[view_curses] fix wrapping issues with CJK characters

Related to #935

src/listview_curses.cc

@@ -425,25 +425,22 @@ listview_curses::do_update()
                     require_ge(attr.sa_range.lr_start, 0);
                 }
 
-                size_t remaining = 0;
+                view_curses::mvwattrline_result write_res;
                 do {
-                    remaining = mvwattrline(this->lv_window,
+                    if (this->lv_word_wrap) {
+                        mvwhline(this->lv_window, y, this->lv_x, ' ', width);
+                    }
+                    write_res = mvwattrline(this->lv_window,
                                             y,
                                             this->lv_x,
                                             al,
                                             lr,
                                             this->vc_default_role);
-                    if (this->lv_word_wrap) {
+                    lr.lr_start += write_res.mr_chars_out;
-                        mvwhline(this->lv_window,
+                    lr.lr_end += write_res.mr_chars_out;
-                                 y,
-                                 this->lv_x + wrap_width,
-                                 ' ',
-                                 width - wrap_width);
-                    }
-                    lr.lr_start += wrap_width;
-                    lr.lr_end += wrap_width;
                     ++y;
-                } while (this->lv_word_wrap && y < bottom && remaining > 0);
+                } while (this->lv_word_wrap && y < bottom
+                         && write_res.mr_bytes_remaining > 0);
 
                 if (this->lv_overlay_source != nullptr) {
                     row_overlay_content.clear();

src/view_curses.cc

@@ -140,7 +140,7 @@ view_curses::awaiting_user_input()
     }
 }
 
-size_t
+view_curses::mvwattrline_result
 view_curses::mvwattrline(WINDOW* window,
                          int y,
                          const int x,
@@ -155,6 +155,7 @@ view_curses::mvwattrline(WINDOW* window,
 
     require(lr_chars.lr_end >= 0);
 
+    mvwattrline_result retval;
     auto line_width_chars = lr_chars.length();
     std::string expanded_line;
     line_range lr_bytes;
@@ -168,6 +169,7 @@ view_curses::mvwattrline(WINDOW* window,
             lr_bytes.lr_start = exp_start_index;
         } else if (char_index == lr_chars.lr_end) {
             lr_bytes.lr_end = exp_start_index;
+            retval.mr_chars_out = char_index;
         }
 
         switch (ch) {
@@ -234,6 +236,10 @@ view_curses::mvwattrline(WINDOW* window,
                     }
                     auto wch = read_res.unwrap();
                     char_index += wcwidth(wch);
+                    if (lr_bytes.lr_end == -1 && char_index > lr_chars.lr_end) {
+                        lr_bytes.lr_end = exp_start_index;
+                        retval.mr_chars_out = char_index - wcwidth(wch);
+                    }
                 }
                 break;
             }
@@ -245,7 +251,10 @@ view_curses::mvwattrline(WINDOW* window,
     if (lr_bytes.lr_end == -1) {
         lr_bytes.lr_end = expanded_line.size();
     }
-    size_t retval = expanded_line.size() - lr_bytes.lr_end;
+    if (retval.mr_chars_out == 0) {
+        retval.mr_chars_out = char_index;
+    }
+    retval.mr_bytes_remaining = expanded_line.size() - lr_bytes.lr_end;
 
     full_line = expanded_line;
 

src/view_curses.hh

@@ -387,12 +387,17 @@ public:
 
     static void awaiting_user_input();
 
-    static size_t mvwattrline(WINDOW* window,
+    struct mvwattrline_result {
-                              int y,
+        size_t mr_chars_out{0};
-                              int x,
+        size_t mr_bytes_remaining{0};
-                              attr_line_t& al,
+    };
-                              const struct line_range& lr,
+
-                              role_t base_role = role_t::VCR_TEXT);
+    static mvwattrline_result mvwattrline(WINDOW* window,
+                                          int y,
+                                          int x,
+                                          attr_line_t& al,
+                                          const struct line_range& lr,
+                                          role_t base_role = role_t::VCR_TEXT);
 
 protected:
     bool vc_visible{true};

test/textfile_cjk.0

@@ -0,0 +1,3 @@
+一二三四五六七八九十Group1一二三四五六七八九十Group2一二三四五六七八九十Group3一二三四五六七八九十Group4一二三四五六七八九十Group5
+
+This is an example of a normally-behavioring text wrap example. All letters are ASCII and containing no CJK letters.