🚀 go-pugleaf

"Lapo" <lapoguidi@inwind.it> wrote in message
news:3ed00a13@newsgroups.borland.com...
> Hi all,
> I'm coding a program to show a serie of jpeg from a network camera in a
> TImage.
> Following suggestions of this newsgroup, I used a TThread to get a jpeg
and
> to show one after another.
> I used the Synchronize method to update the TImage content.
> Now the question:
> I see that every time the TImage is updated using Synchronize, as a said
> before, the Thread seems freezed until the updating is done.

Sure.  That is what Synchronize() is designed to do.  It blocks the calling
thread until the function is called by the main GUI thread.

> Well, I read something about PostMessage/SendMessage to communicate from
> Thread to Main Application, so the thread can ask the main application to
> update the TImage and it doesn't wait for the updating is over.

PostMessage would be the solution here.   Keep in mind that some messages
(eg WM_COPYDATA) can't be sent by PostMessage.  You will also need to
have a defined way of getting data from one thread to the other.

SendMessage blocks the caller until the window receiving the message has
acted on the message.  IOW, you will see exactly the same effect as you
would with using Synchronize().

> I tried to manage it, but I'm lost.
> Maybe somebody have a sample or an url or a code snip... I really hope it.
>

One of the challenges of multithreaded programming comes when you
need to process data on one thread and show (or even access) the
results through another.   Keep in mind that the process of getting data
to the other thread is always something that requires some form of
synchronisation.