$ textview-editor [filename...]
$ git clone https://github.com/esrille/textview-editor.git
$ make
$ sudo make install
To uninstall, use:
$ sudo make uninstall
TextView Editor is a simple GTK 3 based text editor written in Python.
The menu bar at the top of each window includes File, Edit, Settings and Help menus. Each menu provides essential features of text editors such as cut, copy, and paste. When you select Search/Find…, the search bar slides in from the bottom of the window. Hit the enter key to find the next match.
In TextView Editor, a Gtk.Application manages multiple Gtk.ApplicationWindows. Each application window has the following widget hierarchy.
Basic text editing features are provided by Gtk.TextView and its Gtk.TextBuffer. One feature that is missing is the ability to undo and redo. TextView Editor provides an edit history feature by monitoring "insert_text" and "delete_range" signals raised from Gtk.TextBuffer.
TextView Editor is released under the GNU Lesser General Public License. Simple text editors would have been a good starting point to learn about GUI programming. TextView Editor is intended to be one of those programs.
A modeless Input Method Engine (modeless IME) is an emerging technology to input Japanese characters. ibus-replace-with-kanji is an example of such modeless IMEs.
To enter Chinese characters "漢字" with a modeless IME, we use the following steps.
- Type "かんじ", which is the Japanese Hiragana string for "漢字".
- Hit [Convert] key to convert a Hiragana string into Chinese characters.
- Then, a modeless IME deletes "かんじ" by delete_surrounding_text(), and inserts "漢字" by commit_text().
In Step 3, a "delete_range" signal and an "insert_text" signal are issued from Gtk.TextBuffer as the result of delete_surrounding_text() and commit_text() respectively.
So when we undo the convert operation in Step 2, it is preferable if the previous "delete_range" and "insert_text" operations are revoked at the same time. Probably it is better if an IME framework provides replace_surrounding_text() API instead of delete_surrounding_text() and commit_text(). See User Interface: A Personal View by Alan Kay for the design principles.
Anyway, the recent PCs are fast enough to distinguish signals issued by human and by IME. If a "delete_range" signal and an "insert_text" signal are issued very closely in time, like within 1 msec, they are likely to be issued by IME. In TextView Editor, if two signals were issued very closely in time, the Undo command revokes both operations at one time.
Note with the classic IMEs, we use the following steps to enter "漢字".
- Type "かんじ", which are kept in the IME's pre-edit text buffer.
- Hit [Convert] key.
- The IME converts the text in the pre-edit text buffer into "漢字".
- Hit [Enter] key.
- The IME inserts "漢字" into the text editor by commit_text(), and clears the pre-edit text buffer.
From the text editor's point of view, just "漢字" is inserted at Step 5. When you undo Step 4, you can not get "かんじ" back with classic IMEs, which are very stressful especially for non-professional typists.
For modeless IMEs to work, it is crucial that an application supports surrounding text operations like Gtk.TextView does. It seems increasing numbers of text editors support surrounding text operations these days. Various characters of many languages would be entered in the similar manner presented here. The support for the smart undo/redo would be one of the next steps to go.