f773e9b0bb
it breaks other PNGs). git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@30930 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
730 lines
23 KiB
C++
730 lines
23 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: src/common/imagepng.cpp
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// Purpose: wxImage PNG handler
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// Author: Robert Roebling
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// RCS-ID: $Id$
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// Copyright: (c) Robert Roebling
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// Licence: wxWindows licence
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/////////////////////////////////////////////////////////////////////////////
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// ============================================================================
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// declarations
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// ============================================================================
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#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
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#pragma implementation "imagpng.h"
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#endif
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// ----------------------------------------------------------------------------
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// headers
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// ----------------------------------------------------------------------------
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// For compilers that support precompilation, includes "wx.h".
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#include "wx/wxprec.h"
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#ifdef __BORLANDC__
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#pragma hdrstop
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#endif
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#ifndef WX_PRECOMP
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#include "wx/defs.h"
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#endif
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#if wxUSE_IMAGE && wxUSE_LIBPNG
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#include "wx/imagpng.h"
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#include "wx/bitmap.h"
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#include "wx/debug.h"
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#include "wx/log.h"
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#include "wx/app.h"
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#include "png.h"
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#include "wx/filefn.h"
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#include "wx/wfstream.h"
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#include "wx/intl.h"
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#include "wx/module.h"
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// For memcpy
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#include <string.h>
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#ifdef __SALFORDC__
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#ifdef FAR
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#undef FAR
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#endif
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#endif
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// ----------------------------------------------------------------------------
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// constants
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// ----------------------------------------------------------------------------
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// image can not have any transparent pixels at all, have only 100% opaque
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// and/or 100% transparent pixels in which case a simple mask is enough to
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// store this information in wxImage or have a real alpha channel in which case
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// we need to have it in wxImage as well
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enum Transparency
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{
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Transparency_None,
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Transparency_Mask,
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Transparency_Alpha
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};
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// ----------------------------------------------------------------------------
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// local functions
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// ----------------------------------------------------------------------------
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// return the kind of transparency needed for this image assuming that it does
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// have transparent pixels, i.e. either Transparency_Alpha or Transparency_Mask
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static Transparency
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CheckTransparency(unsigned char **lines,
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png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
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size_t numColBytes);
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// init the alpha channel for the image and fill it with 1s up to (x, y)
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static unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y);
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// find a free colour for the mask in the PNG data array
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static void
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FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
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unsigned char& rMask, unsigned char& gMask, unsigned char& bMask);
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// is the pixel with this value of alpha a fully opaque one?
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static inline
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bool IsOpaque(unsigned char a)
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{
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return a == 0xff;
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}
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// is the pixel with this value of alpha a fully transparent one?
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static inline
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bool IsTransparent(unsigned char a)
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{
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return !a;
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}
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// ============================================================================
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// wxPNGHandler implementation
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// ============================================================================
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IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
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#if wxUSE_STREAMS
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#ifndef PNGLINKAGEMODE
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#ifdef __WATCOMC__
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// we need an explicit cdecl for Watcom, at least according to
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//
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// http://sf.net/tracker/index.php?func=detail&aid=651492&group_id=9863&atid=109863
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//
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// more testing is needed for this however, please remove this comment
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// if you can confirm that my fix works with Watcom 11
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#define PNGLINKAGEMODE cdecl
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#else
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#define PNGLINKAGEMODE LINKAGEMODE
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#endif
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#endif
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// VS: wxPNGInfoStruct declared below is a hack that needs some explanation.
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// First, let me describe what's the problem: libpng uses jmp_buf in
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// its png_struct structure. Unfortunately, this structure is
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// compiler-specific and may vary in size, so if you use libpng compiled
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// as DLL with another compiler than the main executable, it may not work
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// (this is for example the case with wxMGL port and SciTech MGL library
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// that provides custom runtime-loadable libpng implementation with jmpbuf
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// disabled altogether). Luckily, it is still possible to use setjmp() &
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// longjmp() as long as the structure is not part of png_struct.
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//
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// Sadly, there's no clean way to attach user-defined data to png_struct.
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// There is only one customizable place, png_struct.io_ptr, which is meant
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// only for I/O routines and is set with png_set_read_fn or
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// png_set_write_fn. The hacky part is that we use io_ptr to store
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// a pointer to wxPNGInfoStruct that holds I/O structures _and_ jmp_buf.
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struct wxPNGInfoStruct
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{
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jmp_buf jmpbuf;
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bool verbose;
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union
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{
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wxInputStream *in;
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wxOutputStream *out;
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} stream;
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};
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#define WX_PNG_INFO(png_ptr) ((wxPNGInfoStruct*)png_get_io_ptr(png_ptr))
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// ----------------------------------------------------------------------------
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// helper functions
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// ----------------------------------------------------------------------------
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extern "C"
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{
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void PNGLINKAGEMODE wx_PNG_stream_reader( png_structp png_ptr, png_bytep data,
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png_size_t length )
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{
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WX_PNG_INFO(png_ptr)->stream.in->Read(data, length);
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}
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void PNGLINKAGEMODE wx_PNG_stream_writer( png_structp png_ptr, png_bytep data,
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png_size_t length )
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{
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WX_PNG_INFO(png_ptr)->stream.out->Write(data, length);
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}
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// from pngerror.c
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// so that the libpng doesn't send anything on stderr
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void
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PNGLINKAGEMODE wx_png_error(png_structp WXUNUSED(png_ptr), png_const_charp message)
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{
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wxLogFatalError( wxString::FromAscii(message) );
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}
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void
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PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
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{
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wxPNGInfoStruct *info = png_ptr ? WX_PNG_INFO(png_ptr) : NULL;
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if ( !info || info->verbose )
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wxLogWarning( wxString::FromAscii(message) );
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}
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} // extern "C"
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// ----------------------------------------------------------------------------
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// LoadFile() helpers
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// ----------------------------------------------------------------------------
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// determine the kind of transparency we need for this image: if the only alpha
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// values it has are 0 (transparent) and 0xff (opaque) then we can simply
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// create a mask for it, we should be ok with a simple mask but otherwise we
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// need a full blown alpha channel in wxImage
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//
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// parameters:
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// lines raw PNG data
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// x, y starting position
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// w, h size of the image
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// numColBytes number of colour bytes (1 for grey scale, 3 for RGB)
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// (NB: alpha always follows the colour bytes)
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Transparency
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CheckTransparency(unsigned char **lines,
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png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
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size_t numColBytes)
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{
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// suppose that a mask will suffice and check all the remaining alpha
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// values to see if it does
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for ( ; y < h; y++ )
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{
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// each pixel is numColBytes+1 bytes, offset into the current line by
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// the current x position
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unsigned const char *ptr = lines[y] + (x * (numColBytes + 1));
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for ( png_uint_32 x2 = x; x2 < w; x2++ )
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{
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// skip the grey or colour byte(s)
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ptr += numColBytes;
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unsigned char a2 = *ptr++;
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if ( !IsTransparent(a2) && !IsOpaque(a2) )
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{
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// not fully opaque nor fully transparent, hence need alpha
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return Transparency_Alpha;
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}
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}
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// during the next loop iteration check all the pixels in the row
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x = 0;
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}
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// mask will be enough
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return Transparency_Mask;
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}
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unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y)
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{
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// create alpha channel
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image->SetAlpha();
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unsigned char *alpha = image->GetAlpha();
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// set alpha for the pixels we had so far
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png_uint_32 end = y * image->GetWidth() + x;
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for ( png_uint_32 i = 0; i < end; i++ )
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{
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// all the previous pixels were opaque
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*alpha++ = 0xff;
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}
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return alpha;
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}
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void
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FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
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unsigned char& rMask, unsigned char& gMask, unsigned char& bMask)
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{
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// choosing the colour for the mask is more
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// difficult: we need to iterate over the entire
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// image for this in order to choose an unused
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// colour (this is not very efficient but what else
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// can we do?)
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wxImageHistogram h;
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unsigned nentries = 0;
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unsigned char r2, g2, b2;
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for ( png_uint_32 y2 = 0; y2 < height; y2++ )
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{
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const unsigned char *p = lines[y2];
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for ( png_uint_32 x2 = 0; x2 < width; x2++ )
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{
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r2 = *p++;
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g2 = *p++;
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b2 = *p++;
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wxImageHistogramEntry&
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entry = h[wxImageHistogram:: MakeKey(r2, g2, b2)];
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if ( entry.value++ == 0 )
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entry.index = nentries++;
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}
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}
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if ( !h.FindFirstUnusedColour(&rMask, &gMask, &bMask) )
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{
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wxLogWarning(_("Too many colours in PNG, the image may be slightly blurred."));
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// use a fixed mask colour and we'll fudge
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// the real pixels with this colour (see
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// below)
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rMask = 0xfe;
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gMask = 0;
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bMask = 0xff;
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}
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}
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// ----------------------------------------------------------------------------
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// reading PNGs
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// ----------------------------------------------------------------------------
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bool wxPNGHandler::DoCanRead( wxInputStream& stream )
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{
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unsigned char hdr[4];
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if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
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return false;
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return memcmp(hdr, "\211PNG", WXSIZEOF(hdr)) == 0;
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}
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// convert data from RGB to wxImage format
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static
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void CopyDataFromPNG(wxImage *image,
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unsigned char **lines,
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png_uint_32 width,
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png_uint_32 height,
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int color_type)
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{
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Transparency transparency = Transparency_None;
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// only non NULL if transparency == Transparency_Alpha
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unsigned char *alpha = NULL;
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// RGB of the mask colour if transparency == Transparency_Mask
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// (but init them anyhow to avoid compiler warnings)
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unsigned char rMask = 0,
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gMask = 0,
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bMask = 0;
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unsigned char *ptrDst = image->GetData();
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if ( !(color_type & PNG_COLOR_MASK_COLOR) )
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{
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// grey image: GAGAGA... where G == grey component and A == alpha
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for ( png_uint_32 y = 0; y < height; y++ )
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{
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const unsigned char *ptrSrc = lines[y];
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for ( png_uint_32 x = 0; x < width; x++ )
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{
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unsigned char g = *ptrSrc++;
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unsigned char a = *ptrSrc++;
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// the first time we encounter a transparent pixel we must
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// decide about what to do about them
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if ( !IsOpaque(a) && transparency == Transparency_None )
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{
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// we'll need at least the mask for this image and
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// maybe even full alpha channel info: the former is
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// only enough if we have alpha values of 0 and 0xff
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// only, otherwisewe need the latter
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transparency = CheckTransparency
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(
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lines,
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x, y,
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width, height,
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1
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);
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if ( transparency == Transparency_Mask )
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{
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// let's choose this colour for the mask: this is
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// not a problem here as all the other pixels are
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// grey, i.e. R == G == B which is not the case for
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// this one so no confusion is possible
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rMask = 0xff;
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gMask = 0;
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bMask = 0xff;
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}
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else // transparency == Transparency_Alpha
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{
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alpha = InitAlpha(image, x, y);
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}
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}
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switch ( transparency )
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{
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case Transparency_Mask:
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if ( IsTransparent(a) )
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{
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*ptrDst++ = rMask;
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*ptrDst++ = bMask;
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*ptrDst++ = gMask;
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break;
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}
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// else: !transparent
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// must be opaque then as otherwise we shouldn't be
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// using the mask at all
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wxASSERT_MSG( IsOpaque(a), _T("logic error") );
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// fall through
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case Transparency_Alpha:
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if ( alpha )
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*alpha++ = a;
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// fall through
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case Transparency_None:
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*ptrDst++ = g;
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*ptrDst++ = g;
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*ptrDst++ = g;
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break;
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}
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}
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}
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}
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else // colour image: RGBRGB...
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{
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for ( png_uint_32 y = 0; y < height; y++ )
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{
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const unsigned char *ptrSrc = lines[y];
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for ( png_uint_32 x = 0; x < width; x++ )
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{
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unsigned char r = *ptrSrc++;
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unsigned char g = *ptrSrc++;
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unsigned char b = *ptrSrc++;
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unsigned char a = *ptrSrc++;
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// the logic here is the same as for the grey case except
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// where noted
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if ( !IsOpaque(a) && transparency == Transparency_None )
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{
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transparency = CheckTransparency
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(
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lines,
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x, y,
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width, height,
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3
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);
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if ( transparency == Transparency_Mask )
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{
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FindMaskColour(lines, width, height,
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rMask, gMask, bMask);
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}
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else // transparency == Transparency_Alpha
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{
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alpha = InitAlpha(image, x, y);
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}
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}
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switch ( transparency )
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{
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case Transparency_Mask:
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if ( IsTransparent(a) )
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{
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*ptrDst++ = rMask;
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*ptrDst++ = bMask;
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*ptrDst++ = gMask;
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break;
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}
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else // !transparent
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{
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// must be opaque then as otherwise we shouldn't be
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// using the mask at all
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wxASSERT_MSG( IsOpaque(a), _T("logic error") );
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// if we couldn't find a unique colour for the
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// mask, we can have real pixels with the same
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// value as the mask and it's better to slightly
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// change their colour than to make them
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// transparent
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if ( r == rMask && g == gMask && b == bMask )
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{
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r++;
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}
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}
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// fall through
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case Transparency_Alpha:
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if ( alpha )
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*alpha++ = a;
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// fall through
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case Transparency_None:
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*ptrDst++ = r;
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*ptrDst++ = g;
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*ptrDst++ = b;
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break;
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}
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}
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}
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}
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if ( transparency == Transparency_Mask )
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{
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image->SetMaskColour(rMask, gMask, bMask);
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}
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}
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// temporarily disable the warning C4611 (interaction between '_setjmp' and
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// C++ object destruction is non-portable) - I don't see any dtors here
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#ifdef __VISUALC__
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#pragma warning(disable:4611)
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#endif /* VC++ */
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bool
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wxPNGHandler::LoadFile(wxImage *image,
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wxInputStream& stream,
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bool verbose,
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int WXUNUSED(index))
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{
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// VZ: as this function uses setjmp() the only fool proof error handling
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// method is to use goto (setjmp is not really C++ dtors friendly...)
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unsigned char **lines = NULL;
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png_infop info_ptr = (png_infop) NULL;
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wxPNGInfoStruct wxinfo;
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wxinfo.verbose = verbose;
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wxinfo.stream.in = &stream;
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image->Destroy();
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png_structp png_ptr = png_create_read_struct
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(
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PNG_LIBPNG_VER_STRING,
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(voidp) NULL,
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wx_png_error,
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wx_png_warning
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);
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if (!png_ptr)
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goto error;
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// NB: please see the comment near wxPNGInfoStruct declaration for
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// explanation why this line is mandatory
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png_set_read_fn( png_ptr, &wxinfo, wx_PNG_stream_reader);
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info_ptr = png_create_info_struct( png_ptr );
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if (!info_ptr)
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goto error;
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if (setjmp(wxinfo.jmpbuf))
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goto error;
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png_uint_32 i, width, height;
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int bit_depth, color_type, interlace_type;
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png_read_info( png_ptr, info_ptr );
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png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
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if (color_type == PNG_COLOR_TYPE_PALETTE)
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png_set_expand( png_ptr );
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// Fix for Bug [ 439207 ] Monochrome PNG images come up black
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if (bit_depth < 8)
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png_set_expand( png_ptr );
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png_set_strip_16( png_ptr );
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|
png_set_packing( png_ptr );
|
|
if (png_get_valid( png_ptr, info_ptr, PNG_INFO_tRNS))
|
|
png_set_expand( png_ptr );
|
|
png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
|
|
|
|
image->Create((int)width, (int)height, (bool) false /* no need to init pixels */);
|
|
|
|
if (!image->Ok())
|
|
goto error;
|
|
|
|
lines = (unsigned char **)malloc( (size_t)(height * sizeof(unsigned char *)) );
|
|
if ( !lines )
|
|
goto error;
|
|
|
|
for (i = 0; i < height; i++)
|
|
{
|
|
if ((lines[i] = (unsigned char *)malloc( (size_t)(width * (sizeof(unsigned char) * 4)))) == NULL)
|
|
{
|
|
for ( unsigned int n = 0; n < i; n++ )
|
|
free( lines[n] );
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
png_read_image( png_ptr, lines );
|
|
png_read_end( png_ptr, info_ptr );
|
|
png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
|
|
|
|
// loaded successfully, now init wxImage with this data
|
|
CopyDataFromPNG(image, lines, width, height, color_type);
|
|
|
|
for ( i = 0; i < height; i++ )
|
|
free( lines[i] );
|
|
free( lines );
|
|
|
|
return true;
|
|
|
|
error:
|
|
if (verbose)
|
|
wxLogError(_("Couldn't load a PNG image - file is corrupted or not enough memory."));
|
|
|
|
if ( image->Ok() )
|
|
{
|
|
image->Destroy();
|
|
}
|
|
|
|
if ( lines )
|
|
{
|
|
free( lines );
|
|
}
|
|
|
|
if ( png_ptr )
|
|
{
|
|
if ( info_ptr )
|
|
{
|
|
png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
|
|
free(info_ptr);
|
|
}
|
|
else
|
|
png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// writing PNGs
|
|
// ----------------------------------------------------------------------------
|
|
|
|
bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbose )
|
|
{
|
|
wxPNGInfoStruct wxinfo;
|
|
|
|
wxinfo.verbose = verbose;
|
|
wxinfo.stream.out = &stream;
|
|
|
|
png_structp png_ptr = png_create_write_struct
|
|
(
|
|
PNG_LIBPNG_VER_STRING,
|
|
NULL,
|
|
wx_png_error,
|
|
wx_png_warning
|
|
);
|
|
if (!png_ptr)
|
|
{
|
|
if (verbose)
|
|
wxLogError(_("Couldn't save PNG image."));
|
|
return false;
|
|
}
|
|
|
|
png_infop info_ptr = png_create_info_struct(png_ptr);
|
|
if (info_ptr == NULL)
|
|
{
|
|
png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
|
|
if (verbose)
|
|
wxLogError(_("Couldn't save PNG image."));
|
|
return false;
|
|
}
|
|
|
|
if (setjmp(wxinfo.jmpbuf))
|
|
{
|
|
png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
|
|
if (verbose)
|
|
wxLogError(_("Couldn't save PNG image."));
|
|
return false;
|
|
}
|
|
|
|
// NB: please see the comment near wxPNGInfoStruct declaration for
|
|
// explanation why this line is mandatory
|
|
png_set_write_fn( png_ptr, &wxinfo, wx_PNG_stream_writer, NULL);
|
|
|
|
png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(), 8,
|
|
PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE,
|
|
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
|
|
|
|
png_color_8 sig_bit;
|
|
sig_bit.red = 8;
|
|
sig_bit.green = 8;
|
|
sig_bit.blue = 8;
|
|
sig_bit.alpha = 8;
|
|
png_set_sBIT( png_ptr, info_ptr, &sig_bit );
|
|
png_write_info( png_ptr, info_ptr );
|
|
png_set_shift( png_ptr, &sig_bit );
|
|
png_set_packing( png_ptr );
|
|
|
|
unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 );
|
|
if (!data)
|
|
{
|
|
png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
|
|
return false;
|
|
}
|
|
|
|
for (int y = 0; y < image->GetHeight(); y++)
|
|
{
|
|
unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
|
|
for (int x = 0; x < image->GetWidth(); x++)
|
|
{
|
|
data[(x << 2) + 0] = *ptr++;
|
|
data[(x << 2) + 1] = *ptr++;
|
|
data[(x << 2) + 2] = *ptr++;
|
|
if ( image->HasAlpha() )
|
|
{
|
|
data[(x << 2) + 3] = image->GetAlpha(x, y);
|
|
}
|
|
else if (( !image->HasMask() ) || \
|
|
(data[(x << 2) + 0] != image->GetMaskRed()) || \
|
|
(data[(x << 2) + 1] != image->GetMaskGreen()) || \
|
|
(data[(x << 2) + 2] != image->GetMaskBlue()))
|
|
{
|
|
data[(x << 2) + 3] = 255;
|
|
}
|
|
else
|
|
{
|
|
data[(x << 2) + 3] = 0;
|
|
}
|
|
}
|
|
png_bytep row_ptr = data;
|
|
png_write_rows( png_ptr, &row_ptr, 1 );
|
|
}
|
|
|
|
free(data);
|
|
png_write_end( png_ptr, info_ptr );
|
|
png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
|
|
|
|
return true;
|
|
}
|
|
|
|
#ifdef __VISUALC__
|
|
#pragma warning(default:4611)
|
|
#endif /* VC++ */
|
|
|
|
#endif // wxUSE_STREAMS
|
|
|
|
#endif // wxUSE_LIBPNG
|