AfterImage and BGRABitmap

[Fred vS]

Hello.

With the image-attachment, stare at the red dot on her nose for 30 seconds, then look at a plain wall while blinking fast.
And discover what is an afterimage.
https://en.wikipedia.org/wiki/Afterimage

Do you have a idea how to create, using BGRABitmap, a negative image from any color-image, to have the same effect "afterimage" as the image-attachment?

Thanks.

Fre;D

[lainz]

From BCFilters.pas:

Code: Pascal  [Select][+][-]

1. procedure Invert(Bitmap: TBGRABitmap);
2. var
3.   i: integer;
4.   p: PBGRAPixel;
5. begin
6.   p := Bitmap.Data;
7.  
8.   for i := Bitmap.NBPixels - 1 downto 0 do
9.   begin
10.     p^.red := not p^.red;
11.     p^.green := not p^.green;
12.     p^.blue := not p^.blue;
13.     //p^.alpha := not p^.alpha;
14.     Inc(p);
15.   end;
16. end;

Edit. if is not simply an invert, you can use the same method to touch each channel here with any formula...

[Fred vS]

Thanks Lainz 

Fre;D

PS: Did you feel the afterimage-effect of the attached-picture?

[lainz]

Thanks Lainz 

Fre;D

PS: Did you feel the afterimage-effect of the attached-picture?

Yes, I've seen like a floating girl in the monitor, with cyan dress.

[circular]

You might get, but I am not sure, doing the negative with gamma correction, by calling TBGRABitmap.Negative function.

That is indeed fun to see the image 

[Fred vS]

You might get, but I am not sure, doing the negative with gamma correction, by calling TBGRABitmap.Negative function.

That is indeed fun to see the image 

Yes, I was impressed the fist time I tried it.
It works too with a blinking background after stare the red dot of the image.
https://forum.lazarus.freepascal.org/index.php/topic,63314.msg479323.html

Conclusion: lot of things in our brain is the reverse of reality... 

[circular]

Conclusion: lot of things in our brain is the reverse of reality... 

Indeed, in fact our cortex is reversed, left is right, top is down, front is back. For example the visual cortex is behind be we see it before our eyes.