aboutsummaryrefslogtreecommitdiff
path: root/examples/circle.sql
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--examples/circle.sql18
1 files changed, 18 insertions, 0 deletions
diff --git a/examples/circle.sql b/examples/circle.sql
new file mode 100644
index 0000000..46874cc
--- /dev/null
+++ b/examples/circle.sql
@@ -0,0 +1,18 @@
+DELETE FROM images WHERE id = 'circle';
+INSERT INTO images (id, width, height) VALUES ('circle', 200, 200) RETURNING id;
+
+WITH RECURSIVE
+ image AS (SELECT * FROM images WHERE id = 'circle'),
+ circle AS (SELECT width/2 AS cx, height/2 AS cy, 80 AS radius FROM image),
+ 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),
+ _pixels(x, y, r, g, b) AS (SELECT
+ x, y,
+ 150,
+ 255 * MAX(0, MIN(1, (SELECT POW(x - cx, 2) + POW(y - cy, 2) - POW(radius, 2) FROM circle))),
+ 150
+ FROM vertical, horizontal
+ )
+INSERT INTO pixels (image_id, x, y, r, g, b) SELECT 'circle', x, y, r, g, b FROM _pixels;