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unit SynEditMarkupSpecialLine;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Graphics, SynEditMarkup, SynEditMiscClasses, Controls, LCLProc;

type

  TSpecialLineMarkupEvent = procedure(Sender: TObject; Line: integer;
    var Special: boolean; Markup: TSynSelectedColor) of object;
  TSpecialLineColorsEvent = procedure(Sender: TObject; Line: integer;
    var Special: boolean; var FG, BG: TColor) of object;

  { TSynEditMarkupSpecialLine }

  TSynEditMarkupSpecialLine = class(TSynEditMarkup)
  private
    FMarkupLineHighlightInfo: TSynSelectedColor;
    FOnSpecialLineColors: TSpecialLineColorsEvent;
    FOnSpecialLineMarkup: TSpecialLineMarkupEvent;
    FSpecialLine : Boolean;
    FHighlightedLine: Integer;
  protected
    procedure DoMarkupLineHighlightInfoChange(Sender: TObject);
    function HasLineHighlight: Boolean;
    procedure DoCaretChanged(Sender: TObject); override;
    procedure DoTopLineChanged(OldTopLine : Integer); override;
    procedure DoLinesInWindoChanged(OldLinesInWindow : Integer); override;
    procedure DoTextChanged(StartLine, EndLine : Integer); override;
    procedure DoMarkupChanged(AMarkup: TSynSelectedColor); override;
  public
    constructor Create(ASynEdit: TSynEditBase);
    destructor Destroy; override;

    procedure PrepareMarkupForRow(ARow: Integer); override;
    function GetMarkupAttributeAtRowCol(const ARow, ACol: Integer): TSynSelectedColor; override;
    function GetNextMarkupColAfterRowCol(const ARow, ACol: Integer): Integer; override;

    procedure InvalidateLineHighlight;

    property MarkupLineHighlightInfo: TSynSelectedColor read FMarkupLineHighlightInfo;

    property OnSpecialLineColors: TSpecialLineColorsEvent
      read FOnSpecialLineColors write FOnSpecialLineColors;
    property OnSpecialLineMarkup: TSpecialLineMarkupEvent
      read FOnSpecialLineMarkup write FOnSpecialLineMarkup;
  end;

implementation

{ TSynEditMarkupBracket }

procedure TSynEditMarkupSpecialLine.DoMarkupLineHighlightInfoChange(
  Sender: TObject);
begin
  if FHighlightedLine > 0 then
    InvalidateSynLines(FHighlightedLine, FHighlightedLine)
  else
    InvalidateLineHighlight;
end;

function TSynEditMarkupSpecialLine.HasLineHighlight: Boolean;
begin
  Result :=
    (FMarkupLineHighlightInfo.Background <> clNone) or
    (FMarkupLineHighlightInfo.Foreground <> clNone);
end;

procedure TSynEditMarkupSpecialLine.DoCaretChanged(Sender: TObject);
begin
  InvalidateLineHighlight;
end;

procedure TSynEditMarkupSpecialLine.DoTopLineChanged(OldTopLine: Integer);
begin
  InvalidateLineHighlight;
end;

procedure TSynEditMarkupSpecialLine.DoLinesInWindoChanged(OldLinesInWindow: Integer);
begin
  InvalidateLineHighlight;
end;

procedure TSynEditMarkupSpecialLine.DoTextChanged(StartLine, EndLine: Integer);
begin
  InvalidateLineHighlight;
end;

procedure TSynEditMarkupSpecialLine.DoMarkupChanged(AMarkup: TSynSelectedColor);
begin
  InvalidateLineHighlight;
end;

constructor TSynEditMarkupSpecialLine.Create(ASynEdit: TSynEditBase);
begin
  inherited Create(ASynEdit);

  FHighlightedLine := -1;
  FMarkupLineHighlightInfo := TSynSelectedColor.Create;
  FMarkupLineHighlightInfo.Background := clNone;
  FMarkupLineHighlightInfo.Foreground := clNone;
  FMarkupLineHighlightInfo.OnChange := @DoMarkupLineHighlightInfoChange;

  MarkupInfo.Style := [];
  MarkupInfo.StyleMask := [];
end;

destructor TSynEditMarkupSpecialLine.Destroy;
begin
  FMarkupLineHighlightInfo.Free;
  inherited Destroy;
end;

procedure TSynEditMarkupSpecialLine.PrepareMarkupForRow(ARow: Integer);
var
  colFg, colBg: TColor;
begin
  FSpecialLine := False;
  if Assigned(FOnSpecialLineMarkup) then
    FOnSpecialLineMarkup(SynEdit, ARow, FSpecialLine, MarkupInfo);
    
  if Assigned(FOnSpecialLineColors) then
  begin
    if FSpecialLine then
    begin
      colFg := MarkupInfo.Foreground;
      colBg := MarkupInfo.Background;
    end else
    begin
      colFg := clNone;
      colBg := clNone;
    end;
    FOnSpecialLineColors(SynEdit, ARow, FSpecialLine, colFg, colBg);
    MarkupInfo.Foreground := colFg;
    MarkupInfo.Background := colBg;
  end;

  // if line is not special then check whether it is a current line
  // if it is so then use own bg,fg colors to setup highlight
  if not FSpecialLine then
  begin
    if (FHighlightedLine = ARow) and HasLineHighlight then
    begin
      FSpecialLine := True;
      MarkupInfo.Assign(FMarkupLineHighlightInfo);
    end;
  end;
end;

function TSynEditMarkupSpecialLine.GetMarkupAttributeAtRowCol(const ARow, ACol : Integer): TSynSelectedColor;
begin
  Result := nil;
  MarkupInfo.StartX := 1;
  MarkupInfo.EndX := MaxInt;
  if FSpecialLine then
    Result := MarkupInfo;
end;

function TSynEditMarkupSpecialLine.GetNextMarkupColAfterRowCol(const ARow, ACol : Integer): Integer;
begin
  Result := -1; // always valid for the whole line
end;

procedure TSynEditMarkupSpecialLine.InvalidateLineHighlight;
var
  NewLine: Integer;
begin
  if (not HasLineHighlight) or (Caret = nil) then
    Exit;

  NewLine := Caret.LinePos;

  // invalidate old line highlighting, if changed
  if (FHighlightedLine > 0) and (NewLine <> FHighlightedLine) then
    InvalidateSynLines(FHighlightedLine, FHighlightedLine);

  // invalidate new line highlighting, if changed
  if (NewLine > 0) and (NewLine <> FHighlightedLine) then
    InvalidateSynLines(NewLine, NewLine);

  FHighlightedLine := NewLine;
end;

end.