TAChart in command line app
lazarus / 55-TAChart

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JohnnieK · 2017-02-10 10:12

Hi

I am trying to get a command line app using TAChart to run on a server
without X or GTX (linux server). I have based my app on the nogui demo
app, but when I try to run the app it complains "Gtk-WARNING **:
cannot open display". So it seems like the app is somehow trying to
still use GTK.
I then compiled the nogui demo and it gives the same error.
I can get it working using xvfb, but it is horribly slow. I have done
a lot of reading and it seems like it is supposed to work, but I just
cannot get it to work. I am using openSUSE Leap 64bit and Lazarus
1.6.2.

Any help will be appreciated.

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wp · 2017-02-10 10:31

Could you try to post a stack trace?

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JohnnieK · 2017-02-14 06:24

Hi

There is no stack trace. The only error displayed is the following
line:
(noguidemo:15232): Gtk-WARNING **: cannot open display:

The app is compiled with debug info on.

Johan

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Thaddy · 2017-02-14 07:02

Remove tachartlazaruspkg from the uses clause.
Also disable the buildintoolset!

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JohnnieK · 2017-02-14 11:24

Removing tachartlazaruspkg results in the compiler error: "Can't find
unit ComponentEditors used by TATransformations" I had to add LCL as a
requirement otherwise it did not find unit Interfaces.

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Thaddy · 2017-02-14 11:48

Try disabling the buildintoolset first. These contain all kind of
visual editors and of course they rely on a window manager/widget set.
I succeeded on arm this morning, but I remember just doing these two.
Maybe the other way around? I will check. I may have editted out more
units...

As it stands, the example code as provided always relies on a
widgetset installed. But it can be eliminated, because apart from the
editors all other code does not rely on widget sets. (So it is a
bug... but it can be done)

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JohnnieK · 2017-02-14 13:40

Can you explain by what is meant by "disabling the buildintoolset".

Thanx

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wp · 2017-02-15 16:00

My problem is that I don't have a suitable testing enviroment at hand,
so this debugging session will be some kind of blind search.

Relying on what Thaddy wrote above I modified the nogui demo as
follows (changes marked by "// wp"):
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
noguidemo; {$mode objfpc}{$H+} uses  {$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads, {$ENDIF}{$ENDIF}  Interfaces, Classes, //tachartlazaruspkg {
you can add units after this },                          // wp: REMOVE
tachartlazaruspkg  FPCanvas, FPImage, FPImgCanv,  TAGraph, TASeries,
TADrawerFPCanvas in '../../TADrawerFPCanvas.pas', TADrawerCanvas,
TADrawUtils; var  chart: TChart;  bs: TBarSeries;  img:
TFPMemoryImage;  c: TFPImageCanvas;  d: IChartDrawer; // wp: ADD THIS
FUNCTIONfunction MyInitBuiltinTools(AChart: TChart):
TBasicChartToolset;begin  Result := nil;end; begin  OnInitBuiltinTools
:= @MyInitBuiltinTools;   // wp: ADD THIS LINE TO DEACTIVATE
CHARTTOOLS   chart := TChart.Create(nil); 
chart.LeftAxis.Marks.LabelFont.Name := 'Arial'; 
chart.LeftAxis.Marks.LabelFont.Size := 10; 
chart.LeftAxis.Marks.LabelFont.Orientation := 450; 
chart.LeftAxis.Marks.Frame.Visible := true; 
chart.LeftAxis.Marks.Frame.Style := psSolid; 
chart.LeftAxis.Marks.Frame.FPColor := colBlack; 
chart.LeftAxis.Grid.FPColor := colDkGray; 
chart.BottomAxis.Marks.Visible := false; 
chart.BottomAxis.Grid.FPColor := colDkGray;  chart.Color := $FFA0A0; 
chart.BackColor := $FFFFFF;  bs := TBarSeries.Create(nil); 
chart.AddSeries(bs);  bs.AddXY(1, 10);  bs.AddXY(2, 7);  bs.AddXY(3,; 
img := TFPMemoryImage.Create(chart.Width, chart.Height);  c :=
TFPImageCanvas.Create(img);  d := TFPCanvasDrawer.Create(c); 
d.DoGetFontOrientation := @CanvasGetFontOrientationFunc; 
chart.Draw(d, Rect(0, 0, chart.Width, chart.Height)); 
img.SaveToFile('test.png');  c.Free;  img.Free;  bs.Free; 
chart.Free;end.
This code removes the initialization of the built-in chart toolset by
overriding the OnInitBuiltinTools function pointer - this function is
called when the chart is created. Unfortunately TChart assumes that
the built-in toolset does exist and crashes, if it does not. So, you
must patch also the sources of TAChart:
Navigate to the folder components/tachart of your Lazarus
installation. Find the file TAGraph.pas Make a backup copy of it Open
TAGraph.pas in Lazarus Find the implementation of the procedure
TChart.DrawIn the var part, immediately below the procedure header,
declare a variable toolsCode: Pascal  [Select][+][-]window.onload =
function(){var x1 = document.getElementById("main_content_section");
if (x1) { var x = document.getElementsByClassName("geshi");for (var i
= 0; i procedure TChart.Draw((ADrawer: IChartDrawer; const ARect:
TRect);var  tools: TBasicChartToolset;   // wp: NEW   ldd:
TChartLegendDrawingData;  s: TBasicChartSeries;Scroll down a bit and
find the line "GetToolset.Draw(self, ADrawer)".Replace it by the
linesCode: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   tools :=
GetToolset;  if Assigned(tools) then tools.Draw(self, ADrawer); Save
and recompile the package TAChartLazarusPck.Please report back if this
fixes your isses, and I'll modify the TAChart repository in the same
way as you did.

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JohnnieK · 2017-02-16 06:52

Hi wp

Thanx for helping out. I did the changes you suggested, but I still
get the GTK error. I have pasted the relevant pieces of code:

noguidemo

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
noguidemo; {$mode objfpc}{$H+} uses  {$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads, {$ENDIF}{$ENDIF}  Interfaces, Classes,  FPCanvas, FPImage,
FPImgCanv,  TAGraph, TASeries, TADrawerFPCanvas in
'../../TADrawerFPCanvas.pas', TADrawerCanvas, TADrawUtils;     var 
chart: TChart;  bs: TBarSeries;  img: TFPMemoryImage;  c:
TFPImageCanvas;  d: IChartDrawer;   // wp: ADD THIS FUNCTION  function
MyInitBuiltinTools(AChart: TChart): TBasicChartToolset;  begin   
Result := nil;  end;  begin  OnInitBuiltinTools :=
@MyInitBuiltinTools;   chart := TChart.Create(nil); 
chart.LeftAxis.Marks.LabelFont.Name := 'Arial'; 
chart.LeftAxis.Marks.LabelFont.Size := 10; 
chart.LeftAxis.Marks.LabelFont.Orientation := 450; 
chart.LeftAxis.Marks.Frame.Visible := true; 
chart.LeftAxis.Marks.Frame.Style := psSolid; 
chart.LeftAxis.Marks.Frame.FPColor := colBlack; 
chart.LeftAxis.Grid.FPColor := colDkGray; 
chart.BottomAxis.Marks.Visible := false; 
chart.BottomAxis.Grid.FPColor := colDkGray;  chart.Color := $FFA0A0; 
chart.BackColor := $FFFFFF;  bs := TBarSeries.Create(nil); 
chart.AddSeries(bs);  bs.AddXY(1, 10);  bs.AddXY(2, 7);  bs.AddXY(3,
8);  img := TFPMemoryImage.Create(chart.Width, chart.Height);  c :=
TFPImageCanvas.Create(img);  d := TFPCanvasDrawer.Create(c); 
d.DoGetFontOrientation := @CanvasGetFontOrientationFunc; 
chart.Draw(d, Rect(0, 0, chart.Width, chart.Height)); 
img.SaveToFile('test.png');  c.Free;  img.Free;  bs.Free; 
chart.Free;end. 
TAGraph

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TChart.Draw(ADrawer: IChartDrawer; const ARect: TRect);var  tools:
TBasicChartToolset;  ldd: TChartLegendDrawingData;  s:
TBasicChartSeries;begin  Prepare;   ADrawer.SetRightToLeft(BiDiMode <>
bdLeftToRight);   FClipRect := ARect;  with MarginsExternal do begin 
 FClipRect.Left += Left;    FClipRect.Top += Top;    FClipRect.Right
-= Right;    FClipRect.Bottom -= Bottom;  end;   with ClipRect do
begin    FTitle.Measure(ADrawer, 1, Left, Right, Top);   
FFoot.Measure(ADrawer, -1, Left, Right, Bottom);  end;   ldd.FItems :=
nil;  if Legend.Visible then    ldd := PrepareLegend(ADrawer,
FClipRect);   try    PrepareAxis(ADrawer);    if Legend.Visible and
not Legend.UseSidebar then      Legend.Prepare(ldd, FClipRect);    if
(FPrevLogicalExtent <> FLogicalExtent) and Assigned(OnExtentChanging)
then      OnExtentChanging(Self);    ADrawer.DrawingBegin(ARect);   
ADrawer.SetAntialiasingMode(AntialiasingMode);    Clear(ADrawer,
ARect);    FTitle.Draw(ADrawer);    FFoot.Draw(ADrawer);   
DrawBackWall(ADrawer);    DisplaySeries(ADrawer);    if Legend.Visible
then begin      if Assigned(FOnDrawLegend) then       
FOnDrawlegend(Self, ldd.FDrawer, ldd.FItems, ldd.FItemSize,
ldd.FBounds,          ldd.FColCount, ldd.FRowCount)      else       
Legend.Draw(ldd);    end;  finally    ldd.FItems.Free;  end; 
DrawReticule(ADrawer);  //GetToolset.Draw(Self, ADrawer);  tools :=
getToolSet;  if Assigned(tools) then tools.Draw(self, ADrawer);   for
s in Series do    s.AfterDraw;   if Assigned(OnAfterDraw) then   
OnAfterDraw(Self, ADrawer);  ADrawer.DrawingEnd;   if
FPrevLogicalExtent <> FLogicalExtent then begin   
FExtentBroadcaster.Broadcast(Self);    if Assigned(OnExtentChanged)
then      OnExtentChanged(Self);    FPrevLogicalExtent :=
FLogicalExtent;  end;   // Undo changes made by the drawer (mainly for
printing). The user may print  // something else after the chart and,
for example, would not expect the font  // to be rotated (Fix for
issue #0027163) or the pen to be in xor mode.  ADrawer.ResetFont; 
ADrawer.SetXor(false);  ADrawer.PrepareSimplePen(clBlack);     //
resets canvas pen mode to pmCopy  ADrawer.SetPenParams(psSolid,
clDefault);  ADrawer.SetBrushParams(bsSolid, clWhite); 
ADrawer.SetAntialiasingMode(amDontCare);end;   
Johan

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wp · 2017-02-16 08:36

Thanks. Your code looks correct.

So, we must do another approach. Please make a backup copy the
original TAGraph.pas. Then, in the TChart.Draw method add a
"writeln()" after every code line, something like this:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TChart.Draw(ADrawer: IChartDrawer; const ARect: TRect);var  tools:
TBasicChartToolset;  ldd: TChartLegendDrawingData;  s:
TBasicChartSeries;begin  WriteLn('ENTER Draw');  Prepare; 
WriteLn('After Prepare');   ADrawer.SetRightToLeft(BiDiMode <>
bdLeftToRight);   FClipRect := ARect;  with MarginsExternal do begin 
 FClipRect.Left += Left;    FClipRect.Top += Top;    FClipRect.Right
-= Right;    FClipRect.Bottom -= Bottom;  end;   with ClipRect do
begin    FTitle.Measure(ADrawer, 1, Left, Right, Top);   
WriteLn('After FTitle.Measure');    FFoot.Measure(ADrawer, -1, Left,
Right, Bottom);    WriteLn('After FFoot.Measure');  end;   ldd.FItems
:= nil;  if Legend.Visible then    ldd := PrepareLegend(ADrawer,
FClipRect);  WriteLn('After PrepareLegend');   try   
PrepareAxis(ADrawer);    WriteLn('After PrepareAxis');    if
Legend.Visible and not Legend.UseSidebar then      Legend.Prepare(ldd,
FClipRect);      WriteLn('After Legend.Prepare');    if
(FPrevLogicalExtent <> FLogicalExtent) and Assigned(OnExtentChanging)
then      OnExtentChanging(Self);    WriteLn('After
OnExtentChanging');    ADrawer.DrawingBegin(ARect);    WriteLn('After
DrawingBegin');    ADrawer.SetAntialiasingMode(AntialiasingMode);   
WriteLn('After SetAntialiasingMode');    Clear(ADrawer, ARect);   
WriteLn('After Clear');    FTitle.Draw(ADrawer);    WriteLn('After
FTitle.Draw');    FFoot.Draw(ADrawer);    WriteLn('After
FFoot.Draw');    DrawBackWall(ADrawer);    WriteLn('After
DrawBackwall'):    DisplaySeries(ADrawer);    WriteLn('After
DisplaySeries');   // ... etc
Then recompile the package TAChartLazarusPkg and compile & run the
demo again. Does the first WriteLn message appear at all? If not the
bug is outside the Draw method. If some WriteLn text does appear then
report the last message, the next statement will be the faulty one.

After the test, restore the backup copy of TAGraph.pas and rebuild the
package again.

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JohnnieK · 2017-02-16 11:02

Hi WP

I managed to get it working. In the project options under "Config and
target" I had to change the Widgetset from GTK2 to nogui. That and the
changes you gave me seemed to have done the trick. Thanx for all the
help.

Johan

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wp · 2017-02-16 11:16

Thank you, that's the best solution. In r54167, I modified the nogui
demo such that the nogui widgetset is active by default.