BGRABitmap图像操作11：渐变生成加上色彩，让她更漂亮

unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
  BGRABitmap, BGRABitmapTypes, BGRAGradientScanner, BGRATransform;

type
  { TBGRAMultiplyScanner }

  TBGRAMultiplyScanner = class(TBGRACustomScanner)
    function ScanAt(X, Y: Single): TBGRAPixel; override;
  end;

type

  { TForm1 }

  TForm1 = class(TForm)
    procedure FormPaint(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;


var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

function TBGRAMultiplyScanner.ScanAt(X, Y: Single): TBGRAPixel;
  function cycle512(value: integer): integer; inline;
  begin
    result := value and 511;
    if result >= 256 then result := 511-result;
  end;


var
  mul: integer;
begin
  mul := round(x*y);
  result := BGRA(cycle512(round(x*10)),cycle512(mul),cycle512(round(y*10)),255);
end;

procedure TForm1.FormPaint(Sender: TObject);
var image: TBGRABitmap;
    grad: TBGRAMultiplyScanner;
    affine: TBGRAAffineScannerTransform;
begin
  image := TBGRABitmap.Create(ClientWidth,ClientHeight, BGRABlack );

  grad := TBGRAMultiplyScanner.Create;
  affine := TBGRAAffineScannerTransform.Create(grad);
  affine.Scale(6,4);
  affine.Translate(ClientWidth/2, ClientHeight/2);
  image.Fill(affine);
  affine.free;
  grad.free;

  image.Draw(Canvas,0,0,True);
  image.free;

end;

end.