unit graphics_2D;

// TODO rename to "graphics" ? or however something that draws on "pixmaps" and uses pixmap units mostly is called anyway.
// TODO just rename "pixmap" to "Image".
{$MODE OBJFPC}
{$M+}

interface
uses framebuffers, images, colors, type_fixes, fonts, rectangles;

type
  TAngle = Single; { in Radians. }

  IPen = interface
    function GetColor() : IColor;
    property Color : IColor read GetColor;
  end;

  IImagePen = interface(IPen) { does not scale the Pixmap before drawing. }
    property Image : IImage;
  end;

  IEmptyPen = interface(IPen)
  end;

  ISimplePen = interface(IPen)
    property Color : IColor;
    property Strength : Word;
  end;

  TBuiltInPenID = (peBox, peCircular, peEmpty);

  TBLITMode = (blCopy, blBlend); // QuickFiltering, blNearestNeighbourFiltering, blBilinearFiltering);

  // TODO Think about using TRect.

  { the default Pen is supposed to be the box pen, width = 1, height = 1. }
  I2DGraphics = interface
    function GetPen : IPen;
    procedure SetPen(const aPen : IPen);

    { left, top, right, bottom. }
    procedure DrawLine(aX1, aY1, aX2, aY2 : TCoordinate);
    procedure DrawRectangle(aX1, aY1, aX2, aY2 : TCoordinate);
    procedure DrawEllipse(aX1, aY1, aX2, aY2 : TCoordinate);
    procedure DrawArc(aX1, aY1, aX2, aY2 : TCoordinate; aBeginning : TAngle; aEnd : TAngle);

    { point array: [ starting_point_1, control_point_1_1, control_point_1_2, ending_point_1=>starting_point_2, control_point_2_1, control_point_2_2, ending_point_2_2... }
    procedure DrawCubicBezier(const aPoints : TPointArray); // TODO beginning, end offset.
    procedure ClearBox(aX1, aY1, aX2, aY2 : TCoordinate; const aColor : IColor);

    // depending on pen, doesn't always actually draw something.    
    function DrawGlyph(const aFont : IFont; aDesiredHeight : TCoordinate; aXLeft, aYBaseline : TCoordinate; aCode : TCardinal{Unicode}) : TRectangle; // FIXME RTL, up-down, context dependency.

    { this does not take care of the aspect ratio (what would it do?). }
    // TODO alpha blending?
    procedure BLIT(const aImage : IImage; aX1, aY1, aX2, aY2 : TCoordinate; aDestinationX1, aDestinationY1 : TCoordinate; aMode : TBLITMode);
    { TODO text, bezier curve. }
    property Pen : IPen read GetPen write SetPen;

    function GetBuiltinPen(aID : TBuiltInPenID; aWidth, aHeight : Cardinal) : IPen;

    { high-level support for clipping? Not here. }
    { TODO auto-fill the interior? }

    // TODO COLOR
  end;

implementation

end.