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Merge pull request #1300 from srcejon/frequency_zoom

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Change frequency zoom so that frequency under cursor remains the same
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Edouard Griffiths 2022-06-22 21:56:42 +02:00 committed by GitHub
commit b6b9bb680d
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1 changed files with 27 additions and 7 deletions
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34
sdrgui/gui/glspectrum.cpp
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@ -3399,6 +3399,20 @@ void GLSpectrum::zoom(QWheelEvent *event)
if ((pwx >= 0.0f) && (pwx <= 1.0f)) if ((pwx >= 0.0f) && (pwx <= 1.0f))
{ {
// When we zoom, we want the frequency under the cursor to remain the same
// Determine frequency at cursor position
float zoomFreq = m_frequencyScale.getRangeMin() + pwx*m_frequencyScale.getRange();
// Calculate current centre frequency
float currentCF = (m_frequencyZoomFactor == 1) ? m_centerFrequency : ((m_frequencyZoomPos - 0.5) * m_sampleRate + m_centerFrequency);
// Calculate difference from frequency under cursor to centre frequency
float freqDiff = (currentCF - zoomFreq);
// Calculate what that difference would be if there was no zoom
float freqDiffZoom1 = freqDiff * m_frequencyZoomFactor;
if (event->angleDelta().y() > 0) // zoom in if (event->angleDelta().y() > 0) // zoom in
{ {
if (m_frequencyZoomFactor < m_maxFrequencyZoom) { if (m_frequencyZoomFactor < m_maxFrequencyZoom) {
@ -3416,7 +3430,17 @@ void GLSpectrum::zoom(QWheelEvent *event)
} }
} }
frequencyZoom(pwx); // Calculate what frequency difference should be at new zoom
float zoomedFreqDiff = freqDiffZoom1 / m_frequencyZoomFactor;
// Then calculate what the center frequency should be
float zoomedCF = zoomFreq + zoomedFreqDiff;
// Calculate zoom position which will set the desired center frequency
float zoomPos = (zoomedCF - m_centerFrequency) / m_sampleRate + 0.5;
zoomPos = std::max(0.0f, zoomPos);
zoomPos = std::min(1.0f, zoomPos);
frequencyZoom(zoomPos);
} }
else else
{ {
@ -3445,13 +3469,9 @@ void GLSpectrum::zoom(QWheelEvent *event)
} }
} }
void GLSpectrum::frequencyZoom(float pw) void GLSpectrum::frequencyZoom(float zoomPos)
{ {
m_frequencyZoomPos += (pw - 0.5f) * (1.0f / m_frequencyZoomFactor); m_frequencyZoomPos = zoomPos;
float lim = 0.5f / m_frequencyZoomFactor;
m_frequencyZoomPos = m_frequencyZoomPos < lim ? lim : m_frequencyZoomPos > 1 - lim ? 1 - lim : m_frequencyZoomPos;
qDebug("GLSpectrum::frequencyZoom: pw: %f p: %f z: %f", pw, m_frequencyZoomPos, m_frequencyZoomFactor);
updateFFTLimits(); updateFFTLimits();
} }