I just made this and tested it a little bit... It seems to work but I can not guarantee it is perfect:
function GetAverage3X3Color(APoint: TPoint; AIEBitmap: TIEBitmap): TColor;
{ Return the average color around a 3x3 sample from a APoint. }
var
iPixelColor: TColor;
iAverageR, iAverageG, iAverageB: Cardinal;
x, y: shortint;
begin
iAverageR := 0;
iAverageG := 0;
iAverageb := 0;
for y := -1 to 1 do
for x := -1 to 1 do
begin
iPixelColor := AIEBitmap.Canvas.Pixels[APoint.x + x, APoint.y + y];
iAverageR := iAverageR + GetRValue(iPixelColor);
iAverageG := iAverageG + GetGValue(iPixelColor);
iAverageB := iAverageB + GetBValue(iPixelColor);
end;
iAverageR := iAverageR div 9;
iAverageG := iAverageG div 9;
iAverageB := iAverageB div 9;
iPixelColor := RGB(Lo(iAverageR), Lo(iAverageG), Lo(iAverageB));
result := iPixelColor;
end;
function GetAverage5X5Color(APoint: TPoint; AIEBitmap: TIEBitmap): TColor;
{ Return the average color around a 5x5 sample from a APoint. }
var
iPixelColor: TColor;
iAverageR, iAverageG, iAverageB: Cardinal;
x, y: shortint;
begin
iAverageR := 0;
iAverageG := 0;
iAverageB := 0;
for y := -2 to 2 do
for x := -2 to 2 do
begin
iPixelColor := AIEBitmap.Canvas.Pixels[APoint.x + x, APoint.y + y];
iAverageR := iAverageR + GetRValue(iPixelColor);
iAverageG := iAverageG + GetGValue(iPixelColor);
iAverageB := iAverageB + GetBValue(iPixelColor);
end;
iAverageR := iAverageR div 25;
iAverageG := iAverageG div 25;
iAverageB := iAverageB div 25;
iPixelColor := RGB(Lo(iAverageR), Lo(iAverageG), Lo(iAverageB));
result := iPixelColor;
end;
function GetAverage9X9Color(APoint: TPoint; AIEBitmap: TIEBitmap): TColor;
{ Return the average color around a 9x9 sample from a APoint. }
var
iPixelColor: TColor;
iAverageR, iAverageG, iAverageB: Cardinal;
x, y: shortint;
begin
iAverageR := 0;
iAverageG := 0;
iAverageB := 0;
for y := -4 to 4 do
for x := -4 to 4 do
begin
iPixelColor := AIEBitmap.Canvas.Pixels[APoint.x + x, APoint.y + y];
iAverageR := iAverageR + GetRValue(iPixelColor);
iAverageG := iAverageG + GetGValue(iPixelColor);
iAverageB := iAverageB + GetBValue(iPixelColor);
end;
iAverageR := iAverageR div 81;
iAverageG := iAverageG div 81;
iAverageB := iAverageB div 81;
iPixelColor := RGB(Lo(iAverageR), Lo(iAverageG), Lo(iAverageB));
result := iPixelColor;
end;
Usage:
iAverageColor := GetAverage3x3Color(Point(Layers[LayersCurrent].ConvXScr2Bmp(X),
Layers[LayersCurrent].ConvYScr2Bmp(Y)), ImageEnView1.IEBitmap);
Shape1.BrushColor := iAverageColor;
Different distinct color values are returned by the methods, but visually I do not see much color difference between them, so I am not sure if my math is correct or if it just difficult to perceive the color differences.
William Miller
Adirondack Software & Graphics
Email: w2m@frontiernet.net
EBook: http://www.imageen.com/ebook/
Apprehend: http://www.frontiernet.net/~w2m/index.html