Mercurial > hg > svcore
changeset 1460:9528c73aa98c horizontal-scale
Simpler & more consistent log scale tick calculation
| author | Chris Cannam |
|---|---|
| date | Wed, 02 May 2018 15:42:36 +0100 |
| parents | 3a128665fa6f |
| children | 45519a9836e6 |
| files | base/ScaleTickIntervals.h base/test/TestScaleTickIntervals.h |
| diffstat | 2 files changed, 62 insertions(+), 100 deletions(-) [+] |
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--- a/base/ScaleTickIntervals.h Wed May 02 14:17:10 2018 +0100 +++ b/base/ScaleTickIntervals.h Wed May 02 15:42:36 2018 +0100 @@ -83,6 +83,7 @@ double limit; // max from original range double spacing; // increment between ticks double roundTo; // what all displayed values should be rounded to + // (if 0.0, then calculate based on precision) Display display; // whether to use fixed precision (%e, %f, or %g) int precision; // number of dp (%f) or sf (%e) bool logUnmap; // true if values represent logs of display values @@ -199,29 +200,28 @@ double inc = (r.max - r.min) / r.n; +#ifdef DEBUG_SCALE_TICK_INTERVALS + SVDEBUG << "ScaleTickIntervals::logInstruction: " + << "Naive increment is " << inc << endl; +#endif + + int precision = 1; + + if (inc < 1.0) { + precision = int(ceil(1.0 - inc)) + 1; + } + double digInc = log10(inc); int precInc = int(floor(digInc)); + double roundIncTo = pow(10.0, precInc); - double roundTo = pow(10.0, precInc); + inc = round(inc / roundIncTo) * roundIncTo; + if (inc < roundIncTo) inc = roundIncTo; #ifdef DEBUG_SCALE_TICK_INTERVALS - SVDEBUG << "ScaleTickIntervals::logInstruction: Naive increment is " - << inc << ", of " << digInc << "-digit length" << endl; SVDEBUG << "ScaleTickIntervals::logInstruction: " - << "So increment is precision " << precInc - << ", yielding rounding for increment of " - << roundTo << endl; + << "Rounded increment to " << inc << endl; #endif - - if (roundTo != 0.0) { - inc = round(inc / roundTo) * roundTo; - if (inc < roundTo) inc = roundTo; - -#ifdef DEBUG_SCALE_TICK_INTERVALS - SVDEBUG << "ScaleTickIntervals::logInstruction: " - << "Rounded increment to " << inc << endl; -#endif - } // if inc is close to giving us powers of two, nudge it if (fabs(inc - 0.301) < 0.01) { @@ -234,59 +234,13 @@ #endif } - // smallest increment as displayed - double minDispInc = - LogRange::unmap(r.min + inc) - LogRange::unmap(r.min); - -#ifdef DEBUG_SCALE_TICK_INTERVALS - SVDEBUG << "ScaleTickIntervals::logInstruction: " - << "Smallest displayed increment is " << minDispInc << endl; -#endif - - int prec = 1; - - if (minDispInc > 0.0) { - prec = int(ceil(log10(minDispInc))) - 1; - if (prec == 0) prec = 1; - if (prec < 0) prec = -prec; - -#ifdef DEBUG_SCALE_TICK_INTERVALS - SVDEBUG << "ScaleTickIntervals::logInstruction: " - << "Precision therefrom is " << prec << endl; -#endif - } - - if (r.max >= -2.0 && r.max <= 3.0 && - r.min >= -3.0 && r.min <= 3.0) { - display = Fixed; - if (prec == 0) prec = 1; - -#ifdef DEBUG_SCALE_TICK_INTERVALS - SVDEBUG << "ScaleTickIntervals::logInstruction: " - << "Min and max within modest range, adjusted precision to " - << prec << " and display to Fixed" << endl; -#endif - } - -#ifdef DEBUG_SCALE_TICK_INTERVALS - SVDEBUG << "ScaleTickIntervals: calculating logInstruction" << endl - << "ScaleTickIntervals: min = " << r.min << ", max = " << r.max - << ", n = " << r.n << ", inc = " << inc - << ", minDispInc = " << minDispInc << ", digInc = " << digInc - << endl; - SVDEBUG << "ScaleTickIntervals: display = " << display - << ", inc = " << inc << ", precInc = " << precInc - << ", prec = " << prec << endl; - SVDEBUG << "ScaleTickIntervals: roundTo = " << roundTo << endl; -#endif - double min = r.min; if (inc != 0.0) { min = ceil(r.min / inc) * inc; if (min > r.max) min = r.max; } - return { min, r.max, inc, 0.0, display, prec, true }; + return { min, r.max, inc, 0.0, display, precision, true }; } static Ticks linearTicks(Range r) { @@ -312,7 +266,7 @@ if (display == Auto) { - int digits = (value != 0.0 ? int(ceil(log10(abs(value)))) : 0); + int digits = (value != 0.0 ? 1 + int(floor(log10(abs(value)))) : 0); // This is not the same logic as %g uses for determining // whether to delegate to use scientific or fixed notation @@ -326,20 +280,14 @@ display = Fixed; // in %.*f, the * indicates decimal places, not sig figs - if (precision > digits) { + if (precision >= digits) { precision -= digits; - } else if (precision == digits) { - precision = 1; - } else if (precision + 1 < digits) { - double r = pow(10, digits - precision - 1); - value = r * round(value / r); - precision = 0; } else { precision = 0; } } } - + const char *spec = (display == Auto ? "%.*g" : display == Scientific ? "%.*e" : "%.*f"); @@ -386,16 +334,30 @@ Ticks ticks; while (true) { + double value = instruction.initial + n * instruction.spacing; + if (value >= max + eps) { break; } + if (instruction.logUnmap) { value = pow(10.0, value); } - if (instruction.roundTo != 0.0) { - value = instruction.roundTo * round(value / instruction.roundTo); + + double roundTo = instruction.roundTo; + + if (roundTo == 0.0 && value != 0.0) { + // We don't want the internal value secretly not + // matching the displayed one + roundTo = + pow(10, ceil(log10(abs(value))) - instruction.precision); } + + if (roundTo != 0.0) { + value = roundTo * round(value / roundTo); + } + ticks.push_back(makeTick(instruction.display, instruction.precision, value));
--- a/base/test/TestScaleTickIntervals.h Wed May 02 14:17:10 2018 +0100 +++ b/base/test/TestScaleTickIntervals.h Wed May 02 15:42:36 2018 +0100 @@ -428,7 +428,7 @@ // pathological range auto ticks = ScaleTickIntervals::linear({ 1, 1, 10 }); ScaleTickIntervals::Ticks expected { - { 1.0, "1.0" } + { 1.0, "1" } }; compareTicks(ticks, expected); } @@ -498,8 +498,8 @@ auto ticks = ScaleTickIntervals::logarithmic({ 1, 10, 2 }); ScaleTickIntervals::Ticks expected { { 1.0, "1.0" }, - { pow(10.0, 0.5), "3.2" }, - { 10.0, "10.0" }, + { 3.2, "3.2" }, + { 10.0, "10" }, }; compareTicks(ticks, expected); } @@ -518,7 +518,7 @@ { auto ticks = ScaleTickIntervals::logarithmic({ M_PI, 6.022140857e23, 7 }); ScaleTickIntervals::Ticks expected { - { 1000, "1000.0" }, + { 1000, "1000" }, { 1e+06, "1e+06" }, { 1e+09, "1e+09" }, { 1e+12, "1e+12" }, @@ -533,17 +533,17 @@ { auto ticks = ScaleTickIntervals::logarithmic({ 0.465, 778.08, 10 }); ScaleTickIntervals::Ticks expected { - { 0.5, "0.5" }, + { 0.5, "0.50" }, { 1, "1.0" }, { 2, "2.0" }, { 4, "4.0" }, { 8, "8.0" }, - { 16, "16.0" }, - { 32, "32.0" }, - { 64, "64.0" }, - { 128, "128.0" }, - { 256, "256.0" }, - { 512, "512.0" }, + { 16, "16" }, + { 32, "32" }, + { 64, "64" }, + { 130, "130" }, + { 260, "260" }, + { 510, "510" }, }; compareTicks(ticks, expected); } @@ -554,14 +554,14 @@ ScaleTickIntervals::Ticks expected { { 1.0, "1.0" }, { 2.5, "2.5" }, - { 6.0, "6.0" }, - { 16.0, "16.0" }, - { 40.0, "40.0" }, - { 100.0, "100.0" }, - { 250.0, "250.0" }, - { 600.0, "600.0" }, - { 1600.0, "1600.0" }, - { 4000.0, "4000.0" }, + { 6.3, "6.3" }, + { 16.0, "16" }, + { 40.0, "40" }, + { 100.0, "100" }, + { 250.0, "250" }, + { 630.0, "630" }, + { 1600.0, "1600" }, + { 4000.0, "4000" }, { 10000.0, "1e+04" }, }; compareTicks(ticks, expected, true); @@ -587,13 +587,13 @@ auto ticks = ScaleTickIntervals::logarithmic({ 80.0, 800000.0, 10 }); ScaleTickIntervals::Ticks expected { { 100, "100" }, - { 251, "251" }, - { 631, "631" }, - { 1580, "1580" }, - { 3980, "3980" }, - { 10000, "10000" }, - { 25100, "2.5e+04" }, - { 63100, "6.3e+04" }, + { 250, "250" }, + { 630, "630" }, + { 1600, "1600" }, + { 4000, "4000" }, + { 10000, "1e+04" }, + { 25000, "2.5e+04" }, + { 63000, "6.3e+04" }, { 160000, "1.6e+05" }, { 400000, "4e+05" }, };