From d989579d62e6b1b37996383f4e36c6a9677c6c4e Mon Sep 17 00:00:00 2001
From: Mike Walters <mike@flomp.net>
Date: Thu, 3 Mar 2016 23:54:59 +0000
Subject: [PATCH] spectrogram: Fix caching/tileIDs

---
 spectrogramplot.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/spectrogramplot.cpp b/spectrogramplot.cpp
index 41f5585..9c9031b 100644
--- a/spectrogramplot.cpp
+++ b/spectrogramplot.cpp
@@ -105,9 +105,15 @@ void SpectrogramPlot::paintMid(QPainter &painter, QRect &rect, range_t<off_t> sa
     if (!inputSource || inputSource->count() == 0)
         return;
 
+    off_t sampleOffset = sampleRange.minimum % getStride();
+    off_t tileID = sampleRange.minimum - sampleOffset;
+    int xoffset = sampleOffset / fftSize;
     for (int x = rect.left(); x < rect.right(); x += linesPerTile()) {
-        QPixmap *tile = getPixmapTile(sampleRange.minimum + x * getStride());
-        painter.drawPixmap(QRect(x, rect.y(), linesPerTile(), fftSize), *tile);
+        QPixmap *tile = getPixmapTile(tileID);
+        // TODO: don't draw past rect.right()
+        painter.drawPixmap(QRect(x, rect.y(), linesPerTile() - xoffset, fftSize), *tile, QRect(xoffset, 0, linesPerTile() - xoffset, fftSize));
+        xoffset = 0;
+        tileID += getStride() * linesPerTile();
     }
 }