Sparklines

A numeric series as one line of block characters, demoing the p/moul/x/daily/sparkline library.

A series

▁▁▂▄▃▅█▆▅▃▂▁

3, 5, 9, 14, 12, 18, 25, 21, 16, 11, 7, 4

Scaled between its own bounds, 3 and 25. The shape is the point; the axis is not.

The ramp

▁▂▃▄▅▆▇█ — eight levels, low to high.

value	0	1	2	3	4	5	6	7
level	▁	▂	▃	▄	▅	▆	▇	█

A flat series

▅▅▅▅ — 1000, 1000, 1000, 1000

Mid-ramp, not along the floor. A series that never moves has no shape, but drawing it at the bottom would claim it was zero, which is a different thing and a wrong one.

Negatives

▁▃▄▅█▅▂ — -8, -3, 0, 4, 9, 2, -5

Nothing special: the window is the minimum and maximum, wherever zero happens to fall.

A fixed window clamps

-20, 0, 25, 50, 75, 100, 140 against 0..100:

▁▁▂▄▆██

-20 pins to the floor and 140 to the ceiling. Choosing the window keeps a percentage readable, and one outlier cannot flatten the rest of the picture — or break the realm that drew it.

Rounding is floor

value in 0..100	level
0	▁
14	▁
50	▄
85	▆
99	▇
100	█

Only the maximum itself reaches the top of the ramp, so the peak of a series is always visually distinct.

Why integers

Scaling is integer division throughout. Render output has to be byte-identical on every validating node, and floating point is the usual way that quietly stops being true.