Comments on: IThumbnailProvider Re-Visited

By: MFC_Convert

MFC_Convert — Wed, 06 Jul 2011 21:55:10 +0000

Thanks a lot Jeremy. The post was straightforward and easy to adapt to. Great Writeup. 10/10.

-Cheers
MFC convert

By: Jeremy

Jeremy — Wed, 06 Jul 2011 17:15:31 +0000

Paul, I’m glad you ( and Dan ) found this helpful. It really pleases me that people are still finding this article helpful even a year after I wrote it

By: Marko

Marko — Tue, 05 Jul 2011 14:30:07 +0000

Could you give us your code please?

Thanks

By: Paul

Paul — Mon, 04 Jul 2011 15:32:23 +0000

Thanks Jeremy! After trying numerous samples to try and get this to work, yours was the first one that actually did – and was very easy to use to boot!

One thing to note for people trying to use this, if it works the result is a completely blank icon (instead of the default blank page icon). I think it was you and Dan having a conversation on another page I found, and a slight variation on your suggested “Hello World” implementation of GetThumbnail is this:

*phbmp = NULL; *pdwAlpha = WTSAT_UNKNOWN;


	ULONG_PTR token;

	GdiplusStartupInput input;

	if (Ok == GdiplusStartup(&token, &input, NULL))

	{

		//gcImage.LogBuffer();

		Bitmap * pBitmap = new Bitmap(188, 141);

		if( pBitmap )

		{

			Graphics xGraphics( pBitmap );

			Font xFont( L"Arial", 12, FontStyleRegular, UnitPoint );

			SolidBrush xBrush( Color( 0, 0, 0) );

			xGraphics.DrawString(L"Hello!", 6, &xFont, PointF(0.0f,0.0f), &xBrush );

			Color color(255, 0, 0);

			pBitmap->GetHBITMAP(color, phbmp);

		}

	}
	GdiplusShutdown(token);
	if( *phbmp != NULL )

		return NOERROR;

return E_NOTIMPL;

Not forgetting to add #include “Gdiplus.h” and link to “gdiplus.lib”.

Interestingly, Dan works at the same company as myself, and sits a few desks away – yet we discovered this page separately and for different purposes.

By: Jeremy

Jeremy — Tue, 29 Mar 2011 21:09:06 +0000

Ralfn,

Have you tried this on Windows 7? According to Microsoft, it “shouldn’t be written managed”. When is it you set your IStream to null?

By: Ralfn

Ralfn — Fri, 11 Mar 2011 12:40:29 +0000

I successfully implemented a ThumbnailProvider in C# by setting all references to IStream to null and calling GC.Collect after the image has been gathered from the stream. Works like a charm.