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Thread: Problem with qwtplot update/ destruction

  1. #1
    Join Date
    Sep 2014
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    Qt products
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    Platforms
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    Default Problem with qwtplot update/ destruction

    Dear,

    I am using a qwt plot and I want to update/or delete on a button click... problem is that i cannot delete the axis scales and when I create new it gets overwrite as shown in pic below.

    Untitled.jpg

    Qt Code:
    1. #include "subwindow_uwi.h"
    2. #include "ui_subwindow_uwi.h"
    3. #include <qwt_scale_draw.h>
    4. #include "dmg_eva.h"
    5. #include <QMessageBox>
    6. #include "plot_frm.h"
    7.  
    8.  
    9. class MyScaleDraw1: public QwtScaleDraw
    10. {
    11. public:
    12. MyScaleDraw1()
    13. {
    14. setTickLength( QwtScaleDiv::MajorTick, 10 );
    15. setTickLength( QwtScaleDiv::MinorTick, 2 );
    16. setTickLength( QwtScaleDiv::MediumTick, 0 );
    17.  
    18. setLabelRotation( 0 );
    19. setLabelAlignment( Qt::AlignLeft | Qt::AlignVCenter );
    20. setSpacing( 10 );
    21. }
    22.  
    23. virtual QwtText label( double value ) const
    24. {
    25. QwtText h=QwtText(QString::number((value*info_Inspection.scanInterval.toFloat())-(info_Inspection.Width.toInt()/2)));
    26. return h;
    27. }
    28. };
    29.  
    30. class MyScaleDraw2: public QwtScaleDraw
    31. {
    32. public:
    33. MyScaleDraw2()
    34. {
    35. setTickLength( QwtScaleDiv::MajorTick, 2 );
    36. setTickLength( QwtScaleDiv::MinorTick, 0 );
    37. setTickLength( QwtScaleDiv::MediumTick, 0 );
    38. setLabelRotation( 0 );
    39. setLabelAlignment( Qt::AlignLeft | Qt::AlignVCenter );
    40. setSpacing( 10 );
    41. }
    42.  
    43. virtual QwtText label( double value ) const
    44. {
    45. QwtText h=QwtText(QString::number((value*25/(info_FPGA.s_points/2))-12.5,'f',1));
    46. return h;
    47. }
    48. };
    49.  
    50. subwindow_uwi::subwindow_uwi(QWidget *parent) :
    51. QDialog(parent),
    52. ui(new Ui::subwindow_uwi)
    53. {
    54. ui->setupUi(this);
    55. }
    56.  
    57. subwindow_uwi::~subwindow_uwi()
    58. {
    59. delete ui;
    60. }
    61.  
    62. void subwindow_uwi::setframe()
    63. {
    64. d_plot_WavenumberSpectrum = new plot_frm( ui->WavenumberSpectrum );
    65. d_plot_WavenumberSpectrum->setGeometry(20,20,400,320);
    66. d_plot_WavenumberSpectrum->updateGeometry();
    67. d_plot_WavenumberSpectrum->updateAxes();
    68. d_plot_WavenumberSpectrum->setcolorbarmax(9);
    69. d_plot_WavenumberSpectrum->setAxisScaleDraw( QwtPlot::xBottom, new MyScaleDraw1() );
    70. d_plot_WavenumberSpectrum->setAxisScaleDraw( QwtPlot::yLeft, new MyScaleDraw2() );
    71. }
    72.  
    73. void subwindow_uwi::on_PB_delete()
    74. {
    75. delete d_plot_WavenumberSpectrum;
    76.  
    77. }
    78.  
    79. void subwindow_uwi::on_PB_WavenumberSpectrum_clicked()
    80. {
    81.  
    82. if(run_wavenumber_vs_frequency_read() != SIPIF_ERR_OK )
    83. { msgb.setText("Cannot read"); msgb.exec();
    84. }
    85.  
    86. setframe();
    87.  
    88. }
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    Best Regards,

    HAIDER

  2. #2
    Join Date
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    Default Re: Problem with qwtplot update/ destruction

    In line 79, you call setFrame() (which creates a new d_plot_WavenumberSpectrum), but you do not delete the old one. So you probably have two plots on top of each other and that is why it looks like there are two sets of axes. I think there are actually two complete plots, but because the center part is a spectrogram one of these covers up the other.
    <=== The Great Pumpkin says ===>
    Please use CODE tags when posting source code so it is more readable. Click "Go Advanced" and then the "#" icon to insert the tags. Paste your code between them.

  3. #3
    Join Date
    Sep 2014
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    Default Re: Problem with qwtplot update/ destruction

    I also have a delete button. and I first delete before making new one

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