Add support for loading old V1 bitmap files to wxBMPHandler.

Such files are apparently still seen in the wild, even though this format has
been superseded since Windows 3.0 (!).

Closes #3433.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76144 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -39,6 +39,7 @@ All (GUI):
 - Added on-demand image loading option to wxRTC.
 - Add wxFont::GetBaseFont() (Melroy Tellis).
 - Update included Scintilla to version 3.3.9 (Christian Walther).
+- Add support for loading old V1 BMP files to wxImage (Artur Wieczorek).
 
 wxGTK:
 

include/wx/imagbmp.h

@@ -60,7 +60,7 @@ protected:
                  bool IsBmp, bool IsMask);
     bool DoLoadDib(wxImage *image, int width, int height, int bpp, int ncolors,
                    int comp, wxFileOffset bmpOffset, wxInputStream& stream,
-                   bool verbose, bool IsBmp, bool hasPalette);
+                   bool verbose, bool IsBmp, bool hasPalette, int colEntrySize = 4);
     bool LoadDib(wxImage *image, wxInputStream& stream, bool verbose, bool IsBmp);
 #endif // wxUSE_STREAMS
 

src/common/imagbmp.cpp

@@ -499,7 +499,8 @@ struct BMPPalette
 bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
                              int bpp, int ncolors, int comp,
                              wxFileOffset bmpOffset, wxInputStream& stream,
-                             bool verbose, bool IsBmp, bool hasPalette)
+                             bool verbose, bool IsBmp, bool hasPalette,
+                             int colEntrySize)
 {
     wxInt32         aDword, rmask = 0, gmask = 0, bmask = 0, amask = 0;
     int             rshift = 0, gshift = 0, bshift = 0, ashift = 0;
@@ -585,7 +586,7 @@ bool wxBMPHandler::DoLoadDib(wxImage * image, int width, int height,
         {
             if (hasPalette)
             {
-                if ( !stream.ReadAll(bbuf, 4) )
+                if ( !stream.ReadAll(bbuf, colEntrySize) )
                     return false;
 
                 cmap[j].b = bbuf[0];
@@ -997,28 +998,57 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
     wxInt32         dbuf[4];
     wxInt8          bbuf[4];
 
+    // offset to bitmap data
+    wxFileOffset offset;
+    // DIB header size (used to distinguish different versions of DIB header)
+    wxInt32 hdrSize;
     if ( IsBmp )
     {
         // read the header off the .BMP format file
         if ( !stream.ReadAll(bbuf, 2) ||
              !stream.ReadAll(dbuf, 16) )
             return false;
+
+        #if 0 // unused
+            wxInt32 size = wxINT32_SWAP_ON_BE(dbuf[0]);
+        #endif
+        offset = wxINT32_SWAP_ON_BE(dbuf[2]);
+        hdrSize = wxINT32_SWAP_ON_BE(dbuf[3]);
     }
     else
     {
         if ( !stream.ReadAll(dbuf, 4) )
             return false;
-    }
-    #if 0 // unused
-        wxInt32 size = wxINT32_SWAP_ON_BE(dbuf[0]);
-    #endif
-    wxFileOffset offset = wxINT32_SWAP_ON_BE(dbuf[2]);
 
+        offset = wxInvalidOffset; // not used in loading ICO/CUR DIBs
+        hdrSize = wxINT32_SWAP_ON_BE(dbuf[0]);
+    }
+
+    // Bitmap files come in old v1 format using BITMAPCOREHEADER or a newer
+    // format (typically BITMAPV5HEADER, in use since Windows 98, but we don't
+    // really support any features specific to later formats such as gamma
+    // correction or ICC profiles, so it doesn't matter much to us).
+    const bool usesV1 = hdrSize == 12;
+
+    int width;
+    int height;
+    if ( usesV1 )
+    {
+        wxInt16 buf[2];
+        if ( !stream.ReadAll(buf, sizeof(buf)) )
+            return false;
+
+        width = wxINT16_SWAP_ON_BE((short)buf[0]);
+        height = wxINT16_SWAP_ON_BE((short)buf[1]);
+    }
+    else // We have at least BITMAPINFOHEADER
+    {
         if ( !stream.ReadAll(dbuf, 4 * 2) )
             return false;
 
-    int width = wxINT32_SWAP_ON_BE((int)dbuf[0]);
+        width = wxINT32_SWAP_ON_BE((int)dbuf[0]);
-    int height = wxINT32_SWAP_ON_BE((int)dbuf[1]);
+        height = wxINT32_SWAP_ON_BE((int)dbuf[1]);
+    }
     if ( !IsBmp)height = height  / 2; // for icons divide by 2
 
     if ( width > 32767 )
@@ -1058,10 +1088,45 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
         return false;
     }
 
+    class Resolution
+    {
+    public:
+        Resolution()
+        {
+            m_valid = false;
+        }
+
+        void Init(int x, int y)
+        {
+            m_x = x;
+            m_y = y;
+            m_valid = false;
+        }
+
+        bool IsValid() const { return m_valid; }
+
+        int GetX() const { return m_x; }
+        int GetY() const { return m_y; }
+
+    private:
+        int m_x, m_y;
+        bool m_valid;
+    } res;
+    int comp;
+    int ncolors;
+
+    if ( usesV1 )
+    {
+        // The only possible format is BI_RGB and colours count is not used.
+        comp = BI_RGB;
+        ncolors = 0;
+    }
+    else // We have at least BITMAPINFOHEADER
+    {
         if ( !stream.ReadAll(dbuf, 4 * 4) )
             return false;
 
-    int comp = wxINT32_SWAP_ON_BE((int)dbuf[0]);
+        comp = wxINT32_SWAP_ON_BE((int)dbuf[0]);
         if ( comp != BI_RGB && comp != BI_RLE4 && comp != BI_RLE8 &&
              comp != BI_BITFIELDS )
         {
@@ -1075,7 +1140,9 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
         if ( !stream.ReadAll(dbuf, 4 * 2) )
             return false;
 
-    int ncolors = wxINT32_SWAP_ON_BE( (int)dbuf[0] );
+        ncolors = wxINT32_SWAP_ON_BE( (int)dbuf[0] );
+        res.Init(dbuf[2]/100, dbuf[3]/100);
+    }
     if (ncolors == 0)
         ncolors = 1 << bpp;
     /* some more sanity checks */
@@ -1092,7 +1159,8 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
 
     //read DIB; this is the BMP image or the XOR part of an icon image
     if ( !DoLoadDib(image, width, height, bpp, ncolors, comp, offset, stream,
-                    verbose, IsBmp, true) )
+                    verbose, IsBmp, true,
+                    usesV1 ? 3 : 4) )
     {
         if (verbose)
         {
@@ -1120,9 +1188,12 @@ bool wxBMPHandler::LoadDib(wxImage *image, wxInputStream& stream,
     }
 
     // the resolution in the bitmap header is in meters, convert to centimeters
+    if ( res.IsValid() )
+    {
         image->SetOption(wxIMAGE_OPTION_RESOLUTIONUNIT, wxIMAGE_RESOLUTION_CM);
-    image->SetOption(wxIMAGE_OPTION_RESOLUTIONX, dbuf[2]/100);
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONX, res.GetX());
-    image->SetOption(wxIMAGE_OPTION_RESOLUTIONY, dbuf[3]/100);
+        image->SetOption(wxIMAGE_OPTION_RESOLUTIONY, res.GetY());
+    }
 
     return true;
 }