I am looking for a (simple) text editor that can handle text in different encodings in the same document.
I need to develop some sites with mixed Japanese and Englis
Notepad++ is highly recommended.
EditPlus seems to be an better option for UTF-8
as I have used it.
Kate. and by extension, any other KDE program that uses Kate as an embedded KPart (KWrite, Quanta+, KDevelop). It handles lots of encodings, but i like to always use UTF-8. It also has a huge collection of syntax highlightings.
I've never had a problem with vim as long as I use a font that actually contains the characters I want. It needs to be a monospace font. :set enc=utf8 to get to utf8 mode. Then you can use :digraph command to get a display of available characters, and see how each is displayed.
To add a font, add it in Windows (Control Panel/Fonts/Add Font). If it's a monospace font, it will then show up in vin in /Edit/Font.
There is an issue with most Unicode-aware text editors: when you select a font, they stick to it. If the font does not include a glyph for a character, then the default substitution character (I believe U+FFFD, REPLACEMENT CHARACTER) is used.
In contrast, web browsers typically try to find a glyph for the characters they have to display among all the fonts provided by the system.
So, what you need, if you don't have the font "Arial Unicode MS" or similar (including Japanese glyphs), is an editor that tries to match glyphs with other fonts except the selected one.
Until someone provides a link for such an editor, I'll suggest a (somewhat extreme :) editor:
The "idle" editor is typically used to edit python code (and test it interactively in the Python shell). However, it can be used as a plain fully-Unicode-aware text editor, and when saving text including non-ASCII chars, it defaults to UTF-8 encoding.
Now, idle is based on Tkinter, which is an interface to tk, which is a gui library for tcl; tcl/tk, like web browsers, when asked to display a character for which no glyph is present in the widget font, it searches other fonts too.
However far-fetched this may seem, I really believe it would help; if no other solution helps you, give it a try.
http://www.ultraedit.com/ is a multiplatform editor that does UTF-8 and all kinds of conversions between formats