unit vtprimitives;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, fpcanvas, fpimage, fpvectorial;

function CreateCircle(APage: TvVectorialPage; CtrX, CtrY, R: Double): TvCircle;
function CreateEllipse(APage: TvVectorialPage; X1, Y1, X2, Y2: Double): TvEllipse;
function CreateRectangle(APage: TvVectorialPage; X1, Y1, X2, Y2: Double): TvRectangle;
function CreateRoundedRect(APage: TvVectorialPage; X1, Y1, X2, Y2, RX, RY: Double): TvRectangle;
function CreatePolygon(APage: TvVectorialPage; const APoints: array of T3DPoint): TvPolygon;
procedure CreateArc(APage: TvVectorialPage; X1,Y1, X2,Y2, CX,CY, RX, RY, Angle: Double;
  Clockwise: Boolean; out Arc: TPath; out Txt1, Txt2: TvText);
procedure CreateBezier(APage: TvVectorialPage; X1,Y1, X2,Y2, X3,Y3, X4,Y4: Double;
  out Bezier, Line1, Line2: TPath; out Txt1, Txt2, Txt3, Txt4: TvText);

function CreateSimpleBrush(AStyle: TFPBrushStyle; AColor: TFPColor): TvBrush; overload;
function CreateSimpleBrush(AStyle: TFPBrushStyle): TvBrush; overload;
function CreateLinearGradientBrush(AStartPt, AEndPt: T2DPoint; AFlags: TvGradientFlags;
  AStartColor, AEndColor: TFPColor): TvBrush;
function CreateRadialGradientBrush(CX, CY, R, FX, FY: Double;
  AStartColor, AEndColor: TFPColor): TvBrush;
function CreatePen(AStyle: TFPPenStyle; AWidth: Integer; AColor: TFPColor): TvPen;

function CreateStdCircle(APage: TvVectorialPage): TvCircle;
function CreateStdEllipse(APage: TvVectorialPage): TvEllipse;
function CreateStdRect(APage: TvVectorialPage): TvRectangle;
function CreateStdRoundedRect(APage: TvVectorialPage): TvRectangle;
function CreateStdPolygon(APage: TvVectorialPage): TvPolygon;
function CreateStdSelfIntersectingPolygon(APage: TvVectorialPage): TvPolygon;
function CreatePathWithHole(APage: TvVectorialPage): TPath;

function StdSolidBrush(AColor: TFPColor): TvBrush;
function StdHorizGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
function StdVertGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
function StdLinearGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
function StdRadialGradientBrush(AColor1, AColor2: TFPColor; CX, CY, R: Double): TvBrush;
function StdPen(AColor: TFPColor; AWidth: Integer): TvPen;

procedure Rotate(APage: TvVectorialPage; AShape: TvEntity; Angle: Double);

const
  PAGE_SIZE = 100;


implementation

uses
  Math, fpvutils;

{ Shapes }

{ circle with specified center and radius.
  Valid for any coordinate system }
function CreateCircle(APage: TvVectorialPage; CtrX, CtrY, R: Double): TvCircle;
begin
  Result := TvCircle.Create(APage);
  Result.X := CtrX;
  Result.Y := CtrY;
  Result.Radius := R;
  Result.Brush := CreateSimpleBrush(bsClear);
  Result.Pen := CreatePen(psSolid, 1, colBlack);
end;

{ Ellipse with specified center and halfaxes.
  Coordinate system uses an upward y axis for input data, but is flipped if needed }
function CreateEllipse(APage: TvVectorialPage; X1, Y1, X2, Y2: Double): TvEllipse;
begin
  Result := TvEllipse.Create(APage);
  Result.X := (X1 + X2) / 2;      // Center
  Result.Y := (Y1 + Y2) / 2;
  if APage.UseTopLeftCoordinates then
    Result.Y := PAGE_SIZE - Result.Y;
  Result.HorzHalfAxis := abs(X2 - X1) / 2;
  Result.VertHalfAxis := abs(Y2 - Y1) / 2;
  Result.Brush := CreateSimpleBrush(bsClear);
  Result.Pen := CreatePen(psSolid, 1, colBlack);
end;

{ Rectangle with specified top/left corner and width and height.
  Coordinate system uses an upward y axis for input data, but is flipped if needed. }
function CreateRectangle(APage: TvVectorialPage; X1, Y1, X2, Y2: Double): TvRectangle;
begin
  Result := TvRectangle.Create(APage);
  Result.X := Min(X1, X2);
  if APage.UseTopLeftCoordinates then
    Result.Y := Min(PAGE_SIZE-Y1, PAGE_SIZE-Y2) else
    Result.Y := Max(Y1, Y2);
  Result.CX := abs(X2 - X1);    // width
  Result.CY := abs(Y2 - Y1);    // height
  Result.Brush := CreateSimpleBrush(bsClear);
  Result.Pen := CreatePen(psSolid, 1, colBlack);
end;

{ Rectangle with rounded corner
  Coordinate system uses an upward y axis for input data, but is flipped if needed. }
function CreateRoundedRect(APage: TvVectorialPage;
  X1, Y1, X2, Y2, RX, RY: Double): TvRectangle;
begin
  Result := TvRectangle.Create(APage);
  Result.X := Min(X1, X2);
  if APage.UseTopLeftCoordinates then
    Result.Y := Min(PAGE_SIZE-Y1, PAGE_SIZE-Y2) else
    Result.Y := Max(Y1, Y2);
  Result.CX := abs(X2 - X1);
  Result.CY := abs(Y2 - Y1);
  Result.RX := RX;
  Result.RY := RY;
  Result.Brush := CreateSimpleBrush(bsClear);
  Result.Pen := CreatePen(psSolid, 1, colBlack);
end;

{ Polygon with vertices specified in the array.
  Valid for any coordinate system. }
function CreatePolygon(APage: TvVectorialPage;
  const APoints: Array of T3DPoint): TvPolygon;
var
  i: Integer;
begin
  Result := TvPolygon.Create(APage);
  SetLength(Result.Points, Length(APoints));
  for i:=0 to High(APoints) do
    Result.Points[i] := APoints[i];
  Result.X := Result.Points[0].X;
  Result.Y := Result.Points[0].Y;
  Result.Brush := CreateSimpleBrush(bsClear);
  Result.Pen := CreatePen(psSolid, 1, colBlack);
end;

procedure CreateArc(APage: TvVectorialPage; X1,Y1, X2,Y2, CX,CY, RX, RY, Angle: Double;
  Clockwise: Boolean; out Arc: TPath; out Txt1, Txt2: TvText);
begin
  if APage.UseTopLeftCoordinates then begin
    Y1 := PAGE_SIZE - Y1;
    Y2 := PAGE_SIZE - Y2;
    CY := PAGE_SIZE - CY;
    Angle := -Angle;
  end;
  // Don't invert "Clockwise" here. It does not matter where the y axis points to.

  APage.StartPath(X1, Y1);
  APage.AddEllipticalArcWithCenterToPath(RX, RY, Angle, X2, Y2, CX, CY, Clockwise);
  Arc := APage.EndPath;
  Arc.Pen := StdPen(colBlack, 4);

  Txt1 := TvText.Create(APage);
  Txt1.Value.Add('1');
  Txt1.X := X1;
  Txt1.Y := Y1;
  Txt1.Font.Color := colRed;
  APage.AddEntity(Txt1);

  Txt2 := TvText.Create(APage);
  Txt2.Value.Add('2');
  Txt2.X := X2;
  Txt2.Y := Y2;
  Txt2.Font.Color := colRed;
  APage.AddEntity(Txt2);
end;

procedure CreateBezier(APage: TvVectorialPage;
  X1,Y1, X2,Y2, X3,Y3, X4,Y4: Double;
  out Bezier, Line1, Line2: TPath; out Txt1, Txt2, Txt3, Txt4: TvText);
var
  txt: TvText;
begin
  if APage.UseTopLeftCoordinates then begin
    Y1 := PAGE_SIZE - Y1;
    Y2 := PAGE_SIZE - Y2;
    Y3 := PAGE_SIZE - Y3;
    Y4 := PAGE_SIZE - Y4;
  end;
  APage.StartPath(X1, Y1);
  APage.AddBezierToPath(X2,Y2, X3,Y3, X4,Y4);
  Bezier := APage.EndPath;
  Bezier.Pen := StdPen(colBlack, 4);

  APage.StartPath(X1, Y1);
  APage.AddLineToPath(X2, Y2);
  Line1 := APage.EndPath;
  Line1.Pen.Color := colRed;
  Line1.Name := 'Line1';

  APage.StartPath(X4, Y4);
  APage.AddLineToPath(X3, Y3);
  Line2 := APage.EndPath;
  Line2.Pen.Color := colRed;
  Line2.Name := 'Line2';

  Txt1 := TvText.Create(APage);
  Txt1.Value.Add('1');
  Txt1.X := X1;
  Txt1.Y := Y1;
  Txt1.Font.Color := colRed;
  APage.AddEntity(Txt1);

  Txt2 := TvText.Create(APage);
  Txt2.Value.Add('2');
  Txt2.X := X2;
  Txt2.Y := Y2;
  Txt2.Font.Color := colRed;
  APage.AddEntity(Txt2);

  Txt3 := TvText.Create(APage);
  Txt3.Value.Add('3');
  Txt3.X := X3;
  Txt3.Y := Y3;
  Txt3.Font.Color := colRed;
  APage.AddEntity(Txt3);

  Txt4 := TvText.Create(APage);
  Txt4.Value.Add('4');
  Txt4.X := X4;
  Txt4.Y := Y4;
  Txt4.Font.Color := colRed;
  APage.AddEntity(Txt4);
end;


{ Brushes }

function CreateSimpleBrush(AStyle: TFPBrushStyle): TvBrush;
begin
  Result := CreateSimpleBrush(AStyle, colBlack);
end;

function CreateSimpleBrush(AStyle: TFPBrushStyle; AColor: TFPColor): TvBrush;
begin
  Result.Kind := bkSimpleBrush;
  Result.Color := TFPColor(AColor);
  Result.Style := AStyle;
end;

function CreateLinearGradientBrush(AStartPt, AEndPt: T2DPoint;
  AFlags: TvGradientFlags; AStartColor, AEndColor: TFPColor): TvBrush;
var
  p1, p2: T2dPoint;
  x1str, x2str, y1str, y2str: String;
begin
  if AStartPt.Y = AEndPt.Y then
    Result.Kind := bkHorizontalGradient
  else if AStartPt.X = AEndPt.X then
    Result.Kind := bkVerticalGradient
  else
    Result.Kind := bkOtherLinearGradient;
  Result.Gradient_start := AStartPt;
  Result.Gradient_end := AEndPt;
  Result.Gradient_flags := AFlags;
  SetLength(Result.Gradient_colors, 2);
  Result.Gradient_colors[0].Color := AStartColor;
  Result.Gradient_colors[0].Position := 0;
  Result.Gradient_colors[1].Color := AEndColor;
  Result.Gradient_colors[1].Position := 1;
end;

function CreateRadialGradientBrush(CX, CY, R, FX, FY: Double;
  AStartColor, AEndColor: TFPColor): TvBrush;
begin
  Result.Kind := bkRadialGradient;
  Result.Gradient_cx := CX;
  Result.Gradient_cy := CY;
  Result.Gradient_r := R;
  // Our renderer does not support a moving center --> put both centers at the same spot
  Result.Gradient_fx := CX;
  Result.Gradient_fy := CY;

  Result.Gradient_cx_Unit := vcuPercentage;
  Result.Gradient_cy_Unit := vcuPercentage;
  Result.Gradient_r_Unit := vcuPercentage;
  Result.Gradient_fx_Unit := vcuPercentage;
  Result.Gradient_fy_Unit := vcuPercentage;

  SetLength(Result.Gradient_colors, 2);
  Result.Gradient_colors[0].Color := AStartColor;
  Result.Gradient_colors[0].Position := 0;
  Result.Gradient_colors[1].Color := AEndColor;
  Result.Gradient_colors[1].Position := 1;
end;
                                          (*
function CreateRadialGradientBrush(CX, CY, R, FX, FY: Double;
  AStartColor, AEndColor: TFPColor): TvBrush;
begin
  Result.Kind := bkRadialGradient;
  Result.Gradient_cx := CX;
  Result.Gradient_cy := CY;
  Result.Gradient_r := R;
  Result.Gradient_fx := FX;
  Result.Gradient_fy := FY;
  SetLength(Result.Gradient_colors, 2);
  Result.Gradient_colors[0].Color := AStartColor;
  Result.Gradient_colors[0].Position := 0;
  Result.Gradient_colors[1].Color := AEndColor;
  Result.Gradient_colors[1].Position := 1;
end;                                        *)


{ Pen }

function CreatePen(AStyle: TFPPenStyle; AWidth: Integer; AColor: TFPColor): TvPen;
begin
  Result.Style := AStyle;
  Result.Width := AWidth;
  Result.Color := AColor;
end;


{ Standardized objects }

{ A circle shifted up }
function CreateStdCircle(APage: TvVectorialPage): TvCircle;
const
  CENTER_X = 50;
  CENTER_Y = 55;  // y points up for this number
  RADIUS = 40;
begin
  if APage.UseTopLeftCoordinates then
    Result := CreateCircle(APage, CENTER_X, PAGE_SIZE - CENTER_Y, RADIUS)
  else
    Result := CreateCircle(APage, CENTER_X, CENTER_Y, RADIUS);
  Result.Pen := StdPen(colBlack, 4);
end;

{ An ellipse shifted up }
function CreateStdEllipse(APage: TvVectorialPage): TvEllipse;
begin
  Result := CreateEllipse(APage, 10, 30, 90, 80);
    // CreateEllipse will invert the axis if needed
  Result.Pen := StdPen(colBlack, 4);
end;

{ A rectangle shifted up }
function CreateStdRect(APage: TvVectorialPage): TvRectangle;
const
  LEFT = 10;
  RIGHT = 90;
  TOP = 95;     // for bottom-up y axis
  BOTTOM = 15;  // dto.
begin
  Result := CreateRectangle(APage, LEFT, TOP, RIGHT, BOTTOM);
    // CreateRect will invert the y axis if needed
  Result.Pen := StdPen(colBlack, 4);
end;

{ A rounded rectangle shifted up }
function CreateStdRoundedRect(APage: TvVectorialPage): TvRectangle;
const
  LEFT = 10;
  RIGHT = 90;
  TOP = 95;     // for bottom-up y axis
  BOTTOM = 15;  // dto.
  RX = 10;
  RY = 10;
begin
  Result := CreateRoundedRect(APage,LEFT, TOP, RIGHT, BOTTOM, RX, RY);
    // CreateRect will invert the y axis if needed
  Result.Pen := StdPen(colBlack, 4);
end;

{ A triangle as polygon, base line at bottom }
function CreateStdPolygon(APage: TvVectorialPage):TvPolygon;
var
  pts: array[0..3] of T3DPoint;
  i: Integer;
begin
  pts[0] := Make3DPoint(10, 10);
  pts[1] := Make3dPoint(90, 10);
  pts[2] := Make3DPoint(50, 90);
  pts[3] := pts[0];
  if APage.UseTopLeftCoordinates then
    for i:=0 to High(pts) do
      pts[i].Y := PAGE_SIZE - pts[i].Y;
  Result := CreatePolygon(APage, pts);
  Result.Pen := StdPen(colBlack, 4);
end;

{ A star-like self-intersecting polygon, tip at bottom }
function CreateStdSelfIntersectingPolygon(APage: TvVectorialPage): TvPolygon;
var
  pts: array[0..5] of T3DPoint;
  i: Integer;
begin
  pts[0] := Make3DPoint(50, 5);
  pts[1] := Make3DPoint(20, 90);
  pts[2] := Make3DPoint(95, 30);
  pts[3] := Make3DPoint(5,  30);
  pts[4] := Make3DPoint(80, 90);
  pts[5] := Make3DPoint(50, 5);
  if APage.UseTopLeftCoordinates then
    for i:=0 to High(pts) do
      pts[i].Y := PAGE_SIZE - pts[i].Y;
  Result := CreatePolygon(APage, pts);
  Result.Pen := StdPen(colBlack, 4);
end;

function CreatePathWithHole(APage: TvVectorialPage): TPath;
const
  OUTER_POINTS: array[0..4] of T2DPoint = (
    (X:10; Y:5), (X:90; Y:5), (X:90; Y:90), (X:10; Y:90), (X:10; Y:5)
  );
  INNER_POINTS: array[0..4] of T2DPoint = (
    (X:50; Y:45), (X:40; Y:55), (X:50; Y:65), (X:60; Y:55), (X:50; Y:45)
  );
var
  i: Integer;
begin
  if APage.UseTopLeftCoordinates then begin
    APage.StartPath(OUTER_POINTS[0].X, PAGE_SIZE - OUTER_POINTS[0].Y);
    for i:=1 to High(OUTER_POINTS) do
      APage.AddLineToPath(OUTER_POINTS[i].X, PAGE_SIZE - OUTER_POINTS[i].Y);
    APage.AddMoveToPath(INNER_POINTS[0].X, PAGE_SIZE - INNER_POINTS[0].Y);
    for i:=1 to High(INNER_POINTS) do
      APage.AddLineToPath(INNER_POINTS[i].X, PAGE_SIZE - INNER_POINTS[i].Y);
  end else begin
    APage.StartPath(OUTER_POINTS[0].X, OUTER_POINTS[0].Y);
    for i:=1 to High(OUTER_POINTS) do
      APage.AddLineToPath(OUTER_POINTS[i].X, OUTER_POINTS[i].Y);
    APage.AddMoveToPath(INNER_POINTS[0].X, INNER_POINTS[0].Y);
    for i:=1 to High(INNER_POINTS) do
      APage.AddLineToPath(INNER_POINTS[i].X, INNER_POINTS[i].Y);
  end;
  Result := APage.EndPath;
  Result.Pen := StdPen(colBlack, 4);
end;

{ ---- }

function StdSolidBrush(AColor: TFPColor): TvBrush;
begin
  Result := CreateSimpleBrush(bsSolid, AColor);
end;

function StdHorizGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
begin
  Result := CreateLinearGradientBrush(Point2D(0, 0), Point2D(1, 0),
    [gfRelStartX, gfRelEndX, gfRelStartY, gfRelEndY],
    AColor1, AColor2);
end;

{ A vertical gradient, AColor1 at top, AColor2 at bottom }
function StdVertGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
var
  P1, P2: T2DPoint;
begin
  P1 := Point2D(0, 0);
  P2 := Point2D(0, 1);
  Result := CreateLinearGradientBrush(P1, P2,
    [gfRelStartX, gfRelEndX, gfRelStartY, gfRelEndY],
    AColor1, AColor2);
end;

{ A diagonal gradient running from bottom/left (AColor1) to top/right (AColor) }
function StdLinearGradientBrush(AColor1, AColor2: TFPColor): TvBrush;
var
  P1, P2: T2DPoint;
begin
  P1 := Point2D(0, 0);
  P2 := Point2D(1, 1);
  Result := CreateLinearGradientBrush(Point2D(0, 0), Point2D(1, 1),
    [gfRelStartX, gfRelEndX, gfRelStartY, gfRelEndY],
    AColor1, AColor2);
end;

function StdRadialGradientBrush(AColor1, AColor2: TFPColor;
  CX, CY, R: Double): TvBrush;
begin
  Result := CreateRadialGradientBrush(CX, CY, R, 0.5, 0.5,
    AColor1, AColor2);
end;

function StdPen(AColor: TFPColor; AWidth: Integer): TvPen;
begin
  Result := CreatePen(psSolid, AWidth, AColor);
end;

procedure Rotate(APage: TvVectorialPage; AShape: TvEntity; Angle: Double);
var
  p: T3dPoint;
  ctr: T3dPoint;  // Center of rotation
  phi: Double;    // Rotation angle in radians
begin;
  ctr.X := 10;
  phi := DegToRad(Angle);
  if APage.UseTopLeftCoordinates then
  begin
    ctr.Y := PAGE_SIZE - 10;
    phi := -phi;
  end else
    ctr.Y := 10;

  if AShape is TvText then
  begin
    // TvText has no Rotate method since it has no Angle element.
    // --> The reference point cannot be rotated in space by TvText itself,
    // we must do it separately.
    p := Rotate3DPointInXY(Make3dPoint(AShape.X, AShape.Y), ctr, -phi);
    AShape.X := p.X;
    AShape.Y := p.Y;
  end else
    AShape.Rotate(phi, ctr);
end;

end.