From 698b2e18426df61b25aaf5e74a2055e7417088de Mon Sep 17 00:00:00 2001
From: Lawrence Lee <billee@ucdavis.edu>
Date: Fri, 7 Aug 2020 15:18:02 -0700
Subject: [PATCH] Finish Cairo surface used for waveform

---
 rtgui/histogrampanel.cc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/rtgui/histogrampanel.cc b/rtgui/histogrampanel.cc
index b87d58d89..b6a27a3c1 100644
--- a/rtgui/histogrampanel.cc
+++ b/rtgui/histogrampanel.cc
@@ -1442,6 +1442,7 @@ void HistogramArea::drawWaveform(Cairo::RefPtr<Cairo::Context> &cr, int w, int h
         cr->set_source(surface, 0, 0);
         cr->set_operator(Cairo::OPERATOR_OVER);
         cr->paint();
+        surface->finish();
     }
     surface = Cairo::ImageSurface::create(
         wave_buffer.get(), Cairo::FORMAT_ARGB32, waveform_width, 256, cairo_stride);