Update of /project/gsharp/cvsroot/gsharp In directory common-lisp.net:/tmp/cvs-serv21978

Modified Files: measure.lisp Log Message: Finished (?) adding comments to measure.lisp.

Date: Thu Nov 17 01:42:42 2005 Author: rstrandh

Index: gsharp/measure.lisp diff -u gsharp/measure.lisp:1.6 gsharp/measure.lisp:1.7 --- gsharp/measure.lisp:1.6 Wed Nov 16 20:44:52 2005 +++ gsharp/measure.lisp Thu Nov 17 01:42:42 2005 @@ -349,14 +349,19 @@ (mark-modified (buffer segment))))

;;; temporary stuff +;;; call fun on every list of measures (which make up a line) +;;; in the buffer (defun new-map-over-obseq-subsequences (fun buf) (loop with m = (obseq-interval buf (buffer-pos buf 0 0)) while m do (multiple-value-bind (left right) + ;; find the end points of the interval that contains m (obseq-interval buf m) (funcall fun (loop for mm = left then (obseq-next buf mm) collect mm until (eq mm right))) + ;; move to the next measure after the rightmost one + ;; in the current line (setf m (obseq-next buf right)))))

(defun buffer-cost-method (buffer) @@ -364,6 +369,7 @@

(defmethod recompute-measures ((buffer rbuffer)) (when (modified-p buffer) + ;; for now, invalidate everything (mapc #'adjust-lowpos-highpos (segments buffer)) ;; initialize cost method from buffer-specific style parameters (setf (obseq-cost-method buffer) @@ -377,6 +383,8 @@ ;;; ;;; Cost functions

+;;; As required by the obseq library, define a cost method +;;; that is passed to the cost-comparison methods. (defclass measure-cost-method (cost-method) (;; the min width is taken from the min width of the buffer (min-width :initarg :min-width :reader min-width) @@ -391,11 +399,15 @@ :spacing-style spacing-style :line-width line-width)) +;;; As required by the obseq library, define a sequence cost, i.e., in +;;; this case the cost of a sequece of measures. (defclass measure-seq-cost (seq-cost) ((min-dist :initarg :min-dist :reader min-dist) (coeff :initarg :coeff :reader coeff) (nb-measures :initarg :nb-measures :reader nb-measures)))

+;;; As required by the obseq library, define a total cost, i.e., in +;;; this case the cost of a sequece of sequences of measures. (defclass measure-total-cost (total-cost) ((cost :initarg :cost :reader measure-total-cost)))

@@ -406,6 +418,15 @@ (print-unreadable-object (obj stream :identity t :type t) (format stream "~D" (measure-total-cost obj))))

+;;; As required by the obseq library, this method computes the +;;; combined cost of a sequence of measures by taking the existing +;;; cost of all but the last measures and combining it with the +;;; characteristics of the last measure. The result is a sequence +;;; cost that has the sum of the coefficients of each measure in the +;;; sequence, the min of the min-dists of each measure in the +;;; sequence, and the total number of measures in the sequence. +;;; As far as Gsharp is concerned, this cost computation is +;;; commutable, so rely on Obseq to supply the symmetric method. (defmethod combine-cost ((method measure-cost-method) (seq-cost measure-seq-cost) (elem measure)) @@ -414,6 +435,17 @@ :min-dist (min (min-dist seq-cost) (measure-min-dist elem)) :nb-measures (1+ (nb-measures seq-cost))))

+;;; As required by the obseq library, this method computes the +;;; combined cost of a sequence of sequences of measures by taking the +;;; existing cost of all but the last sequences of measures and +;;; combining it with the sequence cost of the last sequence of +;;; measures. The result is a total cost that has the max of the cost +;;; of each individual sequence of measures. The reason for using the +;;; max is that we do not want for a good line to be able to +;;; compensate for the badness of another. We thus compute the score +;;; that minimizes the maximum of the badness of each line. As far as +;;; Gsharp is concerned, this cost computation is commutable, so rely +;;; on Obseq to supply the symmetric method. (defmethod combine-cost ((method measure-cost-method) (tcost measure-total-cost) (seq-cost measure-seq-cost)) @@ -428,6 +460,8 @@ :cost (measure-seq-cost method seq-cost)))

+;;; As required by the obseq library, this method computes the +;;; sequence cost of a singleton sequence. (defmethod combine-cost ((method measure-cost-method) (elem measure) (whatever (eql nil))) @@ -436,11 +470,21 @@ :min-dist (measure-min-dist elem) :nb-measures 1))

+;;; As required by the obseq library, this method computes the +;;; sequence cost of a singleton sequence. (defmethod combine-cost ((method measure-cost-method) (whatever (eql nil)) (elem measure)) (combine-cost method elem nil))

+;;; The reduced width of a sequence of measures is the sum of the +;;; widths of the measures in the sequence, but ignoring the space +;;; before first timeline. If the min-dist is 0 (which I think is the +;;; case if each measure has no timelines), then the reduced width is +;;; 0, otherwise we obtain the reduced width by multiplying the sum of +;;; the coefficients of each mesure in the sequence, the min-width to +;;; use for the display, and (1/d_min)^k, where d_min is the duration +;;; of the shortest timeline, and k is the spacing style. (defmethod reduced-width ((method measure-cost-method) (seq-cost measure-seq-cost)) (if (zerop (min-dist seq-cost)) @@ -448,42 +492,54 @@ (* (coeff seq-cost) (min-width method) (expt (/ (min-dist seq-cost)) (spacing-style method)))))

+;;; The natural width of a sequence of mesures is like the reduced +;;; width, except that we do not ignore the space before the first +;;; timeline in each measure. That space might be necessary to +;;; parameterize one day, but for now we just use the w_min. (defmethod natural-width ((method measure-cost-method) (seq-cost measure-seq-cost)) (+ (reduced-width method seq-cost) (* (nb-measures seq-cost) (min-width method))))

+;;; The compress factor indicates how by how much a sequence of +;;; measures must be compressed in order to fit the line width at our +;;; disposal. Values > 1 indicate that the sequence of mesures must +;;; be stretched instead of compressed. (defmethod compress-factor ((method measure-cost-method) (seq-cost measure-seq-cost)) (/ (natural-width method seq-cost) (line-width method)))

+;;; As far as Gsharp is concerned, we define the cost of a sequence of +;;; measures as the max of the compress factor and its inverse. In +;;; other words, we consider it as bad to have to stretch a line by x% +;;; as it is to have to compress it by x%, and the more we have to +;;; compress or expand it, the worse it is. This way of doing it is +;;; not great. At some point, we need to severely penalize compressed +;;; lines that become too short to display without overlaps, unless +;;; the line contains a single measure, of course. (defmethod measure-seq-cost ((method measure-cost-method) (seq-cost measure-seq-cost)) (let ((c (compress-factor method seq-cost))) (max c (/ c))))

+;;; As required by the obseq library, we define a method that +;;; determines whether we can prove that adding another measure to an +;;; existing sequence is guaranteed to make the cost of the sequence +;;; higher. The obseq library uses this to radically diminish the +;;; complexity of the computation. (defmethod seq-cost-cannot-decrease ((method measure-cost-method) (seq-cost measure-seq-cost)) (>= (natural-width method seq-cost) (line-width method)))

+;;; Compare the cost of two sequences of measures (defmethod cost-less ((method measure-cost-method) (c1 measure-seq-cost) (c2 measure-seq-cost)) (< (measure-seq-cost method c1) (measure-seq-cost method c2)))

+;;; Compare the cost of two sequences of sequences of measures (defmethod cost-less ((method measure-cost-method) (c1 measure-total-cost) (c2 measure-total-cost)) (< (measure-total-cost c1) (measure-total-cost c2))) - -(defmethod cost-less ((method measure-cost-method) - (c1 measure-seq-cost) - (c2 measure-seq-cost)) - (< (measure-seq-cost method c1) (measure-seq-cost method c2))) - -(defmethod cost-less ((method measure-cost-method) - (c1 measure-total-cost) - (c2 measure-total-cost)) - (< (measure-total-cost c1) (measure-total-cost c2))) -