Minor header cleaning.

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

diff --git a/src/common/imagpng.cpp b/src/common/imagpng.cpp
index 1b8e2017189f27a9ed42cc7f0c1b2dd6e26baf46..009f133de98c46fc8d432c4f03ae92d27987c8ba 100644 (file)
--- a/src/common/imagpng.cpp
+++ b/src/common/imagpng.cpp
@@ -11,10 +11,6 @@
 // declarations
 // ============================================================================
 
 // declarations
 // ============================================================================
 

-#ifdef __GNUG__
-#pragma implementation "imagpng.h"
-#endif
-

 // ----------------------------------------------------------------------------
 // headers
 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------
 // headers
 // ----------------------------------------------------------------------------


@@ -23,25 +19,25 @@
 #include "wx/wxprec.h"
 
 #ifdef __BORLANDC__
 #include "wx/wxprec.h"
 
 #ifdef __BORLANDC__

-  #pragma hdrstop
-#endif
-
-#ifndef WX_PRECOMP
-  #include "wx/defs.h"
+    #pragma hdrstop

 #endif
 
 #if wxUSE_IMAGE && wxUSE_LIBPNG
 
 #include "wx/imagpng.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"
+
+#ifndef WX_PRECOMP
+    #include "wx/log.h"
+    #include "wx/app.h"
+    #include "wx/bitmap.h"
+    #include "wx/module.h"
+#endif
+

 #include "png.h"
 #include "wx/filefn.h"
 #include "wx/wfstream.h"
 #include "wx/intl.h"
 #include "png.h"
 #include "wx/filefn.h"
 #include "wx/wfstream.h"
 #include "wx/intl.h"

-#include "wx/module.h"
+#include "wx/palette.h"

 
 // For memcpy
 #include <string.h>
 
 // For memcpy
 #include <string.h>


@@ -74,8 +70,9 @@ enum Transparency
 // return the kind of transparency needed for this image assuming that it does
 // have transparent pixels, i.e. either Transparency_Alpha or Transparency_Mask
 static Transparency
 // return the kind of transparency needed for this image assuming that it does
 // have transparent pixels, i.e. either Transparency_Alpha or Transparency_Mask
 static Transparency

-CheckTransparency(const unsigned char *ptr,
-                  png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h);
+CheckTransparency(unsigned char **lines,
+                  png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
+                  size_t numColBytes);

 
 // init the alpha channel for the image and fill it with 1s up to (x, y)
 static unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y);
 
 // init the alpha channel for the image and fill it with 1s up to (x, y)
 static unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y);


@@ -85,6 +82,20 @@ static void
 FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
                unsigned char& rMask, unsigned char& gMask, unsigned char& bMask);
 
 FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
                unsigned char& rMask, unsigned char& gMask, unsigned char& bMask);
 

+// is the pixel with this value of alpha a fully opaque one?
+static inline
+bool IsOpaque(unsigned char a)
+{
+    return a == 0xff;
+}
+
+// is the pixel with this value of alpha a fully transparent one?
+static inline
+bool IsTransparent(unsigned char a)
+{
+    return !a;
+}
+

 // ============================================================================
 // wxPNGHandler implementation
 // ============================================================================
 // ============================================================================
 // wxPNGHandler implementation
 // ============================================================================


@@ -145,42 +156,37 @@ struct wxPNGInfoStruct
 extern "C"
 {
 
 extern "C"
 {
 

-void PNGLINKAGEMODE _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length )
+void PNGLINKAGEMODE wx_PNG_stream_reader( png_structp png_ptr, png_bytep data,
+                                          png_size_t length )

 {
     WX_PNG_INFO(png_ptr)->stream.in->Read(data, 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 )
+void PNGLINKAGEMODE wx_PNG_stream_writer( png_structp png_ptr, png_bytep data,
+                                          png_size_t length )

 {
     WX_PNG_INFO(png_ptr)->stream.out->Write(data, 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
 void

-PNGLINKAGEMODE wx_png_error(png_structp png_ptr, png_const_charp message)
+PNGLINKAGEMODE wx_png_warning(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
+    wxPNGInfoStruct *info = png_ptr ? WX_PNG_INFO(png_ptr) : NULL;
+    if ( !info || info->verbose )
+        wxLogWarning( wxString::FromAscii(message) );

 }
 
 }
 

+// from pngerror.c
+// so that the libpng doesn't send anything on stderr

 void
 void

-PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
+PNGLINKAGEMODE wx_png_error(png_structp png_ptr, png_const_charp message)

 {
 {

-    wxPNGInfoStruct *info = WX_PNG_INFO(png_ptr);
-    if (info->verbose)
-        wxLogWarning( wxString::FromAscii(message) );
+    wx_png_warning(NULL, message);
+
+    // we're not using libpng built-in jump buffer (see comment before
+    // wxPNGInfoStruct above) so we have to return ourselves, otherwise libpng
+    // would just abort
+    longjmp(WX_PNG_INFO(png_ptr)->jmpbuf, 1);

 }
 
 } // extern "C"
 }
 
 } // extern "C"


@@ -189,41 +195,50 @@ PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
 // LoadFile() helpers
 // ----------------------------------------------------------------------------
 
 // LoadFile() helpers
 // ----------------------------------------------------------------------------
 

+// determine the kind of transparency we need for this image: if the only alpha
+// values it has are 0 (transparent) and 0xff (opaque) then we can simply
+// create a mask for it, we should be ok with a simple mask but otherwise we
+// need a full blown alpha channel in wxImage
+//
+// parameters:
+//      lines           raw PNG data
+//      x, y            starting position
+//      w, h            size of the image
+//      numColBytes     number of colour bytes (1 for grey scale, 3 for RGB)
+//                      (NB: alpha always follows the colour bytes)

 Transparency
 Transparency

-CheckTransparency(const unsigned char *ptr,
-                  png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h)
+CheckTransparency(unsigned char **lines,
+                  png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
+                  size_t numColBytes)

 {
 {

-    // suppose that a mask will suffice
-    Transparency transparency = Transparency_Mask;
-
-    // and check all the remaining alpha values to see if it does
-    unsigned char a2;
-    unsigned const char *ptr2 = ptr;
-    for ( png_uint_32 y2 = y; y2 < h; y2++ )
+    // suppose that a mask will suffice and check all the remaining alpha
+    // values to see if it does
+    for ( ; y < h; y++ )

     {
     {

-        for ( png_uint_32 x2 = x + 1; x2 < w; x2++ )
+        // each pixel is numColBytes+1 bytes, offset into the current line by
+        // the current x position
+        unsigned const char *ptr = lines[y] + (x * (numColBytes + 1));
+
+        for ( png_uint_32 x2 = x; x2 < w; x2++ )

         {
         {

-            // skip the grey byte
-            a2 = *++ptr2;
+            // skip the grey or colour byte(s)
+            ptr += numColBytes;
+
+            unsigned char a2 = *ptr++;

 
 

-            if ( a2 && a2 != 0xff )
+            if ( !IsTransparent(a2) && !IsOpaque(a2) )

             {
             {

-                // not fully opeaque nor fully transparent, hence need alpha
-                transparency = Transparency_Alpha;
-                break;
+                // not fully opaque nor fully transparent, hence need alpha
+                return Transparency_Alpha;

             }
             }

-
-            ++ptr2;

         }
 
         }
 

-        if ( transparency == Transparency_Alpha )
-        {
-            // no need to continue
-            break;
-        }
+        // during the next loop iteration check all the pixels in the row
+        x = 0;

     }
 
     }
 

-    return transparency;
+    // mask will be enough
+    return Transparency_Mask;

 }
 
 unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y)
 }
 
 unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y)


@@ -234,13 +249,11 @@ unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y)
     unsigned char *alpha = image->GetAlpha();
 
     // set alpha for the pixels we had so far
     unsigned char *alpha = image->GetAlpha();
 
     // set alpha for the pixels we had so far

-    for ( png_uint_32 y2 = 0; y2 <= y; y2++ )
+    png_uint_32 end = y * image->GetWidth() + x;
+    for ( png_uint_32 i = 0; i < end; i++ )

     {
     {

-        for ( png_uint_32 x2 = 0; x2 < x; x2++ )
-        {
-            // all the previous pixels were opaque
-            *alpha++ = 0xff;
-        }
+        // all the previous pixels were opaque
+        *alpha++ = 0xff;

     }
 
     return alpha;
     }
 
     return alpha;


@@ -266,6 +279,7 @@ FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
             r2 = *p++;
             g2 = *p++;
             b2 = *p++;
             r2 = *p++;
             g2 = *p++;
             b2 = *p++;

+            ++p; // jump over alpha

 
             wxImageHistogramEntry&
                 entry = h[wxImageHistogram:: MakeKey(r2, g2, b2)];
 
             wxImageHistogramEntry&
                 entry = h[wxImageHistogram:: MakeKey(r2, g2, b2)];


@@ -297,7 +311,7 @@ bool wxPNGHandler::DoCanRead( wxInputStream& stream )
     unsigned char hdr[4];
 
     if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
     unsigned char hdr[4];
 
     if ( !stream.Read(hdr, WXSIZEOF(hdr)) )

-        return FALSE;
+        return false;

 
     return memcmp(hdr, "\211PNG", WXSIZEOF(hdr)) == 0;
 }
 
     return memcmp(hdr, "\211PNG", WXSIZEOF(hdr)) == 0;
 }


@@ -335,14 +349,19 @@ void CopyDataFromPNG(wxImage *image,
 
                 // the first time we encounter a transparent pixel we must
                 // decide about what to do about them
 
                 // the first time we encounter a transparent pixel we must
                 // decide about what to do about them

-                if ( a != 0xff && transparency == Transparency_None )
+                if ( !IsOpaque(a) && transparency == Transparency_None )

                 {
                     // we'll need at least the mask for this image and
                     // maybe even full alpha channel info: the former is
                     // only enough if we have alpha values of 0 and 0xff
                     // only, otherwisewe need the latter
                 {
                     // we'll need at least the mask for this image and
                     // maybe even full alpha channel info: the former is
                     // only enough if we have alpha values of 0 and 0xff
                     // only, otherwisewe need the latter

-                    transparency = CheckTransparency(ptrSrc, x, y,
-                                                     width, height);
+                    transparency = CheckTransparency
+                                   (
+                                        lines,
+                                        x, y,
+                                        width, height,
+                                        1
+                                   );

 
                     if ( transparency == Transparency_Mask )
                     {
 
                     if ( transparency == Transparency_Mask )
                     {


@@ -362,8 +381,25 @@ void CopyDataFromPNG(wxImage *image,
 
                 switch ( transparency )
                 {
 
                 switch ( transparency )
                 {

+                    case Transparency_Mask:
+                        if ( IsTransparent(a) )
+                        {
+                            *ptrDst++ = rMask;
+                            *ptrDst++ = gMask;
+                            *ptrDst++ = bMask;
+                            break;
+                        }
+                        // else: !transparent
+
+                        // must be opaque then as otherwise we shouldn't be
+                        // using the mask at all
+                        wxASSERT_MSG( IsOpaque(a), _T("logic error") );
+
+                        // fall through
+

                     case Transparency_Alpha:
                     case Transparency_Alpha:

-                        *alpha++ = a;
+                        if ( alpha )
+                            *alpha++ = a;

                         // fall through
 
                     case Transparency_None:
                         // fall through
 
                     case Transparency_None:


@@ -371,11 +407,6 @@ void CopyDataFromPNG(wxImage *image,
                         *ptrDst++ = g;
                         *ptrDst++ = g;
                         break;
                         *ptrDst++ = g;
                         *ptrDst++ = g;
                         break;

-
-                    case Transparency_Mask:
-                        *ptrDst++ = rMask;
-                        *ptrDst++ = bMask;
-                        *ptrDst++ = gMask;

                 }
             }
         }
                 }
             }
         }


@@ -394,10 +425,15 @@ void CopyDataFromPNG(wxImage *image,
 
                 // the logic here is the same as for the grey case except
                 // where noted
 
                 // the logic here is the same as for the grey case except
                 // where noted

-                if ( a != 0xff && transparency == Transparency_None )
+                if ( !IsOpaque(a) && transparency == Transparency_None )

                 {
                 {

-                    transparency = CheckTransparency(ptrSrc, x, y,
-                                                     width, height);
+                    transparency = CheckTransparency
+                                   (
+                                        lines,
+                                        x, y,
+                                        width, height,
+                                        3
+                                   );

 
                     if ( transparency == Transparency_Mask )
                     {
 
                     if ( transparency == Transparency_Mask )
                     {


@@ -413,8 +449,36 @@ void CopyDataFromPNG(wxImage *image,
 
                 switch ( transparency )
                 {
 
                 switch ( transparency )
                 {

+                    case Transparency_Mask:
+                        if ( IsTransparent(a) )
+                        {
+                            *ptrDst++ = rMask;
+                            *ptrDst++ = gMask;
+                            *ptrDst++ = bMask;
+                            break;
+                        }
+                        else // !transparent
+                        {
+                            // must be opaque then as otherwise we shouldn't be
+                            // using the mask at all
+                            wxASSERT_MSG( IsOpaque(a), _T("logic error") );
+
+                            // if we couldn't find a unique colour for the
+                            // mask, we can have real pixels with the same
+                            // value as the mask and it's better to slightly
+                            // change their colour than to make them
+                            // transparent
+                            if ( r == rMask && g == gMask && b == bMask )
+                            {
+                                r++;
+                            }
+                        }
+
+                        // fall through
+

                     case Transparency_Alpha:
                     case Transparency_Alpha:

-                        *alpha++ = a;
+                        if ( alpha )
+                            *alpha++ = a;

                         // fall through
 
                     case Transparency_None:
                         // fall through
 
                     case Transparency_None:


@@ -422,20 +486,6 @@ void CopyDataFromPNG(wxImage *image,
                         *ptrDst++ = g;
                         *ptrDst++ = b;
                         break;
                         *ptrDst++ = g;
                         *ptrDst++ = b;
                         break;

-
-                    case Transparency_Mask:
-                        // if we couldn't find a unique colour for the mask, we
-                        // can have real pixels with the same value as the mask
-                        // and it's better to slightly change their colour than
-                        // to make them transparent
-                        if ( r == rMask && g == gMask && b == bMask )
-                        {
-                            r++;
-                        }
-
-                        *ptrDst++ = rMask;
-                        *ptrDst++ = bMask;
-                        *ptrDst++ = gMask;

                 }
             }
         }
                 }
             }
         }


@@ -459,30 +509,34 @@ wxPNGHandler::LoadFile(wxImage *image,
                        bool verbose,
                        int WXUNUSED(index))
 {
                        bool verbose,
                        int WXUNUSED(index))
 {

-    // VZ: as this function uses setjmp() the only fool proof error handling
+    // 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 = NULL;
     png_infop info_ptr = (png_infop) NULL;
     wxPNGInfoStruct wxinfo;
 
     //     method is to use goto (setjmp is not really C++ dtors friendly...)
 
     unsigned char **lines = NULL;
     png_infop info_ptr = (png_infop) NULL;
     wxPNGInfoStruct wxinfo;
 

+    png_uint_32 i, width, height = 0;
+    int bit_depth, color_type, interlace_type;
+

     wxinfo.verbose = verbose;
     wxinfo.stream.in = &stream;
 
     image->Destroy();
 
     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 );
+    png_structp png_ptr = png_create_read_struct
+                          (
+                            PNG_LIBPNG_VER_STRING,
+                            (voidp) NULL,
+                            wx_png_error,
+                            wx_png_warning
+                          );

     if (!png_ptr)
         goto error;
 
     if (!png_ptr)
         goto error;
 

-    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
     // 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);
+    png_set_read_fn( png_ptr, &wxinfo, wx_PNG_stream_reader);

 
     info_ptr = png_create_info_struct( png_ptr );
     if (!info_ptr)
 
     info_ptr = png_create_info_struct( png_ptr );
     if (!info_ptr)


@@ -491,9 +545,6 @@ wxPNGHandler::LoadFile(wxImage *image,
     if (setjmp(wxinfo.jmpbuf))
         goto error;
 
     if (setjmp(wxinfo.jmpbuf))
         goto error;
 

-    png_uint_32 i, 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 );
 
     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 );
 


@@ -510,7 +561,7 @@ wxPNGHandler::LoadFile(wxImage *image,
         png_set_expand( png_ptr );
     png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
 
         png_set_expand( png_ptr );
     png_set_filler( png_ptr, 0xff, PNG_FILLER_AFTER );
 

-    image->Create( (int)width, (int)height );
+    image->Create((int)width, (int)height, (bool) false /* no need to init pixels */);

 
     if (!image->Ok())
         goto error;
 
     if (!image->Ok())
         goto error;


@@ -531,6 +582,29 @@ wxPNGHandler::LoadFile(wxImage *image,
 
     png_read_image( png_ptr, lines );
     png_read_end( png_ptr, info_ptr );
 
     png_read_image( png_ptr, lines );
     png_read_end( png_ptr, info_ptr );

+
+#if wxUSE_PALETTE
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+    {
+        const size_t ncolors = info_ptr->num_palette;
+        unsigned char* r = new unsigned char[ncolors];
+        unsigned char* g = new unsigned char[ncolors];
+        unsigned char* b = new unsigned char[ncolors];
+
+        for (size_t j = 0; j < ncolors; j++)
+        {
+            r[j] = info_ptr->palette[j].red;
+            g[j] = info_ptr->palette[j].green;
+            b[j] = info_ptr->palette[j].blue;
+        }
+
+        image->SetPalette(wxPalette(ncolors, r, g, b));
+        delete[] r;
+        delete[] g;
+        delete[] b;
+    }
+#endif // wxUSE_PALETTE
+

     png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 
     // loaded successfully, now init wxImage with this data
     png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 
     // loaded successfully, now init wxImage with this data


@@ -540,7 +614,7 @@ wxPNGHandler::LoadFile(wxImage *image,
         free( lines[i] );
     free( lines );
 
         free( lines[i] );
     free( lines );
 

-    return TRUE;
+    return true;

 
 error:
     if (verbose)
 
 error:
     if (verbose)


@@ -553,6 +627,9 @@ error:
 
     if ( lines )
     {
 
     if ( lines )
     {

+        for ( unsigned int n = 0; n < height; n++ )
+            free( lines[n] );
+

         free( lines );
     }
 
         free( lines );
     }
 


@@ -566,7 +643,7 @@ error:
         else
             png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
     }
         else
             png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
     }

-    return FALSE;
+    return false;

 }
 
 // ----------------------------------------------------------------------------
 }
 
 // ----------------------------------------------------------------------------


@@ -580,23 +657,27 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
     wxinfo.verbose = verbose;
     wxinfo.stream.out = &stream;
 
     wxinfo.verbose = verbose;
     wxinfo.stream.out = &stream;
 

-    png_structp png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    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."));
     if (!png_ptr)
     {
         if (verbose)
            wxLogError(_("Couldn't save PNG image."));

-        return FALSE;
+        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."));
     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;
+        return false;

     }
 
     if (setjmp(wxinfo.jmpbuf))
     }
 
     if (setjmp(wxinfo.jmpbuf))


@@ -604,54 +685,167 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
         png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
         if (verbose)
            wxLogError(_("Couldn't save PNG image."));
         png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
         if (verbose)
            wxLogError(_("Couldn't save PNG image."));

-        return FALSE;
+        return false;

     }
 
     // NB: please see the comment near wxPNGInfoStruct declaration for
     //     explanation why this line is mandatory
     }
 
     // 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_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);
+    const int iColorType = image->HasOption(wxIMAGE_OPTION_PNG_FORMAT)
+                            ? image->GetOptionInt(wxIMAGE_OPTION_PNG_FORMAT)
+                            : wxPNG_TYPE_COLOUR;
+    const int iBitDepth = image->HasOption(wxIMAGE_OPTION_PNG_BITDEPTH)
+                            ? image->GetOptionInt(wxIMAGE_OPTION_PNG_BITDEPTH)
+                            : 8;
+
+    wxASSERT_MSG( iBitDepth == 8 || iBitDepth == 16,
+                    _T("PNG bit depth must be 8 or 16") );
+
+    bool bHasAlpha = image->HasAlpha();
+    bool bHasMask = image->HasMask();
+    bool bUseAlpha = bHasAlpha || bHasMask;
+
+    int iPngColorType;
+    if ( iColorType==wxPNG_TYPE_COLOUR )
+    {
+        iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_RGB_ALPHA
+                                  : PNG_COLOR_TYPE_RGB;
+    }
+    else
+    {
+        iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_GRAY_ALPHA
+                                  : PNG_COLOR_TYPE_GRAY;
+    }

 
 

+    png_set_IHDR( png_ptr, info_ptr, image->GetWidth(), image->GetHeight(),
+                  iBitDepth, iPngColorType,
+                  PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
+                  PNG_FILTER_TYPE_BASE);
+
+    int iElements;

     png_color_8 sig_bit;
     png_color_8 sig_bit;

-    sig_bit.red = 8;
-    sig_bit.green = 8;
-    sig_bit.blue = 8;
-    sig_bit.alpha = 8;
+
+    if ( iPngColorType & PNG_COLOR_MASK_COLOR )
+    {
+        sig_bit.red =
+        sig_bit.green =
+        sig_bit.blue = (png_byte)iBitDepth;
+        iElements = 3;
+    }
+    else // grey
+    {
+        sig_bit.gray = (png_byte)iBitDepth;
+        iElements = 1;
+    }
+
+    if ( iPngColorType & PNG_COLOR_MASK_ALPHA )
+    {
+        sig_bit.alpha = (png_byte)iBitDepth;
+        iElements++;
+    }
+
+    if ( iBitDepth == 16 )
+        iElements *= 2;
+

     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 );
 
     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)
+    unsigned char *
+        data = (unsigned char *)malloc( image->GetWidth() * iElements );
+    if ( !data )

     {
         png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
     {
         png_destroy_write_struct( &png_ptr, (png_infopp)NULL );

-        return FALSE;
+        return false;

     }
 
     }
 

-    for (int y = 0; y < image->GetHeight(); y++)
+    unsigned char *
+        pAlpha = (unsigned char *)(bHasAlpha ? image->GetAlpha() : NULL);
+    int iHeight = image->GetHeight();
+    int iWidth = image->GetWidth();
+
+    unsigned char uchMaskRed = 0, uchMaskGreen = 0, uchMaskBlue = 0;
+
+    if ( bHasMask )

     {
     {

-        unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
-        for (int x = 0; x < image->GetWidth(); x++)
+        uchMaskRed = image->GetMaskRed();
+        uchMaskGreen = image->GetMaskGreen();
+        uchMaskBlue = image->GetMaskBlue();
+    }
+
+    unsigned char *pColors = image->GetData();
+
+    for (int y = 0; y != iHeight; ++y)
+    {
+        unsigned char *pData = data;
+        for (int x = 0; x != iWidth; 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()))
+            unsigned char uchRed = *pColors++;
+            unsigned char uchGreen = *pColors++;
+            unsigned char uchBlue = *pColors++;
+
+            switch ( iColorType )

             {
             {

-                data[(x << 2) + 3] = 255;
+                default:
+                    wxFAIL_MSG( _T("unknown wxPNG_TYPE_XXX") );
+                    // fall through
+
+                case wxPNG_TYPE_COLOUR:
+                    *pData++ = uchRed;
+                    if ( iBitDepth == 16 )
+                        *pData++ = 0;
+                    *pData++ = uchGreen;
+                    if ( iBitDepth == 16 )
+                        *pData++ = 0;
+                    *pData++ = uchBlue;
+                    if ( iBitDepth == 16 )
+                        *pData++ = 0;
+                    break;
+
+                case wxPNG_TYPE_GREY:
+                    {
+                        // where do these coefficients come from? maybe we
+                        // should have image options for them as well?
+                        unsigned uiColor =
+                            (unsigned) (76.544*(unsigned)uchRed +
+                                        150.272*(unsigned)uchGreen +
+                                        36.864*(unsigned)uchBlue);
+
+                        *pData++ = (unsigned char)((uiColor >> 8) & 0xFF);
+                        if ( iBitDepth == 16 )
+                            *pData++ = (unsigned char)(uiColor & 0xFF);
+                    }
+                    break;
+
+                case wxPNG_TYPE_GREY_RED:
+                    *pData++ = uchRed;
+                    if ( iBitDepth == 16 )
+                        *pData++ = 0;
+                    break;

             }
             }

-            else
+
+            if ( bUseAlpha )

             {
             {

-                data[(x << 2) + 3] = 0;
+                unsigned char uchAlpha = 255;
+                if ( bHasAlpha )
+                    uchAlpha = *pAlpha++;
+
+                if ( bHasMask )
+                {
+                    if ( (uchRed == uchMaskRed)
+                            && (uchGreen == uchMaskGreen)
+                                && (uchBlue == uchMaskBlue) )
+                        uchAlpha = 0;
+                }
+
+                *pData++ = uchAlpha;
+                if ( iBitDepth == 16 )
+                    *pData++ = 0;

             }
         }
             }
         }

+

         png_bytep row_ptr = data;
         png_write_rows( png_ptr, &row_ptr, 1 );
     }
         png_bytep row_ptr = data;
         png_write_rows( png_ptr, &row_ptr, 1 );
     }


@@ -660,7 +854,7 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
     png_write_end( png_ptr, info_ptr );
     png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
 
     png_write_end( png_ptr, info_ptr );
     png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
 

-    return TRUE;
+    return true;

 }
 
 #ifdef __VISUALC__
 }
 
 #ifdef __VISUALC__