1;;; animate.el --- make text dance 2 3;; Copyright (C) 2001, 2002, 2003, 2004, 2005, 4;; 2006, 2007 Free Software Foundation, Inc. 5 6;; Maintainer: Richard Stallman <rms@gnu.org> 7;; Keywords: games 8 9;; This file is part of GNU Emacs. 10 11;; GNU Emacs is free software; you can redistribute it and/or modify 12;; it under the terms of the GNU General Public License as published by 13;; the Free Software Foundation; either version 2, or (at your option) 14;; any later version. 15 16;; GNU Emacs is distributed in the hope that it will be useful, 17;; but WITHOUT ANY WARRANTY; without even the implied warranty of 18;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19;; GNU General Public License for more details. 20 21;; You should have received a copy of the GNU General Public License 22;; along with GNU Emacs; see the file COPYING. If not, write to the 23;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 24;; Boston, MA 02110-1301, USA. 25 26;;; Commentary: 27 28;; (animate-string STRING VPOS &optional HPOS) 29;; makes the string STRING appear starting at VPOS, HPOS 30;; by having each letter swoop into place from random starting position. 31 32;; animate-birthday-present was the first application of this program. 33 34;;; Code: 35 36;;; STRING is the string to be displayed, 37;;; and DEST-X, DEST-Y say where on the screen 38;;; it should end up. 39 40;;; This function returns a list describing 41;;; all the characters and the paths they should take. 42;;; Each element has the form 43;;; (CHAR START-Y START-X DEST-Y DEST-X). 44 45;;; The start position of each character is chosen randomly. 46;;; The destination is chosen to put it in the right place 47;;; in the string when the whole string finally reaches its 48;;; specified position. 49 50(defun animate-initialize (string vpos hpos) 51 (let ((characters nil)) 52 (dotimes (i (length string)) 53 (setq characters 54 (cons (list (aref string i) 55 ;; Random starting positions. 56 (random (window-height)) 57 (random (1- (window-width))) 58 ;; All the chars should end up 59 ;; on the specified line. 60 vpos 61 ;; The Ith character in the string 62 ;; needs to end up I positions later. 63 (+ hpos i)) 64 characters))) 65 characters)) 66 67;;; Display the characters in CHARACTERS, 68;;; each one FRACTION of the way from its start to its destination. 69;;; If FRACTION is 0, the characters appear in their starting positions. 70;;; If FRACTION is 1, the characters appear in their destinations. 71 72(defun animate-step (characters fraction) 73 (let ((remains (- 1 fraction))) 74 (dolist (item characters) 75 (let ((vpos (+ (* remains (nth 1 item)) 76 (* fraction (nth 3 item)))) 77 (hpos (+ (* remains (nth 2 item)) 78 (* fraction (nth 4 item))))) 79 (animate-place-char (car item) vpos hpos))))) 80 81;;; Place the character CHAR at position VPOS, HPOS in the current buffer. 82(defun animate-place-char (char vpos hpos) 83 (goto-char (window-start)) 84 (let (abbrev-mode) 85 (dotimes (i vpos) 86 (end-of-line) 87 (if (= (forward-line 1) 1) 88 (insert "\n")))) 89 (beginning-of-line) 90 (move-to-column (floor hpos) t) 91 (unless (eolp) (delete-char 1)) 92 (insert-char char 1)) 93 94(defvar animate-n-steps 10 95 "Number of steps to use `animate-string'.") 96 97;;;###autoload 98(defun animate-string (string vpos &optional hpos) 99 "Display STRING starting at position VPOS, HPOS, using animation. 100The characters start at randomly chosen places, 101and all slide in parallel to their final positions, 102passing through `animate-n-steps' positions before the final ones. 103If HPOS is nil (or omitted), center the string horizontally 104in the current window." 105 (let ((characters 106 (animate-initialize string vpos 107 (or hpos 108 ;; HPOS unspecified, so compute 109 ;; it so as to center the string. 110 (max 0 (/ (- (window-width) (length string)) 2)))))) 111 (dotimes (i animate-n-steps) 112 ;; Bind buffer-undo-list so it will be unchanged when we are done. 113 ;; (We're going to undo all our changes anyway.) 114 (let (buffer-undo-list 115 list-to-undo) 116 ;; Display the characters at the Ith position. 117 ;; This inserts them in the buffer. 118 (animate-step characters (/ i 1.0 animate-n-steps)) 119 ;; Make sure buffer is displayed starting at the beginning. 120 (set-window-start nil 1) 121 ;; Display it, and wait just a little while. 122 (sit-for .05) 123 ;; Now undo the changes we made in the buffer. 124 (setq list-to-undo buffer-undo-list) 125 (while list-to-undo 126 (let ((undo-in-progress t)) 127 (setq list-to-undo (primitive-undo 1 list-to-undo)))))) 128 ;; Insert the characters in their final positions. 129 (animate-step characters 1) 130 ;; Put the cursor at the end of the text on the line. 131 (end-of-line) 132 ;; Redisplay so they appear on the screen there. 133 (sit-for 0) 134 ;; This is so that the undo command, used afterwards, 135 ;; will undo the "animate" calls one by one. 136 (undo-boundary))) 137 138;;;###autoload 139(defun animate-sequence (list-of-strings space) 140 "Display strings from LIST-OF-STRING with animation in a new buffer. 141Strings will be separated from each other by SPACE lines." 142 (let ((vpos (/ (- (window-height) 143 1 ;; For the mode-line 144 (* (1- (length list-of-strings)) space) 145 (length list-of-strings)) 146 2))) 147 (switch-to-buffer (get-buffer-create "*Animation*")) 148 (erase-buffer) 149 (sit-for 0) 150 (setq indent-tabs-mode nil) 151 (while list-of-strings 152 (animate-string (car list-of-strings) vpos) 153 (setq vpos (+ vpos space 1)) 154 (setq list-of-strings (cdr list-of-strings))))) 155 156;;;###autoload 157(defun animate-birthday-present (&optional name) 158 "Display one's birthday present in a new buffer. 159You can specify the one's name by NAME; the default value is \"Sarah\"." 160 (interactive (list (read-string "Name (default Sarah): " 161 nil nil "Sarah"))) 162 ;; Make a suitable buffer to display the birthday present in. 163 (switch-to-buffer (get-buffer-create (format "*%s*" name))) 164 (erase-buffer) 165 ;; Display the empty buffer. 166 (sit-for 0) 167 ;; Make sure indentation does not use tabs. 168 ;; They would confuse things. 169 (setq indent-tabs-mode nil) 170 171 (animate-string "Happy Birthday," 6) 172 (animate-string (format "%s" name) 7) 173 174 (sit-for 1) 175 176 (animate-string "You are my sunshine," 10 30) 177 (sit-for .5) 178 (animate-string "My only sunshine." 11 30) 179 (sit-for .5) 180 (animate-string "I'm awful sad that" 12 30) 181 (sit-for .5) 182 (animate-string "You've moved away." 13 30) 183 (sit-for .5) 184 (animate-string "Let's talk together" 15 30) 185 (sit-for .5) 186 (animate-string "And love more deeply." 16 30) 187 (sit-for .5) 188 (animate-string "Please bring back" 17 30) 189 (animate-string "my sunshine" 18 34) 190 (animate-string "to stay!" 19 34)) 191 192(random t) 193 194(provide 'animate) 195 196;;; arch-tag: 275289a3-6ac4-41da-b527-a1147045392f 197;;; animate.el ends here 198