"""An implementation of tabbed pages using only standard Tkinter.

Originally developed for use in IDLE. Based on tabpage.py.

Classes exported:

TabbedPageSet -- A Tkinter implementation of a tabbed-page widget.

TabSet -- A widget containing tabs (buttons) in one or more rows.

"""

from Tkinter import *

class InvalidNameError(Exception): pass

class AlreadyExistsError(Exception): pass

class TabSet(Frame):

    """A widget containing tabs (buttons) in one or more rows.

    Only one tab may be selected at a time.

    """

    def __init__(self, page_set, select_command,

                 tabs=None, n_rows=1, max_tabs_per_row=5,

                 expand_tabs=False, **kw):

        """Constructor arguments:

        select_command -- A callable which will be called when a tab is

        selected. It is called with the name of the selected tab as an

        argument.

        tabs -- A list of strings, the names of the tabs. Should be specified in

        the desired tab order. The first tab will be the default and first

        active tab. If tabs is None or empty, the TabSet will be initialized

        empty.

        n_rows -- Number of rows of tabs to be shown. If n_rows <= 0 or is

        None, then the number of rows will be decided by TabSet. See

        _arrange_tabs() for details.

        max_tabs_per_row -- Used for deciding how many rows of tabs are needed,

        when the number of rows is not constant. See _arrange_tabs() for

        details.

        """

        Frame.__init__(self, page_set, **kw)

        self.select_command = select_command

        self.n_rows = n_rows

        self.max_tabs_per_row = max_tabs_per_row

        self.expand_tabs = expand_tabs

        self.page_set = page_set

        self._tabs = {}

        self._tab2row = {}

        if tabs:

            self._tab_names = list(tabs)

        else:

            self._tab_names = []

        self._selected_tab = None

        self._tab_rows = []

        self.padding_frame = Frame(self, height=2,

                                   borderwidth=0, relief=FLAT,

                                   background=self.cget('background'))

        self.padding_frame.pack(side=TOP, fill=X, expand=False)

        self._arrange_tabs()

    def add_tab(self, tab_name):

        """Add a new tab with the name given in tab_name."""

        if not tab_name:

            raise InvalidNameError("Invalid Tab name: '%s'" % tab_name)

        if tab_name in self._tab_names:

            raise AlreadyExistsError("Tab named '%s' already exists" %tab_name)

        self._tab_names.append(tab_name)

        self._arrange_tabs()

    def remove_tab(self, tab_name):

        """Remove the tab named <tab_name>"""

        if not tab_name in self._tab_names:

            raise KeyError("No such Tab: '%s" % page_name)

        self._tab_names.remove(tab_name)

        self._arrange_tabs()

    def set_selected_tab(self, tab_name):

        """Show the tab named <tab_name> as the selected one"""

        if tab_name == self._selected_tab:

            return

        if tab_name is not None and tab_name not in self._tabs:

            raise KeyError("No such Tab: '%s" % page_name)

        # deselect the current selected tab

        if self._selected_tab is not None:

            self._tabs[self._selected_tab].set_normal()

        self._selected_tab = None

        if tab_name is not None:

            # activate the tab named tab_name

            self._selected_tab = tab_name

            tab = self._tabs[tab_name]

            tab.set_selected()

            # move the tab row with the selected tab to the bottom

            tab_row = self._tab2row[tab]

            tab_row.pack_forget()

            tab_row.pack(side=TOP, fill=X, expand=0)

    def _add_tab_row(self, tab_names, expand_tabs):

        if not tab_names:

            return

        tab_row = Frame(self)

        tab_row.pack(side=TOP, fill=X, expand=0)

        self._tab_rows.append(tab_row)

        for tab_name in tab_names:

            tab = TabSet.TabButton(tab_name, self.select_command,

                                   tab_row, self)

            if expand_tabs:

                tab.pack(side=LEFT, fill=X, expand=True)

            else:

                tab.pack(side=LEFT)

            self._tabs[tab_name] = tab

            self._tab2row[tab] = tab_row

        # tab is the last one created in the above loop

        tab.is_last_in_row = True

    def _reset_tab_rows(self):

        while self._tab_rows:

            tab_row = self._tab_rows.pop()

            tab_row.destroy()

        self._tab2row = {}

    def _arrange_tabs(self):

        """

        Arrange the tabs in rows, in the order in which they were added.

        If n_rows >= 1, this will be the number of rows used. Otherwise the

        number of rows will be calculated according to the number of tabs and

        max_tabs_per_row. In this case, the number of rows may change when

        adding/removing tabs.

        """

        # remove all tabs and rows

        for tab_name in self._tabs.keys():

            self._tabs.pop(tab_name).destroy()

        self._reset_tab_rows()

        if not self._tab_names:

            return

        if self.n_rows is not None and self.n_rows > 0:

            n_rows = self.n_rows

        else:

            # calculate the required number of rows

            n_rows = (len(self._tab_names) - 1) // self.max_tabs_per_row + 1

        # not expanding the tabs with more than one row is very ugly

        expand_tabs = self.expand_tabs or n_rows > 1

        i = 0 # index in self._tab_names

        for row_index in xrange(n_rows):

            # calculate required number of tabs in this row

            n_tabs = (len(self._tab_names) - i - 1) // (n_rows - row_index) + 1

            tab_names = self._tab_names[i:i + n_tabs]

            i += n_tabs

            self._add_tab_row(tab_names, expand_tabs)

        # re-select selected tab so it is properly displayed

        selected = self._selected_tab

        self.set_selected_tab(None)

        if selected in self._tab_names:

            self.set_selected_tab(selected)

    class TabButton(Frame):

        """A simple tab-like widget."""

        bw = 2 # borderwidth

        def __init__(self, name, select_command, tab_row, tab_set):

            """Constructor arguments:

            name -- The tab's name, which will appear in its button.

            select_command -- The command to be called upon selection of the

            tab. It is called with the tab's name as an argument.

            """

            Frame.__init__(self, tab_row, borderwidth=self.bw, relief=RAISED)

            self.name = name

            self.select_command = select_command

            self.tab_set = tab_set

            self.is_last_in_row = False

            self.button = Radiobutton(

                self, text=name, command=self._select_event,

                padx=5, pady=1, takefocus=FALSE, indicatoron=FALSE,

                highlightthickness=0, selectcolor='', borderwidth=0)

            self.button.pack(side=LEFT, fill=X, expand=True)

            self._init_masks()

            self.set_normal()

        def _select_event(self, *args):

            """Event handler for tab selection.

            With TabbedPageSet, this calls TabbedPageSet.change_page, so that

            selecting a tab changes the page.

            Note that this does -not- call set_selected -- it will be called by

            TabSet.set_selected_tab, which should be called when whatever the

            tabs are related to changes.

            """

            self.select_command(self.name)

            return

        def set_selected(self):

            """Assume selected look"""

            self._place_masks(selected=True)

        def set_normal(self):

            """Assume normal look"""

            self._place_masks(selected=False)

        def _init_masks(self):

            page_set = self.tab_set.page_set

            background = page_set.pages_frame.cget('background')

            # mask replaces the middle of the border with the background color

            self.mask = Frame(page_set, borderwidth=0, relief=FLAT,

                              background=background)

            # mskl replaces the bottom-left corner of the border with a normal

            # left border

            self.mskl = Frame(page_set, borderwidth=0, relief=FLAT,

                              background=background)

            self.mskl.ml = Frame(self.mskl, borderwidth=self.bw,

                                 relief=RAISED)

            self.mskl.ml.place(x=0, y=-self.bw,

                               width=2*self.bw, height=self.bw*4)

            # mskr replaces the bottom-right corner of the border with a normal

            # right border

            self.mskr = Frame(page_set, borderwidth=0, relief=FLAT,

                              background=background)

            self.mskr.mr = Frame(self.mskr, borderwidth=self.bw,

                                 relief=RAISED)

        def _place_masks(self, selected=False):

            height = self.bw

            if selected:

                height += self.bw

            self.mask.place(in_=self,

                            relx=0.0, x=0,

                            rely=1.0, y=0,

                            relwidth=1.0, width=0,

                            relheight=0.0, height=height)

            self.mskl.place(in_=self,

                            relx=0.0, x=-self.bw,

                            rely=1.0, y=0,

                            relwidth=0.0, width=self.bw,

                            relheight=0.0, height=height)

            page_set = self.tab_set.page_set

            if selected and ((not self.is_last_in_row) or

                             (self.winfo_rootx() + self.winfo_width() <

                              page_set.winfo_rootx() + page_set.winfo_width())

                             ):

                # for a selected tab, if its rightmost edge isn't on the

                # rightmost edge of the page set, the right mask should be one

                # borderwidth shorter (vertically)

                height -= self.bw

            self.mskr.place(in_=self,

                            relx=1.0, x=0,

                            rely=1.0, y=0,

                            relwidth=0.0, width=self.bw,

                            relheight=0.0, height=height)

            self.mskr.mr.place(x=-self.bw, y=-self.bw,

                               width=2*self.bw, height=height + self.bw*2)

            # finally, lower the tab set so that all of the frames we just

            # placed hide it

            self.tab_set.lower()

class TabbedPageSet(Frame):

    """A Tkinter tabbed-pane widget.

    Constains set of 'pages' (or 'panes') with tabs above for selecting which

    page is displayed. Only one page will be displayed at a time.

    Pages may be accessed through the 'pages' attribute, which is a dictionary

    of pages, using the name given as the key. A page is an instance of a

    subclass of Tk's Frame widget.

    The page widgets will be created (and destroyed when required) by the

    TabbedPageSet. Do not call the page's pack/place/grid/destroy methods.

    Pages may be added or removed at any time using the add_page() and

    remove_page() methods.

    """

    class Page(object):

        """Abstract base class for TabbedPageSet's pages.

        Subclasses must override the _show() and _hide() methods.

        """

        uses_grid = False

        def __init__(self, page_set):

            self.frame = Frame(page_set, borderwidth=2, relief=RAISED)

        def _show(self):

            raise NotImplementedError

        def _hide(self):

            raise NotImplementedError

    class PageRemove(Page):

        """Page class using the grid placement manager's "remove" mechanism."""

        uses_grid = True

        def _show(self):

            self.frame.grid(row=0, column=0, sticky=NSEW)

        def _hide(self):

            self.frame.grid_remove()

    class PageLift(Page):

        """Page class using the grid placement manager's "lift" mechanism."""

        uses_grid = True

        def __init__(self, page_set):

            super(TabbedPageSet.PageLift, self).__init__(page_set)

            self.frame.grid(row=0, column=0, sticky=NSEW)

            self.frame.lower()

        def _show(self):

            self.frame.lift()

        def _hide(self):

            self.frame.lower()

    class PagePackForget(Page):

        """Page class using the pack placement manager's "forget" mechanism."""

        def _show(self):

            self.frame.pack(fill=BOTH, expand=True)

        def _hide(self):

            self.frame.pack_forget()

    def __init__(self, parent, page_names=None, page_class=PageLift,

                 n_rows=1, max_tabs_per_row=5, expand_tabs=False,

                 **kw):

        """Constructor arguments:

        page_names -- A list of strings, each will be the dictionary key to a

        page's widget, and the name displayed on the page's tab. Should be

        specified in the desired page order. The first page will be the default

        and first active page. If page_names is None or empty, the

        TabbedPageSet will be initialized empty.

        n_rows, max_tabs_per_row -- Parameters for the TabSet which will

        manage the tabs. See TabSet's docs for details.

        page_class -- Pages can be shown/hidden using three mechanisms:

        * PageLift - All pages will be rendered one on top of the other. When

          a page is selected, it will be brought to the top, thus hiding all

          other pages. Using this method, the TabbedPageSet will not be resized

          when pages are switched. (It may still be resized when pages are

          added/removed.)

        * PageRemove - When a page is selected, the currently showing page is

          hidden, and the new page shown in its place. Using this method, the

          TabbedPageSet may resize when pages are changed.

        * PagePackForget - This mechanism uses the pack placement manager.

          When a page is shown it is packed, and when it is hidden it is

          unpacked (i.e. pack_forget). This mechanism may also cause the

          TabbedPageSet to resize when the page is changed.

        """

        Frame.__init__(self, parent, **kw)

        self.page_class = page_class

        self.pages = {}

        self._pages_order = []

        self._current_page = None

        self._default_page = None

        self.columnconfigure(0, weight=1)

        self.rowconfigure(1, weight=1)

        self.pages_frame = Frame(self)

        self.pages_frame.grid(row=1, column=0, sticky=NSEW)

        if self.page_class.uses_grid:

            self.pages_frame.columnconfigure(0, weight=1)

            self.pages_frame.rowconfigure(0, weight=1)

        # the order of the following commands is important

        self._tab_set = TabSet(self, self.change_page, n_rows=n_rows,

                               max_tabs_per_row=max_tabs_per_row,

                               expand_tabs=expand_tabs)

        if page_names:

            for name in page_names:

                self.add_page(name)

        self._tab_set.grid(row=0, column=0, sticky=NSEW)

        self.change_page(self._default_page)

    def add_page(self, page_name):

        """Add a new page with the name given in page_name."""

        if not page_name:

            raise InvalidNameError("Invalid TabPage name: '%s'" % page_name)

        if page_name in self.pages:

            raise AlreadyExistsError(

                "TabPage named '%s' already exists" % page_name)

        self.pages[page_name] = self.page_class(self.pages_frame)

        self._pages_order.append(page_name)

        self._tab_set.add_tab(page_name)

        if len(self.pages) == 1: # adding first page

            self._default_page = page_name

            self.change_page(page_name)

    def remove_page(self, page_name):

        """Destroy the page whose name is given in page_name."""

        if not page_name in self.pages:

            raise KeyError("No such TabPage: '%s" % page_name)

        self._pages_order.remove(page_name)

        # handle removing last remaining, default, or currently shown page

        if len(self._pages_order) > 0:

            if page_name == self._default_page:

                # set a new default page

                self._default_page = self._pages_order[0]

        else:

            self._default_page = None

        if page_name == self._current_page:

            self.change_page(self._default_page)

        self._tab_set.remove_tab(page_name)

        page = self.pages.pop(page_name)

        page.frame.destroy()

    def change_page(self, page_name):

        """Show the page whose name is given in page_name."""

        if self._current_page == page_name:

            return

        if page_name is not None and page_name not in self.pages:

            raise KeyError("No such TabPage: '%s'" % page_name)

        if self._current_page is not None:

            self.pages[self._current_page]._hide()

        self._current_page = None

        if page_name is not None:

            self._current_page = page_name

            self.pages[page_name]._show()

        self._tab_set.set_selected_tab(page_name)

if __name__ == '__main__':

    # test dialog

    root=Tk()

    tabPage=TabbedPageSet(root, page_names=['Foobar','Baz'], n_rows=0,

                          expand_tabs=False,

                          )

    tabPage.pack(side=TOP, expand=TRUE, fill=BOTH)

    Label(tabPage.pages['Foobar'].frame, text='Foo', pady=20).pack()

    Label(tabPage.pages['Foobar'].frame, text='Bar', pady=20).pack()

    Label(tabPage.pages['Baz'].frame, text='Baz').pack()

    entryPgName=Entry(root)

    buttonAdd=Button(root, text='Add Page',

            command=lambda:tabPage.add_page(entryPgName.get()))

    buttonRemove=Button(root, text='Remove Page',

            command=lambda:tabPage.remove_page(entryPgName.get()))

    labelPgName=Label(root, text='name of page to add/remove:')

    buttonAdd.pack(padx=5, pady=5)

    buttonRemove.pack(padx=5, pady=5)

    labelPgName.pack(padx=5)

    entryPgName.pack(padx=5)

    root.mainloop()