Thin diagonals crossing in both directions, forming a mesh of small squares

Crosshatch

Crosshatch crosses two diagonals inside one square cell. Take it to darken a surface without covering it: the mesh reads as shading, and the spacing sets how dark it goes.

Example

<?php

declare(strict_types=1);

use Atelier\Pattern\Pattern;
use Atelier\Pattern\PatternRegistry;
use Atelier\Svg\Document;
use Atelier\Svg\Dumper\CompactXmlDumper;
use Atelier\Svg\Element\Shape\RectElement;

require __DIR__.'/vendor/autoload.php';

$crosshatch = Pattern::crosshatch(spacing: 12, thickness: 1.2);

$document = Document::create(360, 200);

(new PatternRegistry($crosshatch))->attachTo($document);

$surface = new RectElement();
$surface->setX('0')->setY('0')->setWidth('360')->setHeight('200');
$surface->setAttribute('fill', $crosshatch->fill());

$document->getRootElement()?->appendChild($surface);

echo (new CompactXmlDumper())->dump($document);

Options

Pattern::crosshatch() takes two measurements in user units. Style applies afterwards, and each call returns a new tile.

Setting	Default	Effect
`spacing`	`12`	side of the square tile; perpendicular spacing between parallel diagonals is `spacing / sqrt(2)`
`thickness`	`1.2`	line width, at most the spacing
`angle`	`0`	turns the tile at construction; the same result as `withAngle()`, given where the geometry is chosen
`withColor(string)`	`currentColor`	stroke of both diagonals
`withOpacity(?float)`	none	opacity of the tile, applied to the whole drawing at once, so the crossings keep the same tone as the lines
`withAngle(float)`	`0`	turns the mesh; at `45` the diagonals become a horizontal and a vertical rule
`withId(string)`	derived	fixes the identifier instead of deriving it from the tile content

A thickness above the spacing throws InvalidArgumentException.

How the tile closes

The tile is a square of the spacing, and the two diagonals run corner to corner: M 0 0 L s s and M s 0 L 0 s. Every line end sits exactly on a corner of the tile.

The stroke keeps the default butt cap, so the cap of one line meets the cap of the neighbouring tile's line head on, at the same angle, on the same point. The two read as one continuous diagonal, and nothing has to be drawn twice.