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DELETE FROM images WHERE id = 'mandelbrot';
INSERT INTO images (id, width, height) VALUES ('mandelbrot', 400, 400) RETURNING id;
WITH RECURSIVE
image AS (SELECT *, 0.008 AS scale, (width * 5)/7 AS ox, (height / 2) AS oy FROM images WHERE id = 'mandelbrot'),
horizontal(x) AS
(SELECT width FROM image UNION ALL SELECT x - 1 FROM horizontal WHERE x > 1),
vertical(y) AS
(SELECT height FROM image UNION ALL SELECT y - 1 FROM vertical WHERE y > 1),
mando(i, px, py, cx, cy, x, y) AS (
SELECT 0, 0.0, 0.0,
(SELECT (horizontal.x - ox)*scale FROM image), (SELECT (vertical.y - oy)*scale FROM image),
horizontal.x, vertical.y
FROM vertical, horizontal
UNION ALL
SELECT i + 1, px*px - py*py + cx, 2.0*px*py + cy, cx, cy, x, y FROM mando
WHERE (px*px + py*py) < 4.0 AND i < 20
),
mandogrouped(x, y, i) AS (SELECT x, y, max(i) FROM mando GROUP BY x, y),
colors(i, r, g, b) AS (
SELECT 19, 255, 150, 150 UNION ALL
SELECT 10, 150, 120, 120 UNION ALL
SELECT 7, 50, 100, 100 UNION ALL
SELECT 0 , 0, 50, 50
),
_pixels(x, y, r, g, b) AS (
SELECT x, y, c.r, c.g, c.b
FROM mandogrouped g
JOIN colors c ON c.i = (SELECT max(i) FROM colors WHERE i <= g.i)
)
INSERT INTO pixels (image_id, x, y, r, g, b) SELECT 'mandelbrot', x, y, r, g, b FROM _pixels;
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