unsupported stream format in TFNClistbox

FNC TMS FNC UI Pack
12

We have investigated this here and noticed the following registration in one of the Skia units:

TPicture.RegisterFileFormat('svg', 'Scalable Vector Graphics', TSkSvgGraphic);

Which basically registers TSkSvgGraphic as a class for handling SVG file formats and streams.

This conflicts with our own TPicture registration mechanism:

TPicture.RegisterFileFormat('SVG', 'Scalable Vector Graphics (FNC)', TTMSFNCSVGBitmap);

so depending on the way the packages are loaded, either TTMSFNCSVGBitmap or TSkSvgGraphic is registered. At designtime, this means that TSkSvgGraphic is being used as a class for our FNC components. This is no problem at first, but I noticed that the CanLoadFromStream mechanism is actually changing the Position pointer of the stream, when being loaded. So this code:

{$IF CompilerVersion >= 32}
class function TSkGraphic.CanLoadFromStream(AStream: TStream): Boolean;
const
  SupportedFormats = [TSkEncodedImageFormat.WEBP, TSkEncodedImageFormat.WBMP, TSkEncodedImageFormat.DNG];
var
  LCodec: ISkCodec;
begin
  LCodec := TSkCodec.MakeFromStream(AStream);
  Result := Assigned(LCodec) and (LCodec.EncodedImageFormat in SupportedFormats);
end;
{$ENDIF}

Is checking if the stream can be loaded, but it doesn't reset the position, which then means the stream is corrupted. Next, our own checking is applied, and it doesn't find a valid stream anymore which is the reason why it gives an access violation.

I would expect to at least reset back the position of the stream:

{$IF CompilerVersion >= 32}
class function TSkGraphic.CanLoadFromStream(AStream: TStream): Boolean;
const
  SupportedFormats = [TSkEncodedImageFormat.WEBP, TSkEncodedImageFormat.WBMP, TSkEncodedImageFormat.DNG];
var
  LCodec: ISkCodec;
  p: Int64;
begin
  p := AStream.Position;
  try
    LCodec := TSkCodec.MakeFromStream(AStream);
    Result := Assigned(LCodec) and (LCodec.EncodedImageFormat in SupportedFormats);
  finally
    AStream.Position := p;
  end;
end;
{$ENDIF}

So this code needs to be fixed at their side, I've created an issue at github

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