Splitting Picture into Quads using Quadtree ?

[Boleeman]

Was wondering if anyone has been able to use Lazarus to visually split a loaded picture into Quads using Quadtree (as shown in attachments) ?

There are plenty of Python and C++ codes, but nothing much in Lazarus (Pascal) or Delphi.

Corpsman had an example of compressing a grayscale bmp image using the Quadtree Algorithm, but I wanted to load a color png and have it dissected into quads using Quadtree.

Here are some nice Python implementations:
https://github.com/AlexEidt/Quart      (this also has a video at the bottom)
https://github.com/fogleman/Quads


But how to go about doing it in Lazarus using TBgrabmp?

[Boleeman]

Here is a Lazarus quadtree program that uses a set of points.

It was made by Corpsman.


Still trying the work out how to do it for loaded coloured png images !

[Dzandaa]

Hi Eddie,

Try this program.

A big thank you to my wife (she's a PH d mathematician) who helped me fix the last bug

Lower Threshold = Better Resolution

Pan with left button, zoom with the middle button.

Just tested on Windows.


B->

[LeP]

@DZandaa,

thanks for the source.
I tried quickly and seems that there some issues about x, y coordinates (may be exchanged) and generate an AV in various point of your source.

Try with an image with Height <> Width.

I have not time now to debug and report the corrections, but I'll do in the next time.

[Dzandaa]

Hi
@Lep:

Thank  you for testing my program.

Effectively, I just tested the algorithm on squares Pictures !!!

The x and y of the Double array  are reversed.

I corrected that.

B->

[Dzandaa]

Hi,
Here is a new version showing rectangles boundaries

Have a nice day.

B->

[ADMGNS]

hello

several years ago, i'd studied on quadtree algorithm which was on video codecs, but it was in D7.

pls see attachment

regs

[Dzandaa]

Hi,
@ADMGNS :

Sorry, I don't use Delphi, just Pascal Lazarus.

And the conversion doesn't work well.


B->

[ADMGNS]

hello again

lazarus conversion plus some minor changes manually, it works minimally now. here is it..

regs

[Dzandaa]

Hi,

@ADMGNS:

It works now, but if I load an image and click cmdColorCount, I have a crash here:

Code: Pascal  [Select][+][-]

1.   for k:=0 to nSize1-1 do
2.   begin
3.     c := (p^ shl 8) shr 8; // ie, c := c and $00FFFFFF; // <---- here
4.     inc(hist[c]);
5.  
6.     inc(p);
7.   end;
8.  
9.  

Perhaps the size of the picture is too big.

Also, you can test with

Code: Pascal  [Select][+][-]

1.  for k:=0 to Pred(nSize1) do
2.  

I don't know if it is faster.
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