removed virtual modifier from Command handlers, added readonly and color information...

[wxWidgets.git] / src / mac / pnghand.cpp

/////////////////////////////////////////////////////////////////////////////
// Name:        pnghand.cpp
// Purpose:     Implements a PNG reader class + handler
// Author:      Julian Smart
// Modified by: 
// Created:     04/01/98
// RCS-ID:      $Id$
// Copyright:   (c) Julian Smart and Markus Holzem
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

#ifdef __GNUG__
#  pragma implementation "pngread.h"
#  pragma implementation "pnghand.h"
#endif

// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"

#ifdef __BORLANDC__
#  pragma hdrstop
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#if wxUSE_IOSTREAMH
#   include <fstream.h>
#else
#   include <fstream>
#endif

#ifndef __DARWIN__
#  include <windows.h>
#endif
#include "wx/msgdlg.h"
#include "wx/palette.h"
#include "wx/bitmap.h"
#include "wx/mac/pnghand.h"
#include "wx/mac/pngread.h"
#include "wx/mac/private.h"

extern "C" {
#include "png.h"
}

extern "C" void png_read_init PNGARG((png_structp png_ptr));
extern "C" void png_write_init PNGARG((png_structp png_ptr));

extern CTabHandle wxMacCreateColorTable( int numColors ) ;
extern void wxMacDestroyColorTable( CTabHandle colors )  ;
extern void wxMacSetColorTableEntry( CTabHandle newColors , int index , int red , int green ,  int blue ) ;
extern GWorldPtr wxMacCreateGWorld( int width , int height , int depth ) ;
extern void wxMacDestroyGWorld( GWorldPtr gw ) ;

void
ima_png_error(png_struct *png_ptr, char *message)
{
	wxMessageBox(message, "PNG error");
  longjmp(png_ptr->jmpbuf, 1);
}


// static wxGifReaderIter* iter;
wxPalette *wxCopyPalette(const wxPalette *cmap);

wxPNGReader::wxPNGReader(void)
{
  filetype = 0;
  RawImage = NULL;      //  Image data

  Width = 0; Height = 0;       //  Dimensions
  Depth = 0;           // (bits x pixel)
  ColorType = 0;        // Bit 1 = Palette used
                  // Bit 2 = Color used
                  // Bit 3 = Alpha used

  EfeWidth = 0;         // Efective Width

  lpbi = NULL;
  bgindex = -1;
  m_palette = 0;
  imageOK = FALSE;
}

wxPNGReader::wxPNGReader ( char* ImageFileName )
{
  imageOK = FALSE;
  filetype = 0;
  RawImage = NULL;      //  Image data

  Width = 0; Height = 0;       //  Dimensions
  Depth = 0;           // (bits x pixel)
  ColorType = 0;        // Bit 1 = m_palette used
                  // Bit 2 = Color used
                  // Bit 3 = Alpha used

  EfeWidth = 0;         // Efective Width

  lpbi = NULL;
  bgindex = -1;
  m_palette = 0;

  imageOK = ReadFile (ImageFileName);
}

void
wxPNGReader::Create(int width, int height, int depth, int colortype)
{
  Width = width; Height = height; Depth = depth;
  ColorType = (colortype>=0) ? colortype: ((Depth>8) ? COLORTYPE_COLOR: 0);
  delete m_palette;
  m_palette = NULL;
  delete[] RawImage;
  RawImage = NULL;

  if (lpbi) {
  	wxMacDestroyGWorld( (GWorldPtr) lpbi ) ;
  }
  lpbi = wxMacCreateGWorld( Width , Height , Depth);
  if (lpbi)
  {
    EfeWidth = (long)(((long)Width*Depth + 31) / 32) * 4;
    int bitwidth = width ;
    if ( EfeWidth > bitwidth )
    	bitwidth = EfeWidth ;
    	
		RawImage = (byte*) new char[ ( bitwidth * Height * ((Depth+7)>>3) ) ];
    imageOK = TRUE;
  }
}

wxPNGReader::~wxPNGReader ( )
{
    if (RawImage != NULL) {
        delete[] RawImage ;
        RawImage = NULL;
    }
    if (lpbi)  {
  	wxMacDestroyGWorld( (GWorldPtr) lpbi ) ;
        lpbi = NULL;
    }
    if (m_palette != NULL) {
        delete m_palette;
        m_palette = NULL;
    }
}


int wxPNGReader::GetIndex(int x, int y)
{
  if (!Inside(x, y) || (Depth>8)) return -1;

  ImagePointerType ImagePointer = RawImage + EfeWidth*y + (x*Depth >> 3);
  int index = (int)(*ImagePointer);
  return index;
}

bool wxPNGReader::GetRGB(int x, int y, byte* r, byte* g, byte* b)
{
  if (!Inside(x, y)) return FALSE;

  if (m_palette) {
   return m_palette->GetRGB(GetIndex(x, y), r, g, b);
/*   PALETTEENTRY entry;
   ::GetPaletteEntries((HPALETTE) m_palette->GetHPALETTE(), GetIndex(x, y), 1, &entry);
   *r = entry.peRed;
   *g = entry.peGreen;
   *b = entry.peBlue;  */
  } else {
   ImagePointerType ImagePointer = RawImage + EfeWidth*y + (x*Depth >> 3);
   *b = ImagePointer[0];
   *g = ImagePointer[1];
   *r = ImagePointer[2];
  }
  return TRUE;
}


bool wxPNGReader::SetIndex(int x, int y, int index)
{
  if (!Inside(x, y) || (Depth>8)) return FALSE;

  ImagePointerType ImagePointer = RawImage + EfeWidth*y + (x*Depth >> 3);
  *ImagePointer = index;

  return TRUE;
}

bool wxPNGReader::SetRGB(int x, int y, byte r, byte g, byte b)
{
  if (!Inside(x, y)) return FALSE;

  if (ColorType & COLORTYPE_PALETTE)
  {
   if (!m_palette) return FALSE;
   SetIndex(x, y, m_palette->GetPixel(r, g, b));

  } else {
   ImagePointerType ImagePointer = RawImage + EfeWidth*y + (x*Depth >> 3);
   ImagePointer[0] = b;
   ImagePointer[1] = g;
   ImagePointer[2] = r;
  }

  return TRUE;
}

bool wxPNGReader::SetPalette(wxPalette* colourmap)
{
  delete m_palette ;
  if (!colourmap)
   return FALSE;
  ColorType |= (COLORTYPE_PALETTE | COLORTYPE_COLOR);
  m_palette = new wxPalette( *colourmap );
	return true ;
//  return (DibSetUsage(lpbi, (HPALETTE) m_palette->GetHPALETTE(), WXIMA_COLORS ) != 0);
}

bool
wxPNGReader::SetPalette(int n, byte *r, byte *g, byte *b)
{
  delete m_palette ;
  m_palette = new wxPalette();
  if (!m_palette)
   return FALSE;

  if (!g) g = r;
  if (!b) b = g;
  m_palette->Create(n, r, g, b);
  ColorType |= (COLORTYPE_PALETTE | COLORTYPE_COLOR);
	return true ;
//    return (DibSetUsage(lpbi, (HPALETTE) m_palette->GetHPALETTE(), WXIMA_COLORS ) != 0);
}

bool
wxPNGReader::SetPalette(int n, rgb_color_struct *rgb_struct)
{
  delete m_palette ;
  m_palette = new wxPalette();
  if (!m_palette)
   return FALSE;

  byte r[256], g[256], b[256];

  for(int i=0; i<n; i++)
  {
   r[i] = rgb_struct[i].red;
   g[i] = rgb_struct[i].green;
   b[i] = rgb_struct[i].blue;
  }
  // Added by JACS copying from Andrew Davison's additions
  // to GIF-reading code
  // Make transparency colour black...
  if (bgindex != -1)
    r[bgindex] = g[bgindex] = b[bgindex] = 0;

  m_palette->Create(n, r, g, b);
  ColorType |= (COLORTYPE_PALETTE | COLORTYPE_COLOR);
	return true ;
//    return (DibSetUsage(lpbi, (HPALETTE) m_palette->GetHPALETTE(), WXIMA_COLORS ) != 0);
}

void wxPNGReader::NullData()
{
  if (lpbi)  {
  	wxMacDestroyGWorld( (GWorldPtr) lpbi ) ;
        lpbi = NULL;
  }
  if (m_palette != NULL) {
      delete m_palette;
      m_palette = NULL;
  }
}

wxBitmap* wxPNGReader::GetBitmap(void)
{
    wxBitmap *bitmap = new wxBitmap;
    if ( InstantiateBitmap(bitmap) )
        return bitmap;
    else
    {
        delete bitmap;
        return NULL;
    }
}

bool wxPNGReader::InstantiateBitmap(wxBitmap *bitmap)
{
    if ( lpbi )
    {
      bitmap->SetHBITMAP((WXHBITMAP) lpbi);
      bitmap->SetWidth(GetWidth());
      bitmap->SetHeight(GetHeight());
      bitmap->SetDepth(GetDepth());
      if ( GetDepth() > 1 && m_palette )
        bitmap->SetPalette(*m_palette);
      bitmap->SetOk(TRUE);


      // Make a mask if appropriate
      /*
      if ( bgindex > -1 )
      {
        wxMask *mask = CreateMask();
        bitmap->SetMask(mask);
      }
      */
      lpbi = NULL ; // bitmap has taken over ownership
  		return TRUE;
    }
    else
    {
      return FALSE;
    }
/*
  HDC dc = ::CreateCompatibleDC(NULL);

  if (dc)
  {
        // tmpBitmap is a dummy, to satisfy ::CreateCompatibleDC (it
        // is a memory dc that must have a bitmap selected into it)
        HDC dc2 = GetDC(NULL);
        HBITMAP tmpBitmap = ::CreateCompatibleBitmap(dc2, GetWidth(), GetHeight());
        ReleaseDC(NULL, dc2);
        HBITMAP oldBitmap = (HBITMAP) ::SelectObject(dc, tmpBitmap);

        if ( m_palette )
        {
            HPALETTE oldPal = ::SelectPalette(dc, (HPALETTE) m_palette->GetHPALETTE(), FALSE);
        ::RealizePalette(dc);
        }

    HBITMAP hBitmap = ::CreateDIBitmap(dc, lpbi,
        CBM_INIT, RawImage, (LPBITMAPINFO) lpbi, DIB_PAL_COLORS);

        ::SelectPalette(dc, NULL, TRUE);
        ::SelectObject(dc, oldBitmap);
        ::DeleteObject(tmpBitmap);
        ::DeleteDC(dc);

        if ( hBitmap )
        {
          bitmap->SetHBITMAP((WXHBITMAP) hBitmap);
          bitmap->SetWidth(GetWidth());
          bitmap->SetHeight(GetHeight());
          bitmap->SetDepth(GetDepth());
          if ( GetDepth() > 1 && m_palette )
            bitmap->SetPalette(*m_palette);
          bitmap->SetOk(TRUE);


          // Make a mask if appropriate
          if ( bgindex > -1 )
          {
            wxMask *mask = CreateMask();
            bitmap->SetMask(mask);
          }
      return TRUE;
        }
        else
        {
          return FALSE;
        }
  }
  else
    {
    return FALSE;
    }
  */
  return false ;
}

wxPalette *wxCopyPalette(const wxPalette *cmap)
{
  wxPalette *newCmap = new wxPalette( *cmap ) ;
  return newCmap;
}

wxMask *wxPNGReader::CreateMask(void)
{
/*
    HBITMAP hBitmap = ::CreateBitmap(GetWidth(), GetHeight(), 1, 1, NULL);

  HDC dc = ::CreateCompatibleDC(NULL);
    HBITMAP oldBitmap = (HBITMAP) ::SelectObject(dc, hBitmap);

    int bgIndex = GetBGIndex();

    int x,y;

    for (x=0; x<GetWidth(); x++)
    {
        for (y=0; y<GetHeight(); y++)
        {
            int index = GetIndex(x, y);
            if ( index == bgIndex )
                ::SetPixel(dc, x, GetHeight() - y - 1, RGB(0, 0, 0));
            else
                ::SetPixel(dc, x, GetHeight() - y - 1, RGB(255, 255, 255));

      }
    }
    ::SelectObject(dc, oldBitmap);
    wxMask *mask = new wxMask;
    mask->SetMaskBitmap((WXHBITMAP) hBitmap);
    return mask;
   */
   return NULL ;
}

bool wxPNGReader::ReadFile(char * ImageFileName)
{
  int number_passes;

  if (ImageFileName)
   strcpy(filename, ImageFileName);

  FILE *fp;
  png_struct *png_ptr;
   png_info *info_ptr;
  wxPNGReaderIter iter(this);

  /* open the file */
  fp = fopen( ImageFileName , "rb" );

  if (!fp)
    return FALSE;

  /* allocate the necessary structures */
  png_ptr = new (png_struct);
  if (!png_ptr)
  {
    fclose(fp);
    return FALSE;
  }

  info_ptr = new (png_info);
  if (!info_ptr)
  {
    fclose(fp);
    delete png_ptr;
    return FALSE;
  }
  /* set error handling */
  if (setjmp(png_ptr->jmpbuf))
  {
    png_read_destroy(png_ptr, info_ptr, (png_info *)0);
    fclose(fp);
    delete png_ptr;
    delete info_ptr;

    /* If we get here, we had a problem reading the file */
    return FALSE;
  }
        //png_set_error(ima_png_error, NULL);

  /* initialize the structures, info first for error handling */
  png_info_init(info_ptr);
  png_read_init(png_ptr);

  /* set up the input control */
  png_init_io(png_ptr, fp);

  /* read the file information */
  png_read_info(png_ptr, info_ptr);

  /* allocate the memory to hold the image using the fields
    of png_info. */
  png_color_16 my_background={ 0, 31, 127, 255, 0 };

  if (info_ptr->valid & PNG_INFO_bKGD)
    {
    png_set_background(png_ptr, &(info_ptr->background),
      PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
        if ( info_ptr->num_palette > 0 )
            bgindex = info_ptr->background.index;
    }
  else   {
    png_set_background(png_ptr, &my_background,
      PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);

        // Added by JACS: guesswork!
        if ( info_ptr->num_trans != 0 )
            bgindex = info_ptr->num_trans - 1 ;
   }

  /* tell libpng to strip 16 bit depth files down to 8 bits */
  if (info_ptr->bit_depth == 16)
    png_set_strip_16(png_ptr);

  int pixel_depth=(info_ptr->pixel_depth<24) ? info_ptr->pixel_depth: 24;
  Create(info_ptr->width, info_ptr->height, pixel_depth,
    info_ptr->color_type);

  if (info_ptr->num_palette>0)
    {
      SetPalette((int)info_ptr->num_palette, (rgb_color_struct*)info_ptr->palette);
    }

  int row_stride = info_ptr->width * ((pixel_depth+7)>>3);
 //  printf("P = %d D = %d RS= %d ", info_ptr->num_palette, info_ptr->pixel_depth,row_stride);
//  printf("CT = %d TRS = %d BD= %d ", info_ptr->color_type, info_ptr->valid & PNG_INFO_tRNS,info_ptr->bit_depth);

  byte *row_pointers = new byte[row_stride];

  /* turn on interlace handling */
  if (info_ptr->interlace_type)
    number_passes = png_set_interlace_handling(png_ptr);
  else
    number_passes = 1;
//  printf("NP = %d ", number_passes);

  for (int pass=0; pass< number_passes; pass++) 
  {
	  iter.upset();
	  int y=0;
		CGrafPtr 	origPort ;
		GDHandle	origDevice ;
		
		GetGWorld( &origPort , &origDevice ) ;
		// ignore shapedc
		SetGWorld( (GWorldPtr) lpbi , NULL ) ;
	  do  
	  {
	//    (unsigned char *)iter.GetRow();
	    if (info_ptr->interlace_type)  
	    {
	     if (pass>0)
	      iter.GetRow(row_pointers, row_stride);
	     png_read_row(png_ptr, row_pointers, NULL);
	    }
	    else
	     png_read_row(png_ptr, row_pointers, NULL);
			
			if ( info_ptr->palette )
			{
				if ( pixel_depth == 8 )
				{
					for ( int i = 0 ; i < info_ptr->width ; ++i )
					{
						png_color_struct* color ; 
						RGBColor col ;

						int index = row_pointers[i] ;
						color = &info_ptr->palette[index] ;
						col.red = (((int)color->red) << 8) | ((int)color->red) ;
						col.green = (((int)color->green) << 8) | ((int)color->green) ;
						col.blue = (((int)color->blue) << 8) | ((int)color->blue) ;
						SetCPixel( i, y, &col);
					}
					/*
					png_color_struct* color ; 
					RGBColor col ;
					unsigned char* p = &row_pointers[0] ;
					PenNormal() ;
					MoveTo( 0 , y ) ;
					int index = *p ;
					color = &info_ptr->palette[index] ;
					col.red = (color->red << 8) | color->red ;
					col.green = (color->green << 8) | color->green ;
					col.blue = (color->blue << 8) | color->blue ;
					RGBForeColor( &col ) ;
					col.red = col.green = col.blue = 0xFFFF ;
					RGBBackColor( &col ) ;
					for ( int i = 0 ; i < info_ptr->width ; ++i , ++p)
					{
						if ( *p != index )
						{
							LineTo( i , y ) ;
							index = *p ;
							color = &info_ptr->palette[index] ;
							col.red = (((int)color->red) << 8) | ((int)color->red) ;
							col.green = (((int)color->green) << 8) | ((int)color->green) ;
							col.blue = (((int)color->blue) << 8) | ((int)color->blue) ;
							RGBForeColor( &col ) ;
						}
					}
					LineTo( info_ptr->width  , y ) ;
					*/
				}
				else
				{
					for ( int i = 0 ; i < info_ptr->width ; ++i )
					{
						png_color_struct* color ; 
						RGBColor col ;

						int byte = ( i * pixel_depth ) / 8 ;
						int offset = ( 8 - pixel_depth ) - ( i * pixel_depth ) % 8 ;
							
						int index = ( row_pointers[byte] >> offset ) & ( 0xFF >> ( 8 - pixel_depth ) );
						color = &info_ptr->palette[index] ;
						col.red = (((int)color->red) << 8) | ((int)color->red) ;
						col.green = (((int)color->green) << 8) | ((int)color->green) ;
						col.blue = (((int)color->blue) << 8) | ((int)color->blue) ;
						SetCPixel( i, y, &col);
					}
				}
			}
			else
			{
				for ( int i = 0 ; i < info_ptr->width ; ++i )
				{
					png_color_struct* color ; 
					RGBColor col ;
					color =(png_color_struct*) (&row_pointers[i*3]) ;
					col.red = (((int)color->red) << 8) | ((int)color->red) ;
					col.green = (((int)color->green) << 8) | ((int)color->green) ;
					col.blue = (((int)color->blue) << 8) | ((int)color->blue) ;
					SetCPixel( i, y, &col);
				}
			}
			if (number_passes)
				iter.SetRow(row_pointers, row_stride);
	    y++;
	  } 
	  while(iter.PrevRow());
	  SetGWorld( origPort , origDevice ) ;

//  printf("Y=%d ",y);
  }
  delete[] row_pointers;

  /* read the rest of the file, getting any additional chunks
    in info_ptr */
  png_read_end(png_ptr, info_ptr);

  /* clean up after the read, and free any memory allocated */
  png_read_destroy(png_ptr, info_ptr, (png_info *)0);

  /* free the structures */
  delete png_ptr;
  delete info_ptr;

  /* close the file */
  fclose(fp);

  /* that's it */
  return TRUE;
}


/* write a png file */

bool wxPNGReader::SaveFile(char * ImageFileName)
{
  if (ImageFileName)
   strcpy(filename, ImageFileName);

  wxPNGReaderIter iter(this);
  FILE *fp;
   png_struct *png_ptr;
  png_info *info_ptr;

   /* open the file */
  fp = fopen(filename, "wb");
  if (!fp)
    return FALSE;

  /* allocate the necessary structures */
  png_ptr = new (png_struct);
  if (!png_ptr)
  {
    fclose(fp);
    return FALSE;
  }

  info_ptr = new (png_info);
  if (!info_ptr)
  {
    fclose(fp);
    delete png_ptr;
    return FALSE;
  }

  /* set error handling */
  if (setjmp(png_ptr->jmpbuf))
  {
    png_write_destroy(png_ptr);
    fclose(fp);
    delete png_ptr;
    delete info_ptr;

    /* If we get here, we had a problem reading the file */
    return FALSE;
  }
        //png_set_error(ima_png_error, NULL);

//  printf("writig pg %s ", filename);
   /* initialize the structures */
  png_info_init(info_ptr);
  png_write_init(png_ptr);

  int row_stride = GetWidth() * ((GetDepth()+7)>>3);
  /* set up the output control */
   png_init_io(png_ptr, fp);

  /* set the file information here */
  info_ptr->width = GetWidth();
  info_ptr->height = GetHeight();
  info_ptr->pixel_depth = GetDepth();
  info_ptr->channels = (GetDepth()>8) ? 3: 1;
  info_ptr->bit_depth = GetDepth()/info_ptr->channels;
  info_ptr->color_type = GetColorType();
  info_ptr->compression_type = info_ptr->filter_type = info_ptr->interlace_type=0;
  info_ptr->valid = 0;
  info_ptr->rowbytes = row_stride;


// printf("P = %d D = %d RS= %d GD= %d CH= %d ", info_ptr->pixel_depth, info_ptr->bit_depth, row_stride, GetDepth(), info_ptr->channels);
  /* set the palette if there is one */
  if ((GetColorType() & COLORTYPE_PALETTE) && GetPalette())
  {
//    printf("writing paleta[%d %d %x]",GetColorType() ,COLORTYPE_PALETTE, GetPalette());
    info_ptr->valid |= PNG_INFO_PLTE;
    info_ptr->palette = new png_color[256];
    info_ptr->num_palette = 256;
    for (int i=0; i<256; i++)
     GetPalette()->GetRGB(i, &info_ptr->palette[i].red, &info_ptr->palette[i].green, &info_ptr->palette[i].blue);
  }
//    printf("Paleta [%d %d %x]",GetColorType() ,COLORTYPE_PALETTE, GetPalette());


   /* optional significant bit chunk */
//   info_ptr->valid |= PNG_INFO_sBIT;
//   info_ptr->sig_bit = true_bit_depth;

  /* optional gamma chunk */
//   info_ptr->valid |= PNG_INFO_gAMA;
//   info_ptr->gamma = gamma;

  /* other optional chunks */

   /* write the file information */
   png_write_info(png_ptr, info_ptr);

   /* set up the transformations you want.  Note that these are
      all optional.  Only call them if you want them */

  /* shift the pixels up to a legal bit depth and fill in
      as appropriate to correctly scale the image */
//   png_set_shift(png_ptr, &(info_ptr->sig_bit));

  /* pack pixels into bytes */
//   png_set_packing(png_ptr);

  /* flip bgr pixels to rgb */
//   png_set_bgr(png_ptr);

   /* swap bytes of 16 bit files to most significant bit first */
//   png_set_swap(png_ptr);

   /* get rid of filler bytes, pack rgb into 3 bytes */
//   png_set_rgbx(png_ptr);

/* If you are only writing one row at a time, this works */

  byte *row_pointers = new byte[row_stride];
    iter.upset();
  do  {
//    (unsigned char *)iter.GetRow();
    iter.GetRow(row_pointers, row_stride);
    png_write_row(png_ptr, row_pointers);
  } while(iter.PrevRow());

        delete[] row_pointers;

/* write the rest of the file */
   png_write_end(png_ptr, info_ptr);

  /* clean up after the write, and free any memory allocated */
   png_write_destroy(png_ptr);

   /* if you malloced the palette, free it here */
   if (info_ptr->palette)
    delete[] (info_ptr->palette);

  /* free the structures */
  delete png_ptr;
  delete info_ptr;

  /* close the file */
  fclose(fp);

  /* that's it */
  return TRUE;
}

static int Power(int x, int y)
{
    int z = 1;
    int i;
    for ( i = 0; i < y; i++)
    {
        z *= x;
    }
    return z;
}

static char hexArray[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B',
  'C', 'D', 'E', 'F' };

static void DecToHex(int dec, char *buf)
{
  int firstDigit = (int)(dec/16.0);
  int secondDigit = (int)(dec - (firstDigit*16.0));
  buf[0] = hexArray[firstDigit];
  buf[1] = hexArray[secondDigit];
  buf[2] = 0;
}


bool wxPNGReader::SaveXPM(char *filename, char *name)
{
    char nameStr[256];
    if ( name )
        strcpy(nameStr, name);
    else
    {
        strcpy(nameStr, filename);
        wxStripExtension(nameStr);
    }

    if ( GetDepth() > 4 )
    {
        // Only a depth of 4 and below allowed
        return FALSE;
    }

    if ( !GetPalette() )
        return FALSE;

    wxSTD ofstream str(filename);
    if ( str.bad() )
        return FALSE;

    int noColours = Power(2, GetDepth());

    // Output header
    str << "/* XPM */\n";
    str << "static char * " << nameStr << "_xpm[] = {\n";
    str << "\"" << GetWidth() << " " << GetHeight() << " " << noColours << " 1\",\n";

    // Output colourmap
    int base = 97 ; // start from 'a'

    unsigned char red, green, blue;
    char hexBuf[4];
    int i;
    for ( i = 0; i < noColours; i ++)
    {
        str << "\"" << (char)(base + i) << "      c #";
        GetPalette()->GetRGB(i, &red, &green, &blue);
        DecToHex(red, hexBuf);
        str << hexBuf;
        DecToHex(green, hexBuf);
        str << hexBuf;
        DecToHex(blue, hexBuf);
        str << hexBuf;
        str << "\",\n";
    }

    // Output the data
    int x, y;
    for ( y = 0; y < GetHeight(); y++)
    {
        str << "\"";
        for ( x = 0; x < GetWidth(); x++)
        {
            int index = GetIndex(x, y);
            str << (char)(base + index) ;
        }
        str << "\",\n";
    }

    str << "};\n";
    str.flush();

    return TRUE;
}


IMPLEMENT_DYNAMIC_CLASS(wxPNGFileHandler, wxBitmapHandler)

bool wxPNGFileHandler::LoadFile(wxBitmap *bitmap, const wxString& name, long flags,
    int desiredWidth, int desiredHeight)
{
    wxPNGReader reader;
    if (reader.ReadFile((char*) (const char*) name))
    {
        return reader.InstantiateBitmap(bitmap);
    }
    else
        return FALSE;
}

bool wxPNGFileHandler::SaveFile(const wxBitmap *bitmap, const wxString& name, int type, const wxPalette *pal)
{
    return FALSE;
}