TAChart: Correctly support arbitrary label orientation.

As a bonus:
* Fix axis ticks disappearing when the corresponding label is hidden.
* Support Marks.OverlapPolicy in pie series.

git-svn-id: trunk@26771 -

components/tachart/tachartaxis.pas

@@ -361,20 +361,19 @@ procedure TChartAxis.Draw(
   const ATransf: ICoordTransformer; var ARect: TRect);
 
 var
-  prevLabelRect: TRect = (Left: 0; Top: 0; Right: 0; Bottom: 0);
+  prevLabelPoly: TPointArray = nil;
 
-  procedure DrawLabelAndTick(const ALabelRect, ATickRect: TRect; const AText: String);
+  procedure DrawLabelAndTick(
+    const ALabelCenter: TPoint; const ATickRect: TRect; const AText: String);
   begin
-    if Marks.IsLabelHiddenDueToOverlap(prevLabelRect, ALabelRect) then exit;
     PrepareSimplePen(ACanvas, TickColor);
     ACanvas.Line(ATickRect);
-    Marks.DrawLabel(ACanvas, ALabelRect, AText);
+    Marks.DrawLabel(ACanvas, ALabelCenter, ALabelCenter, AText, prevLabelPoly);
   end;
 
   procedure DrawXMark(AY: Integer; AMark: Double; const AText: String);
   var
-    x, t: Integer;
+    x, d: Integer;
-    sz: TSize;
   begin
     x := ATransf.XGraphToImage(AMark);
 
@@ -386,18 +385,17 @@ var
         x, ATransf.YGraphToImage(AExtent.b.Y));
     end;
 
-    sz := Marks.MeasureLabel(ACanvas, AText);
+    d :=
-    t := TickLength + Marks.Distance;
+      TickLength + Marks.Distance + Marks.MeasureLabel(ACanvas, AText).cy div 2;
-    t := IfThen(Alignment = calTop, - t - sz.cy, t);
+    if Alignment = calTop then
+      d := -d;
     DrawLabelAndTick(
-      BoundsSize(x - sz.cx div 2, AY + t, sz),
+      Point(x, AY + d), Rect(x, AY - TickLength, x, AY + TickLength), AText);
-      Rect(x, AY - TickLength, x, AY + TickLength), AText);
   end;
 
   procedure DrawYMark(AX: Integer; AMark: Double; const AText: String);
   var
-    y, t: Integer;
+    y, d: Integer;
-    sz: TSize;
   begin
     y := ATransf.YGraphToImage(AMark);
 
@@ -409,12 +407,12 @@ var
         ATransf.XGraphToImage(AExtent.b.X), y);
     end;
 
-    sz := Marks.MeasureLabel(ACanvas, AText);
+    d :=
-    t := TickLength + Marks.Distance;
+      TickLength + Marks.Distance + Marks.MeasureLabel(ACanvas, AText).cx div 2;
-    t := IfThen(Alignment = calLeft, - t - sz.cx, t);
+    if Alignment = calLeft then
+      d := -d;
     DrawLabelAndTick(
-      BoundsSize(AX + t, y - sz.cy div 2, sz),
+      Point(AX + d, y), Rect(AX - TickLength, y, AX + TickLength, y), AText);
-      Rect(AX - TickLength, y, AX + TickLength, y), AText);
   end;
 
 var
@@ -515,33 +513,30 @@ procedure TChartAxis.Measure(
   ACanvas: TCanvas; const AExtent: TDoubleRect; AFirstPass: Boolean;
   var AMargins: TChartAxisMargins);
 
-const
+  function CalcMarksSize(AMin, AMax: Double): TSize;
-  SOME_DIGIT = '0';
+  const
-
+    SOME_DIGIT = '0';
-  procedure CalcVertSize;
   var
     i: Integer;
+    t: String;
+    sz: TSize;
   begin
-    if AExtent.a.Y = AExtent.b.Y then exit;
+    Result := Size(0, 0);
-    GetMarkValues(AExtent.a.Y, AExtent.b.Y);
+    if AMin = AMax then exit;
-    FSize := 0;
+    GetMarkValues(AMin, AMax);
-    for i := 0 to High(FMarkTexts) do
+    for i := 0 to High(FMarkTexts) do begin
-      with Marks.MeasureLabel(ACanvas, FMarkTexts[i]) do
+      // CalculateTransformationCoeffs changes axis interval, so it is possibile
-        FSize := Max(cx, FSize);
+      // that a new mark longer then existing ones is introduced.
-    // CalculateTransformationCoeffs changes axis interval, so it is possibile
+      // That will change marks width and reduce view area,
-    // that a new mark longer then existing ones is introduced.
+      // requiring another call to CalculateTransformationCoeffs...
-    // That will change marks width and reduce view area,
+      // So punt for now and just reserve space for extra digit unconditionally.
-    // requiring another call to CalculateTransformationCoeffs...
+      t := FMarkTexts[i];
-    // So punt for now and just reserve space for extra digit unconditionally.
+      if AFirstPass then
-    if AFirstPass then
+        t += SOME_DIGIT;
-      FSize += ACanvas.TextWidth(SOME_DIGIT);
+      sz := Marks.MeasureLabel(ACanvas, t);
-  end;
+      Result.cx := Max(sz.cx, Result.cx);
-
+      Result.cy := Max(sz.cy, Result.cy);
-  procedure CalcHorSize;
+    end;
-  begin
-    if AExtent.a.X = AExtent.b.X then exit;
-    GetMarkValues(AExtent.a.X, AExtent.b.X);
-    FSize := Marks.MeasureLabel(ACanvas, SOME_DIGIT).cy;
   end;
 
   procedure CalcTitleSize;
@@ -570,9 +565,9 @@ begin
   FTitleSize := 0;
   if not Visible then exit;
   if IsVertical then
-    CalcVertSize
+    FSize := CalcMarksSize(AExtent.a.Y, AExtent.b.Y).cx
   else
-    CalcHorSize;
+    FSize := CalcMarksSize(AExtent.a.X, AExtent.b.X).cy;
   if FSize > 0 then
     FSize += TickLength + Marks.Distance;
   CalcTitleSize;

components/tachart/taseries.pas

@@ -44,7 +44,6 @@ type
 
   TBasicPointSeries = class(TChartSeries)
   private
-    FPrevLabelRect: TRect;
     procedure SetUseReticule(AValue: Boolean);
 
   protected
@@ -679,6 +678,8 @@ end;
 { TBasicPointSeries }
 
 procedure TBasicPointSeries.DrawLabels(ACanvas: TCanvas);
+var
+  prevLabelPoly: TPointArray;
 
   procedure DrawLabel(
     const AText: String; const ADataPoint: TPoint; ADir: TLabelDirection);
@@ -686,7 +687,6 @@ procedure TBasicPointSeries.DrawLabels(ACanvas: TCanvas);
     OFFSETS: array [TLabelDirection] of TPoint =
       ((X: -1; Y: 0), (X: 0; Y: -1), (X: 1; Y: 0), (X: 0; Y: 1));
   var
-    labelRect: TRect;
     center: TPoint;
     sz: TSize;
   begin
@@ -696,15 +696,7 @@ procedure TBasicPointSeries.DrawLabels(ACanvas: TCanvas);
     center := ADataPoint;
     center.X += OFFSETS[ADir].X * (Marks.Distance + sz.cx div 2);
     center.Y += OFFSETS[ADir].Y * (Marks.Distance + sz.cy div 2);
-    with center do
+    Marks.DrawLabel(ACanvas, ADataPoint, center, AText, prevLabelPoly);
-      labelRect := BoundsSize(X - sz.cx div 2, Y - sz.cy div 2, sz);
-    if Marks.IsLabelHiddenDueToOverlap(FPrevLabelRect, labelRect) then exit;
-
-    // Link between the label and the bar.
-    ACanvas.Pen.Assign(Marks.LinkPen);
-    ACanvas.Line(ADataPoint, center);
-
-    Marks.DrawLabel(ACanvas, labelRect, AText);
   end;
 
 var
@@ -791,8 +783,6 @@ begin
       d := IfThen(dir in [ldLeft, ldRight], cx, cy);
     m[dir] := Max(m[dir], d + Marks.Distance + LABEL_TO_BORDER);
   end;
-
-  FPrevLabelRect := Rect(0, 0, 0, 0);
 end;
 
 { TBarSeries }
@@ -969,7 +959,7 @@ var
     SetLength(labelTexts, Count);
     for i := 0 to Count - 1 do begin
       labelTexts[i] := FormattedMark(i);
-      with ACanvas.TextExtent(labelTexts[i]) do begin
+      with Marks.MeasureLabel(ACanvas, labelTexts[i]) do begin
         labelWidths[i] := cx;
         labelHeights[i] := cy;
       end;
@@ -992,9 +982,10 @@ var
 var
   i, radius: Integer;
   prevAngle: Double = 0;
-  angleStep, sliceCenterAngle: Double;
+  d, angleStep, sliceCenterAngle: Double;
-  a, b, c, center: TPoint;
+  c, center: TPoint;
-  r: TRect;
+  sa, ca: Extended;
+  prevLabelPoly: TPointArray = nil;
 const
   RAD_TO_DEG16 = 360 * 16;
 begin
@@ -1023,21 +1014,14 @@ begin
 
     if not Marks.IsMarkLabelsVisible then continue;
 
-    a := LineEndPoint(c, sliceCenterAngle, radius);
+    // This is a crude approximation of label "radius", it may be improved.
-    b := LineEndPoint(c, sliceCenterAngle, radius + Marks.Distance);
+    SinCos(DegToRad(sliceCenterAngle / 16), sa, ca);
-
+    d := Max(Abs(labelWidths[i] * ca), Abs(labelHeights[i] * sa)) / 2;
-    // line from mark to pie
+    Marks.DrawLabel(
-    ACanvas.Pen.Assign(Marks.LinkPen);
+      ACanvas,
-    ACanvas.Line(a, b);
+      LineEndPoint(c, sliceCenterAngle, radius),
-
+      LineEndPoint(c, sliceCenterAngle, radius + Marks.Distance + d),
-    if b.x < center.x then
+      labelTexts[i], prevLabelPoly);
-      b.x -= labelWidths[i];
-    if b.y < center.y then
-      b.y -= labelHeights[i];
-
-    r := Bounds(b.x, b.y, labelWidths[i], labelHeights[i]);
-    InflateRect(r, MARKS_MARGIN_X, MARKS_MARGIN_Y);
-    Marks.DrawLabel(ACanvas, r, labelTexts[i]);
   end;
 end;
 

components/tachart/tatypes.pas

@@ -116,6 +116,8 @@ type
 
   generic TGenericChartMarks<_TLabelBrush, _TLinkPen, _TFramePen> =
     class(TChartElement)
+  private
+    function LabelAngle: Double; inline;
   protected
     FClipped: Boolean;
     FDistance: TChartDistance;
@@ -145,9 +147,8 @@ type
   public
     procedure Assign(Source: TPersistent); override;
     procedure DrawLabel(
-      ACanvas: TCanvas; const ALabelRect: TRect; const AText: String);
+      ACanvas: TCanvas; const ADataPoint, ALabelCenter: TPoint;
-    function IsLabelHiddenDueToOverlap(
+      const AText: String; var APrevLabelPoly: TPointArray);
-      var APrevLabelRect: TRect; const ALabelRect: TRect): Boolean;
     function IsMarkLabelsVisible: Boolean;
     function MeasureLabel(ACanvas: TCanvas; const AText: String): TSize;
 
@@ -277,7 +278,7 @@ type
 implementation
 
 uses
-  TASources;
+  Math, TASources;
 
 { TChartPen }
 
@@ -450,41 +451,56 @@ begin
 end;
 
 procedure TGenericChartMarks.DrawLabel(
-  ACanvas: TCanvas; const ALabelRect: TRect; const AText: String);
+  ACanvas: TCanvas; const ADataPoint, ALabelCenter: TPoint;
+  const AText: String; var APrevLabelPoly: TPointArray);
 var
   wasClipping: Boolean = false;
-  pt: TPoint;
+  labelPoly: TPointArray;
+  ptSize, ptText: TPoint;
+  a: Double;
+  i: Integer;
 begin
+  ACanvas.Font.Assign(LabelFont);
+  ptText := ACanvas.TextExtent(AText);
+  ptSize := ptText;
+  if IsMarginRequired then
+    ptSize += Point(MARKS_MARGIN_X, MARKS_MARGIN_Y) * 2;
+
+  SetLength(labelPoly, 4);
+  labelPoly[0] := -ptSize div 2;
+  labelPoly[2] := labelPoly[0] + ptSize;
+  labelPoly[1] := Point(labelPoly[2].X, labelPoly[0].Y);
+  labelPoly[3] := Point(labelPoly[0].X, labelPoly[2].Y);
+  a := LabelAngle;
+  for i := 0 to High(labelPoly) do
+    labelPoly[i] := RotatePoint(labelPoly[i], a) + ALabelCenter;
+
+  if
+    (OverlapPolicy = opHideNeighbour) and
+    IsPolygonIntersectsPolygon(APrevLabelPoly, labelPoly)
+  then
+    exit;
+  APrevLabelPoly := labelPoly;
+
   if not Clipped and ACanvas.Clipping then begin
     ACanvas.Clipping := false;
     wasClipping := true;
   end;
-  pt := ALabelRect.TopLeft;
+
-  ACanvas.Font.Assign(LabelFont);
+  ACanvas.Pen.Assign(LinkPen);
+  ACanvas.Line(ADataPoint, ALabelCenter);
   ACanvas.Brush.Assign(LabelBrush);
   if IsMarginRequired then begin
     ACanvas.Pen.Assign(Frame);
-    ACanvas.Rectangle(ALabelRect);
+    ACanvas.Polygon(labelPoly);
-    pt += Point(MARKS_MARGIN_X, MARKS_MARGIN_Y);
   end;
-  ACanvas.TextOut(pt.X, pt.Y, AText);
+
+  ptText := RotatePoint(-ptText div 2, a) + ALabelCenter;
+  ACanvas.TextOut(ptText.X, ptText.Y, AText);
   if wasClipping then
     ACanvas.Clipping := true;
 end;
 
-function TGenericChartMarks.IsLabelHiddenDueToOverlap(
-  var APrevLabelRect: TRect; const ALabelRect: TRect): Boolean;
-var
-  dummy: TRect = (Left: 0; Top: 0; Right: 0; Bottom: 0);
-begin
-  Result :=
-    (OverlapPolicy = opHideNeighbour) and
-    not IsRectEmpty(APrevLabelRect) and
-    IntersectRect(dummy, ALabelRect, APrevLabelRect);
-  if not Result then
-    APrevLabelRect := ALabelRect;
-end;
-
 function TGenericChartMarks.IsMarginRequired: Boolean;
 begin
   Result :=
@@ -497,15 +513,28 @@ begin
   Result := Visible and (Style <> smsNone) and (Format <> '');
 end;
 
+function TGenericChartMarks.LabelAngle: Double;
+begin
+  // Negate to take into account top-down Y axis.
+  Result := -DegToRad(LabelFont.Orientation / 10);
+end;
+
 function TGenericChartMarks.MeasureLabel(
   ACanvas: TCanvas; const AText: String): TSize;
+var
+  pt1, pt2: TPoint;
+  a: Double;
 begin
   ACanvas.Font.Assign(LabelFont);
-  Result := ACanvas.TextExtent(AText);
+  pt1 := ACanvas.TextExtent(AText) div 2;
-  if IsMarginRequired then begin
+  if IsMarginRequired then
-    Result.cx += 2 * MARKS_MARGIN_X;
+    pt1 += Point(MARKS_MARGIN_X, MARKS_MARGIN_Y);
-    Result.cy += 2 * MARKS_MARGIN_Y;
+  pt2 := Point(pt1.X, -pt1.Y);
-  end;
+  a := LabelAngle;
+  pt1 := RotatePoint(pt1, a);
+  pt2 := RotatePoint(pt2, a);
+  Result.cx := Max(Abs(pt1.X), Abs(pt2.X)) * 2;
+  Result.cy := Max(Abs(pt1.Y), Abs(pt2.Y)) * 2;
 end;
 
 procedure TGenericChartMarks.SetClipped(const AValue: Boolean);