avoid rare marker position rounding issue

m0dB · Feb 20, 2023 · c993a20 · c993a20
1 parent aba1759
commit c993a20
Show file tree

Hide file tree

Showing 3 changed files with 14 additions and 3 deletions.
diff --git a/src/waveform/renderers/qopengl/waveformrendermark.cpp b/src/waveform/renderers/qopengl/waveformrendermark.cpp
@@ -315,6 +315,7 @@ void qopengl::WaveformRenderMark::renderGL() {
     }
     m_waveformRenderer->setMarkPositions(marksOnScreen);
 
+    // TODO orientation
     double currentMarkPoint = m_waveformRenderer->getPlayMarkerPosition() *
             m_waveformRenderer->getWidth();
     currentMarkPoint = std::floor(currentMarkPoint);

diff --git a/src/waveform/renderers/waveformwidgetrenderer.cpp b/src/waveform/renderers/waveformwidgetrenderer.cpp
@@ -51,7 +51,8 @@ WaveformWidgetRenderer::WaveformWidgetRenderer(const QString& group)
           m_scaleFactor(1.0),
           m_playMarkerPosition(s_defaultPlayMarkerPosition),
           m_passthroughEnabled(false),
-          m_playPos(-1) {
+          m_playPos(-1.0),
+          m_truePosSample(-1.0) {
     //qDebug() << "WaveformWidgetRenderer";
 
 #ifdef WAVEFORMWIDGETRENDERER_DEBUG
@@ -152,7 +153,7 @@ void WaveformWidgetRenderer::onPreRender(VSyncThread* vsyncThread) {
         m_playPos = round(truePlayPos * m_trackPixelCount) / m_trackPixelCount;
         m_totalVSamples = static_cast<int>(m_trackPixelCount * m_visualSamplePerPixel);
         m_playPosVSample = static_cast<int>(m_playPos * m_totalVSamples);
-
+        m_truePosSample = truePlayPos * static_cast<double>(m_trackSamples);
         double leftOffset = m_playMarkerPosition;
         double rightOffset = 1.0 - m_playMarkerPosition;
 
@@ -169,7 +170,8 @@ void WaveformWidgetRenderer::onPreRender(VSyncThread* vsyncThread) {
         m_firstDisplayedPosition = m_playPos - displayedLengthLeft;
         m_lastDisplayedPosition = m_playPos + displayedLengthRight;
     } else {
-        m_playPos = -1; // disable renderers
+        m_playPos = -1.0; // disable renderers
+        m_truePosSample = -1.0;
     }
 
     //qDebug() << "WaveformWidgetRenderer::onPreRender" <<

diff --git a/src/waveform/renderers/waveformwidgetrenderer.h b/src/waveform/renderers/waveformwidgetrenderer.h
@@ -75,6 +75,13 @@ class WaveformWidgetRenderer {
     // stable and deterministic
     // Transform sample index to pixel in track.
     inline double transformSamplePositionInRendererWorld(double samplePosition) const {
+        if (std::abs(samplePosition - m_truePosSample) < 1.f) {
+            // When asked for the sample position that corresponds with the play
+            // marker, return the play market pixel position. This avoids a rare
+            // rounding issue where a marker at that sample position would be
+            // 1 pixel off.
+            return m_playMarkerPosition * getLength();
+        }
         const double relativePosition = samplePosition / m_trackSamples;
         return transformPositionInRendererWorld(relativePosition);
     }
@@ -219,4 +226,5 @@ class WaveformWidgetRenderer {
 
     bool m_passthroughEnabled;
     double m_playPos;
+    double m_truePosSample;
 };