Polish controller graphs and its views.

controllers/graphs.py

 """ Controllers for building graphs using pandas library
 
 """
-import base64
-import io
-
-
 from citations_tools import (PLOT_ALL,
                              PLOT_PER_DOMAIN,
                              PLOT_PER_PROJECT,
@@ -21,7 +17,14 @@ from models.selector import YEAR_SUBMIT
 
 
 def citations():
-    """Return graphs showing citations
+    """Generate figures with citations plots.
+
+    Returns:
+        dict:
+            * fig1 (matplotlib.Figure)
+            * fig2 (matplotlib.Figure)
+            * fig3 (matplotlib.Figure)
+            * fig4 (matplotlib.Figure)
 
     """
     import pandas as pd
@@ -142,25 +145,7 @@ def citations():
     #
     # rendering
     #
-    dct = {}
-
-    buf1 = io.BytesIO()
-    fig1.savefig(buf1, format="svg")
-    dct["fig1"] = base64.b64encode(buf1.getbuffer()).decode("ascii")
-
-    buf2 = io.BytesIO()
-    fig2.savefig(buf2, format="svg")
-    dct["fig2"] = base64.b64encode(buf2.getbuffer()).decode("ascii")
-
-    buf3 = io.BytesIO()
-    fig3.savefig(buf3, format="svg")
-    dct["fig3"] = base64.b64encode(buf3.getbuffer()).decode("ascii")
-
-    buf4 = io.BytesIO()
-    fig4.savefig(buf4, format="svg")
-    dct["fig4"] = base64.b64encode(buf4.getbuffer()).decode("ascii")
-
-    return dict(**dct)
+    return dict(fig1=fig1, fig2=fig2, fig3=fig3, fig4=fig4)
 
 
 def dashboard():
@@ -168,6 +153,10 @@ def dashboard():
     Cumulative distribution for the publications are shown for
     the current year.
 
+    Returns:
+        dict:
+            * fig (matplotlib.Figure)
+
     """
     current_year = request.now.year
     dashboard_start = current.app.dashboard_start_year
@@ -219,12 +208,8 @@ def dashboard():
     linechart(db, selector, target=ax2, title=title)
 
     # delegate the rendering to the view
-    buf = io.BytesIO()
-    fig.savefig(buf, format="svg")
-    data = base64.b64encode(buf.getbuffer()).decode("ascii")
-
     response.view = "graphs/index.html"
-    return dict(data=data)
+    return dict(fig=fig)
 
 
 def publications_versus_time():
@@ -249,12 +234,5 @@ def publications_versus_time():
         linechart(db, selector, target=ax)
 
     # delegate the rendering to the view
-    extension = request.extension
-    fmt = ("svg" if extension == "html" else extension)
-
-    buf = io.BytesIO()
-    fig.savefig(buf, format=fmt)
-    data = base64.b64encode(buf.getbuffer()).decode("ascii")
-
-    response.view = "graphs/index.%s" % extension
-    return dict(data=data)
+    response.view = f"graphs/index.{request.extension}"
+    return dict(fig=fig)

views/graphs/citations.html

 {{
     #--------------------------------------------------------------------------
     #
-    # The python controller return image as a string:
-    #   - data (string)
+    # The python controller return matplotlib image(s)
     #
     #--------------------------------------------------------------------------
+    import base64
+    import io
     import urllib.parse
 
-    # encode special character bo be used in the image URI
-    fig1 = urllib.parse.quote(fig1)
-    fig2 = urllib.parse.quote(fig2)
-    fig3 = urllib.parse.quote(fig3)
-    fig4 = urllib.parse.quote(fig4)
+    buf1 = io.BytesIO()
+    fig1.savefig(buf1, format="svg")
+    data1 = base64.b64encode(buf1.getbuffer()).decode("ascii")
+    data1 = urllib.parse.quote(data1)
+
+    buf2 = io.BytesIO()
+    fig2.savefig(buf2, format="svg")
+    data2 = base64.b64encode(buf2.getbuffer()).decode("ascii")
+    data2 = urllib.parse.quote(data2)
+
+    buf3 = io.BytesIO()
+    fig3.savefig(buf3, format="svg")
+    data3 = base64.b64encode(buf3.getbuffer()).decode("ascii")
+    data3 = urllib.parse.quote(data3)
+
+    buf4 = io.BytesIO()
+    fig4.savefig(buf4, format="svg")
+    data4 = base64.b64encode(buf4.getbuffer()).decode("ascii")
+    data4 = urllib.parse.quote(data4)
 
 }}
 
@@ -19,7 +34,7 @@
 1 General
 </h2>
 
-<img src="data:image/svg+xml;base64,{{=fig1}}" height=400>
+<img src="data:image/svg+xml;base64,{{=data1}}" height=400>
 
 <h2 class="dbui-h2" style="margin-bottom: 0ex; font-variant: small-caps;">
 2 Evolution of estimators as function of time
@@ -28,19 +43,19 @@
 2.1 Total number of citations
 </h2>
 
-<img src="data:image/svg+xml;base64,{{=fig2}}" height=400>
+<img src="data:image/svg+xml;base64,{{=data2}}" height=400>
 
 <h2 class="dbui-h2" style="margin-bottom: 0ex;margin-top: 0ex;">
 2.2 Average number of citations per article
 </h2>
 
-<img src="data:image/svg+xml;base64,{{=fig3}}" height=400>
+<img src="data:image/svg+xml;base64,{{=data3}}" height=400>
 
 <h2 class="dbui-h2" style="margin-bottom: 0ex;margin-top: 0ex;">
 2.3 h-index
 </h2>
 
-<img src="data:image/svg+xml;base64,{{=fig4}}" height=400>
+<img src="data:image/svg+xml;base64,{{=data4}}" height=400>
 
 {{
     from datetime import datetime

views/graphs/index.html

 {{
     #--------------------------------------------------------------------------
     #
-    # The python controller return image as a string:
-    #   - data (string)
+    # The python controller return matplotlib.Image
     #
     #--------------------------------------------------------------------------
+    import base64
+    import io
     import urllib.parse
 
-    # encode special charactier bo be used in the image URI
+    buf = io.BytesIO()
+    fig.savefig(buf, format="svg")
+    data = base64.b64encode(buf.getbuffer()).decode("ascii")
     data = urllib.parse.quote(data)
 
 }}

views/graphs/index.pdf

 {{
+    import base64
     import io
+
+    buf = io.BytesIO()
+    fig.savefig(buf, format="pdf)
+    data = base64.b64encode(buf.getbuffer()).decode("ascii")
+
     response.body = io.StringIO()
 
     response.headers['Content-Type']='application/pdf'