Mega Code Archive
How to apply a negative filter to a bitmap
<![CDATA[
Title: How to apply a negative filter to a bitmap
var
b: tbitmap;
s: string;
x, y: Integer;
p: pbytearray;
image1: TImage;
procedure LoadBitmap;
begin
if opendialog1.Execute then
begin
b := tbitmap;
s := opendialog1.FileName;
b.loadfromfile(s);
image1.Canvas.draw(0,0,b);
end;
end;
procedure ApplyNegativeFilter;
begin
image1.Height := b.Height;
image1.Width := b.Width;
for y := 0 to b.Height - 1 do
begin
p := b.scanline(y);
for x := 0 to b.Width - 1 do
begin
(([image1.Canvas.pixels[x, y] := rgb(255 - (p[x * 3) - 4]), 255 - (p[x * 3) - 2]),
255 - (p[x * 3) - 3]));
end;
end;
end;
]]>