delphi - Reading Pixels and finding specific RGB -

i load image, , read pixels find rgb, check next pixels across make sure match, , @ right position of bitmap.

i know below code wrong, not sure how go correcting it. know pixels not fastest way read pixels.

thanks guys!

procedure rgb(col: tcolor; var r, g, b: byte); var   color: $0..$ffffffff; begin   color := colortorgb(col);   r := ($000000ff , color);   g := ($0000ff00 , color) shr 8;   b := ($00ff0000 , color) shr 16; end;  procedure tform1.button1click(sender: tobject); var   x,y : integer;   colorn: tcolor;   r, g, b: byte; begin   y := 0 image1.picture.bitmap.height -1   begin     x := 0 image1.picture.bitmap.width -1     begin       inc(i);       colorn := image1.canvas.pixels[x, y];       rgb(colorn, r, g, b);       //memo1.lines.append('line: '+inttostr(i)+' y: '+inttostr(y)+' x: '+inttostr(x)+' r: '+inttostr(r)+' g: '+inttostr(g)+' b: '+inttostr(b));       if (inttostr(r) = '235') , (inttostr(g) = '235') , (inttostr(b) = '235') //y: 500 x: 587       begin         //image1.canvas.moveto(x,y);         //image1.canvas.lineto(x,y);         colorn := image1.canvas.pixels[x +1, y];         rgb(colorn, r, g, b);       end;       if (inttostr(r) = '232') , (inttostr(g) = '232') , (inttostr(b) = '232') //rgb:232,232,232 y: 500 x: 588       begin         colorn := image1.canvas.pixels[x +1, y];         rgb(colorn, r, g, b);         showmessage('test1');       end;       if (inttostr(r) = '231') , (inttostr(g) = '231') , (inttostr(b) = '231') //rgb: 231,231,231 y: 500 x: 589       begin         colorn := image1.canvas.pixels[x +1, y];         rgb(colorn, r, g, b);         showmessage('test2');       end;       if (inttostr(r) = '230') , (inttostr(g) = '230') , (inttostr(b) = '230') //rgb: 230,230,230 y: 500 x: 590       begin         showmessage('test3');       end;     end;   end; end;  procedure tform1.formcreate(sender: tobject); var   b: tbitmap; begin   image1.picture.loadfromfile('e:\delphi projects\detect(xe6)\screen\1.png');   b := tbitmap.create;   b.assign(image1.picture.graphic);   image1.picture.bitmap := b;   freeandnil(b); end; 

there several big issues in code:

1. instead of inttostr(r) = '235' faster check r=235
2. instead of checking r, g , b individually, easier check if colorn=c_gray235 c_gray235 = #00ebebeb;

for application whole i'd use single if:

if (getpixel(x,   y) = c_gray235) ,    (getpixel(x+1, y) = c_gray232) ,    (getpixel(x+2, y) = c_gray231) ,    (getpixel(x+3, y) = c_gray230) begin   //do stuff here end; 

please note for-loop should for x := 0 mybitmap.width - 4 (there's no way if succeed once have less 4 pixels left on line. may av if try access them, depending on way pixels).

now if bitmap 24-bit or 32-bit bitmap, can improve performance quite bit using bitmap.scanline[iline]...