Pmw.ScrolledFrame

Name

Pmw.ScrolledFrame() - frame with optional scrollbars

Inherits

Pmw.MegaWidget

Description

A scrolled frame consists of a scrollable interior frame within a clipping frame. The programmer can create other widgets within the interior frame. If the frame becomes larger than the surrounding clipping frame, the user can position the frame using the horizontal and vertical scrollbars.

The scrollbars can be dynamic, which means that a scrollbar will only be displayed if it is necessary. That is, if the frame is smaller than the surrounding clipping frame, the scrollbar will be hidden.

Options

Options for this megawidget and its base classes are described below.

borderframe

Initialisation option. If true, the borderframe component will be created. The default is 1.

horizflex

Specifies how the width of the scrollable interior frame should be resized relative to the clipping frame.

If 'fixed', the interior frame is set to the natural width, as requested by the child widgets of the frame. If 'expand' and the requested width of the interior frame is less than the width of the clipping frame, the interior frame expands to fill the clipping frame. If 'shrink' and the requested width of the interior frame is more than the width of the clipping frame, the interior frame shrinks to the width of the clipping frame. If 'elastic', the width of the interior frame is always set to the width of the clipping frame. The default is 'fixed'.

horizfraction

Initialisation option. The fraction of the width of the clipper frame to scroll the interior frame when the user clicks on the horizontal scrollbar arrows. The default is 0.05.

hscrollmode

The horizontal scroll mode. If 'none', the horizontal scrollbar will never be displayed. If 'static', the scrollbar will always be displayed. If 'dynamic', the scrollbar will be displayed only if necessary. The default is 'dynamic'.

labelmargin

Initialisation option. If the labelpos option is not None, this specifies the distance between the label component and the rest of the megawidget. The default is 0.

labelpos

Initialisation option. Specifies where to place the label component. If not None, it should be a concatenation of one or two of the letters 'n', 's', 'e' and 'w'. The first letter specifies on which side of the megawidget to place the label. If a second letter is specified, it indicates where on that side to place the label. For example, if labelpos is 'w', the label is placed in the center of the left hand side; if it is 'wn', the label is placed at the top of the left hand side; if it is 'ws', the label is placed at the bottom of the left hand side.

If None, a label component is not created. The default is None.

scrollmargin

Initialisation option. The distance between the scrollbars and the clipping frame. The default is 2.

usehullsize

Initialisation option. If true, the size of the megawidget is determined solely by the width and height options of the hull component.

Otherwise, the size of the megawidget is determined by the width and height of the clipper component, along with the size and/or existence of the other components, such as the label, the scrollbars and the scrollmargin option. All these affect the overall size of the megawidget. The default is 0.

vertflex

Specifies how the height of the scrollable interior frame should be resized relative to the clipping frame.

If 'fixed', the interior frame is set to the natural height, as requested by the child widgets of the frame. If 'expand' and the requested height of the interior frame is less than the height of the clipping frame, the interior frame expands to fill the clipping frame. If 'shrink' and the requested height of the interior frame is more than the height of the clipping frame, the interior frame shrinks to the height of the clipping frame. If 'elastic', the height of the interior frame is always set to the height of the clipping frame. The default is 'fixed'.

vertfraction

Initialisation option. The fraction of the height of the clipper frame to scroll the interior frame when the user clicks on the vertical scrollbar arrows. The default is 0.05.

vscrollmode

The vertical scroll mode. If 'none', the vertical scrollbar will never be displayed. If 'static', the scrollbar will always be displayed. If 'dynamic', the scrollbar will be displayed only if necessary. The default is 'dynamic'.

Components

Components created by this megawidget and its base classes are described below.

borderframe

A frame widget which snuggly fits around the clipper, to give the appearance of a border. It is created with a border so that the clipper, which is created without a border, looks like it has a border. By default, this component is a Tkinter.Frame.

clipper

The frame which is used to provide a clipped view of the frame component. If the borderframe option is true, this is created with a borderwidth of 0 to overcome a known problem with using place to position widgets: if a widget (in this case the frame component) is placed inside a frame (in this case the clipper component) and it extends across one of the edges of the frame, then the widget obscures the border of the frame. Therefore, if the clipper has no border, then this overlapping does not occur. By default, this component is a Tkinter.Frame.

frame

The frame within the clipper to contain the widgets to be scrolled. By default, this component is a Tkinter.Frame.

horizscrollbar

The horizontal scrollbar. By default, this component is a Tkinter.Scrollbar. Its component group is Scrollbar.

hull

This acts as the body for the entire megawidget. Other components are created as children of the hull to further specialise this class. By default, this component is a Tkinter.Frame.

label

If the labelpos option is not None, this component is created as a text label for the megawidget. See the labelpos option for details. Note that to set, for example, the text option of the label, you need to use the label_text component option. By default, this component is a Tkinter.Label.

vertscrollbar

The vertical scrollbar. By default, this component is a Tkinter.Scrollbar. Its component group is Scrollbar.

Methods

Only methods specific to this megawidget are described below. For a description of its inherited methods, see the manual for its base class Pmw.MegaWidget.

interior()

Return the frame within which the programmer may create widgets to be scrolled. This is the same as component('frame').

reposition()

Update the position of the frame component in the clipper and update the scrollbars.

Usually, this method does not need to be called explicitly, since the position of the frame component and the scrollbars are automatically updated whenever the size of the frame or clipper components change or the user clicks in the scrollbars. However, if horizflex or vertflex is 'expand', the megawidget cannot detect when the requested size of the frame increases to greater than the size of the clipper. Therefore, this method should be called when a new widget is added to the frame (or a widget is increased in size) after the initial megawidget construction.

xview(mode = None, value = None, units = None)

Query or change the horizontal position of the scrollable interior frame. If mode is None, return a tuple of two numbers, each between 0.0 and 1.0. The first is the position of the left edge of the visible region of the contents of the scrolled frame, expressed as a fraction of the total width of the contents. The second is the position of the right edge of the visible region.

If mode == 'moveto', adjust the view of the interior so that the fraction value of the total width of the contents is off-screen to the left. The value must be between 0.0 and 1.0.

If mode == 'scroll', adjust the view of the interior left or right by a fixed amount. If what is 'units', move the view in units of horizfraction. If what is pages, move the view in units of the width of the scrolled frame. If value is positive, move to the right, otherwise move to the left.

yview(mode = None, value = None, units = None)

Query or change the vertical position of the scrollable interior frame. If mode is None, return a tuple of two numbers, each between 0.0 and 1.0. The first is the position of the top edge of the visible region of the contents of the scrolled frame, expressed as a fraction of the total height of the contents. The second is the position of the bottom edge of the visible region.

If mode == 'moveto', adjust the view of the interior so that the fraction value of the total height of the contents is off-screen to the top. The value must be between 0.0 and 1.0.

If mode == 'scroll', adjust the view of the interior up or down by a fixed amount. If what is 'units', move the view in units of vertfraction. If what is pages, move the view in units of the height of the scrolled frame. If value is positive, move to down, otherwise move up.

Example

The image at the top of this manual is a snapshot of the window (or part of the window) produced by the following code.

class Demo:
    def __init__(self, parent):
        # Create the ScrolledFrame.
        self.sf = Pmw.ScrolledFrame(parent,
                labelpos = 'n', label_text = 'ScrolledFrame',
                usehullsize = 1,
                hull_width = 400,
                hull_height = 220,
        )

        # Create a group widget to contain the flex options.
        w = Pmw.Group(parent, tag_text='Flex')
        w.pack(side = 'bottom', padx = 5, pady = 3)

        hflex = Pmw.OptionMenu(w.interior(),
                labelpos = 'w',
                label_text = 'Horizontal:',
                items = ['fixed', 'expand', 'shrink', 'elastic'],
                command = self.sethflex,
                menubutton_width = 8,
        )
        hflex.pack(side = 'left', padx = 5, pady = 3)
        hflex.invoke('fixed')

        vflex = Pmw.OptionMenu(w.interior(),
                labelpos = 'w',
                label_text = 'Vertical:',
                items = ['fixed', 'expand', 'shrink', 'elastic'],
                command = self.setvflex,
                menubutton_width = 8,
        )
        vflex.pack(side = 'left', padx = 5, pady = 3)
        vflex.invoke('fixed')

        # Create a group widget to contain the scrollmode options.
        w = Pmw.Group(parent, tag_text='Scroll mode')
        w.pack(side = 'bottom', padx = 5, pady = 0)

        hmode = Pmw.OptionMenu(w.interior(),
                labelpos = 'w',
                label_text = 'Horizontal:',
                items = ['none', 'static', 'dynamic'],
                command = self.sethscrollmode,
                menubutton_width = 8,
        )
        hmode.pack(side = 'left', padx = 5, pady = 3)
        hmode.invoke('dynamic')

        vmode = Pmw.OptionMenu(w.interior(),
                labelpos = 'w',
                label_text = 'Vertical:',
                items = ['none', 'static', 'dynamic'],
                command = self.setvscrollmode,
                menubutton_width = 8,
        )
        vmode.pack(side = 'left', padx = 5, pady = 3)
        vmode.invoke('dynamic')

        self.radio = Pmw.RadioSelect(parent, selectmode = 'multiple',
            command = self.radioSelected)
        self.radio.add('center', text = 'Keep centered vertically')
        self.radio.pack(side = 'bottom')

        buttonBox = Pmw.ButtonBox(parent)
        buttonBox.pack(side = 'bottom')
        buttonBox.add('add', text = 'Add a button', command = self.addButton)
        buttonBox.add('yview', text = 'Show yview', command = self.showYView)
        buttonBox.add('scroll', text = 'Page down', command = self.pageDown)

        # Pack this last so that the buttons do not get shrunk when
        # the window is resized.
        self.sf.pack(padx = 5, pady = 3, fill = 'both', expand = 1)

        self.frame = self.sf.interior()

        self.row = 0
        self.col = 0

        for count in range(15):
            self.addButton()

    def sethscrollmode(self, tag):
        self.sf.configure(hscrollmode = tag)

    def setvscrollmode(self, tag):
        self.sf.configure(vscrollmode = tag)

    def sethflex(self, tag):
        self.sf.configure(horizflex = tag)

    def setvflex(self, tag):
        self.sf.configure(vertflex = tag)

    def addButton(self):
        button = Tkinter.Button(self.frame,
            text = '(%d,%d)' % (self.col, self.row))
        button.grid(row = self.row, column = self.col, sticky = 'nsew')

        self.frame.grid_rowconfigure(self.row, weight = 1)
        self.frame.grid_columnconfigure(self.col, weight = 1)
        if self.sf.cget('horizflex') == 'expand' or \
                self.sf.cget('vertflex') == 'expand':
            self.sf.reposition()

        if 'center' in self.radio.getcurselection():
            self.sf.update_idletasks()
            self.centerPage()

        if self.col == self.row:
            self.col = 0
            self.row = self.row + 1
        else:
            self.col = self.col + 1

    def showYView(self):
        print self.sf.yview()

    def pageDown(self):
        self.sf.yview('scroll', 1, 'page')

    def radioSelected(self, name, state):
        if state:
            self.centerPage()

    def centerPage(self):
        # Example of how to use the yview() method of Pmw.ScrolledFrame.
        top, bottom = self.sf.yview()
        size = bottom - top
        middle = 0.5 - size / 2
        self.sf.yview('moveto', middle)