[vtk-developers] vtkChartXY lines not visible when using logarithmic x axis
Marcus D. Hanwell
marcus.hanwell at kitware.com
Wed Jul 27 11:47:06 EDT 2016
I can take a look when I return, I am currently out on travel and have
limited connectivity.
On Tue, Jul 26, 2016 at 5:56 AM, Mathieu Westphal
<mathieu.westphal at kitware.com> wrote:
> Hello
>
> I indeed reproduce the problem, I will submit a bug report and ping Marcus
> to see if he knows what is going on.
> http://www.paraview.org/Bug/view.php?id=16797
>
> Regards,
>
> Mathieu Westphal
>
> On Tue, Jul 26, 2016 at 11:19 AM, Hagen Mölle <h.moelle at googlemail.com>
> wrote:
>>
>> Hi Andrew, Hi Mathieu,
>>
>> I can not see the line after it disappears. This might be a special
>> feature of the open source radeon graphics driver under Linux.
>>
>> Just for completeness one can easily see the line thickness fluctuation by
>> zooming into the scene just right before the line disappears. At this zoom
>> level just drag the scene using the left mouse button and move the mouse
>> around.
>>
>> In fact it would be very nice if this bug could be fixed at least when
>> logarithmic x axis is enabled. Because when logarithmic x axis is enabled
>> the error is visible after zooming in only a few steps.
>>
>> Hagen
>>
>>
>> On 26.07.2016 10:57, Andrew Maclean wrote:
>>
>> Hi Hagen, Mathieu,
>>
>> I agree with you, if I zoom in when the logarithmic axis is disabled, the
>> thick line vanishes, however if you look carefully there is a very faint
>> thin line. It may be (2) as you outline below.
>>
>> Regards
>> Andrew
>>
>> Andrew Maclean
>>
>>
>> On 26 Jul 2016 5:02 pm, "Hagen Mölle" <h.moelle at googlemail.com> wrote:
>>>
>>> Hi Andrew, Hi Mathieu,
>>>
>>> That's exactly the behaviour I see. By the way I am using ATI/AMD video
>>> cards in my Windows/Linux machine.
>>>
>>> !!!! 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.
>>>
>>>
>>> I am not that familiar with OpenGL. But I can imagine two things:
>>>
>>> (1) Line is clipped
>>> (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.
>>>
>>>
>>> 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.
>>>
>>> Hagen
>>>
>>>
>>> On 26.07.2016 01:52, Andrew Maclean wrote:
>>>
>>> Hi Hagen,
>>> I just tested your example and I get similar behaviou using an NVIDIA
>>> Video card, OpenGL2, VS2015 and the VTK Master.
>>>
>>> I can zoom in and, at some point the line disappears, but zooming out
>>> immediately restores the line.
>>>
>>> It seeme to me that once a certain zoom level is reached the line is not
>>> drawn, however zooming out restores it.
>>>
>>> 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.
>>>
>>> Andrew
>>>
>>>> ---------- Forwarded message ----------
>>>> From: "Hagen Mölle" <h.moelle at googlemail.com>
>>>> To: vtk-developers at vtk.org
>>>> Cc:
>>>> Date: Mon, 25 Jul 2016 10:14:21 +0200
>>>> Subject: [vtk-developers] vtkChartXY lines not visible when using
>>>> logarithmic x axis
>>>> Hi,
>>>>
>>>> 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.
>>>>
>>>> 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.
>>>>
>>>> Bug environment:
>>>> 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.
>>>> 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).
>>>>
>>>> Bug description:
>>>>
>>>> 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:
>>>>
>>>> 1. Zooming more into the chart the line will not appear again.
>>>> 2. Zooming out twice (with mouse wheel) the line will reappear.
>>>>
>>>> How to reproduce the bug:
>>>>
>>>> I basically used the LinePlot example for vtkChartXY (see
>>>> http://www.vtk.org/Wiki/VTK/Examples/Cxx/Plotting/LinePlot).
>>>>
>>>> I added one line to the example code marked with *** (line was added
>>>> after line 54 in example code).
>>>> I added the full code to the end of the Email.
>>>> ---------------
>>>>
>>>> // Add multiple line plots, setting the colors etc
>>>> vtkSmartPointer<vtkChartXY > chart= vtkSmartPointer<vtkChartXY
>>>> >::New(); *** chart.Get()->GetAxis(vtkAxis::BOTTOM)->SetLogScale(true);
>>>> view->GetScene()->AddItem(chart);
>>>>
>>>> ---------------
>>>>
>>>> Compile and execute the program. See my bug description above to
>>>> visualize the bug.
>>>>
>>>>
>>>> Please contact me if you need more information. I can also provide
>>>> images of the bug if needed.
>>>> I hope the bug can be fixed.
>>>>
>>>> Hagen.
>>>>
>>>>
>>>>
>>>>
>>>> #include <vtkVersion.h>
>>>> #include <vtkRenderer.h>
>>>> #include <vtkRenderWindowInteractor.h>
>>>> #include <vtkRenderWindow.h>
>>>> #include <vtkSmartPointer.h>
>>>> #include <vtkChartXY.h>
>>>> #include <vtkAxis.h>
>>>> #include <vtkTable.h>
>>>> #include <vtkPlot.h>
>>>> #include <vtkFloatArray.h>
>>>> #include <vtkContextView.h>
>>>> #include <vtkContextScene.h>
>>>> #include <vtkPen.h>
>>>>
>>>> int main(int, char *[])
>>>> {
>>>> // Create a table with some points in it
>>>> vtkSmartPointer<vtkTable> table =
>>>> vtkSmartPointer<vtkTable>::New();
>>>>
>>>> vtkSmartPointer<vtkFloatArray> arrX =
>>>> vtkSmartPointer<vtkFloatArray>::New();
>>>> arrX->SetName("X Axis");
>>>> table->AddColumn(arrX);
>>>>
>>>> vtkSmartPointer<vtkFloatArray> arrC =
>>>> vtkSmartPointer<vtkFloatArray>::New();
>>>> arrC->SetName("Cosine");
>>>> table->AddColumn(arrC);
>>>>
>>>> vtkSmartPointer<vtkFloatArray> arrS =
>>>> vtkSmartPointer<vtkFloatArray>::New();
>>>> arrS->SetName("Sine");
>>>> table->AddColumn(arrS);
>>>>
>>>> // Fill in the table with some example values
>>>> int numPoints = 69;
>>>> float inc = 7.5 / (numPoints-1);
>>>> table->SetNumberOfRows(numPoints);
>>>> for (int i = 0; i < numPoints; ++i)
>>>> {
>>>> table->SetValue(i, 0, i * inc);
>>>> table->SetValue(i, 1, cos(i * inc));
>>>> table->SetValue(i, 2, sin(i * inc));
>>>> }
>>>>
>>>> // Set up the view
>>>> vtkSmartPointer<vtkContextView> view =
>>>> vtkSmartPointer<vtkContextView>::New();
>>>> view->GetRenderer()->SetBackground(1.0, 1.0, 1.0);
>>>>
>>>> // Add multiple line plots, setting the colors etc
>>>> vtkSmartPointer<vtkChartXY> chart =
>>>> vtkSmartPointer<vtkChartXY>::New();
>>>> chart.Get()->GetAxis(vtkAxis::BOTTOM)->SetLogScale(true);
>>>> view->GetScene()->AddItem(chart);
>>>> vtkPlot *line = chart->AddPlot(vtkChart::LINE);
>>>> #if VTK_MAJOR_VERSION <= 5
>>>> line->SetInput(table, 0, 1);
>>>> #else
>>>> line->SetInputData(table, 0, 1);
>>>> #endif
>>>> line->SetColor(0, 255, 0, 255);
>>>> line->SetWidth(1.0);
>>>> line = chart->AddPlot(vtkChart::LINE);
>>>> #if VTK_MAJOR_VERSION <= 5
>>>> line->SetInput(table, 0, 2);
>>>> #else
>>>> line->SetInputData(table, 0, 2);
>>>> #endif
>>>> line->SetColor(255, 0, 0, 255);
>>>> line->SetWidth(5.0);
>>>>
>>>> // For dotted line, the line type can be from 2 to 5 for different
>>>> dash/dot
>>>> // patterns (see enum in vtkPen containing DASH_LINE, value 2):
>>>> #ifndef WIN32
>>>> line->GetPen()->SetLineType(vtkPen::DASH_LINE);
>>>> #endif
>>>> // (ifdef-ed out on Windows because DASH_LINE does not work on
>>>> Windows
>>>> // machines with built-in Intel HD graphics card...)
>>>>
>>>> //view->GetRenderWindow()->SetMultiSamples(0);
>>>>
>>>> // Start interactor
>>>> view->GetInteractor()->Initialize();
>>>> view->GetInteractor()->Start();
>>>>
>>>> return EXIT_SUCCESS;
>>>> }
>>>>
>>>>
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>>>
>>>
>>>
>>>
>>> --
>>> ___________________________________________
>>> Andrew J. P. Maclean
>>>
>>> ___________________________________________
>>>
>>>
>>
>
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