increase png size and crop padding

Dockerfile

@@ -4,7 +4,7 @@ ARG PLZ_DATA=Postleitzahlengebiete_-_OSM.geojson
 ARG PLZ_HIGHLIGHT=wtf_member_plz_prefixes.json
 
 # Set up environment with dependencies
-RUN apt-get update && apt-get install libblas-dev python3-pip libgeos-dev wget -y
+RUN apt-get update && apt-get install libblas-dev python3-pip libgeos-dev wget optipng imagemagick -y
 COPY requirements.txt ./
 RUN pip install -r requirements.txt
 
@@ -16,5 +16,8 @@ COPY $PLZ_HIGHLIGHT ./
 COPY main.py ./
 RUN python3 main.py --plz-data $PLZ_DATA --plz-highlight $PLZ_HIGHLIGHT --out /tmp/map.png
 
+RUN convert -fuzz 5 -trim /tmp/map.png /tmp/map.png
+RUN optipng -o7 /tmp/map.png
+
 # Output map; use with "docker build -t wtf-map . && docker run wtf-map > map.png"
 CMD ["cat", "/tmp/map.png"]

main.py

@@ -48,9 +48,14 @@ def main(
     )
 
     ax.set_facecolor(image_background_color)
-    plt.tight_layout()
+    plt.axis("off")
+    plt.tight_layout(pad=0.0, h_pad=None, w_pad=None)
     plt.savefig(
-        output_file_path, dpi=300, facecolor=image_background_color, edgecolor="none"
+        output_file_path,
+        dpi=600,
+        facecolor=image_background_color,
+        edgecolor="none",
+        bbox_inches='tight',
     )