Chris@1407: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
Chris@1407:
Chris@1407: /*
Chris@1407: Sonic Visualiser
Chris@1407: An audio file viewer and annotation editor.
Chris@1407: Centre for Digital Music, Queen Mary, University of London.
Chris@1407: This file copyright 2006-2017 Chris Cannam and QMUL.
Chris@1407:
Chris@1407: This program is free software; you can redistribute it and/or
Chris@1407: modify it under the terms of the GNU General Public License as
Chris@1407: published by the Free Software Foundation; either version 2 of the
Chris@1407: License, or (at your option) any later version. See the file
Chris@1407: COPYING included with this distribution for more information.
Chris@1407: */
Chris@1407:
Chris@1407: #ifndef SV_SCALE_TICK_INTERVALS_H
Chris@1407: #define SV_SCALE_TICK_INTERVALS_H
Chris@1407:
Chris@1407: #include <string>
Chris@1407: #include <vector>
Chris@1407: #include <cmath>
Chris@1407:
Chris@1419: #include "LogRange.h"
Chris@1419: #include "Debug.h"
Chris@1411:
Chris@1419: // Can't have this on by default, as we're called on every refresh
Chris@1419: //#define DEBUG_SCALE_TICK_INTERVALS 1
Chris@1414:
Chris@1407: class ScaleTickIntervals
Chris@1407: {
Chris@1407: public:
Chris@1407: struct Range {
Chris@1407: double min; // start of value range
Chris@1407: double max; // end of value range
Chris@1412: int n; // number of divisions (approximate only)
Chris@1407: };
Chris@1407:
Chris@1407: struct Tick {
Chris@1407: double value; // value this tick represents
Chris@1407: std::string label; // value as written
Chris@1407: };
Chris@1407:
Chris@1417: typedef std::vector<Tick> Ticks;
Chris@1418:
Chris@1418: /**
Chris@1418: * Return a set of ticks that divide the range r linearly into
Chris@1418: * roughly r.n equal divisions, in such a way as to yield
Chris@1418: * reasonably human-readable labels.
Chris@1418: */
Chris@1407: static Ticks linear(Range r) {
Chris@1414: return linearTicks(r);
Chris@1414: }
Chris@1407:
Chris@1418: /**
Chris@1418: * Return a set of ticks that divide the range r into roughly r.n
Chris@1418: * logarithmic divisions, in such a way as to yield reasonably
Chris@1418: * human-readable labels.
Chris@1418: */
Chris@1414: static Ticks logarithmic(Range r) {
Chris@1418: LogRange::mapRange(r.min, r.max);
Chris@1418: return logarithmicAlready(r);
Chris@1418: }
Chris@1418:
Chris@1418: /**
Chris@1418: * Return a set of ticks that divide the range r into roughly r.n
Chris@1418: * logarithmic divisions, on the asssumption that r.min and r.max
Chris@1418: * already represent the logarithms of the boundary values rather
Chris@1418: * than the values themselves.
Chris@1418: */
Chris@1418: static Ticks logarithmicAlready(Range r) {
Chris@1414: return logTicks(r);
Chris@1414: }
Chris@1418:
Chris@1414: private:
Chris@1418: enum Display {
Chris@1418: Fixed,
Chris@1418: Scientific,
Chris@1418: Auto
Chris@1418: };
Chris@1418:
Chris@1417: struct Instruction {
Chris@1417: double initial; // value of first tick
Chris@1417: double limit; // max from original range
Chris@1417: double spacing; // increment between ticks
Chris@1417: double roundTo; // what all displayed values should be rounded to
Chris@1418: Display display; // whether to use fixed precision (%e, %f, or %g)
Chris@1417: int precision; // number of dp (%f) or sf (%e)
Chris@1417: bool logUnmap; // true if values represent logs of display values
Chris@1417: };
Chris@1417:
Chris@1417: static Instruction linearInstruction(Range r)
Chris@1414: {
Chris@1418: Display display = Auto;
Chris@1418:
Chris@1407: if (r.max < r.min) {
Chris@1417: return linearInstruction({ r.max, r.min, r.n });
Chris@1407: }
Chris@1418: if (r.n < 1 || r.max == r.min) {
Chris@1418: return { r.min, r.min, 1.0, r.min, display, 1, false };
Chris@1418: }
Chris@1407:
Chris@1407: double inc = (r.max - r.min) / r.n;
Chris@1408:
Chris@1408: double digInc = log10(inc);
Chris@1408: double digMax = log10(fabs(r.max));
Chris@1408: double digMin = log10(fabs(r.min));
Chris@1408:
Chris@1418: int precInc = int(floor(digInc));
Chris@1418: double roundTo = pow(10.0, precInc);
Chris@1408:
Chris@1408: if (precInc > -4 && precInc < 4) {
Chris@1418: display = Fixed;
Chris@1418: } else if ((digMax >= -2.0 && digMax <= 3.0) &&
Chris@1408: (digMin >= -3.0 && digMin <= 3.0)) {
Chris@1418: display = Fixed;
Chris@1418: } else {
Chris@1418: display = Scientific;
Chris@1408: }
Chris@1408:
Chris@1408: int precRange = int(ceil(digMax - digInc));
Chris@1408:
Chris@1408: int prec = 1;
Chris@1408:
Chris@1418: if (display == Fixed) {
Chris@1415: if (digInc < 0) {
Chris@1410: prec = -precInc;
Chris@1415: } else {
Chris@1410: prec = 0;
Chris@1408: }
Chris@1408: } else {
Chris@1408: prec = precRange;
Chris@1408: }
Chris@1408:
Chris@1411: #ifdef DEBUG_SCALE_TICK_INTERVALS
Chris@1419: SVDEBUG << "ScaleTickIntervals: calculating linearInstruction" << endl
Chris@1419: << "ScaleTickIntervals: min = " << r.min << ", max = " << r.max
Chris@1419: << ", n = " << r.n << ", inc = " << inc << endl;
Chris@1419: SVDEBUG << "ScaleTickIntervals: digMax = " << digMax
Chris@1419: << ", digInc = " << digInc << endl;
Chris@1419: SVDEBUG << "ScaleTickIntervals: display = " << display
Chris@1419: << ", inc = " << inc << ", precInc = " << precInc
Chris@1419: << ", precRange = " << precRange
Chris@1419: << ", prec = " << prec << ", roundTo = " << roundTo
Chris@1419: << endl;
Chris@1411: #endif
Chris@1418:
Chris@1418: double min = r.min;
Chris@1408:
Chris@1418: if (roundTo != 0.0) {
Chris@1418: inc = round(inc / roundTo) * roundTo;
Chris@1418: if (inc < roundTo) inc = roundTo;
Chris@1418: min = ceil(min / roundTo) * roundTo;
Chris@1418: if (min > r.max) min = r.max;
Chris@1418: }
Chris@1407:
Chris@1418: if (display == Scientific && min != 0.0) {
Chris@1413: double digNewMin = log10(fabs(min));
Chris@1413: if (digNewMin < digInc) {
Chris@1413: prec = int(ceil(digMax - digNewMin));
Chris@1413: #ifdef DEBUG_SCALE_TICK_INTERVALS
Chris@1419: SVDEBUG << "ScaleTickIntervals: min is smaller than increment, adjusting prec to " << prec << endl;
Chris@1413: #endif
Chris@1413: }
Chris@1413: }
Chris@1413:
Chris@1418: return { min, r.max, inc, roundTo, display, prec, false };
Chris@1418: }
Chris@1418:
Chris@1418: static Instruction logInstruction(Range r)
Chris@1418: {
Chris@1418: Display display = Auto;
Chris@1418:
Chris@1418: if (r.n < 1) {
Chris@1418: return {};
Chris@1418: }
Chris@1418: if (r.max < r.min) {
Chris@1418: return logInstruction({ r.max, r.min, r.n });
Chris@1418: }
Chris@1418: if (r.max == r.min) {
Chris@1418: return { r.min, r.max, 1.0, r.min, display, 1, true };
Chris@1418: }
Chris@1418:
Chris@1418: double inc = (r.max - r.min) / r.n;
Chris@1418:
Chris@1418: double digInc = log10(inc);
Chris@1418: int precInc = int(floor(digInc));
Chris@1418: double roundTo = pow(10.0, precInc);
Chris@1418:
Chris@1418: if (roundTo != 0.0) {
Chris@1418: inc = round(inc / roundTo) * roundTo;
Chris@1418: if (inc < roundTo) inc = roundTo;
Chris@1418: }
Chris@1418:
Chris@1418: // if inc is close to giving us powers of two, nudge it
Chris@1418: if (fabs(inc - 0.301) < 0.01) {
Chris@1418: inc = log10(2.0);
Chris@1418: }
Chris@1418:
Chris@1418: // smallest increment as displayed
Chris@1418: double minDispInc =
Chris@1418: LogRange::unmap(r.min + inc) - LogRange::unmap(r.min);
Chris@1418:
Chris@1418: int prec = 1;
Chris@1418:
Chris@1418: if (minDispInc > 0.0) {
Chris@1418: prec = int(floor(log10(minDispInc)));
Chris@1418: if (prec < 0) prec = -prec;
Chris@1418: }
Chris@1418:
Chris@1418: if (r.max >= -2.0 && r.max <= 3.0 &&
Chris@1418: r.min >= -3.0 && r.min <= 3.0) {
Chris@1418: display = Fixed;
Chris@1418: if (prec == 0) prec = 1;
Chris@1418: }
Chris@1419:
Chris@1418: #ifdef DEBUG_SCALE_TICK_INTERVALS
Chris@1419: SVDEBUG << "ScaleTickIntervals: calculating logInstruction" << endl
Chris@1419: << "ScaleTickIntervals: min = " << r.min << ", max = " << r.max
Chris@1419: << ", n = " << r.n << ", inc = " << inc
Chris@1419: << ", minDispInc = " << minDispInc << ", digInc = " << digInc
Chris@1419: << endl;
Chris@1419: SVDEBUG << "ScaleTickIntervals: display = " << display
Chris@1419: << ", inc = " << inc << ", precInc = " << precInc
Chris@1419: << ", prec = " << prec << endl;
Chris@1419: SVDEBUG << "ScaleTickIntervals: roundTo = " << roundTo << endl;
Chris@1418: #endif
Chris@1418:
Chris@1418: double min = r.min;
Chris@1418: if (inc != 0.0) {
Chris@1418: min = ceil(r.min / inc) * inc;
Chris@1418: if (min > r.max) min = r.max;
Chris@1418: }
Chris@1418:
Chris@1418: return { min, r.max, inc, 0.0, display, prec, true };
Chris@1407: }
Chris@1407:
Chris@1414: static Ticks linearTicks(Range r) {
Chris@1417: Instruction instruction = linearInstruction(r);
Chris@1417: Ticks ticks = explode(instruction);
Chris@1417: return ticks;
Chris@1414: }
Chris@1414:
Chris@1414: static Ticks logTicks(Range r) {
Chris@1418: Instruction instruction = logInstruction(r);
Chris@1417: Ticks ticks = explode(instruction);
Chris@1417: return ticks;
Chris@1414: }
Chris@1418:
Chris@1418: static Tick makeTick(Display display, int precision, double value) {
Chris@1414: const int buflen = 40;
Chris@1414: char buffer[buflen];
Chris@1414: snprintf(buffer, buflen,
Chris@1418: display == Auto ? "%.*g" :
Chris@1418: display == Fixed ? "%.*f" :
Chris@1418: "%.*e",
Chris@1414: precision, value);
Chris@1414: return Tick({ value, std::string(buffer) });
Chris@1414: }
Chris@1414:
Chris@1417: static Ticks explode(Instruction instruction) {
Chris@1417:
Chris@1411: #ifdef DEBUG_SCALE_TICK_INTERVALS
Chris@1419: SVDEBUG << "ScaleTickIntervals::explode:" << endl
Chris@1419: << "initial = " << instruction.initial
Chris@1419: << ", limit = " << instruction.limit
Chris@1419: << ", spacing = " << instruction.spacing
Chris@1419: << ", roundTo = " << instruction.roundTo
Chris@1419: << ", display = " << instruction.display
Chris@1419: << ", precision = " << instruction.precision
Chris@1419: << ", logUnmap = " << instruction.logUnmap
Chris@1419: << endl;
Chris@1411: #endif
Chris@1417:
Chris@1417: if (instruction.spacing == 0.0) {
Chris@1417: return {};
Chris@1414: }
Chris@1417:
Chris@1411: double eps = 1e-7;
Chris@1417: if (instruction.spacing < eps * 10.0) {
Chris@1417: eps = instruction.spacing / 10.0;
Chris@1411: }
Chris@1417:
Chris@1417: double max = instruction.limit;
Chris@1412: int n = 0;
Chris@1417:
Chris@1417: Ticks ticks;
Chris@1417:
Chris@1412: while (true) {
Chris@1417: double value = instruction.initial + n * instruction.spacing;
Chris@1414: if (value >= max + eps) {
Chris@1412: break;
Chris@1412: }
Chris@1417: if (instruction.logUnmap) {
Chris@1414: value = pow(10.0, value);
Chris@1414: }
Chris@1418: if (instruction.roundTo != 0.0) {
Chris@1418: value = instruction.roundTo * round(value / instruction.roundTo);
Chris@1418: }
Chris@1418: ticks.push_back(makeTick(instruction.display,
Chris@1417: instruction.precision,
Chris@1417: value));
Chris@1412: ++n;
Chris@1407: }
Chris@1417:
Chris@1417: return ticks;
Chris@1407: }
Chris@1407: };
Chris@1407:
Chris@1407: #endif