Convert bitmap to PNG in-memory in C++ (win32)

Question

Can I convert a bitmap to PNG in memory (i.e. without writing to a file) using only the Platform SDK? (i.e. no libpng, etc.).

I also want to be able to define a tran

Answer 1

I've used GDI+ for saving a bitmap as a PNG to a file. You should probably check out the MSDN info about GDI+ here and in particular this function GdipSaveImageToStream.

This tutorial here will probably provide some help as well.

Answer 2

On this site the code shows how convert a bitmap to PNG writing it to a file: http://dotnet-snippets.de/dns/gdi-speichern-eines-png-SID814.aspx. Instead of writing to a file, the Save method of Bitmap also supports writing to a IStream (http://msdn.microsoft.com/en-us/library/ms535406%28VS.85%29.aspx). You can create a Stream backed up by memory using the CreateStreamOnHGlobal API function. (http://msdn.microsoft.com/en-us/library/aa378980%28VS.85%29.aspx). The used library, GDI+, is included in Windows up from WindowsXP, and works in Windows up from Windows98. I've never done something with it, just googled around. Looks like you can use that, though.