X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/d26d975463cc7b55bc9304acedede97e47f459d2..a380af4dbff98b71780c32772625f1d974522e4e:/src/common/imagpng.cpp diff --git a/src/common/imagpng.cpp b/src/common/imagpng.cpp index 892b129e48..d0da8f6111 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 // ============================================================================ @@ -190,39 +205,45 @@ PNGLINKAGEMODE wx_png_warning(png_structp png_ptr, png_const_charp message) // ---------------------------------------------------------------------------- // determine the kind of transparency we need for this image: if the only alpha -// values it has are 0 and 0xff 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 +// 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: -// ptr the start of the data to examine +// 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, +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 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++ ) + 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 - ptr2 += numColBytes; - 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 opaque nor fully transparent, hence need alpha return Transparency_Alpha; } } + + // during the next loop iteration check all the pixels in the row + x = 0; } // mask will be enough @@ -237,13 +258,11 @@ 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; @@ -338,7 +357,7 @@ 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 @@ -346,7 +365,7 @@ void CopyDataFromPNG(wxImage *image, // only, otherwisewe need the latter transparency = CheckTransparency ( - ptrSrc, + lines, x, y, width, height, 1 @@ -370,8 +389,25 @@ 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: @@ -379,11 +415,6 @@ void CopyDataFromPNG(wxImage *image, *ptrDst++ = g; *ptrDst++ = g; break; - - case Transparency_Mask: - *ptrDst++ = rMask; - *ptrDst++ = bMask; - *ptrDst++ = gMask; } } } @@ -402,11 +433,11 @@ 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, + lines, x, y, width, height, 3 @@ -426,8 +457,36 @@ 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: @@ -435,20 +494,6 @@ 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; } } }