include/wx/msw/dib.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/msw/dib.h
   3 // Purpose:     wxDIB class representing Win32 device independent bitmaps
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     03.03.03 (replaces the old file with the same name)
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 1997-2003 wxWidgets team
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_MSW_DIB_H_
  13 #define _WX_MSW_DIB_H_
  14
  15 class WXDLLIMPEXP_FWD_CORE wxBitmap;
  16 class WXDLLIMPEXP_FWD_CORE wxPalette;
  17
  18 #include "wx/msw/private.h"
  19
  20 #if wxUSE_WXDIB
  21
  22 // ----------------------------------------------------------------------------
  23 // wxDIB: represents a DIB section
  24 // ----------------------------------------------------------------------------
  25
  26 class WXDLLIMPEXP_CORE wxDIB
  27 {
  28 public:
  29     // ctors and such
  30     // --------------
  31
  32     // create an uninitialized DIB with the given width, height and depth (only
  33     // 24 and 32 bpp DIBs are currently supported)
  34     //
  35     // after using this ctor, GetData() and GetHandle() may be used if IsOk()
  36     // returns true
  37     wxDIB(int width, int height, int depth)
  38         { Init(); (void)Create(width, height, depth); }
  39
  40     // create a DIB from the DDB
  41     wxDIB(const wxBitmap& bmp)
  42         { Init(); (void)Create(bmp); }
  43
  44     // create a DIB from the Windows DDB
  45     wxDIB(HBITMAP hbmp)
  46         { Init(); (void)Create(hbmp); }
  47
  48     // load a DIB from file (any depth is supoprted here unlike above)
  49     //
  50     // as above, use IsOk() to see if the bitmap was loaded successfully
  51     wxDIB(const wxString& filename)
  52         { Init(); (void)Load(filename); }
  53
  54     // same as the corresponding ctors but with return value
  55     bool Create(int width, int height, int depth);
  56     bool Create(const wxBitmap& bmp) { return Create(GetHbitmapOf(bmp)); }
  57     bool Create(HBITMAP hbmp);
  58     bool Load(const wxString& filename);
  59
  60     // dtor is not virtual, this class is not meant to be used polymorphically
  61     ~wxDIB();
  62
  63
  64     // operations
  65     // ----------
  66
  67 #ifndef __WXWINCE__
  68     // create a bitmap compatible with the given HDC (or screen by default) and
  69     // return its handle, the caller is responsible for freeing it (using
  70     // DeleteObject())
  71     HBITMAP CreateDDB(HDC hdc = 0) const;
  72 #endif // !__WXWINCE__
  73
  74     // get the handle from the DIB and reset it, i.e. this object won't destroy
  75     // the DIB after this (but the caller should do it)
  76     HBITMAP Detach() { HBITMAP hbmp = m_handle; m_handle = 0; return hbmp; }
  77
  78 #if wxUSE_PALETTE
  79     // create a palette for this DIB (always a trivial/default one for 24bpp)
  80     wxPalette *CreatePalette() const;
  81 #endif // wxUSE_PALETTE
  82
  83     // save the DIB as a .BMP file to the file with the given name
  84     bool Save(const wxString& filename);
  85
  86
  87     // accessors
  88     // ---------
  89
  90     // return true if DIB was successfully created, false otherwise
  91     bool IsOk() const { return m_handle != 0; }
  92
  93     // get the bitmap size
  94     wxSize GetSize() const { DoGetObject(); return wxSize(m_width, m_height); }
  95     int GetWidth() const { DoGetObject(); return m_width; }
  96     int GetHeight() const { DoGetObject(); return m_height; }
  97
  98     // get the number of bits per pixel, or depth
  99     int GetDepth() const { DoGetObject(); return m_depth; }
 100
 101     // get the DIB handle
 102     HBITMAP GetHandle() const { return m_handle; }
 103
 104     // get raw pointer to bitmap bits, you should know what you do if you
 105     // decide to use it
 106     unsigned char *GetData() const
 107         { DoGetObject(); return (unsigned char *)m_data; }
 108
 109
 110     // HBITMAP conversion
 111     // ------------------
 112
 113     // these functions are only used by wxWidgets internally right now, please
 114     // don't use them directly if possible as they're subject to change
 115
 116 #ifndef __WXWINCE__
 117     // creates a DDB compatible with the given (or screen) DC from either
 118     // a plain DIB or a DIB section (in which case the last parameter must be
 119     // non NULL)
 120     static HBITMAP ConvertToBitmap(const BITMAPINFO *pbi,
 121                                    HDC hdc = 0,
 122                                    void *bits = NULL);
 123
 124     // create a plain DIB (not a DIB section) from a DDB, the caller is
 125     // responsable for freeing it using ::GlobalFree()
 126     static HGLOBAL ConvertFromBitmap(HBITMAP hbmp);
 127
 128     // creates a DIB from the given DDB or calculates the space needed by it:
 129     // if pbi is NULL, only the space is calculated, otherwise pbi is supposed
 130     // to point at BITMAPINFO of the correct size which is filled by this
 131     // function (this overload is needed for wxBitmapDataObject code in
 132     // src/msw/ole/dataobj.cpp)
 133     static size_t ConvertFromBitmap(BITMAPINFO *pbi, HBITMAP hbmp);
 134 #endif // __WXWINCE__
 135
 136
 137     // wxImage conversion
 138     // ------------------
 139
 140 #if wxUSE_IMAGE
 141     // Possible formats for DIBs created by the functions below.
 142     enum PixelFormat
 143     {
 144         PixelFormat_PreMultiplied = 0,
 145         PixelFormat_NotPreMultiplied = 1
 146     };
 147
 148     // Create a DIB from the given image, the DIB will be either 24 or 32 (if
 149     // the image has alpha channel) bpp.
 150     //
 151     // By default the DIB stores pixel data in pre-multiplied format so that it
 152     // can be used with ::AlphaBlend() but it is also possible to disable
 153     // pre-multiplication for the DIB to be usable with ImageList_Draw() which
 154     // does pre-multiplication internally.
 155     wxDIB(const wxImage& image, PixelFormat pf = PixelFormat_PreMultiplied)
 156     {
 157         Init();
 158         (void)Create(image, pf);
 159     }
 160
 161     // same as the above ctor but with the return code
 162     bool Create(const wxImage& image, PixelFormat pf = PixelFormat_PreMultiplied);
 163
 164     // create wxImage having the same data as this DIB
 165     wxImage ConvertToImage() const;
 166 #endif // wxUSE_IMAGE
 167
 168
 169     // helper functions
 170     // ----------------
 171
 172     // return the size of one line in a DIB with given width and depth: the
 173     // point here is that as the scan lines need to be DWORD aligned so we may
 174     // need to add some padding
 175     static unsigned long GetLineSize(int width, int depth)
 176     {
 177         return ((width*depth + 31) & ~31) >> 3;
 178     }
 179
 180 private:
 181     // common part of all ctors
 182     void Init();
 183
 184     // free resources
 185     void Free();
 186
 187     // initialize the contents from the provided DDB (Create() must have been
 188     // already called)
 189     bool CopyFromDDB(HBITMAP hbmp);
 190
 191
 192     // the DIB section handle, 0 if invalid
 193     HBITMAP m_handle;
 194
 195     // NB: we could store only m_handle and not any of the other fields as
 196     //     we may always retrieve them from it using ::GetObject(), but we
 197     //     decide to still store them for efficiency concerns -- however if we
 198     //     don't have them from the very beginning (e.g. DIB constructed from a
 199     //     bitmap), we only retrieve them when necessary and so these fields
 200     //     should *never* be accessed directly, even from inside wxDIB code
 201
 202     // function which must be called before accessing any members and which
 203     // gets their values from m_handle, if not done yet
 204     void DoGetObject() const;
 205
 206     // pointer to DIB bits, may be NULL
 207     void *m_data;
 208
 209     // size and depth of the image
 210     int m_width,
 211         m_height,
 212         m_depth;
 213
 214     // in some cases we could be using a handle which we didn't create and in
 215     // this case we shouldn't free it neither -- this flag tell us if this is
 216     // the case
 217     bool m_ownsHandle;
 218
 219
 220     // DIBs can't be copied
 221     wxDIB(const wxDIB&);
 222     wxDIB& operator=(const wxDIB&);
 223 };
 224
 225 // ----------------------------------------------------------------------------
 226 // inline functions implementation
 227 // ----------------------------------------------------------------------------
 228
 229 inline
 230 void wxDIB::Init()
 231 {
 232     m_handle = 0;
 233     m_ownsHandle = true;
 234
 235     m_data = NULL;
 236
 237     m_width =
 238     m_height =
 239     m_depth = 0;
 240 }
 241
 242 inline
 243 void wxDIB::Free()
 244 {
 245     if ( m_handle && m_ownsHandle )
 246     {
 247         if ( !::DeleteObject(m_handle) )
 248         {
 249             wxLogLastError(wxT("DeleteObject(hDIB)"));
 250         }
 251
 252         Init();
 253     }
 254 }
 255
 256 inline wxDIB::~wxDIB()
 257 {
 258     Free();
 259 }
 260
 261 #endif
 262     // wxUSE_WXDIB
 263
 264 #endif // _WX_MSW_DIB_H_
 265