Color of a screen pixel: Difference between revisions

=={{header|Delphi}}==

<lang Delphi>

program ScreenPixel;

{$APPTYPE CONSOLE}

uses

Windows,

SysUtils,

Graphics;

// Use this function in a GUI application to return the color

function GetPixelColourAsColor(const PixelCoords: TPoint): TColor;

var

dc: HDC;

begin

// Get Device Context of windows desktop

dc := GetDC(0);

// Read the color of the pixel at the given coordinates

Result := GetPixel(dc,PixelCoords.X,PixelCoords.Y);

end;

// Use this function to get a string representation of the current colour

function GetPixelColourAsString(const PixelCoords: TPoint): string;

var

r,g,b: Byte;

col: TColor;

begin

col := GetPixelColourAsColor(PixelCoords);

// Convert the Delphi TColor value to it's RGB components

r := col and $FF;

g := (col shr 8) and $FF;

b := (col shr 16) and $FF;

// Format the result

Result := 'R('+IntToStr(r)+') G('+IntToStr(g)+') G('+IntToStr(b)+')';

{

Alternatively, format the result as follows to get a

string representation of the Delphi TColor value

Result := ColorToString(GetPixel(dc,curP.X,curP.Y));

}

end;

var

s: string;

P: TPoint;

begin

s := '';

Writeln('Move mouse over a pixel. Hit return to get colour of selected pixel.');

repeat

Readln(s);

if s = '' then

begin

GetCursorPos(P);

Writeln('Colour at cursor position X:'+

IntToStr(P.X)+' Y:'+

IntToStr(P.Y) +' = '+

GetPixelColourAsString(P)

);

Writeln('');

Writeln('Move mouse and hit enter again.');

end;

until

SameText(s,'quit');

end.

</lang>

Example output:

<pre>

Move mouse over a pixel. Hit return to get colour of selected pixel.

Colour at cursor position X:429 Y:161 = R(0) G(0) B(0)

Move mouse and hit enter again.

Colour at cursor position X:942 Y:358 = R(182) G(206) B(231)

Move mouse and hit enter again.

Colour at cursor position X:704 Y:103 = R(240) G(240) B(240)

Move mouse and hit enter again.

Colour at cursor position X:2756 Y:59 = R(250) G(196) B(182)

</pre>