1"""Simple text browser for IDLE
2
3"""
4from tkinter import Toplevel, Text, TclError,\
5    HORIZONTAL, VERTICAL, NS, EW, NSEW, NONE, WORD, SUNKEN
6from tkinter.ttk import Frame, Scrollbar, Button
7from tkinter.messagebox import showerror
8
9from idlelib.colorizer import color_config
10
11
12class AutoHideScrollbar(Scrollbar):
13    """A scrollbar that is automatically hidden when not needed.
14
15    Only the grid geometry manager is supported.
16    """
17    def set(self, lo, hi):
18        if float(lo) > 0.0 or float(hi) < 1.0:
19            self.grid()
20        else:
21            self.grid_remove()
22        super().set(lo, hi)
23
24    def pack(self, **kwargs):
25        raise TclError(f'{self.__class__.__name__} does not support "pack"')
26
27    def place(self, **kwargs):
28        raise TclError(f'{self.__class__.__name__} does not support "place"')
29
30
31class ScrollableTextFrame(Frame):
32    """Display text with scrollbar(s)."""
33
34    def __init__(self, master, wrap=NONE, **kwargs):
35        """Create a frame for Textview.
36
37        master - master widget for this frame
38        wrap - type of text wrapping to use ('word', 'char' or 'none')
39
40        All parameters except for 'wrap' are passed to Frame.__init__().
41
42        The Text widget is accessible via the 'text' attribute.
43
44        Note: Changing the wrapping mode of the text widget after
45        instantiation is not supported.
46        """
47        super().__init__(master, **kwargs)
48
49        text = self.text = Text(self, wrap=wrap)
50        text.grid(row=0, column=0, sticky=NSEW)
51        self.grid_rowconfigure(0, weight=1)
52        self.grid_columnconfigure(0, weight=1)
53
54        # vertical scrollbar
55        self.yscroll = AutoHideScrollbar(self, orient=VERTICAL,
56                                         takefocus=False,
57                                         command=text.yview)
58        self.yscroll.grid(row=0, column=1, sticky=NS)
59        text['yscrollcommand'] = self.yscroll.set
60
61        # horizontal scrollbar - only when wrap is set to NONE
62        if wrap == NONE:
63            self.xscroll = AutoHideScrollbar(self, orient=HORIZONTAL,
64                                             takefocus=False,
65                                             command=text.xview)
66            self.xscroll.grid(row=1, column=0, sticky=EW)
67            text['xscrollcommand'] = self.xscroll.set
68        else:
69            self.xscroll = None
70
71
72class ViewFrame(Frame):
73    "Display TextFrame and Close button."
74    def __init__(self, parent, contents, wrap='word'):
75        """Create a frame for viewing text with a "Close" button.
76
77        parent - parent widget for this frame
78        contents - text to display
79        wrap - type of text wrapping to use ('word', 'char' or 'none')
80
81        The Text widget is accessible via the 'text' attribute.
82        """
83        super().__init__(parent)
84        self.parent = parent
85        self.bind('<Return>', self.ok)
86        self.bind('<Escape>', self.ok)
87        self.textframe = ScrollableTextFrame(self, relief=SUNKEN, height=700)
88
89        text = self.text = self.textframe.text
90        text.insert('1.0', contents)
91        text.configure(wrap=wrap, highlightthickness=0, state='disabled')
92        color_config(text)
93        text.focus_set()
94
95        self.button_ok = button_ok = Button(
96                self, text='Close', command=self.ok, takefocus=False)
97        self.textframe.pack(side='top', expand=True, fill='both')
98        button_ok.pack(side='bottom')
99
100    def ok(self, event=None):
101        """Dismiss text viewer dialog."""
102        self.parent.destroy()
103
104
105class ViewWindow(Toplevel):
106    "A simple text viewer dialog for IDLE."
107
108    def __init__(self, parent, title, contents, modal=True, wrap=WORD,
109                 *, _htest=False, _utest=False):
110        """Show the given text in a scrollable window with a 'close' button.
111
112        If modal is left True, users cannot interact with other windows
113        until the textview window is closed.
114
115        parent - parent of this dialog
116        title - string which is title of popup dialog
117        contents - text to display in dialog
118        wrap - type of text wrapping to use ('word', 'char' or 'none')
119        _htest - bool; change box location when running htest.
120        _utest - bool; don't wait_window when running unittest.
121        """
122        super().__init__(parent)
123        self['borderwidth'] = 5
124        # Place dialog below parent if running htest.
125        x = parent.winfo_rootx() + 10
126        y = parent.winfo_rooty() + (10 if not _htest else 100)
127        self.geometry(f'=750x500+{x}+{y}')
128
129        self.title(title)
130        self.viewframe = ViewFrame(self, contents, wrap=wrap)
131        self.protocol("WM_DELETE_WINDOW", self.ok)
132        self.button_ok = button_ok = Button(self, text='Close',
133                                            command=self.ok, takefocus=False)
134        self.viewframe.pack(side='top', expand=True, fill='both')
135
136        self.is_modal = modal
137        if self.is_modal:
138            self.transient(parent)
139            self.grab_set()
140            if not _utest:
141                self.wait_window()
142
143    def ok(self, event=None):
144        """Dismiss text viewer dialog."""
145        if self.is_modal:
146            self.grab_release()
147        self.destroy()
148
149
150def view_text(parent, title, contents, modal=True, wrap='word', _utest=False):
151    """Create text viewer for given text.
152
153    parent - parent of this dialog
154    title - string which is the title of popup dialog
155    contents - text to display in this dialog
156    wrap - type of text wrapping to use ('word', 'char' or 'none')
157    modal - controls if users can interact with other windows while this
158            dialog is displayed
159    _utest - bool; controls wait_window on unittest
160    """
161    return ViewWindow(parent, title, contents, modal, wrap=wrap, _utest=_utest)
162
163
164def view_file(parent, title, filename, encoding, modal=True, wrap='word',
165              _utest=False):
166    """Create text viewer for text in filename.
167
168    Return error message if file cannot be read.  Otherwise calls view_text
169    with contents of the file.
170    """
171    try:
172        with open(filename, 'r', encoding=encoding) as file:
173            contents = file.read()
174    except OSError:
175        showerror(title='File Load Error',
176                  message=f'Unable to load file {filename!r} .',
177                  parent=parent)
178    except UnicodeDecodeError as err:
179        showerror(title='Unicode Decode Error',
180                  message=str(err),
181                  parent=parent)
182    else:
183        return view_text(parent, title, contents, modal, wrap=wrap,
184                         _utest=_utest)
185    return None
186
187
188if __name__ == '__main__':
189    from unittest import main
190    main('idlelib.idle_test.test_textview', verbosity=2, exit=False)
191
192    from idlelib.idle_test.htest import run
193    run(ViewWindow)
194