[elpa] master c96b7b7: Added greenbar package

[Michael Mauger]

branch: master
commit c96b7b7c3958530a51b6be837848439a915f3773
Author: Michael R. Mauger <michael@mauger.com>
Commit: Michael R. Mauger <michael@mauger.com>

    Added greenbar package
---
 packages/greenbar/greenbar.el | 179 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)

diff --git a/packages/greenbar/greenbar.el b/packages/greenbar/greenbar.el
new file mode 100644
index 0000000..f81cc4a
--- /dev/null
+++ b/packages/greenbar/greenbar.el
@@ -0,0 +1,179 @@
+;;; greenbar.el --- Mark comint output with "greenbar" background -*- 
lexical-binding: t -*-
+
+;; Copyright (C) 2013, 2015, 2020  Michael R. Mauger
+
+;; Author: Michael R. Mauger <michael@mauger.com>
+;; Version: 1.0
+;; Package-Type: simple
+;; Keywords: faces, terminals
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; For some of us old neck beards who learned to write software on
+;; pucch cards and print out our code and output on wide line
+;; printers.  When reading long rows of text across a 14 7/8" page it
+;; was helpful to have alternating bands of subtle background coloring
+;; to guide your eyes across the line.  This is also referred to as
+;; `zebra striping` and is enabled in on PostScript output in
+;; `ps-print.el' by enabling the `ps-zebra-stripes' setting.
+
+;; To enable `greenbar-mode' in your `comint-mode' buffers, add the
+;; following to your Emacs configuration:
+
+;;     (add-hook 'comint-mode-hook #'greenbar-mode)
+
+;; If you want to enable `greenbar-mode' only in a single mode derived
+;; from `comint-mode', then you need to add `greenbar-mode' only to
+;; the desired derive mode hook.  Adding `greenbar-mode' to
+;; `comint-mode-hook' enables it for all comint derived modes.
+
+;; The variable `greenbar-color-theme' is a list of predefined bar
+;; background colors.  Each element of the list is a list: the first
+;; member of which is a symbol that is the name of the theme; the rest
+;; of the list are color names which are used as background colors for
+;; successive bands of lines.
+
+;; The variable `greenbar-color-list' controls which set of color bars
+;; are to be applied.  The value is either a name from color theme
+;; defined in `greenbar-color-themes' or it is a list of color names.
+
+;;; Code:
+
+(require 'comint)
+
+(defgroup greenbar nil
+  "Stripe comint output like \"green bar\", or \"zebra stripe\" paper."
+  :group 'comint)
+
+(defvar-local greenbar-current-bar 0
+  "Index into `greenbar-background-colors' that is active.")
+
+(defvar-local greenbar-current-line 0
+  "The line into the bar that is active.")
+
+(defcustom greenbar-lines-per-bar 3
+  "How many lines of output should be colored together."
+  :group 'greenbar
+  :type 'integer)
+
+(defvar greenbar-color-themes
+  (list
+   (cons 'greenbar
+         (if (eq (frame-parameter nil 'background-mode) 'dark)
+             '("#344034" "#343434")
+           '("#e4f0e4" "#f0f0f0")))
+   (cons 'graybar
+         (list
+          (if (eq (frame-parameter nil 'background-mode) 'dark)
+              "gray30" "gray70")
+          (face-background 'default)))
+   (cons 'rainbow
+         (let ((x (if (eq (frame-parameter nil 'background-mode) 'dark) "40" 
"f0"))
+               (o (if (eq (frame-parameter nil 'background-mode) 'dark) "34" 
"e4")))
+
+           (mapcar (lambda (c)
+                     (eval `(concat "#" ,@c)))
+                   `((,x ,x ,o) (,x ,o ,o) (,x ,o ,x) (,o ,o ,x) (,o ,x ,x) 
(,o ,x ,o))))))
+  "Greenbar themes.
+
+A list of greenbar themes, each of which is a list starting with
+a symbol that names the theme followed by the list bar colors.")
+
+(defcustom greenbar-background-colors 'greenbar
+  "List of background colors to be applied to output stripes."
+  :group 'greenbar
+  :type `(choice ,@(mapcar (lambda (c)
+                             (list 'const (car c)))
+                           greenbar-color-themes)
+                 (repeat (color :tag "Background list"))))
+
+(defun greenbar-color-list ()
+  "Get the list of greenbar background colors."
+    (or (cdr (assoc greenbar-background-colors
+                    greenbar-color-themes))
+        greenbar-background-colors))
+
+(defun greenbar-next-bar ()
+  "Reset the local configuration if we are at the end of a bar.
+
+If `greenbar-lines' is zero, reset it to
+`greenbar-lines-per-bar', and move `greenbar-current-bar' to the
+next one."
+
+  (when (zerop greenbar-current-line)
+    (setq greenbar-current-bar (mod (1+ greenbar-current-bar) (length 
(greenbar-color-list)))
+          greenbar-current-line (default-value 'greenbar-lines-per-bar))))
+
+(defun greenbar-output-filter (string)
+  "Stripe comint output in STRING with background colors.
+
+Every `greenbar-lines-per-bar' lines are colored with a rotating
+set of background colors found in
+`greenbar-background-colors'."
+
+  (let ((bg-list (greenbar-color-list))
+        (start comint-last-output-start)
+        (end (process-mark (get-buffer-process (current-buffer)))))
+
+    ;;(message "greenbar: %S %S %S" start end (replace-regexp-in-string "\n" 
"\\\\n" (buffer-substring start end)))
+    (when (and bg-list (listp bg-list) (not (= start end)))
+      (greenbar-next-bar) ; make sure greenbar state is valid
+      (save-excursion
+        (save-restriction
+          ;; Don't highlight partial last line
+          (goto-char end)
+          (forward-line 0)
+          (setq end (point))
+
+          ;; Highlight the beginning of the start line
+          (goto-char start)
+          (forward-line 0)
+          (setq start (point))
+
+          ;; Limit what we can highlight
+          (narrow-to-region start end)
+
+          ;; Mark every set of lines alternating among bar colors
+          (while (< start end)
+            (goto-char start)
+            (setq greenbar-current-line (forward-line greenbar-current-line))
+
+            ;; Mark the bar
+            (let ((bar-face (nth greenbar-current-bar bg-list)))
+              (font-lock-append-text-property
+               start (point)
+               'font-lock-face (list :background bar-face
+                                     :extend t)))
+
+            ;; Get ready for the next bar
+            (setq start (point))
+
+            ;; When the full bar is complete, set up for next bar
+            (greenbar-next-bar))))))
+  string)
+
+(define-minor-mode greenbar-mode
+  "Enable \"green bar striping\" of comint output"
+  nil nil nil
+  (if greenbar-mode
+      (add-hook 'comint-output-filter-functions
+                #'greenbar-output-filter t t)
+    (remove-hook 'comint-output-filter-functions
+                 #'greenbar-output-filter)))
+
+(provide 'greenbar)
+
+;;; greenbar.el ends here