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