modeline: correct alignment

* modeline.el (modeline-format-main, modeline-format-dashboard)
(modeline-dashboard-format-left, modeline-dashboard-format-right)
(modeline-truncate, modeline-format-buffer-name,
modeline-format-vc-mode): Now the mode line catches up with the trend
of using string-pixel-width to measure and correctly align strings.
Now the mode line will have pixel-level precision of alignment, which
is pretty good I guess.

1 files changed, 84 insertions, 34 deletions

diff --git a/modeline.el b/modeline.el
index 52ae9af..49c5f38 100644
--- a/modeline.el
+++ b/modeline.el
@@ -28,16 +28,17 @@
 (defun modeline-format-main ()
   "The main mode line format."
   (let* ((left (modeline-format-left))
-         (right (modeline-format-right))
-         (left-len (string-width left))
-         (right-len (string-width right))
-         (middle (propertize " " 'display
-                             (make-string
-                              (max (- (window-total-width)
-                                      left-len
-                                      right-len)
-                                   0)
-                              32))))
+         (right (string-trim-right (modeline-format-right)))
+         (left-len (string-pixel-width left))
+         (right-len (string-pixel-width right))
+         (middle (propertize
+                  (string 32)
+                  'display
+                  (list
+                   'space
+                   :width
+                   (list
+                    (- (window-pixel-width) left-len right-len))))))
     (concat left middle right)))
 
 (setq-default mode-line-format '("%e" (:eval (modeline-format-main))))
@@ -46,16 +47,17 @@
 (defun modeline-format-dashboard ()
   "The mode line format for the dashboard."
   (let* ((left (modeline-dashboard-format-left))
-         (right (modeline-dashboard-format-right))
-         (left-len (length left))
-         (right-len (length right))
-         (middle (propertize " " 'display
-                             (make-string
-                              (max (- (window-total-width)
-                                      left-len
-                                      right-len)
-                                   0)
-                              32))))
+         (right (string-trim-right (modeline-dashboard-format-right)))
+         (left-len (string-pixel-width left))
+         (right-len (string-pixel-width right))
+         (middle (propertize
+                  (string 32)
+                  'display
+                  (list
+                   'space
+                   :width
+                   (list
+                    (- (window-pixel-width) left-len right-len))))))
     (concat left middle right)))
 
 ;;;###autoload
@@ -63,7 +65,11 @@
   "The left / main part of the mode line for the dashboard."
   (concat
    (modeline-spc)
-   (modeline-format-directory)
+   (modeline-format-buffer-status)
+   (modeline-spc)
+   (modeline-format-buffer-name)
+   (modeline-spc)
+   (modeline-format-keycast)
    (modeline-spc)
    (modeline-format-minor-modes)))
 
@@ -76,8 +82,7 @@
                     ('mode-line-inactive))))
     (concat
      (modeline-propertize
-      (format-mode-line global-mode-string face))
-     (modeline-spc))))
+      (format-mode-line global-mode-string face)))))
 
 ;;;###autoload
 (defun modeline-format-left ()
@@ -147,6 +152,54 @@ Characters that take up more than one column will be counted with
           str)
     (floor len)))
 
+;;; Correct truncation
+
+(defun modeline-truncate (str limit &optional ellipsis)
+  "Truncate the string STR to no longer than LIMIT columns.
+ELLIPSIS has the same meaning as for `truncate-string-to-width'.
+
+This function calculates widths by `string-pixel-width.'"
+  (setq ellipsis
+        (cond ((or (null ellipsis) (stringp ellipsis)) ellipsis)
+              ((truncate-string-ellipsis))))
+  (let* ((substring-list (string-glyph-split str))
+         (str-len (length str))
+         (str-pixels (string-pixel-width str))
+         (ellipsis-pixels
+          (cond (ellipsis (string-pixel-width ellipsis)) (0)))
+         (column 0)
+         (idx 0)
+         (space-width (string-pixel-width (string #x20)))
+         (limit (* space-width limit))
+         last-column last-idx temp-str)
+    (with-current-buffer (get-buffer-create
+                          " *modeline-truncate-to-pixels*")
+      (when (bound-and-true-p display-line-numbers-mode)
+        (display-line-numbers-mode -1))
+      (delete-region (point-min) (point-max))
+      (setq line-prefix nil)
+      (setq wrap-prefix nil)
+      (cond ((and (< limit str-pixels)
+                  (< ellipsis-pixels str-pixels))
+             (setq limit (- limit ellipsis-pixels)))
+            ((setq ellipsis (string))))
+      (condition-case nil
+          (while (< column limit)
+            (setq last-column column)
+            (setq last-idx idx)
+            (setq temp-str (nth idx substring-list))
+            (insert (propertize
+                     temp-str
+                     'line-prefix nil 'wrap-prefix nil))
+            (setq column (car (buffer-text-pixel-size nil nil t)))
+            (setq idx (+ idx (length temp-str))))
+        (t (setq idx str-len)))
+      (cond
+       ((> column limit)
+        (setq column last-column)
+        (setq idx last-idx)))
+      (concat (substring str 0 idx) ellipsis))))
+
 ;;; Conveniently add text properties
 
 ;;;###autoload
@@ -485,7 +538,7 @@ This will be displayed in the mode line."
 	  (orig (format-mode-line "%b" face)))
      (concat
       (format-mode-line "%[" face)
-      (truncate-string-to-width orig name-max 0 nil ellipsis)
+      (modeline-truncate orig name-max ellipsis)
       (format-mode-line "%]" face)))
    nil
    (concat (buffer-file-name)
@@ -596,16 +649,13 @@ on the mode line."
   (cond
    ((and (stringp modeline-vcs-str)
          (not (string= modeline-vcs-str "")))
-    (concat
-     ;; (modeline-spc)
-     (modeline-propertize
-      (cond
-       ((modeline-active-window-p) modeline-vcs-str)
-       (t (propertize modeline-vcs-str 'face 'mode-line-inactive)))
-      nil
-      (get-text-property 1 'help-echo vc-mode)
-      (get-text-property 1 'local-map vc-mode))
-     (modeline-spc)))))
+    (modeline-propertize
+     (cond
+      ((modeline-active-window-p) modeline-vcs-str)
+      (t (propertize modeline-vcs-str 'face 'mode-line-inactive)))
+     nil
+     (get-text-property 1 'help-echo vc-mode)
+     (get-text-property 1 'local-map vc-mode)))))
 
 ;;;; Input method