6.99.37 — ink the size it was drawn, and smoother

Everything reported against v6.99.35 and v6.99.36, measured on the device
rather than guessed at.

A drawing is now the size it was drawn, and sharp

Cropping the picture to the writing in v6.99.35 removed an accident along with
the white space: the old whole-screen picture was being shrunk to fit and
downsampled on the way. Measured at 2x, a 420 pixel picture was laid out at 420
CSS pixels — a 2.00x upscale, and 2.10x the size it was drawn.

Markdown cannot say how big to show an image, so the fix is a pair: ink is saved
at two image pixels for every CSS pixel of drawing, and shown at half size. That
also removed a bug nobody had reported — the same handwriting came out twice as
large in the note if it had been written on the iPad rather than the Mac.

Ink saved by v6.99.34 to v6.99.36 shows at half its size until it is opened and
saved again.

The ink itself is smoother

Two separate faults, both only visible since the nib was thinned to 2.5 CSS
pixels. A wide nib covers them; a fine one draws them.

The Pencil reports every position twice. In a page of handwriting on the
device: of 1038 gaps between consecutive samples, 513 were exactly nought. A
repeated reading says nothing the first one did not, and the pair is a flat step,
so the curve the smoothing followed was a staircase. Dropped rather than
averaged — there is nothing to average. It also halves what a page stores.

And writing fast it leaves gaps. Up to 17 CSS pixels between one reading and
the next, and two long segments meeting is a corner. The path is now filled in
from a Catmull-Rom curve through the readings — a straight fill would put more
points on the same corner and change nothing. Every reading is kept and passed
through, so letter shapes do not move and a ruled line stays straight. Only
steps above 6 pixels are touched; the median is 4.3.

More page than one screen

The canvas is three screens tall, moved with a finger — a finger never draws, so
there is no mode to switch. Gradients at the top and bottom edges show there is
more page in that direction. It stays one tall image.

A drawing reopens where it was left

A saved block is cropped to the writing, so without its position it jumped to the
top left: you saw it where you wrote it the first time and somewhere else every
time after. The position now travels in the file. Where the screen cannot hold it
at that offset — an iPad is a different width in portrait — the ink is brought on
rather than left hanging off an edge where it can be neither seen nor rubbed out.

Ink saved before v6.99.34 carries no position and still opens in the corner.

The tools are icons, and the Ink button stays put

Erase, undo and cancel are labelled icon buttons; Done keeps its word, because it
is the one that ends the drawing.

The Ink button rode up the page as a note grew. Its wrapper was one screen tall
inside a note many screens long, and a sticky element only sticks while its own
box is on screen. The wrapper is now as tall as the note.