interface/metafile.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        metafile.h
   3 // Purpose:     documentation for wxMetafileDC class
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxMetafileDC
  11     @wxheader{metafile.h}
  12
  13     This is a type of device context that allows a metafile object to be
  14     created (Windows only), and has most of the characteristics of a normal
  15     @b wxDC. The wxMetafileDC::Close member must be called after drawing into the
  16     device context, to return a metafile. The only purpose for this at
  17     present is to allow the metafile to be copied to the clipboard (see wxMetafile).
  18
  19     Adding metafile capability to an application should be easy if you
  20     already write to a wxDC; simply pass the wxMetafileDC to your drawing
  21     function instead. You may wish to conditionally compile this code so it
  22     is not compiled under X (although no harm will result if you leave it
  23     in).
  24
  25     Note that a metafile saved to disk is in standard Windows metafile format,
  26     and cannot be imported into most applications. To make it importable,
  27     call the function ::wxMakeMetafilePlaceable after
  28     closing your disk-based metafile device context.
  29
  30     @library{wxcore}
  31     @category{dc}
  32
  33     @seealso
  34     wxMetafile, wxDC
  35 */
  36 class wxMetafileDC : public wxDC
  37 {
  38 public:
  39     /**
  40         Constructor. If no filename is passed, the metafile is created
  41         in memory.
  42     */
  43     wxMetafileDC(const wxString& filename = "");
  44
  45     /**
  46         Destructor.
  47     */
  48     ~wxMetafileDC();
  49
  50     /**
  51         This must be called after the device context is finished with. A
  52         metafile is returned, and ownership of it passes to the calling
  53         application (so it should be destroyed explicitly).
  54     */
  55     wxMetafile * Close();
  56 };
  57
  58
  59 /**
  60     @class wxMetafile
  61     @wxheader{metafile.h}
  62
  63     A @b wxMetafile represents the MS Windows metafile object, so metafile
  64     operations have no effect in X. In wxWidgets, only sufficient functionality
  65     has been provided for copying a graphic to the clipboard; this may be extended
  66     in a future version. Presently, the only way of creating a metafile
  67     is to use a wxMetafileDC.
  68
  69     @library{wxcore}
  70     @category{FIXME}
  71
  72     @seealso
  73     wxMetafileDC
  74 */
  75 class wxMetafile : public wxObject
  76 {
  77 public:
  78     /**
  79         Constructor. If a filename is given, the Windows disk metafile is
  80         read in. Check whether this was performed successfully by
  81         using the @ref isok() wxMetafile:IsOk member.
  82     */
  83     wxMetafile(const wxString& filename = "");
  84
  85     /**
  86         Destructor.
  87         See @ref overview_refcountdestruct "reference-counted object destruction" for
  88         more info.
  89     */
  90     ~wxMetafile();
  91
  92     /**
  93         Returns @true if the metafile is valid.
  94     */
  95 #define bool Ok()     /* implementation is private */
  96
  97     /**
  98         Plays the metafile into the given device context, returning
  99         @true if successful.
 100     */
 101     bool Play(wxDC * dc);
 102
 103     /**
 104         Passes the metafile data to the clipboard. The metafile can no longer be
 105         used for anything, but the wxMetafile object must still be destroyed by
 106         the application.
 107
 108         Below is a example of metafile, metafile device context and clipboard use
 109         from the @c hello.cpp example. Note the way the metafile dimensions
 110         are passed to the clipboard, making use of the device context's ability
 111         to keep track of the maximum extent of drawing commands.
 112     */
 113     bool SetClipboard(int width = 0, int height = 0);
 114 };
 115
 116
 117 // ============================================================================
 118 // Global functions/macros
 119 // ============================================================================
 120
 121 /**
 122     Given a filename for an existing, valid metafile (as constructed using
 123     wxMetafileDC)
 124     makes it into a placeable metafile by prepending a header containing the given
 125     bounding box. The bounding box may be obtained from a device context after
 126     drawing
 127     into it, using the functions wxDC::MinX, wxDC::MinY, wxDC::MaxX and wxDC::MaxY.
 128
 129     In addition to adding the placeable metafile header, this function adds
 130     the equivalent of the following code to the start of the metafile data:
 131     @code
 132     SetMapMode(dc, MM_ANISOTROPIC);
 133      SetWindowOrg(dc, minX, minY);
 134      SetWindowExt(dc, maxX - minX, maxY - minY);
 135     @endcode
 136
 137     This simulates the wxMM_TEXT mapping mode, which wxWidgets assumes.
 138
 139     Placeable metafiles may be imported by many Windows applications, and can be
 140     used in RTF (Rich Text Format) files.
 141
 142     @e scale allows the specification of scale for the metafile.
 143
 144     This function is only available under Windows.
 145 */
 146 bool wxMakeMetafilePlaceable(const wxString& filename, int minX,
 147                              int minY,
 148                              int maxX,
 149                              int maxY,
 150                              float scale=1.0);
 151