Update of /project/gsharp/cvsroot/gsharp In directory common-lisp.net:/tmp/cvs-serv19808

Modified Files: drawing.lisp sdl.lisp Log Message: Added more comments in an attempt to improve maintainability. Plus, it helps me understand what I meant when I initially wrote the code.

Date: Tue Nov 15 19:49:52 2005 Author: rstrandh

Index: gsharp/drawing.lisp diff -u gsharp/drawing.lisp:1.19 gsharp/drawing.lisp:1.20 --- gsharp/drawing.lisp:1.19 Sat Nov 12 08:14:28 2005 +++ gsharp/drawing.lisp Tue Nov 15 19:49:52 2005 @@ -534,6 +534,16 @@ (defun element-has-suspended-notes (element) (not (apply #'= (mapcar #'final-xposition (notes element)))))

+;;; table of x offsets (in staff steps) of accendentals. +;;; The first index represents a notehead or a type of accidental. +;;; The second index represents a type of accidentsl. +;;; The third index is a vertical distance, measured in difference +;;; in staff steps between the two. +;;; The table entry gives how much the accidental represented by +;;; the second parameter must be positioned to the left of the +;;; first one. +;;; Entries in the table are offset by 5 in the last dimension +;;; so that vertical distances between -5 and 5 can be represented (defparameter *accidental-offset* ;;; -5 -4 -3 -2 -1 0 1 2 3 4 5 #3A((( 0 0 0 3.5 3.5 3.5 3.5 3.5 3.5 1 0) ; notehead - dbl flat @@ -567,6 +577,11 @@ ( 0 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 2.8 0) ; dbl sharp - sharp ( 0 0 0 2.8 2.8 2.8 2.8 2.8 0 0 0)))) ; dbl sharp - dbl sharp

+;;; given 1) a type of accidental 2) its position (in staff steps) 3) +;;; a type of accidental or a type of notehead, and 4) its position, +;;; return the x offset of the first accidental, i.e., how many staff +;;; steps to the left that it must be moved in order to avoid overlap +;;; with the second one. (defun accidental-distance (acc1 pos1 acc2 pos2) (let ((dist (- pos2 pos1))) (if (> (abs dist) 5) @@ -587,6 +602,13 @@ (:double-sharp 4)) (+ dist 5)))))

+;;; given two notes (where the first one has an accidental, and the +;;; second one may or may not have an accidental) and the conversion +;;; factor between staff steps and x positions, compute the x offset +;;; of the accidental of the first note. If the second note has +;;; an accidental, but that has not been given a final x offset, then +;;; use the x offset of the notehead instead. +;;; (this funtction should probably be renamed accidental-xoffset) (defun accidental-xpos (note1 note2 staff-step) (let* ((acc1 (final-accidental note1)) (pos1 (note-position note1)) @@ -599,9 +621,18 @@ (final-xposition note2)))) (- xpos2 (* staff-step (accidental-distance acc1 pos1 acc2 pos2)))))

+;;; given a note and a list of notes, compute x offset of the accidental +;;; of the note as required by each of the notes in the list. In order +;;; for the accidental of the note not to overlap any of the others, +;;; we must use the minimum of all the x offsets thus computed. +;;; (this function shoudl probably be renamed accidental-min-xoffset) (defun accidental-min-xpos (note1 notes staff-step) (reduce #'min notes :key (lambda (note) (accidental-xpos note1 note staff-step))))

+;;; given a list of notes that have accidentals to place, and a list of +;;; notes that either have no accidentals or with already-placed accidentals, +;;; compute the note in the first list that can be placed as far to the right +;;; as possible. (defun best-accidental (notes-with-accidentals notes staff-step) (reduce (lambda (note1 note2) (if (>= (accidental-min-xpos note1 notes staff-step) (accidental-min-xpos note2 notes staff-step)) @@ -609,14 +640,20 @@ note2)) notes-with-accidentals))

+;;; for each note in a list of notes, if it has an accidental, compute +;;; the position of that accidental and store it in the note. (defun compute-final-accidental-positions (notes x final-stem-direction) (let* ((staff-step (score-pane:staff-step 1)) + ;; sort the notes from top to bottom (notes (sort (copy-list notes) (lambda (x y) (> (note-position x) (note-position y))))) (notes-with-accidentals (remove-if-not #'final-accidental notes))) ;; initially, no accidental has been placed (loop for note in notes do (setf (accidental-position note) nil)) (when (eq final-stem-direction :up) + ;; when the stem direction is :up and there is a suspended note + ;; i.e., one to the right of the stem, then the accidental of the topmost + ;; suspended note is placed first. (let ((first-suspended-note (find x notes-with-accidentals :test #'/= :key #'final-xposition))) (when first-suspended-note @@ -641,6 +678,16 @@ (setf notes (remove (staff (car notes)) notes :test #'eq :key #'staff))) groups))

+;;; draw a cluster. The stem direction and the stem position have +;;; already been computed. +;;; 1. Group notes by staff. +;;; 2. Determine which notes in each group go to the left and which notes +;;; go to the right of the stem. +;;; 3. Determine which notes in each group should be displayed with an accidental. +;;; 4. Compute the x offset of each accidental to be displayed. +;;; 5. Draw the notes in each group +;;; 6. If necessary, draw ledger lines for notes in a group +;;; 7. Draw the stem, if any (defmethod draw-element (pane (element cluster) x &optional (flags t)) (when (notes element) (let ((direction (final-stem-direction element))

Index: gsharp/sdl.lisp diff -u gsharp/sdl.lisp:1.11 gsharp/sdl.lisp:1.12 --- gsharp/sdl.lisp:1.11 Mon Nov 14 23:52:13 2005 +++ gsharp/sdl.lisp Tue Nov 15 19:49:52 2005 @@ -110,6 +110,9 @@ (declare (ignore initargs)) (with-slots (gf-char x-offset y-offset) glyph (setf x-offset (floor (gf-char-min-m gf-char) 4) + ;; adding 1 to gv-char-max-n is necessary because + ;; of a discrepancy between the GF documentation + ;; and the GF file format y-offset (- (ceiling (1+ (gf-char-max-n gf-char)) 4)))))

(defmethod glyph ((font font) glyph-no) @@ -117,6 +120,9 @@ (let ((left (floor (gf-char-min-m gf-char) 4)) (right (ceiling (1+ (gf-char-max-m gf-char)) 4)) (down (floor (gf-char-min-n gf-char) 4)) + ;; adding 1 to gv-char-max-n is necessary because + ;; of a discrepancy between the GF documentation + ;; and the GF file format (up (ceiling (1+ (gf-char-max-n gf-char)) 4)) (matrix (gf-char-matrix gf-char))) (unless pixmap