Plotting and removing graphs with pyqtgraph

[Guillaume Gotthard]

Hi everybody,

I am curently trying to develop a python based software for reading and manipulating spectroscopy results.
I have written a python script and a Gui, principally based on pyqtgraph widget implemented in PyQt4.

My script allows me to load files from a browser (in a treeView widget), put their names in a listView widget (each items have a checkbox that is checked by default) and at the same time plot this checked item in the pyqtgraph widget.

I show here a view of my gui.



As you can see, I am able to plot spectra each times I load a new spectrum.
However, I am not able to remove each plot separately. I can remove the last plotted spectrum, but not each of them separately.

Since I am a begginer in python scripting, I cannot identify where is my error, and how to fix the code...
I suspect the problem stems from my way to plot and remove spectrum in association with the checkbox status of the listview.

Following are the relevant code parts:

@QtCore.pyqtSlot(QtCore.QModelIndex)
def on_treeview_clicked(index):
    global clicked_spectrum
    global alldata
    global spectra_filenames
    global spectra_data
    global fileName
    global filePath
    global item

    indexItem = model.index(index.row(), 0, index.parent())

    # path or filename selected
    fileName = model.fileName(indexItem)
    fileName = str(fileName)
    # full path/filename selected
    filePath = model.filePath(indexItem)
    filePath = str(filePath)
   
    # if len(clicked_spectrum) == 0:
    #    clicked_spectrum = [(fileName), (filePath)]
    # else:
    clicked_spectrum.append([(fileName), (filePath)])
    spectra_filenames[filePath] = fileName
   

   
    data = np.genfromtxt(filePath, skip_header=18, skip_footer=1, usecols=(0, 1), autostrip=True)
    alldata.append(data)
    print "number of \"good\" spectra:", len(alldata)

    spectra_data[filePath] = data

    item = QtGui.QStandardItem(fileName)
    #item = QtGui.QCheckBox(fileName)

    # add a checkbox to it
    item.setCheckable(True)
    item.setCheckState(2)

    on_item_changed(item)
     
    # Add the item to the model
    model_list.appendRow(item)

       
def on_item_changed(item):
    global filePath
   
    i = 0
    for searchname in clicked_spectrum:
        # print searchname
        if searchname[0] == item.text():
            #print "found!!", searchname
            break
        else:
            i = i+1

    # print "keys:", spectra_filenames.keys()
    for searchname in spectra_filenames.keys():
        # print searchname , spectra_filenames[searchname]
        if spectra_filenames[searchname] == item.text():
            #print "found!!", searchname
            foundname = searchname
            break

    spectrum_data = spectra_data[foundname]

    for searchname in spectra_filenames.keys():
        if item.checkState() == QtCore.Qt.Checked:

            filePath = pg.PlotDataItem(spectra_data[filePath], name=item.text(), pen={'color': (255,0,0), 'width':p.param('Graphics Parameters').param('Line_width').value(), 'style':p.param('Graphics Parameters').param('Line_style').value()})
            ui.graphicsView.addItem(filePath, clickable=True)

            break

        else:

            ui.graphicsView.removeItem(filePath)
            break



##############################
#####    Main Program    #####
##############################

###Browsing widget####

clicked_spectrum  = []
alldata           = []
spectra_filenames = {}
spectra_data      = {}

if os.name == 'nt': # Windows
    basepath = 'C:\\Users\\'
else:
    basepath = '.'   # current directory

model = QtGui.QFileSystemModel()

filters = QStringList("*.txt")
model.setNameFilters(filters) # allows to "grey" files that have not the right extension
#model.setNameFilterDisables(0) #allows to completely hide files that have not the right extension
root = model.setRootPath(basepath)
ui.files_treeView.setModel(model)
ui.files_treeView.setSelectionMode(QTreeView.ExtendedSelection) # allows multiple file selection for loading
ui.files_treeView.setRootIndex(root)
ui.files_treeView.setHeaderHidden(1)
ui.files_treeView.hideColumn(1)
ui.files_treeView.hideColumn(2)
ui.files_treeView.hideColumn(3)


ui.files_treeView.doubleClicked.connect(on_treeview_clicked)

###List of loaded files####
 
list = QtGui.QListView()

model_list = QtGui.QStandardItemModel(list)
ui.listView.setSelectionMode(QAbstractItemView.ExtendedSelection) # allows multiple file selection for unloading



ui.listView.setModel(model_list)

model_list.itemChanged.connect(on_item_changed)


# print model_list.itemFromIndex(QtGui.QModelIndex(2)).text()

#########################
###Plotting of Graphs####
#########################


###Setting graphs rendering####

ui.graphicsView.setLabel('left', text='Absorption [OD]')
ui.graphicsView.setLabel('bottom', text='Wavelength [nm]')

Please, if anyone has an idea, I would be very grateful.

Cheers,

Guillaume

[Mathew Schwartz]

It looks like your using a global variable for the items in your graph, filepath.  I suspect you are overwriting your items each time you load a new one, so the only one that is actually stored is the last one.  You should try avoid globals, but if you dont want to, you can try making a global array or dictionary.  Each time you load a file, you append your new plotitem to that global.  

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