<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">Hi Andrew, Hi Mathieu,<br>
<br>
That's exactly the behaviour I see. By the way I am using ATI/AMD
video cards in my Windows/Linux machine.<br>
<br>
!!!! UPDATE: The error also occurs when logarithmic x axis is not
enabled. But you have to zoom in a lot more. See attached
pictures. I am sorry for not realizing this earlier.<br>
<br>
<br>
I am not that familiar with OpenGL. But I can imagine two things:
<br>
<br>
(1) Line is clipped <br>
(2) If shaders are used to draw the line thickness it might be a
floating point precision problem. Actually this could be the
problem because the line thickness starts fluctuating at some
point of zoom level before it finally disappears. See attached
picture. The line thickness is about the half the original line
thickness.<br>
<br>
<br>
I hope this helps to fix the bug. One might also contact Marcus D.
Hanwell. He is the developer who mainly implemented vtkCharts. I
am not sure if he is still responsible.<br>
<br>
Hagen<br>
<br>
<br>
On 26.07.2016 01:52, Andrew Maclean wrote:<br>
</div>
<blockquote
cite="mid:CAHDsG9NcGLTK247FmRvXLvx6MmsuwFPOagetO88frkOTQPt=Ug@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<div>Hi Hagen,</div>
<div> I just tested your example and I get similar
behaviou using an NVIDIA Video card, OpenGL2, VS2015 and
the VTK Master.</div>
<div> </div>
<div>I can zoom in and, at some point the line disappears,
but zooming out immediately restores the line.</div>
<div><br>
</div>
<div>It seeme to me that once a certain zoom level is
reached the line is not drawn, however zooming out
restores it.</div>
<div><br>
</div>
<div>Attached are two pngs showing the effect.When the line
disappears it should still be visible as the scales on the
axes have only changed slightly.</div>
<div><br>
</div>
<div>Andrew</div>
<div><br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">----------
Forwarded message ----------<br>
From: "Hagen Mölle" <<a moz-do-not-send="true"
href="mailto:h.moelle@googlemail.com">h.moelle@googlemail.com</a>><br>
To: <a moz-do-not-send="true"
href="mailto:vtk-developers@vtk.org">vtk-developers@vtk.org</a><br>
Cc: <br>
Date: Mon, 25 Jul 2016 10:14:21 +0200<br>
Subject: [vtk-developers] vtkChartXY lines not visible
when using logarithmic x axis<br>
Hi,<br>
<br>
Due to spam reasons the bug tracker's user login is
disabled right now. One should send bug reports to the
vtk's user mailing list, which I did twice. My bug report
was totally ignored. That's why I send it here again.
Hopefully someone can finally create a ticket in the bug
tracker. Thanks.<br>
<br>
I want to report a bug for vtkChartXY. So I already send
this Email two days ago to the vtkUsers mailing list
without receiving any answer. The bug is not visible in
the vtk bug tracker too. Thus I send the Email again.<br>
<br>
Bug environment:<br>
a) I am using VTK 6.2. I checked my test code on machines
running Windows 7 (Visual Studio 2012/2015) and Ubuntu
15.10/Ubuntu 16.04 (gcc). On all these systems the bug is
visible.<br>
b) I can also reproduce the bug in VTK 7.0 (here I used an
Ubuntu 16.04 machine and compiled VTK 7.0 using OpenGL2
interface).<br>
<br>
Bug description:<br>
<br>
I am using vtkChartXY to display one line. I also enabled
logarithmic x axis
(chartXY->GetAxis(vtkAxis::BOTTOM)->SetLogScale(true);).
Nothing more special. In the compiled application I start
zooming into the chart using the mouse wheel, making sure
I always have a line displayed in the view. At some zoom
level this line just disappears. At the zoom level the
line disappears I did the following:<br>
<br>
1. Zooming more into the chart the line will not appear
again.<br>
2. Zooming out twice (with mouse wheel) the line will
reappear.<br>
<br>
How to reproduce the bug:<br>
<br>
I basically used the LinePlot example for vtkChartXY (see
<a moz-do-not-send="true"
href="http://www.vtk.org/Wiki/VTK/Examples/Cxx/Plotting/LinePlot"
rel="noreferrer" target="_blank">http://www.vtk.org/Wiki/VTK/Examples/Cxx/Plotting/LinePlot</a>).<br>
<br>
I added one line to the example code marked with *** (line
was added after line 54 in example code).<br>
I added the full code to the end of the Email.<br>
---------------<br>
<br>
// Add multiple line plots, setting the colors etc<br>
vtkSmartPointer<vtkChartXY > chart=
vtkSmartPointer<vtkChartXY >::New(); ***
chart.Get()->GetAxis(vtkAxis::BOTTOM)->SetLogScale(true);
view->GetScene()->AddItem(chart);<br>
<br>
---------------<br>
<br>
Compile and execute the program. See my bug description
above to visualize the bug.<br>
<br>
<br>
Please contact me if you need more information. I can also
provide images of the bug if needed.<br>
I hope the bug can be fixed.<br>
<br>
Hagen.<br>
<br>
<br>
<br>
<br>
#include <vtkVersion.h><br>
#include <vtkRenderer.h><br>
#include <vtkRenderWindowInteractor.h><br>
#include <vtkRenderWindow.h><br>
#include <vtkSmartPointer.h><br>
#include <vtkChartXY.h><br>
#include <vtkAxis.h><br>
#include <vtkTable.h><br>
#include <vtkPlot.h><br>
#include <vtkFloatArray.h><br>
#include <vtkContextView.h><br>
#include <vtkContextScene.h><br>
#include <vtkPen.h><br>
<br>
int main(int, char *[])<br>
{<br>
// Create a table with some points in it<br>
vtkSmartPointer<vtkTable> table =<br>
vtkSmartPointer<vtkTable>::New();<br>
<br>
vtkSmartPointer<vtkFloatArray> arrX =<br>
vtkSmartPointer<vtkFloatArray>::New();<br>
arrX->SetName("X Axis");<br>
table->AddColumn(arrX);<br>
<br>
vtkSmartPointer<vtkFloatArray> arrC =<br>
vtkSmartPointer<vtkFloatArray>::New();<br>
arrC->SetName("Cosine");<br>
table->AddColumn(arrC);<br>
<br>
vtkSmartPointer<vtkFloatArray> arrS =<br>
vtkSmartPointer<vtkFloatArray>::New();<br>
arrS->SetName("Sine");<br>
table->AddColumn(arrS);<br>
<br>
// Fill in the table with some example values<br>
int numPoints = 69;<br>
float inc = 7.5 / (numPoints-1);<br>
table->SetNumberOfRows(numPoints);<br>
for (int i = 0; i < numPoints; ++i)<br>
{<br>
table->SetValue(i, 0, i * inc);<br>
table->SetValue(i, 1, cos(i * inc));<br>
table->SetValue(i, 2, sin(i * inc));<br>
}<br>
<br>
// Set up the view<br>
vtkSmartPointer<vtkContextView> view =<br>
vtkSmartPointer<vtkContextView>::New();<br>
view->GetRenderer()->SetBackground(1.0, 1.0,
1.0);<br>
<br>
// Add multiple line plots, setting the colors etc<br>
vtkSmartPointer<vtkChartXY> chart =<br>
vtkSmartPointer<vtkChartXY>::New();<br>
chart.Get()->GetAxis(vtkAxis::BOTTOM)->SetLogScale(true);<br>
view->GetScene()->AddItem(chart);<br>
vtkPlot *line = chart->AddPlot(vtkChart::LINE);<br>
#if VTK_MAJOR_VERSION <= 5<br>
line->SetInput(table, 0, 1);<br>
#else<br>
line->SetInputData(table, 0, 1);<br>
#endif<br>
line->SetColor(0, 255, 0, 255);<br>
line->SetWidth(1.0);<br>
line = chart->AddPlot(vtkChart::LINE);<br>
#if VTK_MAJOR_VERSION <= 5<br>
line->SetInput(table, 0, 2);<br>
#else<br>
line->SetInputData(table, 0, 2);<br>
#endif<br>
line->SetColor(255, 0, 0, 255);<br>
line->SetWidth(5.0);<br>
<br>
// For dotted line, the line type can be from 2 to 5
for different dash/dot<br>
// patterns (see enum in vtkPen containing DASH_LINE,
value 2):<br>
#ifndef WIN32<br>
line->GetPen()->SetLineType(vtkPen::DASH_LINE);<br>
#endif<br>
// (ifdef-ed out on Windows because DASH_LINE does not
work on Windows<br>
// machines with built-in Intel HD graphics card...)<br>
<br>
//view->GetRenderWindow()->SetMultiSamples(0);<br>
<br>
// Start interactor<br>
view->GetInteractor()->Initialize();<br>
view->GetInteractor()->Start();<br>
<br>
return EXIT_SUCCESS;<br>
}<br>
<br>
<br>
_______________________________________________<br>
Powered by <a moz-do-not-send="true"
href="http://www.kitware.com" rel="noreferrer"
target="_blank">www.kitware.com</a><br>
<br>
Visit other Kitware open-source projects at <a
moz-do-not-send="true"
href="http://www.kitware.com/opensource/opensource.html"
rel="noreferrer" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br>
<br>
Search the list archives at: <a moz-do-not-send="true"
href="http://markmail.org/search/?q=vtk-developers"
rel="noreferrer" target="_blank">http://markmail.org/search/?q=vtk-developers</a><br>
<br>
Follow this link to subscribe/unsubscribe:<br>
<a moz-do-not-send="true"
href="http://public.kitware.com/mailman/listinfo/vtk-developers"
rel="noreferrer" target="_blank">http://public.kitware.com/mailman/listinfo/vtk-developers</a><br>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
<div class="gmail_signature">___________________________________________<br>
Andrew J. P. Maclean<br>
<br>
___________________________________________</div>
</div>
</div>
</blockquote>
<p><br>
</p>
</body>
</html>