source: trunk/UCompare.pas

unit UCompare;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Graphics, ExtCtrls, Contnrs;

type
  TFile = class

  end;

  { TTextFile }

  TTextFile = class(TFile)
    Lines: TStrings;
    constructor Create;
    procedure LoadFromFile(FileName: string);
  end;

  TLine = class
    Text: string;
    Number: Integer;
  end;

  TCompare = class

  end;

  { TTextCompare }

  TTextCompare = class(TCompare)
    TextFile: TTextFile;
    Lines: TObjectList; // TLine
    CharsPerLine: Integer;
    WordWrap: Boolean;
    LineNumbersWidth: Integer;
    LineHeight: Integer;
    procedure Rebuild;
    procedure Render(Canvas: TCanvas; FromLine: Integer);
    procedure Clear;
    constructor Create;
    destructor Destroy; override;
  end;

  TImageFile = class(TFile)
    Image: TImage;
  end;

  TImageCompare = class(TCompare)

  end;

implementation

{ TTextFile }

constructor TTextFile.Create;
begin
  Lines := TStringList.Create;
end;

procedure TTextFile.LoadFromFile(FileName: string);
begin
  Lines.LoadFromFile(FileName);
end;

{ TTextCompare }

procedure TTextCompare.Rebuild;
var
  I: Integer;
  NewLine: TLine;
  Text: string;
begin
  Lines.Clear;
  for I := 0 to TextFile.Lines.Count - 1 do begin
    Text := TextFile.Lines[I];
    while True do begin
      if WordWrap and (CharsPerLine > 0) and (Length(Text) > CharsPerLine) then begin
        NewLine := TLine.Create;
        NewLine.Text := Copy(Text, 1, CharsPerLine);
        NewLine.Number := I + 1;
        Lines.Add(NewLine);
        Delete(Text, 1, CharsPerLine);
      end else begin
        NewLine := TLine.Create;
        NewLine.Text := Text;
        NewLine.Number := I + 1;
        Lines.Add(NewLine);
        Break;
      end;
    end;
  end;
end;

procedure TTextCompare.Render(Canvas: TCanvas; FromLine: Integer);
var
  I: Integer;
  CurrentLineNum: Integer;
begin
  Canvas.Font.Name := 'Courier New';
  Canvas.Brush.Style := bsClear;
  CurrentLineNum := -1;
  for I := 0 to (Canvas.Height div LineHeight) - 1 do
  if (FromLine + I) < Lines.Count then begin
    if CurrentLineNum <> TLine(Lines[FromLine + I]).Number then begin
      CurrentLineNum := TLine(Lines[FromLine + I]).Number;
      Canvas.TextOut(0, I * LineHeight, IntToStr(CurrentLineNum));
    end;
    Canvas.TextOut(LineNumbersWidth, I * LineHeight, TLine(Lines[FromLine + I]).Text);
  end;
  Canvas.Pen.Color := clBlack;
  Canvas.MoveTo(LineNumbersWidth - 3, 0);
  Canvas.LineTo(LineNumbersWidth - 3, Canvas.Height);
end;

procedure TTextCompare.Clear;
begin
  TextFile.Lines.Clear;
  Lines.Clear;
end;

constructor TTextCompare.Create;
begin
  LineHeight := 16;
  LineNumbersWidth := 50;
  CharsPerLine := 80;
  TextFile := TTextFile.Create;
  Lines := TObjectList.Create;
end;

destructor TTextCompare.Destroy;
begin
  FreeAndNil(Lines);
  FreeAndNil(TextFile);
  inherited;
end;

end.