My hobby project #2 (ASCII art)
lazarus / 39-Graphics

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anyone · 2020-10-06 12:27

Hi all, again.

Further to my first Graphical hobby project two days ago, as promised,
I have tweaked that "img2chr" program a little bit so that now it
displays ASCII art from image file.

The concept behind it is to get 16 different intensity values from
24-bit color pixel.

As defined in MS docs for ToARGB():
QuoteThe byte-ordering of the 32-bit ARGB value is AARRGGBB. The most
significant byte (MSB), represented by AA, is the alpha component
value. The second, third, and fourth bytes, represented by RR, GG, and
BB, respectively, are the color components red, green, and blue,
respectively
(I use back the trick in my original C# code to get the 16 different
grey intensity values -- hopefully it is correct because I see it is
working anyway)

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i           
              pixel := img.Colors[x,y];             r := (pixel.Red
shr 8) and $00ff;             g := (pixel.Green shr 8) and $00ff;    
       b := (pixel.Blue shr 8) and $00ff;             newPix := ((r
shl 16) or (g shl 8) or (b)) and $00ffffff;

Then there is an array of 'pattern' to match the 16 different grey
intensity value accordingly.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i const 
pattern:array [0..15] of char =
('#','#','@','@','%','%',';',';','*','*',',',',','.','.',' ','
');......             Write(pattern[(newPix div 1048576)]);
The logic in my code assumes the input image file is always 24-bit.
(Alpha channel in ARGB is ignored)

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i {$mode
objfpc}{$h+}uses fpreadgif, fpreadpng, fpreadbmp, fpreadjpeg, fpimage,
classes, sysutils, Crt; var img : TFPMemoryImage;    ReadFile :
string;    pixel : TFPColor;    x, y:integer;    ratioX,
ratioY:integer;  procedure Init;begin  ReadFile := ParamStr(1);  img
:= TFPMemoryImage.Create(0,0);end; procedure ReadImage;const 
pattern:array [0..15] of char =
('#','#','@','@','%','%',';',';','*','*',',',',','.','.',' ',' ');var 
r, g, b:byte;  newPix: integer;  readerClass:
TFPCustomImageReaderClass;  reader: TFPCustomImageReader;  stream:
TStream;begin   if FileExists(ReadFile) then   begin     stream :=
TFileStream.Create(ReadFile, fmOpenRead + fmShareDenyNone);     try  
   stream.Position := 0;       readerClass :=
TFPCustomImage.FindHandlerFromStream(stream).Reader;       if
Assigned(readerClass) then begin         reader :=
readerClass.Create;         try           img.LoadFromStream(stream,
reader);         finally           reader.Free;         end;        
 ratioY := img.Height div 30;         ratioX := img.Width div 90;    
    y:=0;         x:=0;          while (y<img.Height) do       
 begin           while (x<img.Width) do           begin           
 pixel := img.Colors[x,y];             r := (pixel.Red shr 8) and
$00ff;             g := (pixel.Green shr 8) and $00ff;             b
:= (pixel.Blue shr 8) and $00ff;             newPix := ((r shl 16) or
(g shl 8) or (b)) and $00ffffff;              Write(pattern[(newPix
div 1048576)]);              x:=x+ratioX;           end;          
 WriteLn;           x:=0;           y:=y+ratioY;         end;     
 end else         WriteLn('Unknown image format.');     finally     
 stream.Free;     end;   end   else      WriteLn (ReadFile,' file not
found.');end; procedure Dipose;begin  Img.Free;end; begin  if
(ParamCount=0) then  begin    WriteLn('img2asc ,developed by
bookhanming@outlook.my and Lazarus forum members');   
WriteLn('Generate ASCII art from image file.');    WriteLn;   
WriteLn('img2asc <image filename>');  end  else    try      Init;    
ReadImage;      Dipose;    except      on e : exception do       
writeln ('Error: ',e.message);    end;   WriteLn('Press Enter to
quit...');  ReadLn;end. 
The screen shot showing the output of this "img2asc.pp" program.
Result might not be ideal. (You can change the pattern array to
finetune the result):

Enjoy!

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Handoko · 2020-10-06 12:38

It looks good.
Thumbs up!

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Lulu · 2020-10-06 13:50

Cool, thanks you to share !

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anyone · 2020-10-06 13:59

Thank you, @Handoko and @Lulu.

We can even create ASCII art Video from MP4 (convert frame by frame)
and use a frame delimiter (e.g. '$') to separate each frame in the
.mp4.txt.

It is fun to watch the playback of ASCII art Video if each fixed-width
character is small enough (e.g. 3-point Courier font).

I have done it in C# but I think I'll just stop here (for porting it
to Free Pascal).

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Ñuño_Martínez · 2020-10-10 10:06

Cool.  Remembers me a lot to AAlib.

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anyone · 2020-10-14 11:33

Thanks @Ñuño_Martínez. Someone has already done the AAlib in 1997,
much earlier than me.... 

Now I have a website specially for these projects (img2chr and
img2asc).
It is called http://asciiartonline.com (although it does not support
image file uploading and instant ASCII art conversion, as its name
implies.)