X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/1de255d61341d80cfad92d4b34e9a73f6888e800..87f0b1323b7ac77f02133b836c8dfee63b0fd387:/src/common/imagpng.cpp

diff --git a/src/common/imagpng.cpp b/src/common/imagpng.cpp
index 8088193617..7fee6adbdb 100644
--- a/src/common/imagpng.cpp
+++ b/src/common/imagpng.cpp
@@ -43,7 +43,7 @@
 // constants
 // ----------------------------------------------------------------------------
 
-// image can not have any transparent pixels at all, have only 100% opaque
+// image cannot 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
@@ -116,11 +116,9 @@ IMPLEMENT_DYNAMIC_CLASS(wxPNGHandler,wxImageHandler)
 //     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.
+//     as DLL with another compiler than the main executable, it may not work.
+//     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
@@ -522,7 +520,7 @@ wxPNGHandler::LoadFile(wxImage *image,
     png_structp png_ptr = png_create_read_struct
                           (
                             PNG_LIBPNG_VER_STRING,
-                            (voidp) NULL,
+                            NULL,
                             wx_png_error,
                             wx_png_warning
                           );
@@ -558,7 +556,7 @@ wxPNGHandler::LoadFile(wxImage *image,
 
     image->Create((int)width, (int)height, (bool) false /* no need to init pixels */);
 
-    if (!image->Ok())
+    if (!image->IsOk())
         goto error;
 
     // initialize all line pointers to NULL to ensure that they can be safely
@@ -602,6 +600,47 @@ wxPNGHandler::LoadFile(wxImage *image,
     }
 #endif // wxUSE_PALETTE
 
+
+    // set the image resolution if it's available
+    png_uint_32 resX, resY;
+    int unitType;
+    if (png_get_pHYs(png_ptr, info_ptr, &resX, &resY, &unitType)
+        == PNG_INFO_pHYs)
+    {
+        wxImageResolution res = wxIMAGE_RESOLUTION_CM;
+
+        switch (unitType)
+        {
+            default:
+                wxLogWarning(_("Unknown PNG resolution unit %d"), unitType);
+                // fall through
+
+            case PNG_RESOLUTION_UNKNOWN:
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONX, resX);
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONY, resY);
+
+                res = wxIMAGE_RESOLUTION_NONE;
+                break;
+
+            case PNG_RESOLUTION_METER:
+                /*
+                Convert meters to centimeters.
+                Use a string to not lose precision (converting to cm and then
+                to inch would result in integer rounding error).
+                If an app wants an int, GetOptionInt will convert and round
+                down for them.
+                */
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONX,
+                    wxString::FromCDouble((double) resX / 100.0, 2));
+                image->SetOption(wxIMAGE_OPTION_RESOLUTIONY,
+                    wxString::FromCDouble((double) resY / 100.0, 2));
+                break;
+        }
+
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONUNIT, res);
+    }
+
+
     png_destroy_read_struct( &png_ptr, &info_ptr, (png_infopp) NULL );
 
     // loaded successfully, now init wxImage with this data
@@ -619,7 +658,7 @@ error:
        wxLogError(_("Couldn't load a PNG image - file is corrupted or not enough memory."));
     }
 
-    if ( image->Ok() )
+    if ( image->IsOk() )
     {
         image->Destroy();
     }
@@ -646,23 +685,41 @@ error:
 }
 
 // ----------------------------------------------------------------------------
-// SaveFile() helpers
+// SaveFile() palette helpers
 // ----------------------------------------------------------------------------
 
-static int PaletteFind(const png_color& clr,
-    const png_color *pal, png_uint_16 palCount)
+typedef wxLongToLongHashMap PaletteMap;
+
+static unsigned long PaletteMakeKey(const png_color_8& clr)
+{
+    return (wxImageHistogram::MakeKey(clr.red, clr.green, clr.blue) << 8) | clr.alpha;
+}
+
+static long PaletteFind(const PaletteMap& palette, const png_color_8& clr)
 {
-   for (png_uint_16 i = 0; i < palCount; i++)
-   {
-      if (    (clr.red   == pal[i].red)
-           && (clr.green == pal[i].green)
-           && (clr.blue  == pal[i].blue))
-      {
-         return i;
-      }
-   }
-
-   return wxNOT_FOUND;
+    unsigned long value = PaletteMakeKey(clr);
+    PaletteMap::const_iterator it = palette.find(value);
+
+    return (it != palette.end()) ? it->second : wxNOT_FOUND;
+}
+
+static long PaletteAdd(PaletteMap *palette, const png_color_8& clr)
+{
+    unsigned long value = PaletteMakeKey(clr);
+    PaletteMap::const_iterator it = palette->find(value);
+    size_t index;
+
+    if (it == palette->end())
+    {
+        index = palette->size();
+        (*palette)[value] = index;
+    }
+    else
+    {
+        index = it->second;
+    }
+
+    return index;
 }
 
 // ----------------------------------------------------------------------------
@@ -717,6 +774,9 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
     //     explanation why this line is mandatory
     png_set_write_fn( png_ptr, &wxinfo, wx_PNG_stream_writer, NULL);
 
+    const int iHeight = image->GetHeight();
+    const int iWidth = image->GetWidth();
+
     const bool bHasPngFormatOption
         = image->HasOption(wxIMAGE_OPTION_PNG_FORMAT);
 
@@ -727,72 +787,104 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
     bool bHasAlpha = image->HasAlpha();
     bool bHasMask = image->HasMask();
 
+    bool bUsePalette = iColorType == wxPNG_TYPE_PALETTE
 #if wxUSE_PALETTE
-    /*
-    Only save as an indexed image if the number of palette entries does not
-    exceed libpng's limit (256).
-    We assume here that we will need an extra palette entry if there's an
-    alpha or mask, regardless of whether a possibly needed conversion from
-    alpha to a mask fails (unlikely), or whether the mask colour already
-    can be found in the palette (more likely). In the latter case an extra
-    palette entry would not be required later on and the image could actually
-    be saved as a palettised PNG (instead now it will be saved as true colour).
-    A little bit of precision is lost, but at the benefit of a lot more
-    simplified code.
-    */
-    bool bUsePalette =
-        (!bHasPngFormatOption || iColorType == wxPNG_TYPE_PALETTE)
-        && image->HasPalette()
-        && image->GetPalette().GetColoursCount()
-            + ((bHasAlpha || bHasMask) ? 1 : 0) <= PNG_MAX_PALETTE_LENGTH;
-
-    wxImage temp_image(*image);
-    if (bUsePalette && image->HasAlpha() && !bHasMask)
+        || (!bHasPngFormatOption && image->HasPalette() )
+#endif
+    ;
+
+    png_color_8 mask = { 0, 0, 0, 0, 0 };
+
+    if (bHasMask)
+    {
+        mask.red   = image->GetMaskRed();
+        mask.green = image->GetMaskGreen();
+        mask.blue  = image->GetMaskBlue();
+    }
+
+    PaletteMap palette;
+
+    if (bUsePalette)
     {
-        /*
-        Only convert alpha to mask if saving as a palettised image was
-        explicitly requested. We don't want to lose alpha's precision
-        by converting to a mask just to be able to save palettised.
-        */
-        if (iColorType == wxPNG_TYPE_PALETTE
-            && temp_image.ConvertAlphaToMask())
+        png_color png_rgb  [PNG_MAX_PALETTE_LENGTH];
+        png_byte  png_trans[PNG_MAX_PALETTE_LENGTH];
+
+        const unsigned char *pColors = image->GetData();
+        const unsigned char* pAlpha  = image->GetAlpha();
+
+        if (bHasMask && !pAlpha)
         {
-            image = &temp_image;
-            bHasMask = true;
-            bHasAlpha = image->HasAlpha();
+            // Mask must be first
+            PaletteAdd(&palette, mask);
         }
-        else
+
+        for (int y = 0; y < iHeight; y++)
+        {
+            for (int x = 0; x < iWidth; x++)
+            {
+                png_color_8 rgba;
+
+                rgba.red   = *pColors++;
+                rgba.green = *pColors++;
+                rgba.blue  = *pColors++;
+                rgba.gray  = 0;
+                rgba.alpha = (pAlpha && !bHasMask) ? *pAlpha++ : 0;
+
+                // save in our palette
+                long index = PaletteAdd(&palette, rgba);
+
+                if (index < PNG_MAX_PALETTE_LENGTH)
+                {
+                    // save in libpng's palette
+                    png_rgb[index].red   = rgba.red;
+                    png_rgb[index].green = rgba.green;
+                    png_rgb[index].blue  = rgba.blue;
+                    png_trans[index]     = rgba.alpha;
+                }
+                else
+                {
+                    bUsePalette = false;
+                    break;
+                }
+            }
+        }
+
+        if (bUsePalette)
         {
-            bUsePalette = false;
-            iColorType = wxPNG_TYPE_COLOUR;
+            png_set_PLTE(png_ptr, info_ptr, png_rgb, palette.size());
+
+            if (bHasMask && !pAlpha)
+            {
+                wxASSERT(PaletteFind(palette, mask) == 0);
+                png_trans[0] = 0;
+                png_set_tRNS(png_ptr, info_ptr, png_trans, 1, NULL);
+            }
+            else if (pAlpha && !bHasMask)
+            {
+                png_set_tRNS(png_ptr, info_ptr, png_trans, palette.size(), NULL);
+            }
         }
     }
-#else
-    bool bUsePalette = false;
-#endif // wxUSE_PALETTE
-
-    bool bUseAlpha = !bUsePalette && (bHasAlpha || bHasMask);
 
-    png_color mask;
-    if (bHasMask)
+    /*
+    If saving palettised was requested but it was decided we can't use a
+    palette then reset the colour type to RGB.
+    */
+    if (!bUsePalette && iColorType == wxPNG_TYPE_PALETTE)
     {
-        mask.red   = image->GetMaskRed();
-        mask.green = image->GetMaskGreen();
-        mask.blue  = image->GetMaskBlue();
+        iColorType = wxPNG_TYPE_COLOUR;
     }
 
+    bool bUseAlpha = !bUsePalette && (bHasAlpha || bHasMask);
 
     int iPngColorType;
 
-#if wxUSE_PALETTE
     if (bUsePalette)
     {
         iPngColorType = PNG_COLOR_TYPE_PALETTE;
         iColorType = wxPNG_TYPE_PALETTE;
     }
-    else
-#endif // wxUSE_PALETTE
-    if ( iColorType==wxPNG_TYPE_COLOUR )
+    else if ( iColorType==wxPNG_TYPE_COLOUR )
     {
         iPngColorType = bUseAlpha ? PNG_COLOR_TYPE_RGB_ALPHA
                                   : PNG_COLOR_TYPE_RGB;
@@ -827,63 +919,6 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
                   PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
                   PNG_FILTER_TYPE_BASE);
 
-#if wxUSE_PALETTE
-    png_colorp palette = NULL;
-    int numPalette = 0;
-
-    if (bUsePalette)
-    {
-        const wxPalette& pal = image->GetPalette();
-        const int palCount = pal.GetColoursCount();
-        palette = (png_colorp) malloc(
-            (palCount + 1 /*headroom for trans */) * sizeof(png_color));
-
-        if (!palette)
-        {
-            png_destroy_write_struct( &png_ptr, (png_infopp)NULL );
-            if (verbose)
-            {
-               wxLogError(_("Couldn't save PNG image."));
-            }
-            return false;
-        }
-
-        png_uint_16 i;
-        for (i = 0; i < palCount; ++i)
-        {
-            pal.GetRGB(i, &palette[i].red, &palette[i].green, &palette[i].blue);
-        }
-
-        numPalette = palCount;
-        if (bHasMask)
-        {
-            int index = PaletteFind(mask, palette, numPalette);
-
-            if (index)
-            {
-                if (index == wxNOT_FOUND)
-                {
-                    numPalette++;
-                    index = palCount;
-                    palette[index] = mask;
-                }
-
-                wxSwap(palette[0], palette[index]);
-            }
-
-            png_byte trans = 0;
-            png_set_tRNS(png_ptr, info_ptr, &trans, 1, NULL);
-        }
-
-        png_set_PLTE(png_ptr, info_ptr, palette, numPalette);
-        free (palette);
-        palette = NULL;
-
-        // Let palette point to libpng's copy of the palette.
-        (void) png_get_PLTE(png_ptr, info_ptr, &palette, &numPalette);
-    }
-#endif // wxUSE_PALETTE
-
     int iElements;
     png_color_8 sig_bit;
 
@@ -900,7 +935,7 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
         iElements = 1;
     }
 
-    if ( iPngColorType & PNG_COLOR_MASK_ALPHA )
+    if ( bUseAlpha )
     {
         sig_bit.alpha = (png_byte)iBitDepth;
         iElements++;
@@ -949,22 +984,22 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
         return false;
     }
 
-    unsigned char *
-        pAlpha = (unsigned char *)(bHasAlpha ? image->GetAlpha() : NULL);
-    int iHeight = image->GetHeight();
-    int iWidth = image->GetWidth();
+    const unsigned char *
+        pAlpha = (const unsigned char *)(bHasAlpha ? image->GetAlpha() : NULL);
 
-    unsigned char *pColors = image->GetData();
+    const unsigned char *pColors = image->GetData();
 
     for (int y = 0; y != iHeight; ++y)
     {
         unsigned char *pData = data;
         for (int x = 0; x != iWidth; x++)
         {
-            png_color clr;
+            png_color_8 clr;
             clr.red   = *pColors++;
             clr.green = *pColors++;
             clr.blue  = *pColors++;
+            clr.gray  = 0;
+            clr.alpha = (bUsePalette && pAlpha) ? *pAlpha++ : 0; // use with wxPNG_TYPE_PALETTE only
 
             switch ( iColorType )
             {
@@ -1006,8 +1041,7 @@ bool wxPNGHandler::SaveFile( wxImage *image, wxOutputStream& stream, bool verbos
                     break;
 
                 case wxPNG_TYPE_PALETTE:
-                    *pData++ = (unsigned char) PaletteFind(clr,
-                        palette, numPalette);
+                    *pData++ = (unsigned char) PaletteFind(palette, clr);
                     break;
             }