From ac8e42442cc628f4a9eb858e0cf644c3b3760bb7 Mon Sep 17 00:00:00 2001
From: Antonio Piccolboni <antonio@piccolboni.info>
Date: Tue, 18 Sep 2018 21:59:51 -0700
Subject: [PATCH] support for altair figures

---
 pweave/altair/__init__.py | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 pweave/altair/__init__.py

diff --git a/pweave/altair/__init__.py b/pweave/altair/__init__.py
new file mode 100644
index 0000000..69ddf9a
--- /dev/null
+++ b/pweave/altair/__init__.py
@@ -0,0 +1,29 @@
+from IPython.core.display import display_html
+import hashlib
+
+display_html(
+    """
+<script src="https://cdn.jsdelivr.net/npm/vega@3"></script>
+<script src="https://cdn.jsdelivr.net/npm/vega-lite@2"></script>
+<script src="https://cdn.jsdelivr.net/npm/vega-embed@3"></script>
+""",
+    raw=True)
+
+
+def show(plot):
+    """
+    Include an Altair (vega) figure in Pweave document.
+    Generates html output.
+    """
+    json = plot.to_json()
+    id = "A" + hashlib.sha256(json.encode()).hexdigest()
+    display_html(
+        """
+ <div id="{id}"></div>
+  <script type="text/javascript">
+    var spec = {json};
+    var opt = {{"renderer": "canvas", "actions": false}};
+    vegaEmbed("#{id}", spec, opt);
+  </script>
+  """.format(id=id, json=json),
+        raw=True)