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{
fpGUI - Free Pascal GUI Toolkit
Copyright (C) 2006 - 2010 See the file AUTHORS.txt, included in this
distribution, for details of the copyright.
See the file COPYING.modifiedLGPL, included in this distribution,
for details about redistributing fpGUI.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Description:
Some handly image manipulation functions to use with TfpgImage class.
Included is a gray color conversion matrix.
}
unit fpg_imgutils;
{$mode objfpc}{$H+}
{ TODO : Make the conversion matrix a plugable architecture. Similar to the
interpolation handling in TfpgCanvas. }
interface
uses
fpg_base,
fpg_main;
type
TGrayConvMatrix = record
red: single;
green: single;
blue: single;
end;
var
GrayConvMatrix: TGrayConvMatrix;
GrayBrightness: Boolean;
GrayBrightnessPercentage: integer;
const
GCM_NTSC: TGrayConvMatrix = (red:0.299; green:0.587; blue:0.114); // NTSC method
GCM_Mathematical: TGrayConvMatrix = (red:0.334; green:0.333; blue:0.333); // Intensity method
GCM_Photoshop: TGrayConvMatrix = (red:0.212671; green:0.715160; blue:0.072169); // Y of YUV from B/W TV's
procedure fpgApplyGreyFilter(var AImg: TfpgImage);
function fpgCalculateGray(const AFrom: TfpgColor; const ABrighter: boolean = False; const APercent: integer = 0): TfpgColor;
implementation
procedure fpgApplyGreyFilter(var AImg: TfpgImage);
var
x, y: integer;
c: TfpgColor;
begin
for x := 0 to AImg.Width-1 do
begin
for y := 0 to AImg.Height-1 do
begin
c := AImg.Colors[x, y];
AImg.Colors[x, y] := fpgCalculateGray(c, GrayBrightness, GrayBrightnessPercentage);
end;
end;
AImg.UpdateImage;
end;
{ AFrom is the original color we want to change
ABrighter = True goes to direction of White. False goes to direction of Black
APercent = 0 zero is straight conversion to gray. 100% is pure black or
white, depending on ABrighter value. }
function fpgCalculateGray(const AFrom: TfpgColor; const ABrighter: boolean = False; const APercent: integer = 0): TfpgColor;
var
g: integer;
rgb: TFPColor;
begin
with GrayConvMatrix do
begin
rgb := fpgColorToFPColor(AFrom);
g := round(red*rgb.red + green*rgb.green + blue*rgb.blue);
if ABrighter then
g := trunc(255 - ((255 - g) * (100 - APercent) / 100))
else
g := trunc(g * (100 - APercent) / 100);
if (g < 0) then g := 0;
if (g > 255) then g := 255;
rgb.Red := g;
rgb.Green := g;
rgb.Blue := g;
end;
Result := FPColorTofpgColor(rgb);
end;
initialization
GrayConvMatrix := GCM_NTSC;
GrayBrightness := True;
GrayBrightnessPercentage := 40;
end.
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