Is it possible to display a png using fpimage and using ptcgraph?

[TBMan]

I found something, but it isn't working. Any help would be appreciated.

Code: Pascal  [Select][+][-]

1. program bwtest;
2. uses ptcgraph,fpimage,fpreadpng,fpcanvas, fpimgcanv,ptccrt;
3. var
4.   gm,gd:smallint;
5.   r,c,
6.   x,y:integer;
7.   myImage: TFPMemoryImage;
8.   reader : TFPCustomImageReader;
9.   canvas : tfpcustomcanvas;
10.  
11.   color:word;
12.    colors:tfpcolor;
13.  
14.  
15.    function RGBToInteger(R, G, B: Byte): Integer;
16.    begin
17.      Result := (Integer(B) shl 16) or (Integer(G) shl 8) or Integer(R);
18.    end;
19.  
20.  
21.  
22. begin
23.  
24.   gd := vesa;
25.     Gm := installusermode(800, 600, 256, 2, 10000, 8000);
26.     WindowTitle := 'BW Design';
27.     initgraph(gd, gm, '');
28.     myImage := TFPMemoryImage.Create(400, 400); // larger than file dimensions
29.     Reader := TFPReaderPNG.create;
30.     canvas := tfpimagecanvas.create(myimage);
31.     try
32.       myImage.LoadFromFile('qc.png',reader);
33.     except
34.       // Handle file not found or other load errors
35.       WriteLn('Error loading PNG file');
36.     end;
37.     x := 100; y := 100;
38.   for r := 0 to myImage.Height - 1 do
39.   begin
40.     for c := 0 to myImage.Width - 1 do
41.     begin
42.       color := rgbtointeger(canvas.colors[c,r].red, canvas.colors[c,r].green,canvas.colors[c,r].blue);
43.       PutPixel(x+c, y+r,color);
44.  
45.     end;
46.  
47.   end;
48.  
49.  
50.  
51.     repeat until keypressed;
52. closegraph;
53.  
54. end.
55.  
56.  
57.  
58.  

[Thausand]

Yes, can work display png fpimage use ptcgraph but have caveat.

You example have ptcgraph 256 color. png can have many more color and not fit (can, if quantize color but then need palette from you) . If png 256 color then can always make work because png also can have palette.

If use png fpimage TFpColor then color 64-bit (4 x word, is not usual because usual is 32-bit) and need scale down. If image have palette then ptcgraph need use setpalette (https://www.freepascal.org/daily/packages/graph/ptcgraph/setpalette.html).

Can not make easy example because not know what is colors "qc.png" and not know how convert color. Maybe can tell or give (example) picture ?

PS: this simple very example 8-bit palette and 64-bit color convert for ptcgraph.

Code: Pascal  [Select][+][-]

1. program test;
2.  
3. {$mode objfpc}{$h+}
4.  
5. uses
6.   {$ifdef linux}cthreads,{$endif}
7.   sysutils,ptcgraph,ptccrt,
8.   fpimage,fpreadpng;
9.  
10. type
11.   TColorType=packed record
12.     case byte of
13.       0:(r,g,b,a:byte);
14.       1:(value:longword);
15.   end;
16.  
17. function fpColorToColorType(fpColor:TFPColor):TColorType;
18. begin
19.   result.value:=0;
20.   result.r:=(fpColor.Red   shr 8) and $00ff;
21.   result.g:=(fpColor.Green shr 8) and $00ff;
22.   result.b:=(fpColor.Blue  shr 8) and $00ff;
23. end;
24.  
25. procedure start;
26. var
27.   gm,gd:smallint;
28. begin
29.   gd:=vesa;
30.   gm:=installusermode(800,600,256,2,10000,8000);
31.   WindowTitle:='BW Design';
32.   initgraph(gd,gm,'');
33. end;
34.  
35. procedure stop;
36. begin
37.   repeat until keypressed;
38.   closegraph;
39. end;
40.  
41. procedure load256ColorPng(Filename:string);
42. var
43.   Image:TFPMemoryImage;
44.   ColorType:TColorType;
45.   x,y,w,h:integer;
46.   index:integer;
47.   Color:integer;
48. begin
49.   if FileExists(Filename) then
50.   begin
51.     Image:=TFPMemoryImage.Create(0,0);
52.     try
53.       // have palette load
54.       Image.UsePalette:=true;
55.       Image.LoadFromFile(Filename);
56.  
57.       // make palette color image copy to ptcpas
58.       for index:=0 to Image.Palette.Count-1 do
59.       begin
60.         colorType:=fpColorToColorType(Image.Palette[Index]);
61.         SetRGBPalette(index,ColorType.r,ColorType.g,ColorType.b);
62.       end;
63.  
64.       // make pixel image copy to ptcpas
65.       x:=100; y:=100;
66.       for w:=0 to Image.Height-1 do
67.       begin
68.         for h:=0 to Image.Width-1 do
69.         begin
70.           Color:=Image.Pixels[w,h];
71.           PutPixel(x+w,y+h,Color);
72.         end;
73.       end;
74.     except
75.       // Handle file not found or other load errors
76.       WriteLn('Error loading PNG file');
77.     end;
78.   end
79.   else writeln(Filename,' not exist!');
80. end;
81.  
82. begin
83.   start;
84.   // picture: https://bp0.blogger.com/_5Z1NzpeMhcs/Rut53DRL_DI/AAAAAAAAAdI/XxZbdMkDS1I/s1600-h/color_palette_256_deluxepaint.png
85.   load256ColorPng('color_palette_256_deluxepaint.png');
86.   stop;
87. end.
88.  

[TBMan]

Thanks!

[Thausand]

You welcome TBMan 

I tell and sorry, I have make copy-paste you code then adjust and (you and me) forget to have free Image so have leak memory. Please make add Image.Free to have fix.

[TBMan]

Thanks again, much appreciated!