/////////////////////////////////////////////////////////////////////////////
-// Name: imagepng.cpp
+// Name: src/common/imagepng.cpp
// Purpose: wxImage PNG handler
// Author: Robert Roebling
// RCS-ID: $Id$
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-/*
- We don't put pragma implement in this file because it is already present in
- src/common/image.cpp
-*/
+// ============================================================================
+// declarations
+// ============================================================================
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
#include "wx/defs.h"
#endif
-#if wxUSE_LIBPNG
+#if wxUSE_IMAGE && wxUSE_LIBPNG
-#include "wx/image.h"
+#include "wx/imagpng.h"
#include "wx/bitmap.h"
#include "wx/debug.h"
#include "wx/log.h"
#endif
#endif
-#ifdef __WXMSW__
-#include <windows.h>
-#endif
+// ----------------------------------------------------------------------------
+// constants
+// ----------------------------------------------------------------------------
-//-----------------------------------------------------------------------------
-// wxPNGHandler
-//-----------------------------------------------------------------------------
+// image can not have any transparent pixels at all, have only 100% opaque
+// and/or 100% transparent pixels in which case a simple mask is enough to
+// store this information in wxImage or have a real alpha channel in which case
+// we need to have it in wxImage as well
+enum Transparency
+{
+ Transparency_None,
+ Transparency_Mask,
+ Transparency_Alpha
+};
+
+// ----------------------------------------------------------------------------
+// local functions
+// ----------------------------------------------------------------------------
+
+// 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(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);
+
+// find a free colour for the mask in the PNG data array
+static void
+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
+// ============================================================================
-#if !USE_SHARED_LIBRARIES
IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
+
+#if wxUSE_STREAMS
+
+#ifndef PNGLINKAGEMODE
+ #if defined(__WATCOMC__) && ( defined(__WXMSW__) || defined(__WXMGL__) )
+ // we need an explicit cdecl for Watcom, at least according to
+ //
+ // http://sf.net/tracker/index.php?func=detail&aid=651492&group_id=9863&atid=109863
+ //
+ // more testing is needed for this however, please remove this comment
+ // if you can confirm that my fix works with Watcom 11
+ #define PNGLINKAGEMODE cdecl
+ #else
+ #define PNGLINKAGEMODE LINKAGEMODE
+ #endif
#endif
-#if wxUSE_LIBPNG
-#if defined(__VISAGECPP__)
-#define LINKAGEMODE _Optlink
-#else
-#define 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;
-static void LINKAGEMODE _PNG_stream_reader( png_structp png_ptr, png_bytep data, png_size_t length )
+ union
+ {
+ wxInputStream *in;
+ wxOutputStream *out;
+ } stream;
+};
+
+#define WX_PNG_INFO(png_ptr) ((wxPNGInfoStruct*)png_get_io_ptr(png_ptr))
+
+// ----------------------------------------------------------------------------
+// helper functions
+// ----------------------------------------------------------------------------
+
+extern "C"
{
- ((wxInputStream*) png_get_io_ptr( png_ptr )) -> Read(data, 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);
}
-static void LINKAGEMODE _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 )
{
- ((wxOutputStream*) png_get_io_ptr( png_ptr )) -> 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
-LINKAGEMODE png_silent_error(png_structp png_ptr, png_const_charp WXUNUSED(message))
+PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message)
{
-#ifdef USE_FAR_KEYWORD
- {
- jmp_buf jmpbuf;
- png_memcpy(jmpbuf,png_ptr->jmpbuf,sizeof(jmp_buf));
- longjmp(jmpbuf, 1);
- }
-#else
- longjmp(png_ptr->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
-LINKAGEMODE png_silent_warning(png_structp WXUNUSED(png_ptr), png_const_charp WXUNUSED(message))
+PNGLINKAGEMODE wx_png_error(png_structp png_ptr, png_const_charp 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);
}
-bool wxPNGHandler::LoadFile( wxImage *image, wxInputStream& stream, bool verbose, int WXUNUSED(index) )
+} // extern "C"
+
+// ----------------------------------------------------------------------------
+// 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
+CheckTransparency(unsigned char **lines,
+ png_uint_32 x, png_uint_32 y, png_uint_32 w, png_uint_32 h,
+ size_t numColBytes)
{
- // VZ: as this function uses setjmp() the only fool proof error handling
- // method is to use goto (setjmp is not really C++ dtors friendly...)
+ // suppose that a mask will suffice and check all the remaining alpha
+ // values to see if it does
+ for ( ; y < h; y++ )
+ {
+ // 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));
- unsigned char **lines;
- unsigned int i;
- png_infop info_ptr = (png_infop) NULL;
+ for ( png_uint_32 x2 = x; x2 < w; x2++ )
+ {
+ // skip the grey or colour byte(s)
+ ptr += numColBytes;
- image->Destroy();
+ unsigned char a2 = *ptr++;
- 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;
+ if ( !IsTransparent(a2) && !IsOpaque(a2) )
+ {
+ // not fully opaque nor fully transparent, hence need alpha
+ return Transparency_Alpha;
+ }
+ }
- // the file example.c explain how to guess if the stream is a png image
- if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_warning);
+ // during the next loop iteration check all the pixels in the row
+ x = 0;
+ }
- info_ptr = png_create_info_struct( png_ptr );
- if (!info_ptr)
- goto error_nolines;
+ // mask will be enough
+ return Transparency_Mask;
+}
- if (setjmp(png_ptr->jmpbuf))
- goto error_nolines;
+unsigned char *InitAlpha(wxImage *image, png_uint_32 x, png_uint_32 y)
+{
+ // create alpha channel
+ image->SetAlpha();
- if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
- goto error_nolines;
+ unsigned char *alpha = image->GetAlpha();
- png_set_read_fn( png_ptr, &stream, _PNG_stream_reader);
+ // set alpha for the pixels we had so far
+ png_uint_32 end = y * image->GetWidth() + x;
+ for ( png_uint_32 i = 0; i < end; i++ )
+ {
+ // all the previous pixels were opaque
+ *alpha++ = 0xff;
+ }
- png_uint_32 width,height;
- int bit_depth,color_type,interlace_type;
+ return alpha;
+}
- 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 );
+void
+FindMaskColour(unsigned char **lines, png_uint_32 width, png_uint_32 height,
+ unsigned char& rMask, unsigned char& gMask, unsigned char& bMask)
+{
+ // choosing the colour for the mask is more
+ // difficult: we need to iterate over the entire
+ // image for this in order to choose an unused
+ // colour (this is not very efficient but what else
+ // can we do?)
+ wxImageHistogram h;
+ unsigned nentries = 0;
+ unsigned char r2, g2, b2;
+ for ( png_uint_32 y2 = 0; y2 < height; y2++ )
+ {
+ const unsigned char *p = lines[y2];
+ for ( png_uint_32 x2 = 0; x2 < width; x2++ )
+ {
+ r2 = *p++;
+ g2 = *p++;
+ b2 = *p++;
- if (color_type == PNG_COLOR_TYPE_PALETTE)
- png_set_expand( png_ptr );
+ wxImageHistogramEntry&
+ entry = h[wxImageHistogram:: MakeKey(r2, g2, b2)];
- 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 );
+ if ( entry.value++ == 0 )
+ entry.index = nentries++;
+ }
+ }
- image->Create( width, height );
+ if ( !h.FindFirstUnusedColour(&rMask, &gMask, &bMask) )
+ {
+ wxLogWarning(_("Too many colours in PNG, the image may be slightly blurred."));
+
+ // use a fixed mask colour and we'll fudge
+ // the real pixels with this colour (see
+ // below)
+ rMask = 0xfe;
+ gMask = 0;
+ bMask = 0xff;
+ }
+}
- if (!image->Ok())
- goto error_nolines;
+// ----------------------------------------------------------------------------
+// reading PNGs
+// ----------------------------------------------------------------------------
- lines = (unsigned char **)malloc( height * sizeof(unsigned char *) );
- if (lines == NULL)
- goto error_nolines;
+bool wxPNGHandler::DoCanRead( wxInputStream& stream )
+{
+ unsigned char hdr[4];
- for (i = 0; i < height; i++)
- {
- if ((lines[i] = (unsigned char *)malloc(width * (sizeof(unsigned char) * 4))) == NULL)
- {
- for ( unsigned int n = 0; n < i; n++ )
- free( lines[n] );
- goto error;
- }
- }
+ if ( !stream.Read(hdr, WXSIZEOF(hdr)) )
+ return false;
- // loaded successfully!
+ return memcmp(hdr, "\211PNG", WXSIZEOF(hdr)) == 0;
+}
+
+// convert data from RGB to wxImage format
+static
+void CopyDataFromPNG(wxImage *image,
+ unsigned char **lines,
+ png_uint_32 width,
+ png_uint_32 height,
+ int color_type)
+{
+ Transparency transparency = Transparency_None;
+
+ // only non NULL if transparency == Transparency_Alpha
+ unsigned char *alpha = NULL;
+
+ // RGB of the mask colour if transparency == Transparency_Mask
+ // (but init them anyhow to avoid compiler warnings)
+ unsigned char rMask = 0,
+ gMask = 0,
+ bMask = 0;
+
+ unsigned char *ptrDst = image->GetData();
+ if ( !(color_type & PNG_COLOR_MASK_COLOR) )
{
- 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))
+ // grey image: GAGAGA... where G == grey component and A == alpha
+ for ( png_uint_32 y = 0; y < height; y++ )
{
- for (unsigned int y = 0; y < height; y++)
+ const unsigned char *ptrSrc = lines[y];
+ for ( png_uint_32 x = 0; x < width; x++ )
{
- unsigned char *ptr2 = lines[y];
- for (unsigned int x = 0; x < width; x++)
+ unsigned char g = *ptrSrc++;
+ unsigned char a = *ptrSrc++;
+
+ // the first time we encounter a transparent pixel we must
+ // decide about what to do about them
+ if ( !IsOpaque(a) && transparency == Transparency_None )
{
- unsigned char r = *ptr2++;
- unsigned char a = *ptr2++;
- if (a < 128)
+ // 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
+ (
+ lines,
+ x, y,
+ width, height,
+ 1
+ );
+
+ if ( transparency == Transparency_Mask )
{
- *ptr++ = 255;
- *ptr++ = 0;
- *ptr++ = 255;
- transp = 1;
+ // let's choose this colour for the mask: this is
+ // not a problem here as all the other pixels are
+ // grey, i.e. R == G == B which is not the case for
+ // this one so no confusion is possible
+ rMask = 0xff;
+ gMask = 0;
+ bMask = 0xff;
}
- else
+ else // transparency == Transparency_Alpha
{
- *ptr++ = r;
- *ptr++ = r;
- *ptr++ = r;
+ alpha = InitAlpha(image, x, y);
}
}
+
+ switch ( transparency )
+ {
+ case Transparency_Mask:
+ if ( IsTransparent(a) )
+ {
+ *ptrDst++ = rMask;
+ *ptrDst++ = bMask;
+ *ptrDst++ = gMask;
+ 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:
+ if ( alpha )
+ *alpha++ = a;
+ // fall through
+
+ case Transparency_None:
+ *ptrDst++ = g;
+ *ptrDst++ = g;
+ *ptrDst++ = g;
+ break;
+ }
}
}
- else
+ }
+ else // colour image: RGBRGB...
+ {
+ for ( png_uint_32 y = 0; y < height; y++ )
{
- for (unsigned int y = 0; y < height; y++)
+ const unsigned char *ptrSrc = lines[y];
+ for ( png_uint_32 x = 0; x < width; x++ )
{
- unsigned char *ptr2 = lines[y];
- for (unsigned int x = 0; x < width; x++)
+ unsigned char r = *ptrSrc++;
+ unsigned char g = *ptrSrc++;
+ unsigned char b = *ptrSrc++;
+ unsigned char a = *ptrSrc++;
+
+ // the logic here is the same as for the grey case except
+ // where noted
+ if ( !IsOpaque(a) && transparency == Transparency_None )
{
- unsigned char r = *ptr2++;
- unsigned char g = *ptr2++;
- unsigned char b = *ptr2++;
- unsigned char a = *ptr2++;
- if (a < 128)
+ transparency = CheckTransparency
+ (
+ lines,
+ x, y,
+ width, height,
+ 3
+ );
+
+ if ( transparency == Transparency_Mask )
{
- *ptr++ = 255;
- *ptr++ = 0;
- *ptr++ = 255;
- transp = 1;
+ FindMaskColour(lines, width, height,
+ rMask, gMask, bMask);
}
- else
+ else // transparency == Transparency_Alpha
{
- if ((r == 255) && (g == 0) && (b == 255)) r = 254;
- *ptr++ = r;
- *ptr++ = g;
- *ptr++ = b;
+ alpha = InitAlpha(image, x, y);
}
+
+ }
+
+ switch ( transparency )
+ {
+ case Transparency_Mask:
+ if ( IsTransparent(a) )
+ {
+ *ptrDst++ = rMask;
+ *ptrDst++ = bMask;
+ *ptrDst++ = gMask;
+ 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:
+ if ( alpha )
+ *alpha++ = a;
+ // fall through
+
+ case Transparency_None:
+ *ptrDst++ = r;
+ *ptrDst++ = g;
+ *ptrDst++ = b;
+ break;
}
}
}
+ }
- for ( unsigned int j = 0; j < height; j++ )
- free( lines[j] );
- free( lines );
+ if ( transparency == Transparency_Mask )
+ {
+ image->SetMaskColour(rMask, gMask, bMask);
+ }
+}
- if (transp)
- {
- image->SetMaskColour( 255, 0, 255 );
- }
- else
+// 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 = 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();
+
+ 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;
+
+ // NB: please see the comment near wxPNGInfoStruct declaration for
+ // explanation why this line is mandatory
+ png_set_read_fn( png_ptr, &wxinfo, wx_PNG_stream_reader);
+
+ info_ptr = png_create_info_struct( png_ptr );
+ if (!info_ptr)
+ goto error;
+
+ if (setjmp(wxinfo.jmpbuf))
+ goto error;
+
+ 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, (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)
{
- image->SetMask( FALSE );
+ for ( unsigned int n = 0; n < i; n++ )
+ free( lines[n] );
+ goto error;
}
}
- return TRUE;
+ png_read_image( png_ptr, lines );
+ png_read_end( png_ptr, info_ptr );
+ png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
- error_nolines:
- lines = NULL; // called from before it was set
- error:
+ // 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 ( lines )
{
+ for ( unsigned int n = 0; n < height; n++ )
+ free( lines[n] );
+
free( lines );
}
else
png_destroy_read_struct( &png_ptr, (png_infopp) NULL, (png_infopp) NULL );
}
- return FALSE;
+ 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)
{
- png_structp png_ptr = png_create_write_struct( PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
- if (!png_ptr)
- {
- return FALSE;
- }
+ if (verbose)
+ wxLogError(_("Couldn't save PNG image."));
+ return false;
+ }
- if (!verbose) png_set_error_fn(png_ptr, (png_voidp)NULL, png_silent_error, png_silent_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;
+ }
- png_infop info_ptr = png_create_info_struct(png_ptr);
- if (info_ptr == NULL)
- {
- png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
- 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;
+ }
- if (setjmp(png_ptr->jmpbuf))
- {
- png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
- 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_write_fn( png_ptr, &stream, _PNG_stream_writer, NULL);
+ 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;
- 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);
+ wxASSERT_MSG( iBitDepth == 8 || iBitDepth == 16,
+ _T("PNG bit depth must be 8 or 16") );
- 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 );
+ bool bHasAlpha = image->HasAlpha();
+ bool bHasMask = image->HasMask();
+ bool bUseAlpha = bHasAlpha || bHasMask;
- unsigned char *data = (unsigned char *)malloc( image->GetWidth()*4 );
- if (!data)
- {
- png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
- return FALSE;
- }
+ 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;
+ }
- for (int y = 0; y < image->GetHeight(); y++)
+ 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;
+
+ 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 );
+
+ unsigned char *
+ data = (unsigned char *)malloc( image->GetWidth() * iElements );
+ if ( !data )
+ {
+ png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
+ return false;
+ }
+
+ 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 )
+ {
+ 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++)
{
- unsigned char *ptr = image->GetData() + (y * image->GetWidth() * 3);
- for (int x = 0; x < image->GetWidth(); x++)
+ unsigned char uchRed = *pColors++;
+ unsigned char uchGreen = *pColors++;
+ unsigned char uchBlue = *pColors++;
+
+ switch ( iColorType )
{
- 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
+ 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;
+ }
+
+ if ( bUseAlpha )
+ {
+ unsigned char uchAlpha = 255;
+ if ( bHasAlpha )
+ uchAlpha = *pAlpha++;
+
+ if ( bHasMask )
{
- data[(x << 2) + 3] = 0;
+ 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 );
}
- free(data);
- png_write_end( png_ptr, info_ptr );
- png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
+ png_bytep row_ptr = data;
+ png_write_rows( png_ptr, &row_ptr, 1 );
}
- return TRUE;
-}
-bool wxPNGHandler::DoCanRead( wxInputStream& stream )
-{
- unsigned char hdr[4];
+ free(data);
+ png_write_end( png_ptr, info_ptr );
+ png_destroy_write_struct( &png_ptr, (png_infopp)&info_ptr );
- stream.Read(&hdr, 4);
- stream.SeekI(-4, wxFromCurrent);
- return (hdr[0] == 0x89 && hdr[1] == 'P' && hdr[2] == 'N' && hdr[3] == 'G');
+ return true;
}
+#ifdef __VISUALC__
+ #pragma warning(default:4611)
+#endif /* VC++ */
+
#endif // wxUSE_STREAMS
#endif // wxUSE_LIBPNG
projects / wxWidgets.git / blobdiff