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fpvectorial: Implements support for arc in the postscript reader
git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@1766 8e941d3f-bd1b-0410-a28a-d453659cc2b4
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sekelsenmat
@ -1455,6 +1455,9 @@ function TvEPSVectorialReader.ExecutePathConstructionOperator(
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var
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Param1, Param2, Param3, Param4, Param5, Param6: TPSToken;
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PosX, PosY, PosX2, PosY2, PosX3, PosY3, BaseX, BaseY: Double;
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// For Arc
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P1, P2, P3, P4: T3DPoint;
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startAngle, endAngle: Double;
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begin
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Result := False;
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@ -1506,7 +1509,7 @@ begin
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Param1 := TPSToken(Stack.Pop);
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Param2 := TPSToken(Stack.Pop);
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PostScriptCoordsToFPVectorialCoords(Param1, Param2, PosX, PosY);
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AData.GetCurrenPathPenPos(BaseX, BaseY);
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AData.GetCurrentPathPenPos(BaseX, BaseY);
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PosX := PosX + CurrentGraphicState.TranslateX;
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PosY := PosY + CurrentGraphicState.TranslateY;
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{$ifdef FPVECTORIALDEBUG_PATHS}
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@ -1534,7 +1537,8 @@ begin
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PostScriptCoordsToFPVectorialCoords(Param5, Param6, PosX, PosY);
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PostScriptCoordsToFPVectorialCoords(Param3, Param4, PosX2, PosY2);
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PostScriptCoordsToFPVectorialCoords(Param1, Param2, PosX3, PosY3);
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AData.GetCurrenPathPenPos(BaseX, BaseY);
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AData.GetCurrentPathPenPos(BaseX, BaseY);
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// First move to the start of the arc
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BaseX := BaseX + CurrentGraphicState.TranslateX;
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BaseY := BaseY + CurrentGraphicState.TranslateY;
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{$ifdef FPVECTORIALDEBUG_PATHS}
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@ -1558,19 +1562,47 @@ begin
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Exit(True);
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end;
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// x y r angle1 angle2 arc – Append counterclockwise arc
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{
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x y r angle1 angle2 arc – Append counterclockwise arc
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Arcs in PostScript are described by a center (x, y), a radius r and
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two angles, angle1 for the start and angle2 for the end. These two
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angles are relative to the X axis growing to the right (positive direction).
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}
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if AToken.StrValue = 'arc' then
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begin
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Param1 := TPSToken(Stack.Pop);
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Param2 := TPSToken(Stack.Pop);
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Param3 := TPSToken(Stack.Pop);
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Param4 := TPSToken(Stack.Pop);
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Param5 := TPSToken(Stack.Pop);
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Param1 := TPSToken(Stack.Pop); // angle2
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Param2 := TPSToken(Stack.Pop); // angle1
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Param3 := TPSToken(Stack.Pop); // r
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Param4 := TPSToken(Stack.Pop); // y
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Param5 := TPSToken(Stack.Pop); // x
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PostScriptCoordsToFPVectorialCoords(Param4, Param5, PosX, PosY);
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PosX := PosX + CurrentGraphicState.TranslateX;
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PosY := PosY + CurrentGraphicState.TranslateY;
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startAngle := Param2.FloatValue * Pi / 180;
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endAngle := Param1.FloatValue * Pi / 180;
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// If the angle is too big we need to use two beziers
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if endAngle - startAngle > Pi then
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begin
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CircularArcToBezier(PosX, PosY, Param3.FloatValue, startAngle, endAngle - Pi, P1, P2, P3, P4);
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AData.AddMoveToPath(P1.X, P1.Y);
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AData.AddBezierToPath(P2.X, P2.Y, P3.X, P3.Y, P4.X, P4.Y);
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CircularArcToBezier(PosX, PosY, Param3.FloatValue, startAngle + Pi, endAngle, P1, P2, P3, P4);
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AData.AddMoveToPath(P1.X, P1.Y);
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AData.AddBezierToPath(P2.X, P2.Y, P3.X, P3.Y, P4.X, P4.Y);
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end
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else
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begin
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CircularArcToBezier(PosX, PosY, Param3.FloatValue, startAngle, endAngle, P1, P2, P3, P4);
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AData.AddMoveToPath(P1.X, P1.Y);
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AData.AddBezierToPath(P2.X, P2.Y, P3.X, P3.Y, P4.X, P4.Y);
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end;
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// {$ifdef FPVECTORIALDEBUG}
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// WriteLn(Format('[TvEPSVectorialReader.ExecutePathConstructionOperator] rcurveto %f, %f', [BaseX + PosX, BaseY + PosY]));
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// {$endif}
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// AData.AddBezierToPath(BaseX + PosX, BaseY + PosY, BaseX + PosX2, BaseY + PosY2, BaseX + PosX3, BaseY + PosY3);
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{$ifdef FPVECTORIALDEBUG_PATHS}
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WriteLn(Format('[TvEPSVectorialReader.ExecutePathConstructionOperator] arc %f, %f', [PosX, PosY]));
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{$endif}
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@ -295,7 +295,7 @@ type
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procedure AddLineToPath(AX, AY: Double); overload;
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procedure AddLineToPath(AX, AY: Double; AColor: TFPColor); overload;
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procedure AddLineToPath(AX, AY, AZ: Double); overload;
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procedure GetCurrenPathPenPos(var AX, AY: Double);
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procedure GetCurrentPathPenPos(var AX, AY: Double);
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procedure AddBezierToPath(AX1, AY1, AX2, AY2, AX3, AY3: Double); overload;
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procedure AddBezierToPath(AX1, AY1, AZ1, AX2, AY2, AZ2, AX3, AY3, AZ3: Double); overload;
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procedure SetBrushColor(AColor: TFPColor);
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@ -661,10 +661,10 @@ end;
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{@@
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Gets the current Pen Pos in the temporary path
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}
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procedure TvVectorialDocument.GetCurrenPathPenPos(var AX, AY: Double);
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procedure TvVectorialDocument.GetCurrentPathPenPos(var AX, AY: Double);
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begin
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// Check if we are the first segment in the tmp path
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if FTmpPath.PointsEnd = nil then raise Exception.Create('[TvVectorialDocument.GetCurrenPathPenPos] One cannot obtain the Pen Pos if there are no segments in the temporary path');
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if FTmpPath.PointsEnd = nil then raise Exception.Create('[TvVectorialDocument.GetCurrentPathPenPos] One cannot obtain the Pen Pos if there are no segments in the temporary path');
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AX := T2DSegment(FTmpPath.PointsEnd).X;
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AY := T2DSegment(FTmpPath.PointsEnd).Y;
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@ -31,6 +31,9 @@ function RGBToFPColor(AR, AG, AB: byte): TFPColor; inline;
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function CanvasCoordsToFPVectorial(AY: Integer; AHeight: Integer): Integer; inline;
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function CanvasTextPosToFPVectorial(AY: Integer; ACanvasHeight, ATextHeight: Integer): Integer;
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function SeparateString(AString: string; ASeparator: char): T10Strings;
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// Mathematical routines
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procedure EllipticalArcToBezier(Xc, Yc, Rx, Ry, startAngle, endAngle: Double; var P1, P2, P3, P4: T3DPoint);
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procedure CircularArcToBezier(Xc, Yc, R, startAngle, endAngle: Double; var P1, P2, P3, P4: T3DPoint);
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implementation
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@ -110,5 +113,56 @@ begin
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end;
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end;
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{ Considering a counter-clockwise arc, elliptical and alligned to the axises
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An elliptical Arc can be converted to
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the following Cubic Bezier control points:
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P1 = E(startAngle) <- start point
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P2 = P1+alfa * dE(startAngle) <- control point
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P3 = P4−alfa * dE(endAngle) <- control point
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P4 = E(endAngle) <- end point
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source: http://www.spaceroots.org/documents/ellipse/elliptical-arc.pdf
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The equation of an elliptical arc is:
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X(t) = Xc + Rx * cos(t)
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Y(t) = Yc + Ry * sin(t)
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dX(t)/dt = - Rx * sin(t)
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dY(t)/dt = + Ry * cos(t)
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}
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procedure EllipticalArcToBezier(Xc, Yc, Rx, Ry, startAngle, endAngle: Double;
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var P1, P2, P3, P4: T3DPoint);
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var
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halfLength, arcLength, alfa: Double;
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begin
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arcLength := endAngle - startAngle;
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halfLength := (endAngle - startAngle) / 2;
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alfa := sin(arcLength) * (Sqrt(4 + 3*sqr(tan(halfLength))) - 1) / 3;
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// Start point
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P1.X := Xc + Rx * cos(startAngle);
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P1.Y := Yc + Ry * sin(startAngle);
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// End point
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P4.X := Xc + Rx * cos(endAngle);
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P4.Y := Yc + Ry * sin(endAngle);
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// Control points
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P2.X := P1.X + alfa * -1 * Rx * sin(startAngle);
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P2.Y := P1.Y + alfa * Ry * cos(startAngle);
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P3.X := P4.X - alfa * -1 * Rx * sin(endAngle);
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P3.Y := P4.Y - alfa * Ry * cos(endAngle);
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end;
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procedure CircularArcToBezier(Xc, Yc, R, startAngle, endAngle: Double; var P1,
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P2, P3, P4: T3DPoint);
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begin
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EllipticalArcToBezier(Xc, Yc, R, R, startAngle, endAngle, P1, P2, P3, P4);
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end;
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end.
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@ -14,8 +14,37 @@
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<VersionInfo>
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<StringTable ProductVersion=""/>
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</VersionInfo>
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<BuildModes Count="1">
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<BuildModes Count="2">
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<Item1 Name="default" Default="True"/>
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<Item2 Name="qt">
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<MacroValues Count="1">
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<Macro1 Name="LCLWidgetType" Value="qt"/>
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</MacroValues>
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<CompilerOptions>
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<Version Value="10"/>
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<Target>
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<Filename Value="fpvviewer"/>
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</Target>
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<SearchPaths>
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<IncludeFiles Value="$(ProjOutDir)"/>
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<OtherUnitFiles Value="fpvectorialsrc"/>
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<UnitOutputDirectory Value="lib/$(TargetCPU)-$(TargetOS)"/>
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</SearchPaths>
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<Linking>
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<Options>
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<Win32>
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<GraphicApplication Value="True"/>
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</Win32>
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</Options>
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</Linking>
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<Other>
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<CompilerMessages>
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<UseMsgFile Value="True"/>
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</CompilerMessages>
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<CompilerPath Value="$(CompPath)"/>
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</Other>
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</CompilerOptions>
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</Item2>
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</BuildModes>
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<PublishOptions>
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<Version Value="2"/>
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