X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/27bb2b7cea271d91e272452ff361f948e38dc539..8471ea90331c42693823ede04ded5fd4d5bf008b:/src/common/imagpng.cpp diff --git a/src/common/imagpng.cpp b/src/common/imagpng.cpp index 1b8e201718..250fac506a 100644 --- a/src/common/imagpng.cpp +++ b/src/common/imagpng.cpp @@ -11,7 +11,7 @@ // declarations // ============================================================================ -#ifdef __GNUG__ +#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA) #pragma implementation "imagpng.h" #endif @@ -74,8 +74,9 @@ 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 -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); @@ -85,6 +86,20 @@ 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 // ============================================================================ @@ -145,12 +160,14 @@ struct wxPNGInfoStruct 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); } -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); } @@ -189,41 +206,50 @@ PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message) // 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(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) @@ -234,13 +260,11 @@ 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 - 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; @@ -335,14 +359,19 @@ void CopyDataFromPNG(wxImage *image, // 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 - transparency = CheckTransparency(ptrSrc, x, y, - width, height); + transparency = CheckTransparency + ( + lines, + x, y, + width, height, + 1 + ); if ( transparency == Transparency_Mask ) { @@ -362,8 +391,25 @@ void CopyDataFromPNG(wxImage *image, 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: - *alpha++ = a; + if ( alpha ) + *alpha++ = a; // fall through case Transparency_None: @@ -371,11 +417,6 @@ void CopyDataFromPNG(wxImage *image, *ptrDst++ = g; *ptrDst++ = g; break; - - case Transparency_Mask: - *ptrDst++ = rMask; - *ptrDst++ = bMask; - *ptrDst++ = gMask; } } } @@ -394,10 +435,15 @@ void CopyDataFromPNG(wxImage *image, // 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 ) { @@ -413,8 +459,36 @@ void CopyDataFromPNG(wxImage *image, 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: - *alpha++ = a; + if ( alpha ) + *alpha++ = a; // fall through case Transparency_None: @@ -422,20 +496,6 @@ void CopyDataFromPNG(wxImage *image, *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; } } } @@ -482,7 +542,7 @@ wxPNGHandler::LoadFile(wxImage *image, // 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) @@ -609,7 +669,7 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos // 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,