[Buildroot] [PATCH 1/2] scripts/graph-build-time: clarify backend selection

Luca Ceresoli luca at lucaceresoli.net
Sun Oct 12 10:52:21 UTC 2014


This instruction in the middle of 'import' lines looks very strange.

Also, it was not obvious to me what the 'Agg' backend is.

Both things are actually correct, but it took a while to find out why.
So clarify with a comment to save someone else's time.

Signed-off-by: Luca Ceresoli <luca at lucaceresoli.net>
Cc: Sascha Arthur <sascha.arthur at gmail.com>
Cc: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Signed-off-by: Luca Ceresoli <luca at lucaceresoli.net>
---
 support/scripts/graph-build-time | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/support/scripts/graph-build-time b/support/scripts/graph-build-time
index 4bb90c2..b2817bd 100755
--- a/support/scripts/graph-build-time
+++ b/support/scripts/graph-build-time
@@ -52,7 +52,12 @@
 import matplotlib as mpl
 import numpy
 
+# Use the Agg backend (which produces a PNG output, see
+# http://matplotlib.org/faq/usage_faq.html#what-is-a-backend),
+# otherwise an incorrect backend is used on soe host machines).
+# Note: matplotlib.use() must be called *before* matplotlib.pyplot.
 mpl.use('Agg')
+
 import matplotlib.pyplot as plt
 import matplotlib.font_manager as fm
 import csv
-- 
1.9.1



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