1.179 class stroke_style

A stroke_style describes how the lines of a graphical are drawn, beyond their thickness (graphical<-pen) and colour. It is used as the graphical<-texture, in place of one of the texture names such as dashed. One stroke_style may be shared by many graphicals.

new(S, stroke_style(round, round, vector(8, 4))),
send(Path, pen, 3),
send(Path, texture, S).

Using a gradient as stroke_style<-paint, a line can change colour along its length:

new(G, gradient(linear, point(0,0), point(200,0))),
send(G, add_stop, 0, colour(red)),
send(G, add_stop, 1, colour(blue)),
send(Line, texture, stroke_style(paint := G)).

Round and square caps and miter joins make a line cover more than the area spanned by its points. Class line and class path take this into account when computing their area.

1.179.1 Instance variables

stroke_style <-> cap: {butt,round,square}

Shape of the ends of a line. butt ends at the end point, round and square extend half the pen beyond it.

Defaults: butt

stroke_style <-> join: {miter,round,bevel}

Shape of the corners of a line.

Defaults: miter

stroke_style <-> miter_limit: num

Miter joins whose tip is more than this times the pen away from the corner are drawn as bevel joins, to avoid long spikes at sharp corners.

Defaults: 10

stroke_style <- dash: texture_name|vector*

Either the name of a dash pattern as accepted by graphical<-texture or a vector of numbers holding the lengths of alternating dashes and gaps. @nil draws a solid line.

Defaults: @nil

stroke_style <-> dash_offset: num

Distance into the dash pattern at the start of the line.

Defaults: 0

stroke_style <-> paint: colour|gradient*

Paint used for the line. If @nil, the line is drawn using graphical<-colour. The paint is ignored for an inactive graphical, which is drawn in its inactive colour.

Defaults: @nil

1.179.2 Send methods

stroke_style ->initialise: cap=[{butt,round,square}], join=[{miter,round,bevel}], dash=[texture_name|vector*], paint=[colour|gradient*]

Create a stroke style.