Re: How to create the GDI+ Bitmap object from images stored in memory?

From:

"David Ching" <dc@remove-this.dcsoft.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Tue, 25 Dec 2007 02:16:59 GMT

Message-ID:

<vKZbj.27158$4V6.5261@newssvr14.news.prodigy.net>

<ccbruce@gmail.com> wrote in message
news:5a9cc137-5ffa-4c2e-9437-830822466a5c@i29g2000prf.googlegroups.com...

I have many png files to show in my application. But I don't want to
store them outside of the execution. So I choose to store them as
resources.

I packed them into a tar file (Because I don't want to process that
png files by myself), and make the tar file be one of resources of my
execution. I also wrote some functions for extracting binary data
(stored in memory as unsigned char array) of png files from the
resourcized tar file (loaded by LoadResource).

But I don't know how to make gdi+ to load them and generate a Bitmap
object. After document studying, I found a method
Bitmap::FromStream(IStream *) might help me to do this. But I don't
know how to make my png data to be an IStream and loaded by
Bitmap::FromStream...

The following might be a way to solve this problem...I think...

1. LoadReousrce()...I got a HGLOBAL of that tar.
2. Extract the png files that I need and save them in unsigned char
array
3. GlobalHandle()...So I can retrive the HGLOBAL of the array of png
file.
4. CreateStreamOnHGlobal()...OK...I got an IStream object...
5. pass the IStream object into Bitmap::FromStream...
6. After the Bitmap object successfully been created, Call
IStream::Release() and GlobalFree()...

Does anyone can tell my above way works or not? Or tell me another
better, simple way?

Looks about right. See
http://msdn.microsoft.com/msdnmag/code/Default.aspx?level=root%2cImgView3&file=Picture.cpp&url=http%3a%2f%2fmsdn.microsoft.com%2fmsdnmag%2fissues%2f02%2f10%2fCQA%2fDefault.aspx
for Paul di Lascia's CPicture class that does the same thing.

-- David