SOLVED: Special effects

[AsleyCruz]

Good morning coders

Does anybody have any functions of how to apply special effects on images?
Effects like grayscale, sepia, invert colors, brightness, horizontal/vertical flip

Thanks in advance, guys.

[winni]

hI1

Everything you asked for is built in the BGRAbitmap:

grayscale, grayscaleInPlace, negative, horizontalFlip, verticalFlip.

Brightness and Sepia I am not shure and now I have not Lazarus at hand.

Winni

[winni]

Hi!

Here  is the algorithm foe Sepia:

https://www.geeksforgeeks.org/image-procesing-java-set-6-colored-image-sepia-image-conversion/

Winni

[circular]

About Brightness you can use the Normalize function to use all possible colors from black to white.

Otherwise you can simply multiply the values of each RGB channels or add/substract a constant.

[lucamar]

A good source for those (and lots more) kind of things was Earl F. Glynn's Reference Library, most of which can be found at the Internet Archive's Wayback Machine.

[winni]

Hi!

Just implemented the missing Sepia.
The function Sepia () create  a copy of the TBGRAbitmap but in Sepia color.

Code: Pascal  [Select][+][-]

1. function range2byte (float: single) : byte; inline;
2. begin
3. if float > 255 then float := 255 else
4.    if float < 0 then float := 0;
5.    result := round (float);
6. end;
7.  
8. function toSepia (col : TBGRAPixel) : TBGRAPixel; inline;
9. begin
10. result.red :=   range2Byte (0.393*col.red + 0.769*col.green + 0.189*col.blue);
11. result.green:= range2Byte (0.349*col.red + 0.686*col.green + 0.168*col.blue);
12. result.blue :=  range2Byte (0.272*col.red + 0.534*col.green + 0.131*col.blue);
13. result.alpha := col.alpha;
14. end;
15.  
16. function Sepia (Orig: TBGRABitmap) : TBGRABitmap;
17. var dest : TBGRABitmap;
18.     i : Integer;
19.     p,q : PBGRAPixel;
20.  
21. begin
22. dest := TBGRAbitmap.create (Orig.width, Orig.height);
23. p := Orig.Data;;
24. q := dest.Data;
25. for i := 0 to Orig.NbPixels-1 do
26.    begin
27.    q^ := toSepia (p^);
28.    inc(p);
29.    inc(q);
30.    end; // i
31.  dest.InvalidateBitmap;
32.  result := dest;
33. end;                      
34.  
35.  

Winni

[winni]

Hi!

As test:

"Marianne" in Sepia.
Long llive the french revolution!

Winni

[AsleyCruz]

hI1

Everything you asked for is built in the BGRAbitmap:
grayscale, grayscaleInPlace, negative, horizontalFlip, verticalFlip.

Many thanks Winni,
I will check the functions out. I haven't used BGRAbitmap too much.

Great sample code with sepia... Thanks for your time.

[circular]

  yeah revolution! Well these days, not really able to go out though.

Channels are in sRGB colorspace, which has a gamma. If you want to do transformations in linear RGB, first transform the value with GammaExpansionTab and in the end back with GammaCompressionTab.

Using linear RGB will give you less dark areas.

Code: Pascal  [Select][+][-]

1. function CompressF (float: single) : byte; inline;
2. begin
3.   if float > 65535 then float := 65535 else
4.    if float < 0 then float := 0;
5.    result := GammaCompressionTab[round (float)];
6. end;
7.  
8. function toSepia (col : TBGRAPixel) : TBGRAPixel; inline;
9. begin
10.   with GammaExpansion(col) do
11.   begin
12.     result.red :=   CompressF (0.393*red + 0.769*green + 0.189*blue);
13.     result.green:= CompressF (0.349*red + 0.686*green + 0.168*blue);
14.     result.blue :=  CompressF (0.272*red + 0.534*green + 0.131*blue);
15.   end;
16.   result.alpha := col.alpha;
17. end;

[winni]

A good source for those (and lots more) kind of things was Earl F. Glynn's Reference Library, most of which can be found at the Internet Archive's Wayback Machine.

Thanx! I did not know that efg is reorganizing his pages.
A good source since decades!

Winni