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ffproc.py

#!/usr/bin/env python
'''
    Copyright (C) 2004 Aaron Cyril Spike

    This file is part of FretFind 2-D.

    FretFind 2-D 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 2 of the License, or
    (at your option) any later version.

    FretFind 2-D 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 FretFind 2-D; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
'''
import sys
from ffgeom import *
threshold=0.0000000001

def FindFrets(strings, meta, scale, tuning, numfrets):
    scale = scale['steps']

    #if the string ends don't fall on the nut and bridge
    #don't look for partial frets.
    numStrings = len(strings)
    doPartials = True
    parallelFrets = True
    
    nut = Segment(strings[0][0],strings[-1][0])
    bridge = Segment(strings[0][1],strings[-1][1])
    midline = Segment(
        Point((nut[1]['x']+nut[0]['x'])/2.0,(nut[1]['y']+nut[0]['y'])/2.0),
        Point((bridge[1]['x']+bridge[0]['x'])/2.0,(bridge[1]['y']+bridge[0]['y'])/2.0))
    for s in strings:
        if nut.perpDistanceToPoint(s[0])>=threshold or bridge.perpDistanceToPoint(s[1])>=threshold:
            doPartials = False
            break

    denom = ((bridge[1]['y']-bridge[0]['y'])*(nut[1]['x']-nut[0]['x']))-((bridge[1]['x']-bridge[0]['x'])*(nut[1]['y']-nut[0]['y']))
    if denom != 0:
        parallelFrets = False

    fretboard = []
    tones = len(scale)-1
    for i in range(len(strings)):
        base = tuning[i]
        frets = []
        if doPartials:
            frets.append(Segment(meta[i][0],meta[i+1][0]))
        else:
            frets.append(Segment(strings[i][0],strings[i][0]))
        last = strings[i][0]

        for j in range(numfrets):
            step=((base+j-1)%(tones))+1
            ratio=1.0-((scale[step][1]*scale[step-1][0])/(scale[step][0]*scale[step-1][1]))
            x = last['x']+(ratio*(strings[i][1]['x']-last['x']))
            y = last['y']+(ratio*(strings[i][1]['y']-last['y']))
            current = Point(x,y)    
            temp = Segment(strings[i][0],current)
            totalRatio = temp.length()/strings[i].length()
            
            if doPartials:
                #partials depending on outer strings (questionable)
                if parallelFrets:
                    temp = nut.createParallel(current)
                else:
                    temp = Segment(strings[0].pointAtLength(strings[0].length()*totalRatio),
                        strings[-1].pointAtLength(strings[-1].length()*totalRatio))
                frets.append(Segment(intersectSegments(temp,meta[i]),intersectSegments(temp,meta[i+1])))
            else:
                frets.append(Segment(current,current))
            last = current
        fretboard.append(frets)
    return fretboard
    
def FindStringsSingleScale(numStrings,scaleLength,nutWidth,bridgeWidth,oNF,oBF,oNL,oBL):
    strings = []
    meta = []
    nutHalf = nutWidth/2
    bridgeHalf = bridgeWidth/2
    nutCandidateCenter = (nutHalf) + oNL
    bridgeCandidateCenter = (bridgeHalf) + oBL
    if bridgeCandidateCenter >= nutCandidateCenter:
        center = bridgeCandidateCenter
    else:
        center = nutCandidateCenter
    nutStringSpacing = nutWidth/(numStrings-1)
    bridgeStringSpacing = bridgeWidth/(numStrings-1)
    
    for i in range(numStrings):
        strings.append(Segment(Point(center+nutHalf-(i*nutStringSpacing),0),
            Point(center+bridgeHalf-(i*bridgeStringSpacing),scaleLength)))

    meta.append(Segment(Point(center+nutHalf+oNF,0),Point(center+bridgeHalf+oBF,scaleLength)))
    for i in range(1,numStrings):
        meta.append(Segment(
            Point((strings[i-1][0]['x']+strings[i][0]['x'])/2.0,
                (strings[i-1][0]['y']+strings[i][0]['y'])/2.0),
            Point((strings[i-1][1]['x']+strings[i][1]['x'])/2.0,
                (strings[i-1][1]['y']+strings[i][1]['y'])/2.0)))
    meta.append(Segment(Point(center-(nutHalf+oNL),0),Point(center-(bridgeHalf+oBL),scaleLength)))

    return strings, meta

def FindStringsMultiScale(numStrings,scaleLengthF,scaleLengthL,nutWidth,bridgeWidth,perp,oNF,oBF,oNL,oBL):
    strings = []
    meta = []
    nutHalf = nutWidth/2
    bridgeHalf = bridgeWidth/2
    nutCandidateCenter = (nutHalf)+oNL
    bridgeCandidateCenter = (bridgeHalf)+oBL
    if bridgeCandidateCenter >= nutCandidateCenter:
        xcenter = bridgeCandidateCenter
    else:
        nutCandidateCenter

    fbnxf = xcenter+nutHalf+oNF
    fbbxf = xcenter+bridgeHalf+oBF
    fbnxl = xcenter-(nutHalf+oNL)
    fbbxl = xcenter-(bridgeHalf+oBL)

    snxf = xcenter+nutHalf
    sbxf = xcenter+bridgeHalf
    snxl = xcenter-nutHalf
    sbxl = xcenter-bridgeHalf

    fdeltax = sbxf-snxf
    ldeltax = sbxl-snxl
    fdeltay = math.sqrt((scaleLengthF*scaleLengthF)-(fdeltax*fdeltax))
    ldeltay = math.sqrt((scaleLengthL*scaleLengthL)-(ldeltax*ldeltax))

    fperp = perp*fdeltay
    lperp = perp*ldeltay

    #temporarily place first and last strings
    first = Segment(Point(snxf,0),Point(sbxf,fdeltay))
    last = Segment(Point(snxl,0),Point(sbxl,ldeltay))
    
    if fdeltay<=ldeltay:
        first.translate(0,(lperp-fperp))
    else:
        last.translate(0,(fperp-lperp))

    nut = Segment(first[0].copy(),last[0].copy())
    bridge = Segment(first[1].copy(),last[1].copy())
    #overhang measurements are now converted from delta x to along line lengths
    oNF = (oNF*nut.length())/nutWidth
    oNL = (oNL*nut.length())/nutWidth
    oBF = (oBF*bridge.length())/bridgeWidth
    oBL = (oBL*bridge.length())/bridgeWidth
    #place fretboard edges
    fbf = Segment(nut.pointAtLength(-oNF),bridge.pointAtLength(-oBF))
    fbl = Segment(nut.pointAtLength(nut.length()+oNL),bridge.pointAtLength(bridge.length()+oBL))
    #normalize values into the first quadrant via translate
    if fbf[0]['y']<0 or fbl[0]['y']<0:
        if fbf[0]['y']<=fbl[0]['y']:
            move = -fbf[0]['y']
        else:
            move = -fbl[0]['y']
        
        first.translate(0,move)
        last.translate(0,move)
        nut.translate(0,move)
        bridge.translate(0,move)
        fbf.translate(0,move)
        fbl.translate(0,move)

    #output values
    nutStringSpacing = nut.length()/(numStrings-1)
    bridgeStringSpacing = bridge.length()/(numStrings-1)
    strings.append(first)
    for i in range(1,numStrings-1):
        n = nut.pointAtLength(i*nutStringSpacing)
        b = bridge.pointAtLength(i*bridgeStringSpacing)
        strings.append(Segment(Point(n['x'],n['y']),Point(b['x'],b['y'])))
    strings.append(last)

    meta.append(fbf)
    for i in range(1,numStrings):
        meta.append(Segment(
            Point((strings[i-1][0]['x']+strings[i][0]['x'])/2.0,
                (strings[i-1][0]['y']+strings[i][0]['y'])/2.0),
            Point((strings[i-1][1]['x']+strings[i][1]['x'])/2.0,
                (strings[i-1][1]['y']+strings[i][1]['y'])/2.0)))
    
    meta.append(fbl)
    
    return strings, meta

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