From 2ff24ec235c729444df0f5963ee9fe7a00a84658 Mon Sep 17 00:00:00 2001
From: wp <wp.no-reply@lazarus-ide-org>
Date: Thu, 14 Feb 2019 11:07:44 +0000
Subject: [PATCH] TAChart: Avoid multiple painting of series labels and error
 bars in case of multi-y-valued line series. Issue #35077.

git-svn-id: trunk@60420 -
---
 components/tachart/fpdoc/tacustomseries.xml |  6 ++----
 components/tachart/fpdoc/tagraph.xml        |  5 +----
 components/tachart/tacustomseries.pas       | 13 +++++++++++--
 components/tachart/taseries.pas             |  5 +++--
 4 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/components/tachart/fpdoc/tacustomseries.xml b/components/tachart/fpdoc/tacustomseries.xml
index 4abe819736..2509a7a142 100644
--- a/components/tachart/fpdoc/tacustomseries.xml
+++ b/components/tachart/fpdoc/tacustomseries.xml
@@ -62,8 +62,7 @@
       </element>
       <element name="TChartSeries.OnGetMark">
         <short>Called before the drawing of each mark.</short>
-        <seealso>
-          <link id="TChartSeries.Marks">Marks</link>
+        <seealso><link id="TChartSeries.Marks">Marks</link>
         </seealso>
       </element>
       <element name="TChartSeries">
@@ -87,8 +86,7 @@ from a <link id="TACustomSource.TCustomChartSource"><var>chart source</var>
       </element>
       <element name="TChartSeries.Extent">
         <short>Return the bounding rectangle for all points in the serie.</short>
-        <seealso>
-          <link id="TASources.TCustomChartSource.Extent">TCustomChartSource.Extent</link>
+        <seealso><link id="TASources.TCustomChartSource.Extent">TCustomChartSource.Extent</link>
         </seealso>
       </element>
       <element name="TChartSeries.FormattedMark">
diff --git a/components/tachart/fpdoc/tagraph.xml b/components/tachart/fpdoc/tagraph.xml
index 5003854972..6a04d32017 100644
--- a/components/tachart/fpdoc/tagraph.xml
+++ b/components/tachart/fpdoc/tagraph.xml
@@ -240,10 +240,7 @@ For example, <link id="TASeries.TPieSeries">pie series</link> displays a separat
       </element>
       <element name="TChart.GraphToImage">
         <short>Converts a point from graph coordinates to image coordinates.</short>
-        <seealso>          
-          <link id="TChart.ImageToGraph"/>
-          <link id="TChart.XGraphToImage"/>
-          <link id="TChart.YGraphToImage"/>
+        <seealso><link id="TChart.ImageToGraph"/><link id="TChart.XGraphToImage"/><link id="TChart.YGraphToImage"/>
         </seealso>
       </element>
       <element name="TChart.ImageToGraph">
diff --git a/components/tachart/tacustomseries.pas b/components/tachart/tacustomseries.pas
index 84c7f6e95b..c179e154d8 100644
--- a/components/tachart/tacustomseries.pas
+++ b/components/tachart/tacustomseries.pas
@@ -290,7 +290,7 @@ type
     procedure AfterDrawPointer(
       ADrawer: IChartDrawer; AIndex: Integer; const APos: TPoint); virtual;
     procedure DrawErrorBars(ADrawer: IChartDrawer);
-    procedure DrawLabels(ADrawer: IChartDrawer);
+    procedure DrawLabels(ADrawer: IChartDrawer; AYIndex: Integer = -1);
     procedure DrawPointers(ADrawer: IChartDrawer; AStyleIndex: Integer = 0;
       UseDataColors: Boolean = false);
     procedure FindExtentInterval(
@@ -1243,7 +1243,8 @@ begin
   end;
 end;
 
-procedure TBasicPointSeries.DrawLabels(ADrawer: IChartDrawer);
+procedure TBasicPointSeries.DrawLabels(ADrawer: IChartDrawer; AYIndex: Integer = -1);
+// Using AYIndex is workaround for issue #35077
 var
   prevLabelPoly: TPointArray;
 
@@ -1320,6 +1321,14 @@ begin
         if Stacked then
           prev := curr;
 
+        // Draw only the requested y index
+        if (AYIndex >= 0) then begin
+          if si < AYIndex then
+            Continue
+          else if si > AYIndex then
+            exit;
+        end;
+
         with ParentChart do
           if
             ((Marks.YIndex = MARKS_YINDEX_ALL) or (Marks.YIndex = si)) and
diff --git a/components/tachart/taseries.pas b/components/tachart/taseries.pas
index 374d1e38a6..14daccccc1 100644
--- a/components/tachart/taseries.pas
+++ b/components/tachart/taseries.pas
@@ -667,8 +667,9 @@ begin
     else
       DrawColoredLines;
   end;
-  DrawErrorBars(ADrawer);
-  DrawLabels(ADrawer);
+  if AIndex = 0 then
+    DrawErrorBars(ADrawer);
+  DrawLabels(ADrawer, AIndex);
   if ShowPoints then
     DrawPointers(ADrawer, AIndex, FColorEach in [cePoint, cePointAndLineBefore, cePointAndLineAfter]);
 end;