Make code reading BMP files more robust.

[wxWidgets.git] / src / common / imagtiff.cpp

diff --git a/src/common/imagtiff.cpp b/src/common/imagtiff.cpp
index b7871ba99454aa574c8ec7821324f620456003c1..1c3e22632dc4f6e25265c50a97a0f8428574e42a 100644 (file)
--- a/src/common/imagtiff.cpp
+++ b/src/common/imagtiff.cpp
@@ -7,6 +7,14 @@
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 

+// ============================================================================
+// declarations
+// ============================================================================
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+

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


@@ -17,6 +25,7 @@
 #if wxUSE_IMAGE && wxUSE_LIBTIFF
 
 #include "wx/imagtiff.h"
 #if wxUSE_IMAGE && wxUSE_LIBTIFF
 
 #include "wx/imagtiff.h"

+#include "wx/versioninfo.h"

 
 #ifndef WX_PRECOMP
     #include "wx/log.h"
 
 #ifndef WX_PRECOMP
     #include "wx/log.h"


@@ -24,10 +33,14 @@
     #include "wx/intl.h"
     #include "wx/bitmap.h"
     #include "wx/module.h"
     #include "wx/intl.h"
     #include "wx/bitmap.h"
     #include "wx/module.h"

+    #include "wx/wxcrtvararg.h"

 #endif
 
 extern "C"
 {
 #endif
 
 extern "C"
 {

+#ifdef __DMC__
+    #include "tif_config.h"
+#endif

     #include "tiff.h"
     #include "tiffio.h"
 }
     #include "tiff.h"
     #include "tiffio.h"
 }


@@ -35,19 +48,70 @@ extern "C"
 #include "wx/wfstream.h"
 
 #ifndef TIFFLINKAGEMODE
 #include "wx/wfstream.h"
 
 #ifndef TIFFLINKAGEMODE

-    #if defined(__WATCOMC__) && defined(__WXMGL__)
-        #define TIFFLINKAGEMODE cdecl
-    #else
-        #define TIFFLINKAGEMODE LINKAGEMODE
-    #endif
+    #define TIFFLINKAGEMODE LINKAGEMODE

 #endif
 
 #endif
 

+// ============================================================================
+// implementation
+// ============================================================================
+
+// ----------------------------------------------------------------------------
+// TIFF library error/warning handlers
+// ----------------------------------------------------------------------------
+
+static wxString
+FormatTiffMessage(const char *module, const char *fmt, va_list ap)
+{
+    char buf[512];
+    if ( wxCRT_VsnprintfA(buf, WXSIZEOF(buf), fmt, ap) <= 0 )
+    {
+        // this isn't supposed to happen, but if it does, it's better
+        // than nothing
+        strcpy(buf, "Incorrectly formatted TIFF message");
+    }
+    buf[WXSIZEOF(buf)-1] = 0; // make sure it is always NULL-terminated
+
+    wxString msg(buf);
+    if ( module )
+        msg += wxString::Format(_(" (in module \"%s\")"), module);
+
+    return msg;
+}
+
+extern "C"
+{
+
+static void
+TIFFwxWarningHandler(const char* module, const char *fmt, va_list ap)
+{
+    wxLogWarning("%s", FormatTiffMessage(module, fmt, ap));
+}
+
+static void
+TIFFwxErrorHandler(const char* module, const char *fmt, va_list ap)
+{
+    wxLogError("%s", FormatTiffMessage(module, fmt, ap));
+}
+
+} // extern "C"
+

 //-----------------------------------------------------------------------------
 // wxTIFFHandler
 //-----------------------------------------------------------------------------
 
 IMPLEMENT_DYNAMIC_CLASS(wxTIFFHandler,wxImageHandler)
 
 //-----------------------------------------------------------------------------
 // wxTIFFHandler
 //-----------------------------------------------------------------------------
 
 IMPLEMENT_DYNAMIC_CLASS(wxTIFFHandler,wxImageHandler)
 

+wxTIFFHandler::wxTIFFHandler()
+{
+    m_name = wxT("TIFF file");
+    m_extension = wxT("tif");
+    m_altExtensions.Add(wxT("tiff"));
+    m_type = wxBITMAP_TYPE_TIFF;
+    m_mime = wxT("image/tiff");
+    TIFFSetWarningHandler((TIFFErrorHandler) TIFFwxWarningHandler);
+    TIFFSetErrorHandler((TIFFErrorHandler) TIFFwxErrorHandler);
+}
+

 #if wxUSE_STREAMS
 
 // helper to translate our, possibly 64 bit, wxFileOffset to TIFF, always 32
 #if wxUSE_STREAMS
 
 // helper to translate our, possibly 64 bit, wxFileOffset to TIFF, always 32


@@ -59,7 +123,7 @@ static toff_t wxFileOffsetToTIFF(wxFileOffset ofs)
 
     toff_t tofs = wx_truncate_cast(toff_t, ofs);
     wxCHECK_MSG( (wxFileOffset)tofs == ofs, (toff_t)-1,
 
     toff_t tofs = wx_truncate_cast(toff_t, ofs);
     wxCHECK_MSG( (wxFileOffset)tofs == ofs, (toff_t)-1,

-                    _T("TIFF library doesn't support large files") );
+                    wxT("TIFF library doesn't support large files") );

 
     return tofs;
 }
 
     return tofs;
 }


@@ -124,8 +188,42 @@ wxTIFFSeekOProc(thandle_t handle, toff_t off, int whence)
 {
     wxOutputStream *stream = (wxOutputStream*) handle;
 
 {
     wxOutputStream *stream = (wxOutputStream*) handle;
 

-    return wxFileOffsetToTIFF(stream->SeekO((wxFileOffset)off,
-                                            wxSeekModeFromTIFF(whence)));
+    toff_t offset = wxFileOffsetToTIFF(
+        stream->SeekO((wxFileOffset)off, wxSeekModeFromTIFF(whence)) );
+
+    if (offset != (toff_t) -1 || whence != SEEK_SET)
+    {
+        return offset;
+    }
+
+
+    /*
+    Try to workaround problems with libtiff seeking past the end of streams.
+
+    This occurs when libtiff is writing tag entries past the end of a
+    stream but hasn't written the directory yet (which will be placed
+    before the tags and contain offsets to the just written tags).
+    The behaviour for seeking past the end of a stream is not consistent
+    and doesn't work with for example wxMemoryOutputStream. When this type
+    of seeking fails (with SEEK_SET), fill in the gap with zeroes and try
+    again.
+    */
+
+    wxFileOffset streamLength = stream->GetLength();
+    if (streamLength != wxInvalidOffset && (wxFileOffset) off > streamLength)
+    {
+       if (stream->SeekO(streamLength, wxFromStart) == wxInvalidOffset)
+       {
+           return (toff_t) -1;
+       }
+
+       for (wxFileOffset i = 0; i < (wxFileOffset) off - streamLength; ++i)
+       {
+           stream->PutC(0);
+       }
+    }
+
+    return wxFileOffsetToTIFF( stream->TellO() );

 }
 
 int TIFFLINKAGEMODE
 }
 
 int TIFFLINKAGEMODE


@@ -165,38 +263,6 @@ wxTIFFUnmapProc(thandle_t WXUNUSED(handle),
 {
 }
 
 {
 }
 

-static void
-TIFFwxWarningHandler(const char* module,
-                     const char* WXUNUSED_IN_UNICODE(fmt),
-                     va_list WXUNUSED_IN_UNICODE(ap))
-{
-    if (module != NULL)
-        wxLogWarning(_("tiff module: %s"), wxString::FromAscii(module).c_str());
-
-    // FIXME: this is not terrible informative but better than crashing!
-#if wxUSE_UNICODE
-    wxLogWarning(_("TIFF library warning."));
-#else
-    wxVLogWarning(fmt, ap);
-#endif
-}
-
-static void
-TIFFwxErrorHandler(const char* module,
-                   const char* WXUNUSED_IN_UNICODE(fmt),
-                   va_list WXUNUSED_IN_UNICODE(ap))
-{
-    if (module != NULL)
-        wxLogError(_("tiff module: %s"), wxString::FromAscii(module).c_str());
-
-    // FIXME: as above
-#if wxUSE_UNICODE
-    wxLogError(_("TIFF library error."));
-#else
-    wxVLogError(fmt, ap);
-#endif
-}
-

 } // extern "C"
 
 TIFF*
 } // extern "C"
 
 TIFF*


@@ -223,16 +289,6 @@ TIFFwxOpen(wxOutputStream &stream, const char* name, const char* mode)
     return tif;
 }
 
     return tif;
 }
 

-wxTIFFHandler::wxTIFFHandler()
-{
-    m_name = wxT("TIFF file");
-    m_extension = wxT("tif");
-    m_type = wxBITMAP_TYPE_TIF;
-    m_mime = wxT("image/tiff");
-    TIFFSetWarningHandler((TIFFErrorHandler) TIFFwxWarningHandler);
-    TIFFSetErrorHandler((TIFFErrorHandler) TIFFwxErrorHandler);
-}
-

 bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int index )
 {
     if (index == -1)
 bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int index )
 {
     if (index == -1)


@@ -245,7 +301,9 @@ bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
     if (!tif)
     {
         if (verbose)
     if (!tif)
     {
         if (verbose)

+        {

             wxLogError( _("TIFF: Error loading image.") );
             wxLogError( _("TIFF: Error loading image.") );

+        }

 
         return false;
     }
 
         return false;
     }


@@ -253,7 +311,9 @@ bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
     if (!TIFFSetDirectory( tif, (tdir_t)index ))
     {
         if (verbose)
     if (!TIFFSetDirectory( tif, (tdir_t)index ))
     {
         if (verbose)

+        {

             wxLogError( _("Invalid TIFF image index.") );
             wxLogError( _("Invalid TIFF image index.") );

+        }

 
         TIFFClose( tif );
 
 
         TIFFClose( tif );
 


@@ -261,20 +321,57 @@ bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
     }
 
     uint32 w, h;
     }
 
     uint32 w, h;

-    uint32 npixels;

     uint32 *raster;
 
     TIFFGetField( tif, TIFFTAG_IMAGEWIDTH, &w );
     TIFFGetField( tif, TIFFTAG_IMAGELENGTH, &h );
 
     uint32 *raster;
 
     TIFFGetField( tif, TIFFTAG_IMAGEWIDTH, &w );
     TIFFGetField( tif, TIFFTAG_IMAGELENGTH, &h );
 

-    npixels = w * h;
+    uint16 samplesPerPixel = 0;
+    (void) TIFFGetFieldDefaulted(tif, TIFFTAG_SAMPLESPERPIXEL, &samplesPerPixel);

 
 

-    raster = (uint32*) _TIFFmalloc( npixels * sizeof(uint32) );
+    uint16 bitsPerSample = 0;
+    (void) TIFFGetFieldDefaulted(tif, TIFFTAG_BITSPERSAMPLE, &bitsPerSample);
+
+    uint16 extraSamples;
+    uint16* samplesInfo;
+    TIFFGetFieldDefaulted(tif, TIFFTAG_EXTRASAMPLES,
+                          &extraSamples, &samplesInfo);
+
+    uint16 photometric;
+    if (!TIFFGetField(tif, TIFFTAG_PHOTOMETRIC, &photometric))
+    {
+        photometric = PHOTOMETRIC_MINISWHITE;
+    }
+    const bool hasAlpha = (extraSamples >= 1
+        && ((samplesInfo[0] == EXTRASAMPLE_UNSPECIFIED)
+            || samplesInfo[0] == EXTRASAMPLE_ASSOCALPHA
+            || samplesInfo[0] == EXTRASAMPLE_UNASSALPHA))
+        || (extraSamples == 0 && samplesPerPixel == 4
+            && photometric == PHOTOMETRIC_RGB);
+
+    // guard against integer overflow during multiplication which could result
+    // in allocating a too small buffer and then overflowing it
+    const double bytesNeeded = (double)w * (double)h * sizeof(uint32);
+    if ( bytesNeeded >= wxUINT32_MAX )
+    {
+        if ( verbose )
+        {
+            wxLogError( _("TIFF: Image size is abnormally big.") );
+        }
+
+        TIFFClose(tif);
+
+        return false;
+    }
+
+    raster = (uint32*) _TIFFmalloc( (uint32)bytesNeeded );

 
     if (!raster)
     {
         if (verbose)
 
     if (!raster)
     {
         if (verbose)

+        {

             wxLogError( _("TIFF: Couldn't allocate memory.") );
             wxLogError( _("TIFF: Couldn't allocate memory.") );

+        }

 
         TIFFClose( tif );
 
 
         TIFFClose( tif );
 


@@ -282,10 +379,12 @@ bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
     }
 
     image->Create( (int)w, (int)h );
     }
 
     image->Create( (int)w, (int)h );

-    if (!image->Ok())
+    if (!image->IsOk())

     {
         if (verbose)
     {
         if (verbose)

+        {

             wxLogError( _("TIFF: Couldn't allocate memory.") );
             wxLogError( _("TIFF: Couldn't allocate memory.") );

+        }

 
         _TIFFfree( raster );
         TIFFClose( tif );
 
         _TIFFfree( raster );
         TIFFClose( tif );


@@ -293,10 +392,85 @@ bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
         return false;
     }
 
         return false;
     }
 

-    if (!TIFFReadRGBAImage( tif, w, h, raster, 0 ))
+    if ( hasAlpha )
+        image->SetAlpha();
+
+    uint16 planarConfig = PLANARCONFIG_CONTIG;
+    (void) TIFFGetField(tif, TIFFTAG_PLANARCONFIG, &planarConfig);
+
+    bool ok = true;
+    char msg[1024] = "";
+    if
+    (
+        (planarConfig == PLANARCONFIG_CONTIG && samplesPerPixel == 2
+            && extraSamples == 1)
+        &&
+        (
+            ( !TIFFRGBAImageOK(tif, msg) )
+            || (bitsPerSample == 8)
+        )
+    )
+    {
+        const bool isGreyScale = (bitsPerSample == 8);
+        unsigned char *buf = (unsigned char *)_TIFFmalloc(TIFFScanlineSize(tif));
+        uint32 pos = 0;
+        const bool minIsWhite = (photometric == PHOTOMETRIC_MINISWHITE);
+        const int minValue =  minIsWhite ? 255 : 0;
+        const int maxValue = 255 - minValue;
+
+        /*
+        Decode to ABGR format as that is what the code, that converts to
+        wxImage, later on expects (normally TIFFReadRGBAImageOriented is
+        used to decode which uses an ABGR layout).
+        */
+        for (uint32 y = 0; y < h; ++y)
+        {
+            if (TIFFReadScanline(tif, buf, y, 0) != 1)
+            {
+                ok = false;
+                break;
+            }
+
+            if (isGreyScale)
+            {
+                for (uint32 x = 0; x < w; ++x)
+                {
+                    uint8 val = minIsWhite ? 255 - buf[x*2] : buf[x*2];
+                    uint8 alpha = minIsWhite ? 255 - buf[x*2+1] : buf[x*2+1];
+                    raster[pos] = val + (val << 8) + (val << 16)
+                        + (alpha << 24);
+                    pos++;
+                }
+            }
+            else
+            {
+                for (uint32 x = 0; x < w; ++x)
+                {
+                    int mask = buf[x*2/8] << ((x*2)%8);
+
+                    uint8 val = mask & 128 ? maxValue : minValue;
+                    raster[pos] = val + (val << 8) + (val << 16)
+                        + ((mask & 64 ? maxValue : minValue) << 24);
+                    pos++;
+                }
+            }
+        }
+
+        _TIFFfree(buf);
+    }
+    else
+    {
+        ok = TIFFReadRGBAImageOriented( tif, w, h, raster,
+            ORIENTATION_TOPLEFT, 0 ) != 0;
+    }
+
+
+    if (!ok)

     {
         if (verbose)
     {
         if (verbose)

+        {

             wxLogError( _("TIFF: Error reading image.") );
             wxLogError( _("TIFF: Error reading image.") );

+        }

 
         _TIFFfree( raster );
         image->Destroy();
 
         _TIFFfree( raster );
         image->Destroy();


@@ -305,51 +479,109 @@ bool wxTIFFHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbos
         return false;
     }
 
         return false;
     }
 

-    bool hasmask = false;
-

     unsigned char *ptr = image->GetData();
     unsigned char *ptr = image->GetData();

-    ptr += w*3*(h-1);
+
+    unsigned char *alpha = image->GetAlpha();
+

     uint32 pos = 0;
 
     for (uint32 i = 0; i < h; i++)
     {
         for (uint32 j = 0; j < w; j++)
         {
     uint32 pos = 0;
 
     for (uint32 i = 0; i < h; i++)
     {
         for (uint32 j = 0; j < w; j++)
         {

-            unsigned char alpha = (unsigned char)TIFFGetA(raster[pos]);
-            if (alpha < 127)
-            {
-                hasmask = true;
-                ptr[0] = image->GetMaskRed();
-                ptr++;
-                ptr[0] = image->GetMaskGreen();
-                ptr++;
-                ptr[0] = image->GetMaskBlue();
-                ptr++;
-            }
-            else
-            {
-                ptr[0] = (unsigned char)TIFFGetR(raster[pos]);
-                ptr++;
-                ptr[0] = (unsigned char)TIFFGetG(raster[pos]);
-                ptr++;
-                ptr[0] = (unsigned char)TIFFGetB(raster[pos]);
-                ptr++;
-            }
+            *(ptr++) = (unsigned char)TIFFGetR(raster[pos]);
+            *(ptr++) = (unsigned char)TIFFGetG(raster[pos]);
+            *(ptr++) = (unsigned char)TIFFGetB(raster[pos]);
+            if ( hasAlpha )
+                *(alpha++) = (unsigned char)TIFFGetA(raster[pos]);
+

             pos++;
         }
             pos++;
         }

-        ptr -= 2*w*3; // subtract line we just added plus one line
+    }
+
+
+    image->SetOption(wxIMAGE_OPTION_TIFF_PHOTOMETRIC, photometric);
+
+    uint16 compression;
+    /*
+    Copy some baseline TIFF tags which helps when re-saving a TIFF
+    to be similar to the original image.
+    */
+    if (samplesPerPixel)
+    {
+        image->SetOption(wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL, samplesPerPixel);
+    }
+
+    if (bitsPerSample)
+    {
+        image->SetOption(wxIMAGE_OPTION_TIFF_BITSPERSAMPLE, bitsPerSample);
+    }
+
+    if ( TIFFGetFieldDefaulted(tif, TIFFTAG_COMPRESSION, &compression) )
+    {
+        image->SetOption(wxIMAGE_OPTION_TIFF_COMPRESSION, compression);
+    }
+
+    // Set the resolution unit.
+    wxImageResolution resUnit = wxIMAGE_RESOLUTION_NONE;
+    uint16 tiffRes;
+    if ( TIFFGetFieldDefaulted(tif, TIFFTAG_RESOLUTIONUNIT, &tiffRes) )
+    {
+        switch (tiffRes)
+        {
+            default:
+                wxLogWarning(_("Unknown TIFF resolution unit %d ignored"),
+                    tiffRes);
+                // fall through
+
+            case RESUNIT_NONE:
+                resUnit = wxIMAGE_RESOLUTION_NONE;
+                break;
+
+            case RESUNIT_INCH:
+                resUnit = wxIMAGE_RESOLUTION_INCHES;
+                break;
+
+            case RESUNIT_CENTIMETER:
+                resUnit = wxIMAGE_RESOLUTION_CM;
+                break;
+        }
+    }
+
+    image->SetOption(wxIMAGE_OPTION_RESOLUTIONUNIT, resUnit);
+
+    /*
+    Set the image resolution if it's available. Resolution tag is not
+    dependent on RESOLUTIONUNIT != RESUNIT_NONE (according to TIFF spec).
+    */
+    float resX, resY;
+
+    if ( TIFFGetField(tif, TIFFTAG_XRESOLUTION, &resX) )
+    {
+        /*
+        Use a string value to not lose precision.
+        rounding to int as cm and then converting to inch may
+        result in whole integer rounding error, eg. 201 instead of 200 dpi.
+        If an app wants an int, GetOptionInt will convert and round down.
+        */
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONX,
+            wxString::FromCDouble((double) resX));
+    }
+
+    if ( TIFFGetField(tif, TIFFTAG_YRESOLUTION, &resY) )
+    {
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONY,
+            wxString::FromCDouble((double) resY));

     }
 
     _TIFFfree( raster );
 
     TIFFClose( tif );
 
     }
 
     _TIFFfree( raster );
 
     TIFFClose( tif );
 

-    image->SetMask( hasmask );
-

     return true;
 }
 
     return true;
 }
 

-int wxTIFFHandler::GetImageCount( wxInputStream& stream )
+int wxTIFFHandler::DoGetImageCount( wxInputStream& stream )

 {
     TIFF *tif = TIFFwxOpen( stream, "image", "r" );
 
 {
     TIFF *tif = TIFFwxOpen( stream, "image", "r" );
 


@@ -363,6 +595,9 @@ int wxTIFFHandler::GetImageCount( wxInputStream& stream )
 
     TIFFClose( tif );
 
 
     TIFFClose( tif );
 

+    // NOTE: this function modifies the current stream position but it's ok
+    //       (see wxImageHandler::GetImageCount)
+

     return dircount;
 }
 
     return dircount;
 }
 


@@ -373,65 +608,142 @@ bool wxTIFFHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbo
     if (!tif)
     {
         if (verbose)
     if (!tif)
     {
         if (verbose)

+        {

             wxLogError( _("TIFF: Error saving image.") );
             wxLogError( _("TIFF: Error saving image.") );

+        }

 
         return false;
     }
 
 
         return false;
     }
 

-    TIFFSetField(tif, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT);
-    TIFFSetField(tif, TIFFTAG_IMAGEWIDTH,  (uint32)image->GetWidth());
+    const int imageWidth = image->GetWidth();
+    TIFFSetField(tif, TIFFTAG_IMAGEWIDTH,  (uint32) imageWidth);

     TIFFSetField(tif, TIFFTAG_IMAGELENGTH, (uint32)image->GetHeight());
     TIFFSetField(tif, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT);
     TIFFSetField(tif, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
 
     TIFFSetField(tif, TIFFTAG_IMAGELENGTH, (uint32)image->GetHeight());
     TIFFSetField(tif, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT);
     TIFFSetField(tif, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
 

-    if ( image->HasOption(wxIMAGE_OPTION_RESOLUTIONX) &&
-            image->HasOption(wxIMAGE_OPTION_RESOLUTIONY) )
+    // save the image resolution if we have it
+    int xres, yres;
+    const wxImageResolution res = GetResolutionFromOptions(*image, &xres, &yres);
+    uint16 tiffRes;
+    switch ( res )

     {
     {

-        TIFFSetField(tif, TIFFTAG_XRESOLUTION,
-                        (float)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONX));
-        TIFFSetField(tif, TIFFTAG_YRESOLUTION,
-                        (float)image->GetOptionInt(wxIMAGE_OPTION_RESOLUTIONY));
+        default:
+            wxFAIL_MSG( wxT("unknown image resolution units") );
+            // fall through
+
+        case wxIMAGE_RESOLUTION_NONE:
+            tiffRes = RESUNIT_NONE;
+            break;
+
+        case wxIMAGE_RESOLUTION_INCHES:
+            tiffRes = RESUNIT_INCH;
+            break;
+
+        case wxIMAGE_RESOLUTION_CM:
+            tiffRes = RESUNIT_CENTIMETER;
+            break;
+    }
+
+    if ( tiffRes != RESUNIT_NONE )
+    {
+        TIFFSetField(tif, TIFFTAG_RESOLUTIONUNIT, tiffRes);
+        TIFFSetField(tif, TIFFTAG_XRESOLUTION, (float)xres);
+        TIFFSetField(tif, TIFFTAG_YRESOLUTION, (float)yres);

     }
 
     }
 

-    int spp = image->GetOptionInt(wxIMAGE_OPTION_SAMPLESPERPIXEL);
+
+    int spp = image->GetOptionInt(wxIMAGE_OPTION_TIFF_SAMPLESPERPIXEL);

     if ( !spp )
         spp = 3;
 
     if ( !spp )
         spp = 3;
 

-    int bpp = image->GetOptionInt(wxIMAGE_OPTION_BITSPERSAMPLE);
-    if ( !bpp )
-        bpp=8;
+    int bps = image->GetOptionInt(wxIMAGE_OPTION_TIFF_BITSPERSAMPLE);
+    if ( !bps )
+    {
+        bps = 8;
+    }
+    else if (bps == 1)
+    {
+        // One bit per sample combined with 3 samples per pixel is
+        // not allowed and crashes libtiff.
+        spp = 1;
+    }
+
+    int photometric = PHOTOMETRIC_RGB;

 
 

-    int compression = image->GetOptionInt(wxIMAGE_OPTION_COMPRESSION);
-    if ( !compression )
+    if ( image->HasOption(wxIMAGE_OPTION_TIFF_PHOTOMETRIC) )

     {
     {

-        // we can't use COMPRESSION_LZW because current version of libtiff
+        photometric = image->GetOptionInt(wxIMAGE_OPTION_TIFF_PHOTOMETRIC);
+        if (photometric == PHOTOMETRIC_MINISWHITE
+            || photometric == PHOTOMETRIC_MINISBLACK)
+        {
+            // either b/w or greyscale
+            spp = 1;
+        }
+    }
+    else if (spp <= 2)
+    {
+        photometric = PHOTOMETRIC_MINISWHITE;
+    }
+
+    const bool hasAlpha = image->HasAlpha();
+
+    int compression = image->GetOptionInt(wxIMAGE_OPTION_TIFF_COMPRESSION);
+    if ( !compression || (compression == COMPRESSION_JPEG && hasAlpha) )
+    {
+        // We can't use COMPRESSION_LZW because current version of libtiff

         // doesn't implement it ("no longer implemented due to Unisys patent
         // enforcement") and other compression methods are lossy so we
         // doesn't implement it ("no longer implemented due to Unisys patent
         // enforcement") and other compression methods are lossy so we

-        // shouldn't use them by default -- and the only remaining one is none
+        // shouldn't use them by default -- and the only remaining one is none.
+        // Also JPEG compression for alpha images is not a good idea (viewers
+        // not opening the image properly).

         compression = COMPRESSION_NONE;
     }
 
         compression = COMPRESSION_NONE;
     }
 

-    TIFFSetField(tif, TIFFTAG_SAMPLESPERPIXEL, spp);
-    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, bpp);
-    TIFFSetField(tif, TIFFTAG_PHOTOMETRIC, spp*bpp == 1 ? PHOTOMETRIC_MINISBLACK
-                                                        : PHOTOMETRIC_RGB);
+    if
+    (
+        (photometric == PHOTOMETRIC_RGB && spp == 4)
+        || (photometric <= PHOTOMETRIC_MINISBLACK && spp == 2)
+    )
+    {
+        // Compensate for user passing a SamplesPerPixel that includes
+        // the alpha channel.
+        spp--;
+    }
+
+
+    int extraSamples = hasAlpha ? 1 : 0;
+
+    TIFFSetField(tif, TIFFTAG_SAMPLESPERPIXEL, spp + extraSamples);
+    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, bps);
+    TIFFSetField(tif, TIFFTAG_PHOTOMETRIC, photometric);

     TIFFSetField(tif, TIFFTAG_COMPRESSION, compression);
 
     TIFFSetField(tif, TIFFTAG_COMPRESSION, compression);
 

-    // scanlinesize if determined by spp and bpp
-    tsize_t linebytes = (tsize_t)image->GetWidth() * spp * bpp / 8;
+    if (extraSamples)
+    {
+        uint16 extra[] = { EXTRASAMPLE_UNSPECIFIED };
+        TIFFSetField(tif, TIFFTAG_EXTRASAMPLES, (long) 1, &extra);
+    }

 
 

-    if ( (image->GetWidth() % 8 > 0) && (spp * bpp < 8) )
-        linebytes+=1;
+    // scanlinesize is determined by spp+extraSamples and bps
+    const tsize_t linebytes =
+        (tsize_t)((imageWidth * (spp + extraSamples) * bps + 7) / 8);

 
     unsigned char *buf;
 
 
     unsigned char *buf;
 

-    if (TIFFScanlineSize(tif) > linebytes || (spp * bpp < 24))
+    const bool isColouredImage = (spp > 1)
+        && (photometric != PHOTOMETRIC_MINISWHITE)
+        && (photometric != PHOTOMETRIC_MINISBLACK);
+
+
+    if (TIFFScanlineSize(tif) > linebytes || !isColouredImage || hasAlpha)

     {
         buf = (unsigned char *)_TIFFmalloc(TIFFScanlineSize(tif));
         if (!buf)
         {
             if (verbose)
     {
         buf = (unsigned char *)_TIFFmalloc(TIFFScanlineSize(tif));
         if (!buf)
         {
             if (verbose)

+            {

                 wxLogError( _("TIFF: Couldn't allocate memory.") );
                 wxLogError( _("TIFF: Couldn't allocate memory.") );

+            }

 
             TIFFClose( tif );
 
 
             TIFFClose( tif );
 


@@ -445,27 +757,84 @@ bool wxTIFFHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbo
 
     TIFFSetField(tif, TIFFTAG_ROWSPERSTRIP,TIFFDefaultStripSize(tif, (uint32) -1));
 
 
     TIFFSetField(tif, TIFFTAG_ROWSPERSTRIP,TIFFDefaultStripSize(tif, (uint32) -1));
 

+    const int bitsPerPixel = (spp + extraSamples) * bps;
+    const int bytesPerPixel = (bitsPerPixel + 7) / 8;
+    const int pixelsPerByte = 8 / bitsPerPixel;
+    int remainingPixelCount = 0;
+
+    if (pixelsPerByte)
+    {
+        // How many pixels to write in the last byte column?
+        remainingPixelCount = imageWidth % pixelsPerByte;
+        if (!remainingPixelCount) remainingPixelCount = pixelsPerByte;
+    }
+
+    const bool minIsWhite = (photometric == PHOTOMETRIC_MINISWHITE);

     unsigned char *ptr = image->GetData();
     for ( int row = 0; row < image->GetHeight(); row++ )
     {
         if ( buf )
         {
     unsigned char *ptr = image->GetData();
     for ( int row = 0; row < image->GetHeight(); row++ )
     {
         if ( buf )
         {

-            if ( spp * bpp > 1 )
+            if (isColouredImage)

             {
             {

-                // color image
-                memcpy(buf, ptr, image->GetWidth());
+                // colour image
+                if (hasAlpha)
+                {
+                    for ( int column = 0; column < imageWidth; column++ )
+                    {
+                        buf[column*4    ] = ptr[column*3    ];
+                        buf[column*4 + 1] = ptr[column*3 + 1];
+                        buf[column*4 + 2] = ptr[column*3 + 2];
+                        buf[column*4 + 3] = image->GetAlpha(column, row);
+                    }
+                }
+                else
+                {
+                    memcpy(buf, ptr, imageWidth * 3);
+                }
+            }
+            else if (spp * bps == 8) // greyscale image
+            {
+                for ( int column = 0; column < imageWidth; column++ )
+                {
+                    uint8 value = ptr[column*3 + 1];
+                    if (minIsWhite)
+                    {
+                        value = 255 - value;
+                    }
+
+                    buf[column * bytesPerPixel] = value;
+
+                    if (hasAlpha)
+                    {
+                        value = image->GetAlpha(column, row);
+                        buf[column*bytesPerPixel+1]
+                            = minIsWhite ? 255 - value : value;
+                    }
+                }

             }
             else // black and white image
             {
                 for ( int column = 0; column < linebytes; column++ )
                 {
                     uint8 reverse = 0;
             }
             else // black and white image
             {
                 for ( int column = 0; column < linebytes; column++ )
                 {
                     uint8 reverse = 0;

-                    for ( int bp = 0; bp < 8; bp++ )
+                    int pixelsPerByteCount = (column + 1 != linebytes)
+                        ? pixelsPerByte
+                        : remainingPixelCount;
+                    for ( int bp = 0; bp < pixelsPerByteCount; bp++ )

                     {
                     {

-                        if ( ptr[column*24 + bp*3] > 0 )
+                        if ( (ptr[column * 3 * pixelsPerByte + bp*3 + 1] <=127)
+                            == minIsWhite )
+                        {
+                            // check only green as this is sufficient
+                            reverse |= (uint8) (128 >> (bp * bitsPerPixel));
+                        }
+
+                        if (hasAlpha
+                            && (image->GetAlpha(column * pixelsPerByte + bp,
+                                    row) <= 127) == minIsWhite)

                         {
                         {

-                            // check only red as this is sufficient
-                            reverse = (uint8)(reverse | 128 >> bp);
+                            reverse |= (uint8) (64 >> (bp * bitsPerPixel));

                         }
                     }
 
                         }
                     }
 


@@ -477,7 +846,9 @@ bool wxTIFFHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbo
         if ( TIFFWriteScanline(tif, buf ? buf : ptr, (uint32)row, 0) < 0 )
         {
             if (verbose)
         if ( TIFFWriteScanline(tif, buf ? buf : ptr, (uint32)row, 0) < 0 )
         {
             if (verbose)

+            {

                 wxLogError( _("TIFF: Error writing image.") );
                 wxLogError( _("TIFF: Error writing image.") );

+            }

 
             TIFFClose( tif );
             if (buf)
 
             TIFFClose( tif );
             if (buf)


@@ -486,7 +857,7 @@ bool wxTIFFHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbo
             return false;
         }
 
             return false;
         }
 

-        ptr += image->GetWidth()*3;
+        ptr += imageWidth * 3;

     }
 
     (void) TIFFClose(tif);
     }
 
     (void) TIFFClose(tif);


@@ -501,7 +872,7 @@ bool wxTIFFHandler::DoCanRead( wxInputStream& stream )
 {
     unsigned char hdr[2];
 
 {
     unsigned char hdr[2];
 

-    if ( !stream.Read(&hdr[0], WXSIZEOF(hdr)) )
+    if ( !stream.Read(&hdr[0], WXSIZEOF(hdr)) )     // it's ok to modify the stream position here

         return false;
 
     return (hdr[0] == 'I' && hdr[1] == 'I') ||
         return false;
 
     return (hdr[0] == 'I' && hdr[1] == 'I') ||


@@ -510,4 +881,27 @@ bool wxTIFFHandler::DoCanRead( wxInputStream& stream )
 
 #endif  // wxUSE_STREAMS
 
 
 #endif  // wxUSE_STREAMS
 

+/*static*/ wxVersionInfo wxTIFFHandler::GetLibraryVersionInfo()
+{
+    int major,
+        minor,
+        micro;
+
+    const wxString ver(::TIFFGetVersion());
+    if ( wxSscanf(ver, "LIBTIFF, Version %d.%d.%d", &major, &minor, &micro) != 3 )
+    {
+        wxLogDebug("Unrecognized libtiff version string \"%s\"", ver);
+
+        major =
+        minor =
+        micro = 0;
+    }
+
+    wxString copyright;
+    const wxString desc = ver.BeforeFirst('\n', &copyright);
+    copyright.Replace("\n", "");
+
+    return wxVersionInfo("libtiff", major, minor, micro, desc, copyright);
+}
+

 #endif  // wxUSE_LIBTIFF
 #endif  // wxUSE_LIBTIFF