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 #ifdef __WXMSW__
  41     // create a DIB from the DDB
  42     wxDIB(const wxBitmap& bmp)
  43         { Init(); (void)Create(bmp); }
  44 #endif // __WXMSW__
  45
  46     // create a DIB from the Windows DDB
  47     wxDIB(HBITMAP hbmp)
  48         { Init(); (void)Create(hbmp); }
  49
  50     // load a DIB from file (any depth is supoprted here unlike above)
  51     //
  52     // as above, use IsOk() to see if the bitmap was loaded successfully
  53     wxDIB(const wxString& filename)
  54         { Init(); (void)Load(filename); }
  55
  56     // same as the corresponding ctors but with return value
  57     bool Create(int width, int height, int depth);
  58 #ifdef __WXMSW__
  59     bool Create(const wxBitmap& bmp) { return Create(GetHbitmapOf(bmp)); }
  60 #endif
  61     bool Create(HBITMAP hbmp);
  62     bool Load(const wxString& filename);
  63
  64     // dtor is not virtual, this class is not meant to be used polymorphically
  65     ~wxDIB();
  66
  67
  68     // operations
  69     // ----------
  70
  71 #ifndef __WXWINCE__
  72     // create a bitmap compatible with the given HDC (or screen by default) and
  73     // return its handle, the caller is responsible for freeing it (using
  74     // DeleteObject())
  75     HBITMAP CreateDDB(HDC hdc = 0) const;
  76 #endif // !__WXWINCE__
  77
  78     // get the handle from the DIB and reset it, i.e. this object won't destroy
  79     // the DIB after this (but the caller should do it)
  80     HBITMAP Detach() { HBITMAP hbmp = m_handle; m_handle = 0; return hbmp; }
  81
  82 #if wxUSE_PALETTE
  83     // create a palette for this DIB (always a trivial/default one for 24bpp)
  84     wxPalette *CreatePalette() const;
  85 #endif // wxUSE_PALETTE
  86
  87     // save the DIB as a .BMP file to the file with the given name
  88     bool Save(const wxString& filename);
  89
  90
  91     // accessors
  92     // ---------
  93
  94     // return true if DIB was successfully created, false otherwise
  95     bool IsOk() const { return m_handle != 0; }
  96
  97     // get the bitmap size
  98     wxSize GetSize() const { DoGetObject(); return wxSize(m_width, m_height); }
  99     int GetWidth() const { DoGetObject(); return m_width; }
 100     int GetHeight() const { DoGetObject(); return m_height; }
 101
 102     // get the number of bits per pixel, or depth
 103     int GetDepth() const { DoGetObject(); return m_depth; }
 104
 105     // get the DIB handle
 106     HBITMAP GetHandle() const { return m_handle; }
 107
 108     // get raw pointer to bitmap bits, you should know what you do if you
 109     // decide to use it
 110     unsigned char *GetData() const
 111         { DoGetObject(); return (unsigned char *)m_data; }
 112
 113
 114     // HBITMAP conversion
 115     // ------------------
 116
 117     // these functions are only used by wxWidgets internally right now, please
 118     // don't use them directly if possible as they're subject to change
 119
 120 #ifndef __WXWINCE__
 121     // creates a DDB compatible with the given (or screen) DC from either
 122     // a plain DIB or a DIB section (in which case the last parameter must be
 123     // non NULL)
 124     static HBITMAP ConvertToBitmap(const BITMAPINFO *pbi,
 125                                    HDC hdc = 0,
 126                                    void *bits = NULL);
 127
 128     // create a plain DIB (not a DIB section) from a DDB, the caller is
 129     // responsable for freeing it using ::GlobalFree()
 130     static HGLOBAL ConvertFromBitmap(HBITMAP hbmp);
 131
 132     // creates a DIB from the given DDB or calculates the space needed by it:
 133     // if pbi is NULL, only the space is calculated, otherwise pbi is supposed
 134     // to point at BITMAPINFO of the correct size which is filled by this
 135     // function (this overload is needed for wxBitmapDataObject code in
 136     // src/msw/ole/dataobj.cpp)
 137     static size_t ConvertFromBitmap(BITMAPINFO *pbi, HBITMAP hbmp);
 138 #endif // __WXWINCE__
 139
 140
 141     // wxImage conversion
 142     // ------------------
 143
 144 #if wxUSE_IMAGE
 145     // Possible formats for DIBs created by the functions below.
 146     enum PixelFormat
 147     {
 148         PixelFormat_PreMultiplied = 0,
 149         PixelFormat_NotPreMultiplied = 1
 150     };
 151
 152     // Create a DIB from the given image, the DIB will be either 24 or 32 (if
 153     // the image has alpha channel) bpp.
 154     //
 155     // By default the DIB stores pixel data in pre-multiplied format so that it
 156     // can be used with ::AlphaBlend() but it is also possible to disable
 157     // pre-multiplication for the DIB to be usable with ImageList_Draw() which
 158     // does pre-multiplication internally.
 159     wxDIB(const wxImage& image, PixelFormat pf = PixelFormat_PreMultiplied)
 160     {
 161         Init();
 162         (void)Create(image, pf);
 163     }
 164
 165     // same as the above ctor but with the return code
 166     bool Create(const wxImage& image, PixelFormat pf = PixelFormat_PreMultiplied);
 167
 168     // create wxImage having the same data as this DIB
 169     wxImage ConvertToImage() const;
 170 #endif // wxUSE_IMAGE
 171
 172
 173     // helper functions
 174     // ----------------
 175
 176     // return the size of one line in a DIB with given width and depth: the
 177     // point here is that as the scan lines need to be DWORD aligned so we may
 178     // need to add some padding
 179     static unsigned long GetLineSize(int width, int depth)
 180     {
 181         return ((width*depth + 31) & ~31) >> 3;
 182     }
 183
 184 private:
 185     // common part of all ctors
 186     void Init();
 187
 188     // free resources
 189     void Free();
 190
 191     // initialize the contents from the provided DDB (Create() must have been
 192     // already called)
 193     bool CopyFromDDB(HBITMAP hbmp);
 194
 195
 196     // the DIB section handle, 0 if invalid
 197     HBITMAP m_handle;
 198
 199     // NB: we could store only m_handle and not any of the other fields as
 200     //     we may always retrieve them from it using ::GetObject(), but we
 201     //     decide to still store them for efficiency concerns -- however if we
 202     //     don't have them from the very beginning (e.g. DIB constructed from a
 203     //     bitmap), we only retrieve them when necessary and so these fields
 204     //     should *never* be accessed directly, even from inside wxDIB code
 205
 206     // function which must be called before accessing any members and which
 207     // gets their values from m_handle, if not done yet
 208     void DoGetObject() const;
 209
 210     // pointer to DIB bits, may be NULL
 211     void *m_data;
 212
 213     // size and depth of the image
 214     int m_width,
 215         m_height,
 216         m_depth;
 217
 218     // in some cases we could be using a handle which we didn't create and in
 219     // this case we shouldn't free it neither -- this flag tell us if this is
 220     // the case
 221     bool m_ownsHandle;
 222
 223
 224     // DIBs can't be copied
 225     wxDIB(const wxDIB&);
 226     wxDIB& operator=(const wxDIB&);
 227 };
 228
 229 // ----------------------------------------------------------------------------
 230 // inline functions implementation
 231 // ----------------------------------------------------------------------------
 232
 233 inline
 234 void wxDIB::Init()
 235 {
 236     m_handle = 0;
 237     m_ownsHandle = true;
 238
 239     m_data = NULL;
 240
 241     m_width =
 242     m_height =
 243     m_depth = 0;
 244 }
 245
 246 inline
 247 void wxDIB::Free()
 248 {
 249     if ( m_handle && m_ownsHandle )
 250     {
 251         if ( !::DeleteObject(m_handle) )
 252         {
 253             wxLogLastError(wxT("DeleteObject(hDIB)"));
 254         }
 255
 256         Init();
 257     }
 258 }
 259
 260 inline wxDIB::~wxDIB()
 261 {
 262     Free();
 263 }
 264
 265 #endif
 266     // wxUSE_WXDIB
 267
 268 #endif // _WX_MSW_DIB_H_
 269