Mercurial > hg > svgui
changeset 1253:822edd9bb665
Restrict colour 3d plot log scale range to 10 orders of magnitude
| author | Chris Cannam |
|---|---|
| date | Tue, 28 Feb 2017 16:34:59 +0000 |
| parents | b0b5776d2156 |
| children | b3603483228d |
| files | layer/ColourScale.cpp |
| diffstat | 1 files changed, 18 insertions(+), 1 deletions(-) [+] |
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--- a/layer/ColourScale.cpp Tue Feb 28 16:34:01 2017 +0000 +++ b/layer/ColourScale.cpp Tue Feb 28 16:34:59 2017 +0000 @@ -44,7 +44,24 @@ if (m_params.scaleType == ColourScaleType::Log) { - LogRange::mapRange(m_mappedMin, m_mappedMax); + // When used in e.g. spectrogram, we have a range with a min + // value of zero. The LogRange converts that to a threshold + // value of -10, so for a range of e.g. (0,1) we end up with + // (-10,0) as the mapped range. + // + // But in other contexts we could end up with a mapped range + // much larger than that if we have a small non-zero minimum + // value (less than 1e-10), or a particularly large + // maximum. That's unlikely to give us good results, so let's + // insist that the mapped log range has no more than 10 + // difference between min and max, to match the behaviour when + // min == 0 at the input. + // + double threshold = -10.0; + LogRange::mapRange(m_mappedMin, m_mappedMax, threshold); + if (m_mappedMin < m_mappedMax + threshold) { + m_mappedMin = m_mappedMax + threshold; + } } else if (m_params.scaleType == ColourScaleType::PlusMinusOne) {