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imagpng.cpp
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C/C++ Source or Header
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2002-11-04
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13KB
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434 lines
/////////////////////////////////////////////////////////////////////////////
// Name: imagepng.cpp
// Purpose: wxImage PNG handler
// Author: Robert Roebling
// RCS-ID: $Id: imagpng.cpp,v 1.27.2.2 2002/10/29 21:47:45 RR Exp $
// Copyright: (c) Robert Roebling
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifdef __GNUG__
#pragma implementation "imagpng.h"
#endif
// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
#ifdef __BORLANDC__
#pragma hdrstop
#endif
#ifndef WX_PRECOMP
#include "wx/defs.h"
#endif
#if wxUSE_IMAGE && wxUSE_LIBPNG
#include "wx/imagpng.h"
#include "wx/bitmap.h"
#include "wx/debug.h"
#include "wx/log.h"
#include "wx/app.h"
#include "png.h"
#include "wx/filefn.h"
#include "wx/wfstream.h"
#include "wx/intl.h"
#include "wx/module.h"
// For memcpy
#include <string.h>
#ifdef __SALFORDC__
#ifdef FAR
#undef FAR
#endif
#endif
#ifdef __WXMSW__
#include <windows.h>
#endif
//-----------------------------------------------------------------------------
// wxPNGHandler
//-----------------------------------------------------------------------------
IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
#if wxUSE_LIBPNG
#ifndef PNGLINKAGEMODE
#define PNGLINKAGEMODE LINKAGEMODE
#endif
// VS: wxPNGInfoStruct declared below is a hack that needs some explanation.
// First, let me describe what's the problem: libpng uses jmp_buf in
// its png_struct structure. Unfortunately, this structure is
// compiler-specific and may vary in size, so if you use libpng compiled
// as DLL with another compiler than the main executable, it may not work
// (this is for example the case with wxMGL port and SciTech MGL library
// that provides custom runtime-loadable libpng implementation with jmpbuf
// disabled altogether). Luckily, it is still possible to use setjmp() &
// longjmp() as long as the structure is not part of png_struct.
//
// Sadly, there's no clean way to attach user-defined data to png_struct.
// There is only one customizable place, png_struct.io_ptr, which is meant
// only for I/O routines and is set with png_set_read_fn or
// png_set_write_fn. The hacky part is that we use io_ptr to store
// a pointer to wxPNGInfoStruct that holds I/O structures _and_ jmp_buf.
struct wxPNGInfoStruct
{
jmp_buf jmpbuf;
bool verbose;
union
{
wxInputStream *in;
wxOutputStream *out;
} stream;
};
#define WX_PNG_INFO(png_ptr) ((wxPNGInfoStruct*)png_get_io_ptr(png_ptr))
extern "C"
{
void PNGLINKAGEMODE _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length )
{
WX_PNG_INFO(png_ptr)->stream.in->Read(data, length);
}
void PNGLINKAGEMODE _PNG_stream_writer( png_structp png_ptr, png_bytep data, png_size_t length )
{
WX_PNG_INFO(png_ptr)->stream.out->Write(data, length);
}
// from pngerror.c
// so that the libpng doesn't send anything on stderr
void
PNGLINKAGEMODE wx_png_error(png_structp png_ptr, png_const_charp message)
{
wxPNGInfoStruct *info = WX_PNG_INFO(png_ptr);
if (info->verbose)
wxLogError( wxString::FromAscii(message) );
#ifdef USE_FAR_KEYWORD
{
jmp_buf jmpbuf;
png_memcpy(jmpbuf,info->jmpbuf,sizeof(jmp_buf));
longjmp(jmpbuf, 1);
}
#else
longjmp(info->jmpbuf, 1);
#endif
}
void
PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
{
wxPNGInfoStruct *info = WX_PNG_INFO(png_ptr);
if (info->verbose)
wxLogWarning( wxString::FromAscii(message) );
}
} // extern "C"
// temporarily disable the warning C4611 (interaction between '_setjmp' and
// C++ object destruction is non-portable) - I don't see any dtors here
#ifdef __VISUALC__
#pragma warning(disable:4611)
#endif /* VC++ */
bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
{
// VZ: as this function uses setjmp() the only fool proof error handling
// method is to use goto (setjmp is not really C++ dtors friendly...)
unsigned char **lines;
unsigned int i;
png_infop info_ptr = (png_infop) NULL;
wxPNGInfoStruct wxinfo;
wxinfo.verbose = verbose;
wxinfo.stream.in = &stream;
image->Destroy();
png_structp png_ptr = png_create_read_struct( PNG_LIBPNG_VER_STRING,
(voidp) NULL,
(png_error_ptr) NULL,
(png_error_ptr) NULL );
if (!png_ptr)
goto error_nolines;
png_set_error_fn(png_ptr, (png_voidp)NULL, wx_png_error, wx_png_warning);
// NB: please see the comment near wxPNGInfoStruct declaration for
// explanation why this line is mandatory
png_set_read_fn( png_ptr, &wxinfo, _PNG_stream_reader);
info_ptr = png_create_info_struct( png_ptr );
if (!info_ptr)
goto error_nolines;
if (setjmp(wxinfo.jmpbuf))
goto error_nolines;
if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
goto error_nolines;
png_uint_32 width,height;
int bit_depth,color_type,interlace_type;
png_read_info( png_ptr, info_ptr );
png_get_IHDR( png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, &interlace_type, (int*) NULL, (int*) NULL );
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_expand( png_ptr );
// Fix for Bug [ 439207 ] Monochrome PNG images come up black
if (bit_depth < 8)
png_set_expand( png_ptr );
png_set_strip_16( png_ptr );
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 );
if (!image->Ok())
goto error_nolines;
lines = (unsigned char **)malloc( (size_t)(height * sizeof(unsigned char *)) );
if (lines == NULL)
goto error_nolines;
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;
}
}
// loaded successfully!
{
int transp = 0;
png_read_image( png_ptr, lines );
png_read_end( png_ptr, info_ptr );
png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
unsigned char *ptr = image->GetData();
if ((color_type == PNG_COLOR_TYPE_GRAY) ||
(color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
{
for (unsigned int y = 0; y < height; y++)
{
unsigned char *ptr2 = lines[y];
for (unsigned int x = 0; x < width; x++)
{
unsigned char r = *ptr2++;
unsigned char a = *ptr2++;
if (a < 128)
{
*ptr++ = 255;
*ptr++ = 0;
*ptr++ = 255;
transp = 1;
}
else
{
*ptr++ = r;
*ptr++ = r;
*ptr++ = r;
}
}
}
}
else
{
for (unsigned int y = 0; y < height; y++)
{
unsigned char *ptr2 = lines[y];
for (unsigned int x = 0; x < width; x++)
{
unsigned char r = *ptr2++;
unsigned char g = *ptr2++;
unsigned char b = *ptr2++;
unsigned char a = *ptr2++;
if (a < 128)
{
*ptr++ = 255;
*ptr++ = 0;
*ptr++ = 255;
transp = 1;
}
else
{
if ((r == 255) && (g == 0) && (b == 255)) r = 254;
*ptr++ = r;
*ptr++ = g;
*ptr++ = b;
}
}
}
}
for ( unsigned int j = 0; j < height; j++ )
free( lines[j] );
free( lines );
if (transp)
{
image->SetMaskColour( 255, 0, 255 );
}
else
{
image->SetMask( FALSE );
}
}
return TRUE;
error_nolines:
lines = NULL; // called from before it was set
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;
}
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, NULL, NULL);
if (!png_ptr)
{
if (verbose)
wxLogError(_("Couldn't save PNG image."));
return FALSE;
}
png_set_error_fn(png_ptr, (png_voidp)NULL, wx_png_error, wx_png_warning);
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, _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->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++ */
bool wxPNGHandler::DoCanRead( wxInputStream& stream )
{
unsigned char hdr[4];
if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
return FALSE;
return memcmp(hdr, "\211PNG", WXSIZEOF(hdr)) == 0;
}
#endif // wxUSE_STREAMS
#endif // wxUSE_LIBPNG