Add support for saving 256*256 ICOs in PNG format.

Allow saving icons larger than 127*127 pixels (up to 256*256 which is the
maximal size supported by the ICO format) and save large icons with the item
data in PNG format, as it is normally done for these sizes.

See #15918.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76132 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -54,6 +54,7 @@ wxMSW:
 - Support multiline strings in wxDC::DrawRotatedText() (Artur Wieczorek).
 - Fix stretchable spacers in vertical toolbars (Artur Wieczorek).
 - Add wxEnhMetaFile::Detach() (Luca Bacci).
+- Add support for saving 256*256 ICOs in PNG format (Artur Wieczorek).
 
 wxOSX/Cocoa:
 

src/common/imagbmp.cpp

@@ -1188,8 +1188,8 @@ bool wxICOHandler::SaveFile(wxImage *image,
                             bool verbose)
 
 {
-    //sanity check; icon must be less than 127 pixels high and 255 wide
-    if ( image->GetHeight () > 127 )
+    // sanity check; icon must be no larger than 256x256
+    if ( image->GetHeight () > 256 )
     {
         if ( verbose )
         {
@@ -1197,7 +1197,7 @@ bool wxICOHandler::SaveFile(wxImage *image,
         }
         return false;
     }
-    if ( image->GetWidth () > 255 )
+    if ( image->GetWidth () > 256 )
     {
         if ( verbose )
         {
@@ -1284,25 +1284,48 @@ bool wxICOHandler::SaveFile(wxImage *image,
 
         //calculate size and offset of image and mask
         wxCountingOutputStream cStream;
-        bool bResult = SaveDib(image, cStream, verbose, IsBmp, IsMask);
-        if ( !bResult )
+        bool bResult;
+#if wxUSE_LIBPNG
+        // Typically, icons larger then 128x128 are saved as PNG images.
+        bool saveAsPNG = false;
+        if ( image->GetHeight() > 128 || image->GetWidth() > 128 )
         {
-            if ( verbose )
+            wxPNGHandler handlerPNG;
+            bResult = handlerPNG.SaveFile(image, cStream, verbose);
+            if ( !bResult )
             {
-                wxLogError(_("ICO: Error writing the image file!"));
+                if ( verbose )
+                {
+                    wxLogError(_("ICO: Error writing the image file!"));
+                }
+                return false;
             }
-            return false;
-        }
-        IsMask = true;
 
-        bResult = SaveDib(&mask, cStream, verbose, IsBmp, IsMask);
-        if ( !bResult )
+            saveAsPNG = true;
+        }
+        if ( !saveAsPNG )
+#endif // wxUSE_LIBPNG
         {
-            if ( verbose )
+            bResult = SaveDib(image, cStream, verbose, IsBmp, IsMask);
+            if ( !bResult )
             {
-                wxLogError(_("ICO: Error writing the image file!"));
+                if ( verbose )
+                {
+                    wxLogError(_("ICO: Error writing the image file!"));
+                }
+                return false;
+            }
+            IsMask = true;
+
+            bResult = SaveDib(&mask, cStream, verbose, IsBmp, IsMask);
+            if ( !bResult )
+            {
+                if ( verbose )
+                {
+                    wxLogError(_("ICO: Error writing the image file!"));
+                }
+                return false;
             }
-            return false;
         }
         wxUint32 Size = cStream.GetSize();
 
@@ -1321,8 +1344,11 @@ bool wxICOHandler::SaveFile(wxImage *image,
 
         offset = offset + sizeof(ICONDIRENTRY);
 
+        // Notice that the casts work correctly for width/height of 256 as it's
+        // represented by 0 in ICO file format -- and larger values are not
+        // allowed at all.
         icondirentry.bWidth = (wxUint8)image->GetWidth();
-        icondirentry.bHeight = (wxUint8)(2 * image->GetHeight());
+        icondirentry.bHeight = (wxUint8)image->GetHeight();
         icondirentry.bColorCount = 0;
         icondirentry.bReserved = 0;
         icondirentry.wPlanes = wxUINT16_SWAP_ON_BE(1);
@@ -1364,26 +1390,44 @@ bool wxICOHandler::SaveFile(wxImage *image,
         }
 
         // actually save it:
-        IsMask = false;
-        bResult = SaveDib(image, stream, verbose, IsBmp, IsMask);
-        if ( !bResult )
+#if wxUSE_LIBPNG
+        if ( saveAsPNG )
         {
-            if ( verbose )
+            wxPNGHandler handlerPNG;
+            bResult = handlerPNG.SaveFile(image, stream, verbose);
+            if ( !bResult )
             {
-                wxLogError(_("ICO: Error writing the image file!"));
+                if ( verbose )
+                {
+                    wxLogError(_("ICO: Error writing the image file!"));
+                }
+                return false;
             }
-            return false;
         }
-        IsMask = true;
-
-        bResult = SaveDib(&mask, stream, verbose, IsBmp, IsMask);
-        if ( !bResult )
+        else
+#endif // wxUSE_LIBPNG
         {
-            if ( verbose )
+            IsMask = false;
+            bResult = SaveDib(image, stream, verbose, IsBmp, IsMask);
+            if ( !bResult )
             {
-                wxLogError(_("ICO: Error writing the image file!"));
+                if ( verbose )
+                {
+                    wxLogError(_("ICO: Error writing the image file!"));
+                }
+                return false;
+            }
+            IsMask = true;
+
+            bResult = SaveDib(&mask, stream, verbose, IsBmp, IsMask);
+            if ( !bResult )
+            {
+                if ( verbose )
+                {
+                    wxLogError(_("ICO: Error writing the image file!"));
+                }
+                return false;
             }
-            return false;
         }
 
     } // end of for loop