alrocar alrocar

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

	import os
	import sys
	import argparse
	try:
	from urllib2 import urlopen
	except ImportError:
	from urllib.request import urlopen

	try:
	from StringIO import BytesIO

	with lines as
	(SELECT cartodb_id, color, ord, ST_Segmentize(ST_MakeLine(st_centroid(the_geom), lead(st_centroid(the_geom)) OVER (ORDER BY ord))::geography, 100000)::geometry as the_geom
	FROM world_borders_four_colors_1_adjacency_list),
	tosplit AS (
	SELECT * FROM lines
	WHERE ST_XMax(the_geom) - ST_XMin(the_geom) > 180
	),
	nosplit AS (
	SELECT * FROM lines
	WHERE ST_XMax(the_geom) - ST_XMin(the_geom) <= 180

	# first create a palette of the portion of the video with more colors

	ffmpeg -y -ss 20 -t 3 -i input.mp4 -vf fps=50,scale=640:-1:flags=lanczos,palettegen palette.png

	# then use the palette to obtain high quality colors

	ffmpeg -i input.mp4 -i palette.png -filter_complex "fps=50,scale=640:-1:flags=lanczos[x];[x][1:v]paletteuse" output.gif

	# -ss -> start from second
	# -t -> duration

	CREATE OR REPLACE FUNCTION adjacency_list(table_name regclass, user_name text) RETURNS void AS $$
	BEGIN
	EXECUTE format('DROP TABLE IF EXISTS %s_adjacency_list;
	CREATE TABLE %s_adjacency_list AS
	SELECT DISTINCT a.cartodb_id,
	array_agg(b.cartodb_id) over (PARTITION BY a.cartodb_id) AS adjacent,
	count(b.*) over (PARTITION BY a.cartodb_id) AS valence,
	0 AS color
	FROM %s a,
	%s b

	A snippet to make a query to BigQuery and import the result in CARTO using both Python client libraries:

	```
	#!/usr/bin/env python

	import argparse
	import time
	import uuid
	from tempfile import NamedTemporaryFile

	<!DOCTYPE html>
	<html>
	<head>
	<title>Reacciones al #AccordDeParis</title>
	<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
	<meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
	<link rel="shortcut icon" href="http://cartodb.com/assets/favicon.ico" />
	<style>
	html, body, #map {
	height: 100%;

	SELECT cartodb_id, ele, time, ST_MAKELINE(the_geom,the_geom2) as the_geom FROM (
	SELECT cartodb_id, row_number() OVER w AS ele, time, the_geom, lead(the_geom) OVER w AS the_geom2
	FROM TRACK_POINTS WINDOW w AS (PARTITION BY track_fid ORDER BY cartodb_id) ) as q
	WHERE the_geom2 IS NOT NULL

	insert into SEGMENTED_DATASET SELECT cartodb_id+n, ST_LineSubstring(the_geom, 100.00*n/length,
	CASE
	WHEN 100.00(n+1) < length THEN 100.00(n+1)/length
	ELSE 1
	END) As the_geom
	FROM
	(SELECT TRACK_GPS.cartodb_id,
	ST_LineMerge(TRACK_GPS.the_geom) AS the_geom,
	ST_Length(TRACK_GPS.the_geom::geography) As length
	FROM TRACK_GPS

	<!DOCTYPE HTML>
	<html>

	<head>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
	<link rel="stylesheet" href="http://libs.cartocdn.com/cartodb.js/v3/3.15/themes/css/cartodb.css" />
	<!-- <link rel="stylesheet" href="https://cartodb-libs.global.ssl.fastly.net/cartodb.js/v3/3.15/themes/css/cartodb.css" /> -->

	<style type="text/css">
	html,