interface/renderer.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        renderer.h
   3 // Purpose:     interface of wxSplitterRenderParams
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxSplitterRenderParams
  11     @wxheader{renderer.h}
  12
  13     This is just a simple @c struct used as a return value of
  14     wxRendererNative::GetSplitterParams.
  15
  16     It doesn't have any methods and all of its fields are constant and so can be
  17     only examined but not modified.
  18
  19     @library{wxbase}
  20     @category{FIXME}
  21 */
  22 class wxSplitterRenderParams
  23 {
  24 public:
  25     /**
  26         const wxCoord border
  27         The width of the border drawn by the splitter inside it, may be 0.
  28     */
  29
  30
  31     /**
  32         const bool isHotSensitive
  33         @true if the sash changes appearance when the mouse passes over it, @false
  34         otherwise.
  35     */
  36
  37
  38     /**
  39         const wxCoord widthSash
  40         The width of the splitter sash.
  41     */
  42 };
  43
  44
  45
  46 /**
  47     @class wxDelegateRendererNative
  48     @wxheader{renderer.h}
  49
  50     wxDelegateRendererNative allows reuse of renderers code by forwarding all the
  51     wxRendererNative methods to the given object and
  52     thus allowing you to only modify some of its methods -- without having to
  53     reimplement all of them.
  54
  55     Note that the "normal", inheritance-based approach, doesn't work with the
  56     renderers as it is impossible to derive from a class unknown at compile-time
  57     and the renderer is only chosen at run-time. So suppose that you want to only
  58     add something to the drawing of the tree control buttons but leave all the
  59     other methods unchanged -- the only way to do it, considering that the renderer
  60     class which you want to customize might not even be written yet when you write
  61     your code (it could be written later and loaded from a DLL during run-time), is
  62     by using this class.
  63
  64     Except for the constructor, it has exactly the same methods as
  65     wxRendererNative and their implementation is
  66     trivial: they are simply forwarded to the real renderer. Note that the "real"
  67     renderer may, in turn, be a wxDelegateRendererNative as well and that there may
  68     be arbitrarily many levels like this -- but at the end of the chain there must
  69     be a real renderer which does the drawing.
  70
  71     @library{wxcore}
  72     @category{FIXME}
  73 */
  74 class wxDelegateRendererNative : public wxRendererNative
  75 {
  76 public:
  77     //@{
  78     /**
  79         The default constructor does the same thing as the other one except that it
  80         uses the @ref wxRendererNative::getgeneric "generic renderer" instead of the
  81         user-specified @e rendererNative.
  82         In any case, this sets up the delegate renderer object to follow all calls to
  83         the specified real renderer.
  84         Note that this object does not take ownership of (i.e. won't delete)
  85         @e rendererNative.
  86     */
  87     wxDelegateRendererNative();
  88     wxDelegateRendererNative(wxRendererNative& rendererNative);
  89     //@}
  90
  91     /**
  92         This class also provides all the virtual methods of
  93         wxRendererNative, please refer to that class
  94         documentation for the details.
  95     */
  96     DrawXXX(...);
  97 };
  98
  99
 100
 101 /**
 102     @class wxRendererNative
 103     @wxheader{renderer.h}
 104
 105     First, a brief introduction to wxRenderer and why it is needed.
 106
 107     Usually wxWidgets uses the underlying low level GUI system to draw all the
 108     controls - this is what we mean when we say that it is a "native" framework.
 109     However not all controls exist under all (or even any) platforms and in this
 110     case wxWidgets provides a default, generic, implementation of them written in
 111     wxWidgets itself.
 112
 113     These controls don't have the native appearance if only the standard
 114     line drawing and other graphics primitives are used, because the native
 115     appearance is different under different platforms while the lines are always
 116     drawn in the same way.
 117
 118     This is why we have renderers: wxRenderer is a class which virtualizes the
 119     drawing, i.e. it abstracts the drawing operations and allows you to draw say, a
 120     button, without caring about exactly how this is done. Of course, as we
 121     can draw the button differently in different renderers, this also allows us to
 122     emulate the native look and feel.
 123
 124     So the renderers work by exposing a large set of high-level drawing functions
 125     which are used by the generic controls. There is always a default global
 126     renderer but it may be changed or extended by the user, see
 127     @ref overview_samplerender "Render sample".
 128
 129     All drawing functions take some standard parameters:
 130
 131      @e win is the window being drawn. It is normally not used and when
 132     it is it should only be used as a generic wxWindow
 133     (in order to get its low level handle, for example), but you should
 134     not assume that it is of some given type as the same renderer
 135     function may be reused for drawing different kinds of control.
 136      @e dc is the wxDC to draw on. Only this device
 137     context should be used for drawing. It is not necessary to restore
 138     pens and brushes for it on function exit but, on the other hand, you
 139     shouldn't assume that it is in any specific state on function entry:
 140     the rendering functions should always prepare it.
 141      @e rect the bounding rectangle for the element to be drawn.
 142      @e flags the optional flags (none by default) which can be a
 143     combination of the @c wxCONTROL_XXX constants below.
 144
 145     Note that each drawing function restores the wxDC attributes if
 146     it changes them, so it is safe to assume that the same pen, brush and colours
 147     that were active before the call to this function are still in effect after it.
 148
 149     @library{wxcore}
 150     @category{gdi}
 151 */
 152 class wxRendererNative
 153 {
 154 public:
 155     /**
 156         Virtual destructor as for any base class.
 157     */
 158     ~wxRendererNative();
 159
 160     /**
 161         Draw a check box (used by wxDataViewCtrl).
 162         @a flags may have the @c wxCONTROL_CHECKED, @c wxCONTROL_CURRENT or
 163         @c wxCONTROL_UNDETERMINED bit set.
 164     */
 165     void DrawCheckBox(wxWindow* win, wxDC& dc, const wxRect& rect,
 166                       int flags);
 167
 168     /**
 169         Draw a button like the one used by wxComboBox to show a
 170         drop down window. The usual appearance is a downwards pointing arrow.
 171         @a flags may have the @c wxCONTROL_PRESSED or @c wxCONTROL_CURRENT bit set.
 172     */
 173     void DrawComboBoxDropButton(wxWindow* win, wxDC& dc,
 174                                 const wxRect& rect,
 175                                 int flags);
 176
 177     /**
 178         Draw a drop down arrow that is suitable for use outside a combo box. Arrow will
 179         have
 180         transparent background.
 181         @a rect is not entirely filled by the arrow. Instead, you should use bounding
 182         rectangle of a drop down button which arrow matches the size you need.
 183         @a flags may have the @c wxCONTROL_PRESSED or @c wxCONTROL_CURRENT bit set.
 184     */
 185     void DrawDropArrow(wxWindow* win, wxDC& dc, const wxRect& rect,
 186                        int flags);
 187
 188     /**
 189         Draw a focus rectangle using the specified rectangle.
 190         wxListCtrl. The only supported flags is
 191         @c wxCONTROL_SELECTED for items which are selected.
 192     */
 193     void DrawFocusRect(wxWindow* win, wxDC& dc, const wxRect& rect,
 194                        int flags = 0);
 195
 196     /**
 197         Draw the header control button (used, for example, by
 198         wxListCtrl).  Depending on platforms the
 199         @a flags parameter may support the @c wxCONTROL_SELECTED
 200         @c wxCONTROL_DISABLED and @c wxCONTROL_CURRENT bits.
 201         The @a sortArrow parameter can be one of
 202         @c wxHDR_SORT_ICON_NONE, @c wxHDR_SORT_ICON_UP, or
 203         @c wxHDR_SORT_ICON_DOWN.  Additional values controlling the
 204         drawing of a text or bitmap label can be passed in @e params.  The
 205         value returned is the optimal width to contain the the unabreviated
 206         label text or bitmap, the sort arrow if present, and internal margins.
 207     */
 208     int DrawHeaderButton(wxWindow* win, wxDC& dc, const wxRect& rect,
 209                          int flags = 0,
 210                          wxHeaderSortIconType sortArrow = wxHDR_SORT_ICON_NONE,
 211                          wxHeaderButtonParams* params = NULL);
 212
 213     /**
 214         Draw a selection rectangle underneath the text as used e.g. in a
 215         wxListCtrl. The supported @a flags are
 216         @c wxCONTROL_SELECTED for items which are selected (e.g. often a blue
 217         rectangle) and @c wxCONTROL_CURRENT for the item that has the focus
 218         (often a dotted line around the item's text). @c wxCONTROL_FOCUSED may
 219         be used to indicate if the control has the focus (othewise the the selection
 220         rectangle is e.g. often grey and not blue). This may be ignored by the renderer
 221         or deduced by the code directly from the @e win.
 222     */
 223     void DrawItemSelectionRect(wxWindow* win, wxDC& dc,
 224                                const wxRect& rect,
 225                                int flags = 0);
 226
 227     /**
 228         Draw a blank push button that looks very similar to wxButton.
 229         @a flags may have the @c wxCONTROL_PRESSED, @c wxCONTROL_CURRENT or
 230         @c wxCONTROL_ISDEFAULT bit set.
 231     */
 232     void DrawPushButton(wxWindow* win, wxDC& dc, const wxRect& rect,
 233                         int flags);
 234
 235     /**
 236         Draw the border for sash window: this border must be such that the sash
 237         drawn by @ref drawsplittersash() DrawSash blends into it
 238         well.
 239     */
 240     void DrawSplitterBorder(wxWindow* win, wxDC& dc,
 241                             const wxRect& rect,
 242                             int flags = 0);
 243
 244     /**
 245         Draw a sash. The @a orient parameter defines whether the sash should be
 246         vertical or horizontal and how the @a position should be interpreted.
 247     */
 248     void DrawSplitterSash(wxWindow* win, wxDC& dc,
 249                           const wxSize& size,
 250                           wxCoord position,
 251                           wxOrientation orient,
 252                           int flags = 0);
 253
 254     /**
 255         Draw the expanded/collapsed icon for a tree control item. To draw an expanded
 256         button the @a flags parameter must contain @c wxCONTROL_EXPANDED bit.
 257     */
 258     void DrawTreeItemButton(wxWindow* win, wxDC& dc,
 259                             const wxRect& rect,
 260                             int flags = 0);
 261
 262     /**
 263         Return the currently used renderer.
 264     */
 265     wxRendererNative Get();
 266
 267     /**
 268         Return the default (native) implementation for this platform -- this is also
 269         the one used by default but this may be changed by calling
 270         Set() in which case the return value of this
 271         method may be different from the return value of Get().
 272     */
 273     wxRendererNative GetDefault();
 274
 275     /**
 276         Return the generic implementation of the renderer. Under some platforms, this
 277         is the default renderer implementation, others have platform-specific default
 278         renderer which can be retrieved by calling GetDefault().
 279     */
 280     wxRendererNative GetGeneric();
 281
 282     /**
 283         Returns the height of a header button, either a fixed platform height if
 284         available, or a
 285         generic height based on the window's font.
 286     */
 287     int GetHeaderButtonHeight(const wxWindow* win);
 288
 289     /**
 290         Get the splitter parameters, see
 291         wxSplitterRenderParams.
 292     */
 293     wxSplitterRenderParams GetSplitterParams(const wxWindow* win);
 294
 295     /**
 296         This function is used for version checking: Load()
 297         refuses to load any shared libraries implementing an older or incompatible
 298         version.
 299         The implementation of this method is always the same in all renderers (simply
 300         construct wxRendererVersion using the
 301         @c wxRendererVersion::Current_XXX values), but it has to be in the derived,
 302         not base, class, to detect mismatches between the renderers versions and so you
 303         have to implement it anew in all renderers.
 304     */
 305     wxRendererVersion GetVersion() const;
 306
 307     /**
 308         Load the renderer from the specified DLL, the returned pointer must be
 309         deleted by caller if not @NULL when it is not used any more.
 310         The @a name should be just the base name of the renderer and not the full
 311         name of the DLL file which is constructed differently (using
 312         wxDynamicLibrary::CanonicalizePluginName)
 313         on different systems.
 314     */
 315     wxRendererNative* Load(const wxString& name);
 316
 317     /**
 318         Set the renderer to use, passing @NULL reverts to using the default
 319         renderer (the global renderer must always exist).
 320         Return the previous renderer used with Set() or @NULL if none.
 321     */
 322     wxRendererNative* Set(wxRendererNative* renderer);
 323 };
 324
 325
 326
 327 /**
 328     @class wxRendererVersion
 329     @wxheader{renderer.h}
 330
 331     This simple struct represents the wxRendererNative
 332     interface version and is only used as the return value of
 333     wxRendererNative::GetVersion.
 334
 335     The version has two components: the version itself and the age. If the main
 336     program and the renderer have different versions they are never compatible with
 337     each other because the version is only changed when an existing virtual
 338     function is modified or removed. The age, on the other hand, is incremented
 339     each time a new virtual method is added and so, at least for the compilers
 340     using a common C++ object model, the calling program is compatible with any
 341     renderer which has the age greater or equal to its age. This verification is
 342     done by IsCompatible() method.
 343
 344     @library{wxbase}
 345     @category{FIXME}
 346 */
 347 class wxRendererVersion
 348 {
 349 public:
 350     /**
 351         Checks if the main program is compatible with the renderer having the version
 352         @e ver, returns @true if it is and @false otherwise.
 353         This method is used by
 354         wxRendererNative::Load to determine whether a
 355         renderer can be used.
 356     */
 357     static bool IsCompatible(const wxRendererVersion& ver);
 358
 359     /**
 360         const int age
 361         The age component.
 362     */
 363
 364
 365     /**
 366         const int version
 367         The version component.
 368     */
 369 };
 370