{
 *****************************************************************************
 *                                                                           *
 *  See the file COPYING.modifiedLGPL.txt, included in this distribution,    *
 *  for details about the copyright.                                         *
 *                                                                           *
 *  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.                     *
 *                                                                           *
 *****************************************************************************

Authors: Alexander Klenin

}

unit TADrawUtils;

{$H+}

interface

uses
  Classes, FPCanvas, FPImage, Types, TAChartUtils;

type
  // Same types as in Graphics unit, but without dependency.
  TChartAntialiasingMode = (amDontCare, amOn, amOff);

type

  ISimpleTextOut = interface
    procedure SimpleTextOut(AX, AY: Integer; const AText: String);
    function SimpleTextExtent(const AText: String): TPoint;
    function GetFontAngle: Double;
  end;

  { TChartTextOut }

  TChartTextOut = class
  strict private
    FAlignment: TAlignment;
    FPos: TPoint;
    FSimpleTextOut: ISimpleTextOut;
    FText1: String;
    FText2: TStrings;
    FWidth: Integer;

    procedure DoTextOutList;
    procedure DoTextOutString;
  public
    constructor Create(ASimpleTextOut: ISimpleTextOut);
  public
    function Alignment(AAlignment: TAlignment): TChartTextOut;
    procedure Done;
    function Pos(AX, AY: Integer): TChartTextOut;
    function Pos(const APos: TPoint): TChartTextOut;
    function Text(const AText: String): TChartTextOut;
    function Text(AText: TStrings): TChartTextOut;
    function Width(AWidth: Integer): TChartTextOut;
  end;

  TChartColorToFPColorFunc = function (AColor: TChartColor): TFPColor;
  TGetFontOrientationFunc = function (AFont: TFPCustomFont): Integer;

  TChartTransparency = 0..255;

  { IChartDrawer }

  IChartDrawer = interface
    procedure AddToFontOrientation(ADelta: Integer);
    procedure ClippingStart(const AClipRect: TRect);
    procedure ClippingStart;
    procedure ClippingStop;
    procedure DrawingBegin(const ABoundingBox: TRect);
    procedure DrawingEnd;
    procedure DrawLineDepth(AX1, AY1, AX2, AY2, ADepth: Integer);
    procedure DrawLineDepth(const AP1, AP2: TPoint; ADepth: Integer);
    procedure Ellipse(AX1, AY1, AX2, AY2: Integer);
    procedure FillRect(AX1, AY1, AX2, AY2: Integer);
    function GetBrushColor: TChartColor;
    procedure SetDoChartColorToFPColorFunc(AValue: TChartColorToFPColorFunc);
    procedure Line(AX1, AY1, AX2, AY2: Integer);
    procedure Line(const AP1, AP2: TPoint);
    procedure LineTo(AX, AY: Integer);
    procedure LineTo(const AP: TPoint);
    procedure MoveTo(AX, AY: Integer);
    procedure MoveTo(const AP: TPoint);
    procedure Polygon(
      const APoints: array of TPoint; AStartIndex, ANumPts: Integer);
    procedure Polyline(
      const APoints: array of TPoint; AStartIndex, ANumPts: Integer);
    procedure PrepareSimplePen(AColor: TChartColor);
    procedure RadialPie(
      AX1, AY1, AX2, AY2: Integer;
      AStartAngle16Deg, AAngleLength16Deg: Integer);
    procedure Rectangle(const ARect: TRect);
    procedure Rectangle(AX1, AY1, AX2, AY2: Integer);
    function Scale(ADistance: Integer): Integer;
    procedure SetAntialiasingMode(AValue: TChartAntialiasingMode);
    procedure SetBrushColor(AColor: TChartColor);
    procedure SetBrush(ABrush: TFPCustomBrush);
    procedure SetBrushParams(AStyle: TFPBrushStyle; AColor: TChartColor);
    procedure SetFont(AValue: TFPCustomFont);
    procedure SetGetFontOrientationFunc(AValue: TGetFontOrientationFunc);
    procedure SetPen(APen: TFPCustomPen);
    procedure SetPenParams(AStyle: TFPPenStyle; AColor: TChartColor);
    procedure SetTransparency(ATransparency: TChartTransparency);
    procedure SetXor(AXor: Boolean);
    function TextExtent(const AText: String): TPoint;
    function TextExtent(AText: TStrings): TPoint;
    function TextOut: TChartTextOut;

    property Brush: TFPCustomBrush write SetBrush;
    property BrushColor: TChartColor read GetBrushColor write SetBrushColor;
    property Font: TFPCustomFont write SetFont;
    property Pen: TFPCustomPen write SetPen;
    property DoChartColorToFPColor: TChartColorToFPColorFunc
      write SetDoChartColorToFPColorFunc;
    property DoGetFontOrientation: TGetFontOrientationFunc
      write SetGetFontOrientationFunc;
  end;

  { TBasicDrawer }

  TBasicDrawer = class(TInterfacedObject, ISimpleTextOut)
  strict protected
    FChartColorToFPColorFunc: TChartColorToFPColorFunc;
    FGetFontOrientationFunc: TGetFontOrientationFunc;
    FTransparency: TChartTransparency;
    FXor: Boolean;
    function GetFontAngle: Double; virtual; abstract;
    function SimpleTextExtent(const AText: String): TPoint; virtual; abstract;
    procedure SimpleTextOut(AX, AY: Integer; const AText: String); virtual; abstract;
  public
    constructor Create;
    procedure DrawingBegin(const ABoundingBox: TRect); virtual;
    procedure DrawingEnd; virtual;
    procedure DrawLineDepth(AX1, AY1, AX2, AY2, ADepth: Integer);
    procedure DrawLineDepth(const AP1, AP2: TPoint; ADepth: Integer);
    procedure LineTo(AX, AY: Integer); virtual; abstract;
    procedure LineTo(const AP: TPoint);
    procedure MoveTo(AX, AY: Integer); virtual; abstract;
    procedure MoveTo(const AP: TPoint);
    procedure Polygon(
      const APoints: array of TPoint; AStartIndex, ANumPts: Integer); virtual; abstract;
    function Scale(ADistance: Integer): Integer; virtual;
    procedure SetAntialiasingMode(AValue: TChartAntialiasingMode);
    procedure SetDoChartColorToFPColorFunc(AValue: TChartColorToFPColorFunc);
    procedure SetGetFontOrientationFunc(AValue: TGetFontOrientationFunc);
    procedure SetTransparency(ATransparency: TChartTransparency);
    procedure SetXor(AXor: Boolean);
    function TextExtent(const AText: String): TPoint;
    function TextExtent(AText: TStrings): TPoint;
    function TextOut: TChartTextOut;
  end;

  function ChartColorToFPColor(AChartColor: TChartColor): TFPColor;
  function FPColorToChartColor(AFPColor: TFPColor): TChartColor;
  function ColorDef(AColor, ADefaultColor: TChartColor): TChartColor; inline;

implementation

uses
  Math, TAGeometry;

const
  LINE_INTERVAL = 2;

function ChartColorToFPColor(AChartColor: TChartColor): TFPColor;
begin
  with Result do begin
    red := AChartColor and $FF;
    red += red shl 8;
    green := (AChartColor and $FF00);
    green += green shr 8;
    blue := (AChartColor and $FF0000) shr 8;
    blue += blue shr 8;
    alpha := alphaOpaque;
  end;
end;

function DummyGetFontOrientationFunc(AFont: TFPCustomFont): Integer;
begin
  Unused(AFont);
  Result := 0;
end;

function FPColorToChartColor(AFPColor: TFPColor): TChartColor;
begin
  Result :=
    ((AFPColor.red shr 8) and $FF) or
    (AFPColor.green and $FF00) or
    ((AFPColor.blue shl 8) and $FF0000);
end;

function ColorDef(AColor, ADefaultColor: TChartColor): TChartColor;
begin
  Result := IfThen(AColor = clTAColor, ADefaultColor, AColor);
end;

{ TChartTextOut }

function TChartTextOut.Alignment(AAlignment: TAlignment): TChartTextOut;
begin
  FAlignment := AAlignment;
  Result := Self;
end;

constructor TChartTextOut.Create(ASimpleTextOut: ISimpleTextOut);
begin
  FSimpleTextOut := ASimpleTextOut;
  FAlignment := taLeftJustify;
end;

procedure TChartTextOut.Done;
begin
  if FText2 = nil then
    DoTextOutString
  else
    DoTextOutList;
  Free;
end;

procedure TChartTextOut.DoTextOutList;
var
  i: Integer;
  a: Double;
  lineExtent, p: TPoint;
begin
  a := -FSimpleTextOut.GetFontAngle;
  for i := 0 to FText2.Count - 1 do begin
    lineExtent := FSimpleTextOut.SimpleTextExtent(FText2[i]);
    p := FPos;
    case FAlignment of
      taCenter: p += RotatePointX((FWidth - lineExtent.X) div 2, a);
      taRightJustify: p += RotatePointX(FWidth - lineExtent.X, a);
    end;
    FSimpleTextOut.SimpleTextOut(p.X, p.Y, FText2[i]);
    FPos += RotatePoint(Point(0, lineExtent.Y + LINE_INTERVAL), a);
  end;
end;

procedure TChartTextOut.DoTextOutString;
begin
  if System.Pos(LineEnding, FText1) = 0 then begin
    FSimpleTextOut.SimpleTextOut(FPos.X, FPos.Y, FText1);
    exit;
  end;
  FText2 := TStringList.Create;
  try
    FText2.Text := FText1;
    DoTextOutList;
  finally
    FText2.Free;
  end;
end;

function TChartTextOut.Pos(AX, AY: Integer): TChartTextOut;
begin
  FPos := Point(AX, AY);
  Result := Self;
end;

function TChartTextOut.Pos(const APos: TPoint): TChartTextOut;
begin
  FPos := APos;
  Result := Self;
end;

function TChartTextOut.Text(const AText: String): TChartTextOut;
begin
  FText1 := AText;
  Result := Self;
end;

function TChartTextOut.Text(AText: TStrings): TChartTextOut;
begin
  FText2 := AText;
  Result := Self;
end;

function TChartTextOut.Width(AWidth: Integer): TChartTextOut;
begin
  FWidth := AWidth;
  Result := Self;
end;

{ TBasicDrawer }

constructor TBasicDrawer.Create;
begin
  FChartColorToFPColorFunc := @ChartColorToFPColor;
  FGetFontOrientationFunc := @DummyGetFontOrientationFunc;
end;

procedure TBasicDrawer.DrawingBegin(const ABoundingBox: TRect);
begin
  Unused(ABoundingBox);
end;

procedure TBasicDrawer.DrawingEnd;
begin
  // Empty
end;

procedure TBasicDrawer.DrawLineDepth(AX1, AY1, AX2, AY2, ADepth: Integer);
begin
  DrawLineDepth(Point(AX1, AY1), Point(AX2, AY2), ADepth);
end;

procedure TBasicDrawer.DrawLineDepth(const AP1, AP2: TPoint; ADepth: Integer);
var
  d: TPoint;
begin
  d := Point(ADepth, -ADepth);
  Polygon([AP1, AP1 + d, AP2 + d, AP2], 0, 4);
end;

procedure TBasicDrawer.LineTo(const AP: TPoint);
begin
  LineTo(AP.X, AP.Y)
end;

procedure TBasicDrawer.MoveTo(const AP: TPoint);
begin
  MoveTo(AP.X, AP.Y)
end;

function TBasicDrawer.Scale(ADistance: Integer): Integer;
begin
  Result := ADistance;
end;

procedure TBasicDrawer.SetAntialiasingMode(AValue: TChartAntialiasingMode);
begin
  Unused(AValue);
end;

procedure TBasicDrawer.SetDoChartColorToFPColorFunc(
  AValue: TChartColorToFPColorFunc);
begin
  FChartColorToFPColorFunc := AValue;
end;

procedure TBasicDrawer.SetGetFontOrientationFunc(
  AValue: TGetFontOrientationFunc);
begin
  FGetFontOrientationFunc := AValue;
end;

procedure TBasicDrawer.SetTransparency(ATransparency: TChartTransparency);
begin
  FTransparency := ATransparency;
end;

procedure TBasicDrawer.SetXor(AXor: Boolean);
begin
  FXor := AXor;
end;

function TBasicDrawer.TextExtent(const AText: String): TPoint;
var
  sl: TStrings;
begin
  if Pos(LineEnding, AText) = 0 then
    exit(SimpleTextExtent(AText));
  sl := TStringList.Create;
  try
    sl.Text := AText;
    Result := TextExtent(sl);
  finally
    sl.Free;
  end;
end;

function TBasicDrawer.TextExtent(AText: TStrings): TPoint;
var
  i: Integer;
begin
  Result := Size(0, -LINE_INTERVAL);
  for i := 0 to AText.Count - 1 do
    with SimpleTextExtent(AText[i]) do begin
      Result.X := Max(Result.X, X);
      Result.Y += Y + LINE_INTERVAL;
    end;
end;

function TBasicDrawer.TextOut: TChartTextOut;
begin
  Result := TChartTextOut.Create(Self);
end;

end.