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 WXDLLEXPORT wxBitmap;
  16 class WXDLLEXPORT 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 WXDLLEXPORT 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     // load a DIB from file (any depth is supoprted here unlike above)
  45     //
  46     // as above, use IsOk() to see if the bitmap was loaded successfully
  47     wxDIB(const wxString& filename)
  48         { Init(); (void)Load(filename); }
  49
  50     // same as the corresponding ctors but with return value
  51     bool Create(int width, int height, int depth);
  52     bool Create(const wxBitmap& bmp);
  53     bool Load(const wxString& filename);
  54
  55     // dtor is not virtual, this class is not meant to be used polymorphically
  56     ~wxDIB();
  57
  58
  59     // operations
  60     // ----------
  61
  62 #ifndef __WXWINCE__
  63     // create a bitmap compatiblr with the given HDC (or screen by default) and
  64     // return its handle, the caller is responsible for freeing it (using
  65     // DeleteObject())
  66     HBITMAP CreateDDB(HDC hdc = 0) const;
  67 #endif // !__WXWINCE__
  68
  69     // get the handle from the DIB and reset it, i.e. this object won't destroy
  70     // the DIB after this (but the caller should do it)
  71     HBITMAP Detach() { HBITMAP hbmp = m_handle; m_handle = 0; return hbmp; }
  72
  73 #if wxUSE_PALETTE
  74     // create a palette for this DIB (always a trivial/default one for 24bpp)
  75     wxPalette *CreatePalette() const;
  76 #endif // wxUSE_PALETTE
  77
  78     // save the DIB as a .BMP file to the file with the given name
  79     bool Save(const wxString& filename);
  80
  81
  82     // accessors
  83     // ---------
  84
  85     // return true if DIB was successfully created, false otherwise
  86     bool IsOk() const { return m_handle != 0; }
  87
  88     // get the bitmap size
  89     wxSize GetSize() const { DoGetObject(); return wxSize(m_width, m_height); }
  90     int GetWidth() const { DoGetObject(); return m_width; }
  91     int GetHeight() const { DoGetObject(); return m_height; }
  92
  93     // get the number of bits per pixel, or depth
  94     int GetDepth() const { DoGetObject(); return m_depth; }
  95
  96     // get the DIB handle
  97     HBITMAP GetHandle() const { return m_handle; }
  98
  99     // get raw pointer to bitmap bits, you should know what you do if you
 100     // decide to use it
 101     void *GetData() const { DoGetObject(); return m_data; }
 102
 103
 104     // HBITMAP conversion
 105     // ------------------
 106
 107     // these functions are only used by wxWidgets internally right now, please
 108     // don't use them directly if possible as they're subject to change
 109
 110 #ifndef __WXWINCE__
 111     // creates a DDB compatible with the given (or screen) DC from either
 112     // a plain DIB or a DIB section (in which case the last parameter must be
 113     // non NULL)
 114     static HBITMAP ConvertToBitmap(const BITMAPINFO *pbi,
 115                                    HDC hdc = 0,
 116                                    void *bits = NULL);
 117
 118     // create a plain DIB (not a DIB section) from a DDB, the caller is
 119     // responsable for freeing it using ::GlobalFree()
 120     static HGLOBAL ConvertFromBitmap(HBITMAP hbmp);
 121
 122     // creates a DIB from the given DDB or calculates the space needed by it:
 123     // if pbi is NULL, only the space is calculated, otherwise pbi is supposed
 124     // to point at BITMAPINFO of the correct size which is filled by this
 125     // function (this overload is needed for wxBitmapDataObject code in
 126     // src/msw/ole/dataobj.cpp)
 127     static size_t ConvertFromBitmap(BITMAPINFO *pbi, HBITMAP hbmp);
 128 #endif // __WXWINCE__
 129
 130
 131     // wxImage conversion
 132     // ------------------
 133
 134 #if wxUSE_IMAGE
 135     // create a DIB from the given image, the DIB will be either 24 or 32 (if
 136     // the image has alpha channel) bpp
 137     wxDIB(const wxImage& image) { Init(); (void)Create(image); }
 138
 139     // same as the above ctor but with the return code
 140     bool Create(const wxImage& image);
 141
 142     // create wxImage having the same data as this DIB
 143     wxImage ConvertToImage() const;
 144 #endif // wxUSE_IMAGE
 145
 146
 147     // helper functions
 148     // ----------------
 149
 150     // return the size of one line in a DIB with given width and depth: the
 151     // point here is that as the scan lines need to be DWORD aligned so we may
 152     // need to add some padding
 153     static unsigned long GetLineSize(int width, int depth)
 154     {
 155         return ((width*depth + 31) & ~31) >> 3;
 156     }
 157
 158 private:
 159     // common part of all ctors
 160     void Init();
 161
 162     // free resources
 163     void Free();
 164
 165     // initialize the contents from the provided DDB (Create() must have been
 166     // already called)
 167     bool CopyFromDDB(HBITMAP hbmp);
 168
 169
 170     // the DIB section handle, 0 if invalid
 171     HBITMAP m_handle;
 172
 173     // NB: we could store only m_handle and not any of the other fields as
 174     //     we may always retrieve them from it using ::GetObject(), but we
 175     //     decide to still store them for efficiency concerns -- however if we
 176     //     don't have them from the very beginning (e.g. DIB constructed from a
 177     //     bitmap), we only retrieve them when necessary and so these fields
 178     //     should *never* be accessed directly, even from inside wxDIB code
 179
 180     // function which must be called before accessing any members and which
 181     // gets their values from m_handle, if not done yet
 182     void DoGetObject() const;
 183
 184     // pointer to DIB bits, may be NULL
 185     void *m_data;
 186
 187     // size and depth of the image
 188     int m_width,
 189         m_height,
 190         m_depth;
 191
 192     // in some cases we could be using a handle which we didn't create and in
 193     // this case we shouldn't free it neither -- this flag tell us if this is
 194     // the case
 195     bool m_ownsHandle;
 196
 197
 198     // DIBs can't be copied
 199     wxDIB(const wxDIB&);
 200     wxDIB& operator=(const wxDIB&);
 201 };
 202
 203 // ----------------------------------------------------------------------------
 204 // inline functions implementation
 205 // ----------------------------------------------------------------------------
 206
 207 inline
 208 void wxDIB::Init()
 209 {
 210     m_handle = 0;
 211     m_ownsHandle = true;
 212
 213     m_data = NULL;
 214
 215     m_width =
 216     m_height =
 217     m_depth = 0;
 218 }
 219
 220 inline
 221 void wxDIB::Free()
 222 {
 223     if ( m_handle && m_ownsHandle )
 224     {
 225         if ( !::DeleteObject(m_handle) )
 226         {
 227             wxLogLastError(wxT("DeleteObject(hDIB)"));
 228         }
 229
 230         Init();
 231     }
 232 }
 233
 234 inline wxDIB::~wxDIB()
 235 {
 236     Free();
 237 }
 238
 239 #endif
 240     // wxUSE_WXDIB
 241
 242 #endif // _WX_MSW_DIB_H_
 243