extract frames from png animations

[Cosmin]

Zitat von Luckie:

By the way the png Object is never freed.

Correct. And the 3 streams too.
The code is just in "getting results" stage, so the nonreleasing used memory did not seem so important since in this moment I use the code only for tests in Delphi.
But thank you.

Zitat von Luckie:

I would fragment the whole procedure into separate procedures. That will make it easier to locate problems and bugs. Your long procedure is way too confusing. And if you use a class you can even avoid passing arguments around.

You could be right, although this code seems simple to me + breaking the code into small procedures affects the overall speed.


@FarAndBeyond

Thank you I'll have a look.
I've worked with Lazarus a few times, even made a dictionary component. So it's not so new to me.

[Luckie]

Well. Better slow working code than fast not working code. But does speed really matter in the end?

Bu as you wrote yourself: "getting results stage". So, i still would break in small pieces. Because it helps finding bugs, isolating prolems and it will be more readable.

[Cosmin]

Just to see what I'm trying to do.

Here is a test application: https://drive.google.com/open?id=0By...WZFYVlFQ1BzVlU

And here are some test files:

https://drive.google.com/open?id=0By...VZKcXdmb00zSmc
https://drive.google.com/open?id=0By...U9COFFmTUtjS1k
https://drive.google.com/open?id=0By...VRUa2tGZEYybGs

Use the button "Load Ajpeg" and then click on Preview.

[Cosmin]

@FarAndBeyond

That function seems to do ONLY png decompression of a frame received through its parameters.
But what I didn't find is how that frame is assembled from fdAT and IDAT chunks.

I also tried that library in Lazarus but couldn't make it work.

@Luckie

The reason my code isn't working is not because is buggy, is because is not finished. And is not finished because I can't find more detailed informations about the apng internal structure and/or find simple examples in Delphi/Pascal code to show how is done.
I knew my code will not work from the minute I started working on it. But I was hoping one of you will help me finish it.

A paradox: you don't seem to understand my code, which is so simple and short compared with that library function.
But I am suppose to understand a 3..4 times bigger and more complex function from a dozens times bigger and more complex library?

You guys are great helpers but unfortunately you know nothing about png animations.

Thank you and goodbye.