Add SVG output option

[simonw]

I have a hunch that this might perform better. Need to try it out to see.

[simonw]

SVG version:

~ % ab -n 100 -c 1 'http://127.0.0.1:8009/penguins/penguins.seaborn?_seaborn=relplot'
This is ApacheBench, Version 2.3 <$Revision: 1843412 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 127.0.0.1 (be patient).....done


Server Software:        uvicorn
Server Hostname:        127.0.0.1
Server Port:            8009

Document Path:          /penguins/penguins.seaborn?_seaborn=relplot
Document Length:        217486 bytes

Concurrency Level:      1
Time taken for tests:   49.957 seconds
Complete requests:      100
Failed requests:        0
Total transferred:      21764600 bytes
HTML transferred:       21748600 bytes
Requests per second:    2.00 [#/sec] (mean)
Time per request:       499.565 [ms] (mean)
Time per request:       499.565 [ms] (mean, across all concurrent requests)
Transfer rate:          425.46 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.0      0       0
Processing:   455  499  30.3    500     642
Waiting:      455  499  30.3    500     642
Total:        455  500  30.3    500     642

Percentage of the requests served within a certain time (ms)
  50%    500
  66%    514
  75%    516
  80%    520
  90%    533
  95%    553
  98%    569
  99%    642
 100%    642 (longest request)

PNG version:

~ % ab -n 100 -c 1 'http://127.0.0.1:8009/penguins/penguins.seaborn?_seaborn=relplot'
This is ApacheBench, Version 2.3 <$Revision: 1843412 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking 127.0.0.1 (be patient).....done


Server Software:        uvicorn
Server Hostname:        127.0.0.1
Server Port:            8009

Document Path:          /penguins/penguins.seaborn?_seaborn=relplot
Document Length:        42362 bytes

Concurrency Level:      1
Time taken for tests:   44.464 seconds
Complete requests:      100
Failed requests:        0
Total transferred:      4251800 bytes
HTML transferred:       4236200 bytes
Requests per second:    2.25 [#/sec] (mean)
Time per request:       444.641 [ms] (mean)
Time per request:       444.641 [ms] (mean, across all concurrent requests)
Transfer rate:          93.38 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.0      0       0
Processing:   418  444  24.1    435     533
Waiting:      418  444  24.0    435     533
Total:        418  445  24.1    436     533

Percentage of the requests served within a certain time (ms)
  50%    436
  66%    442
  75%    466
  80%    472
  90%    478
  95%    484
  98%    525
  99%    533
 100%    533 (longest request)

[simonw]

PNG performed a little better. But this is odd:

SVG = 217486 bytes
PNG = 42362 bytes

I don't think I believe that. Should dig further.

[simonw]

SVG: https://gist.githubusercontent.com/simonw/f656d4623f944ed31026b9b37f9fca68/raw/65ed5773311914e7cc76d8f81457f9837678d058/penguins.seaborn.svg

[simonw]

I'm going to add a ?_seaborn_output=svg option to opt-in to this.

[simonw]

Here's my prototype:

+++ b/datasette_seaborn/__init__.py
@@ -35,15 +35,15 @@ def render_seaborn(columns, rows, request):
     method_fn = getattr(sns, method)
 
     figure = method_fn(data=df, **kwargs)
-    png = io.BytesIO()
+    image_bytes = io.BytesIO()
     if not hasattr(figure, "savefig"):
         figure = figure.get_figure()
-    figure.savefig(png, format="png")
+    figure.savefig(image_bytes, format="svg")
     if hasattr(figure, "clf"):
         figure.clf()
     else:
         figure.fig.clf()
-    return {"body": png.getvalue(), "content_type": "image/png"}
+    return {"body": image_bytes.getvalue(), "content_type": "image/svg+xml"}