxTextCtrl">
 140         <value>hello</value>
 141         <size>100,-1d</size>
 142     </object>
 143     <object name="bar" class="wxTextCtrl">
 144         <value>bar</value>
 145         <size>100,-1d</size>
 146     </object>
 147
 148
 149
 150 3. Common attribute types
 151 =========================
 152
 153 There are several attribute types (see section 1. Terminology) that are common
 154 to many attributes of different classes:
 155
 156 String
 157 ------
 158 Any text. Some characters have special interpretation and are translated
 159 by XRC parser according to this table:
 160     "_"    -> "&"  ('&' is used to underline e.g. menu items in wxWidgets)
 161     "__"   -> "_"
 162     "\n"   -> line break (C character '\n')
 163     "\r"   -> carriage return (C character '\r')
 164     "\t"   -> tab (C character '\t')
 165     "\\"   -> "\"
 166               (introduced in version 2.5.3.0, not done in earlier versions)
 167
 168 Version Note:
 169     '$' was used instead of '_' prior to version 2.3.0.1.
 170
 171
 172 I18nString
 173 ----------
 174 Like String, but the value is translated to native language using wxLocale
 175 at runtime (unless it was disabled by not passing wxXRC_USE_LOCALE flag to
 176 wxXmlResource constructor). Used for strings that are "visible" in the GUI.
 177
 178
 179 UnsignedInteger
 180 ---------------
 181 This is obvious. Only digits 0-9 may be present and there must be at least
 182 one digit.
 183
 184
 185 Integer
 186 -------
 187 Like UnsignedInteger but may be prefixed with '-' (ints less than zero).
 188
 189
 190 Position
 191 --------
 192 Specifies (window's) position in 2D space. Syntax is <integer>,<integer>[d]
 193 where <integer> is valid value of Integer type.
 194
 195
 196 Size
 197 ----
 198 Syntax is same as Position's syntax, but the values are interpreted as window
 199 size (wxSize type) and not position (wxPosition type).
 200
 201
 202 Style[wxSomeClass]
 203 ------------------
 204 List of style flags that can be passed to wxSomeClass' constructor. Flags are
 205 written in same way as in C++ code (e.g. "wxSUNKEN_BORDER",
 206 "wxHW_SCROLLBAR_NEVER") and are delimited with any combination of whitespaces
 207 and '|'. Possible flags are class-dependent and are not described in this
 208 technote. Please refer to wxWidgets manual for all styles that given class can
 209 accept; if XRC does not accept a flag listed in wxWidgets documentation, it is
 210 a bug.
 211
 212
 213 Bitmap
 214 ------
 215 Attribute value is interpreted as filename (either absolute or relative to
 216 the location of XRC resource file). In addition, attribute node may have
 217 "stock_id" and "stock_client" properties. Their values may be any of wxArtID (or
 218 wxArtClient respectively) values as used by wxArtProvider (because the user may
 219 define own constants, effectively any string is legal here). Examples are
 220 "wxART_FILE_OPEN" (id) or "wxART_MENU" (client).
 221
 222 Any of "stock_id" or "stock_client" properties or the filename may be omitted.
 223 XRC determines the bitmap to use according to this algorithm:
 224   1. If there is non-empty "stock_id" property, query wxArtProvider for the
 225      bitmap (if there is no "stock_client", use default one, which is usually
 226      wxART_OTHER; exceptions are noted in class-specific sections below). If
 227      the query fails, continue to 2.
 228   2. Load the bitmap from the file in attribute value.
 229
 230
 231 Boolean
 232 -------
 233 Boolean value, either "0" (false) or "1" (true).
 234
 235
 236 Font
 237 ----
 238 Font value. A font can be described either in terms of its elementary
 239 properties, or it can be derived from one of system fonts. The font node
 240 may contain following subnodes (the table lists subnode name on the left and
 241 variable type as per the definitions above on the right side):
 242
 243 size            UnsignedInteger
 244 style           normal | italic | slant
 245 weight          normal | bold | light
 246 family          roman | script | decorative | swiss | modern | teletype
 247 underlined      Boolean
 248 face            comma-separated list of faces
 249 encoding        charset of the font (meaningless in Unicode build), as string
 250 sysfont         symbolic name of system standard font
 251                 (one of wxSYS_*_FONT constants)
 252 relativesize    Float, font size relative to choosen system font's size;
 253                 can only be used when 'sysfont' is used and when 'size' is not
 254                 used
 255
 256 All of them are optional, if they are missing, wxFont default is used.
 257
 258 Examples:
 259
 260     <font>
 261         <face>arial,helvetica</face>
 262         <size>12</size>
 263     </font>
 264
 265     <font>
 266         <sysfont>wxSYS_DEFAULT_GUI_FONT</sysfont>
 267         <weight>bold</weight>
 268         <relativesize>1.5</relativesize>
 269     </font>
 270
 271
 272 Colour
 273 ------
 274 A colour value is either explicit RGB value in the standard #rrggbb format
 275 where rr, gg and bb are hexadecimal case-insensitive values in the 00..FF
 276 range, or a symbolic name. Symbolic names are wxSYS_COLOUR_* constants defined
 277 by wxWidgets, written as strings.
 278
 279 Example:
 280
 281     <bg>wxSYS_COLOUR_SCROLLBAR</bg>
 282     <fg>#FF0000</fg>
 283
 284
 285
 286 4. Supported classes
 287 ====================
 288
 289 Attributes are listed in tables in the following format:
 290 attribute name             attribute type          default value, if any
 291                            [(optional remarks....................
 292                            ...................................)]
 293
 294 Common attributes
 295 -----------------
 296 These attributes are supported by all windows:
 297
 298 exstyle                    Int
 299 bg                         Colour
 300 fg                         Colour
 301 enabled                    Boolean                 true
 302 focused                    Boolean                 false
 303 hidden                     Boolean                 false
 304 tooltip                    I18nString
 305 font                       Font
 306 help                       I18nString
 307
 308 wxBitmap
 309 --------
 310 This is a special case, because it does not create a wxWindow instance but
 311 creates wxBitmap instead. Another exceptional thing is that it does not have
 312 any attributes. Instead, the node itself is interpreted as if it were attribute
 313 of type Bitmap.
 314
 315 Example: <object class="wxBitmap">bitmaps/foo.gif</object>
 316
 317
 318 wxIcon
 319 ------
 320 Identical to wxBitmap class, except that it creates wxIcon instead of wxBitmap.
 321
 322
 323 wxButton
 324 --------
 325 pos                        Position                -1,-1
 326 size                       Size                    -1,-1
 327 style                      Style[wxButton]
 328
 329 label                      I18nString
 330 default                    Boolean                 false
 331                            (Is the button default button?)
 332
 333
 334 wxCalendarCtrl
 335 --------------
 336 pos                        Position                -1,-1
 337 size                       Size                    -1,-1
 338 style                      Style[wxCalendarCtrl]
 339
 340
 341 wxCheckBox
 342 ----------
 343 pos                        Position                -1,-1
 344 size                       Size                    -1,-1
 345 style                      Style[wxCheckBox]
 346 checked                    Boolean                 false
 347
 348
 349 wxCheckList
 350 -----------
 351 pos                        Position                -1,-1
 352 size                       Size                    -1,-1
 353 style                      Style[wxCheckList]
 354 content                    (see below)             (empty)
 355
 356 Optional "content" attribute does not have attribute value. Instead,
 357 arbitrary number of <item> nodes may be rooted under it (the control
 358 is filled with strings contained in these nodes). Each <item>
 359 node must contain I18nString value and may have "checked" property
 360 with possible values "0" or "1" indicating the the item is initially
 361 checked.
 362
 363 Example:
 364 <object class="wxCheckList">
 365     <content>
 366       <item>One</item>
 367       <item checked="1">Two</item>
 368       <item checked="1">Three</item>
 369       <item>Four</item>
 370     </content>
 371 </object>
 372
 373
 374 wxDatePickerCtrl
 375 ----------------
 376 pos                        Position                -1,-1
 377 size                       Size                    -1,-1
 378 style                      Style[wxDatePickerCtrl]
 379
 380
 381 wxDialog
 382 --------
 383 pos                        Position                -1,-1
 384 size                       Size                    -1,-1
 385 style                      Style[wxDialog]         wxDEFAULT_DIALOG_STYLE
 386 title                      I18nString              ""
 387 icon                       Bitmap                  (empty)
 388 centered                   Boolean                 false
 389
 390 wxDialog may have children objects.
 391
 392
 393 wxFrame
 394 --------
 395 pos                        Position                -1,-1
 396 size                       Size                    -1,-1
 397 style                      Style[wxDialog]         wxDEFAULT_FRAME_STYLE
 398 title                      I18nString              ""
 399 icon                       Bitmap                  (empty)
 400 centered                   Boolean                 false
 401
 402 wxFrame may have children objects. There can be at most one wxToolBar,
 403 wxMenuBar and wxStatusBar children; objects of these types are automatically
 404 set as frame's tool-, menu- and statusbar respectively.
 405
 406
 407 wxMDIParentFrame
 408 ----------------
 409
 410 Supports same attributes and children nodes as wxFrame. Additionally, children
 411 may be of the wxMDIChildFrame type.
 412
 413
 414 wxMDIChildFrame
 415 ---------------
 416
 417 Supports same attributes and children nodes as wxFrame.
 418
 419
 420 wxRadioBox
 421 ----------
 422
 423 This control may have "dimension" (major dimension) and (initial) "selection"
 424 Integer subelements and a composite "content" element similar to wxCheckList.
 425 The only difference is that the "item" subelements can have an optional
 426 "tooltip=I18nString" and "helptext=I18nString" attributes to specify
 427 the per-item tooltip and helptext.
 428
 429
 430 wxScrolledWindow
 431 ----------------
 432 pos                        Position                -1,-1
 433 size                       Size                    -1,-1
 434 style                      Style[wxScrolledWindow] wxHSCROLL | wxVSCROLL
 435 scrollrate                 Size                    0,0
 436
 437 wxScolledWindow may have children objects.
 438
 439
 440 wxSplitterWindow
 441 ----------------
 442 pos                        Position                -1,-1
 443 size                       Size                    -1,-1
 444 style                      Style[wxSplitterWindow] wxSP_3D
 445 sashpos                    Integer                 0
 446                            (Initial sash position)
 447 minsize                    Integer                 -1
 448                            (Minimal panel size)
 449 orientation                "horizontal"|"vertical" horizontal
 450
 451 wxSplitterWindow must have at least one and at most two children objects.
 452 If there's only one child object, it is passed to wxSplitterWindow::Initialize
 453 and the splitter is created unsplit. If there are two children, the
 454 splitter is created split, either horizontally or vertically depending
 455 on the value of "orientation" attribute.
 456
 457
 458 wxStaticText
 459 ------------
 460
 461 wxStaticText supports one class-specific attribute which wraps the controls
 462 contents at the specified boundary:
 463
 464 wrap                       Integer, in pixels     None
 465
 466 wxStatusBar
 467 -----------
 468 fields                     Integer number of fields
 469 widths                     Width1, Width2, Width3, ...
 470
 471
 472 wxToolBar
 473 ---------
 474 pos                        Position                -1,-1
 475 size                       Size                    -1,-1
 476 style                      Style[wxToolBar]        wxNO_BORDER|wxTB_HORIZONTAL
 477 bitmapsize                 Size                    -1,-1
 478                            (Size of contained bitmaps)
 479 margins                    Size                    -1,-1
 480 packing                    Integer                 -1
 481 separation                 Integer                 -1
 482 bg                         Background colour       None
 483 dontattachtoframe          Boolean                 False
 484
 485 wxToolBar node may have children <object> and <object_ref> nodes. Their class
 486 may be either "tool", "separator" or any wxWidgets class derived from
 487 wxControl. "tool" and "separator" are special pseudo-classes that may only
 488 appear within wxToolBar node. Their attributes are as follows:
 489
 490     separator
 491     ---------
 492     (doesn't have any attributes)
 493
 494     tool
 495     ----
 496     bitmap                 Bitmap
 497     bitmap2                Bitmap                  wxNullBitmap
 498     toggle                 Boolean                 0
 499     radio                  Boolean                 0
 500     disabled               Boolean                 0
 501     label                  I18nString              ""
 502     tooltip                I18nString              ""
 503     longhelp               I18nString              ""
 504
 505     Constraints:
 506       At most one of "toggle" and "radio" attributes may be 1.
 507
 508 Children objects are added to the toolbar using AddTool for "tool" class,
 509 AddSeparator for "separator" and AddControl for other classes.
 510
 511
 512
 513 5. More features
 514 ================
 515
 516 FIXME -- "platform" property handling
 517
 518
 519 === EOF ===
 520
 521 Version: $Id$