From cafb66bd93c9ac7871468c99ba4ec685383df64b Mon Sep 17 00:00:00 2001
From: Christophe Bliard <christophe.bliard@hiptest.net>
Date: Tue, 8 Aug 2017 10:33:26 +0200
Subject: [PATCH] Add fallback font and missing libs for .png generation

If Verdana.ttf can't be loaded, the font file pointed by the
FALLBACK_FONT_PATH environment variable will be loaded.

This fixes width computation errors that can occur with non-latin
characters when running with Docker.
---
 Dockerfile          | 6 ++++--
 lib/measure-text.js | 6 +++++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 180ec4f066..0d300ab897 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,7 @@
 FROM node:6.9.2-alpine
 
-RUN apk add --update gettext
+RUN apk add --no-cache gettext imagemagick librsvg ttf-dejavu
+ENV FALLBACK_FONT_PATH /usr/share/fonts/ttf-dejavu/DejaVuSans.ttf
 
 RUN mkdir -p /usr/src/app
 RUN mkdir /usr/src/app/private
@@ -9,7 +10,8 @@ WORKDIR /usr/src/app
 ARG NODE_ENV
 ENV NODE_ENV $NODE_ENV
 COPY package.json /usr/src/app/
-RUN npm install
+RUN npm install && \
+    rm -rf /tmp/npm-* /root/.npm
 COPY . /usr/src/app
 
 CMD envsubst < secret.tpl.json > ./private/secret.json && npm start
diff --git a/lib/measure-text.js b/lib/measure-text.js
index dac5f75330..80be4a608f 100644
--- a/lib/measure-text.js
+++ b/lib/measure-text.js
@@ -16,7 +16,11 @@ function loadFont(path, callback) {
   }
 }
 
-loadFont(path.join(__dirname, '..', 'Verdana.ttf'));
+loadFont(path.join(__dirname, '..', 'Verdana.ttf'), function (err) {
+  if (err && process.env.FALLBACK_FONT_PATH) {
+    loadFont(process.env.FALLBACK_FONT_PATH);
+  }
+});
 doc = doc.fontSize(11);
 
 function measure(str) {