Fix cjk width

[mattn]

Related issue #69 #72

[mattn]

termui

works fine

[mattn]

peco

works fine too

[mattn]

@nsf do you know the another famous product which should be check this change?

[nsf]

Our own _demos/output.go has some cjk characters in it. But no, have no idea.

[mattn]

Is this your expected?

[nsf]

Yes, looks good. But that's how it looks on my machine (that's what I meant by "it doesn't work for me"):

[mattn]

What is your code page?

[nsf]

What do you mean code page? It's a typical windows setup with russian/english locales.

[mattn]

please type chcp on cmd.exe

[nsf]

Says 866.

[mattn]

@nsf because cell width is hard-coded as 2. https://github.com/nsf/termbox-go/blob/master/_demos/output.go#L57

[nsf]

@mattn But what does it change? I mean when font doesn't support CJK runes things get broken?

[mattn]

ok, I could reproduce your problem.

chcp 866

I'll look into it.

[mattn]

It seems that prepare_diff_messages should be fixed I think.

[mattn]

About making diffs, diffs should be separated per lines. because columns is not width in CJK.

diff --git a/termbox_windows.go b/termbox_windows.go
index 62ac3fa..45b69e5 100644
--- a/termbox_windows.go
+++ b/termbox_windows.go
@@ -456,6 +456,14 @@ const (
    surr_self        = 0x10000
 )

+func rune_width(r rune) int {
+   w := runewidth.RuneWidth(r)
+   if w == 0 || w == 2 && runewidth.IsAmbiguousWidth(r) {
+       w = 1
+   }
+   return w
+}
+
 func append_diff_line(y int) int {
    n := 0
    for x := 0; x < front_buffer.width; {
@@ -463,16 +471,10 @@ func append_diff_line(y int) int {
        back := &back_buffer.cells[cell_offset]
        front := &front_buffer.cells[cell_offset]
        attr, char := cell_to_char_info(*back)
-       w := runewidth.RuneWidth(back.Ch)
-       if w == 0 {
-           w = 1
-       }
-       if w == 0 || w == 2 && runewidth.IsAmbiguousWidth(back.Ch) {
-           w = 1
-       }
        charbuf = append(charbuf, char_info{attr: attr, char: char[0]})
-       n++
        *front = *back
+       n++
+       w := rune_width(back.Ch)
        x += w
    }
    return n
@@ -498,25 +500,17 @@ func prepare_diff_messages() {
                break
            }
        }
-       if same && diff.lines > 0 {
-           diffbuf = append(diffbuf, diff)
-           diff = diff_msg{}
-       }
        if !same {
+           diff = diff_msg{}
            beg := len(charbuf)
            end := beg + append_diff_line(y)
-           if diff.lines == 0 {
-               diff.pos = short(y)
-               gbeg = beg
-           }
-           diff.lines++
+           diff.lines = 1
+           diff.pos = short(y)
+           gbeg = beg
            diff.chars = charbuf[gbeg:end]
+           diffbuf = append(diffbuf, diff)
        }
    }
-   if diff.lines > 0 {
-       diffbuf = append(diffbuf, diff)
-       diff = diff_msg{}
-   }
 }

 func cell_to_char_info(c Cell) (attr word, wc [2]wchar) {

But it seems to be problem in another part.

[pomutemu]

Microsoft Windows [Version 10.0.10074]
(c) 2015 Microsoft Corporation. All rights reserved.

C:\Windows\system32>chcp 932
現在のコード ページ: 932

[mattn]

Probably your font is not rasterfont. right?

[pomutemu]

You are right.
Thanks!