freesewing/markdown/dev/guides/plugins/macros/en.md

title	order
Macros	90

Plugin structure for macros is similar, with a few changes:

• Rather than the hook name, you provide the macro name (that you choose yourself)
• The context (this) of a macro method is always a Part object.

Apart from these, the structure is very similar:

import {name, version} from '../package.json';

export default {
  name,
  version,
  macros: {
    box: function(so) {
      this.points.boxTopLeft = so.anchor;
      this.points.boxTopRight = so.anchor.shift(0, so.size);
      this.points.boxBottomRight = this.points.boxTopRight.shift(-90, so.size);
      this.points.boxBottomLeft = new this.Point(so.anchor.x, this.points.boxBottomRight.y);
     
      this.paths.box = new this.Path()
        .move(this.points.boxTopLeft)
        .line(this.points.boxTopRight)
        .line(this.points.boxBottomRight)
        .line(this.points.boxBottomLeft)
        .close()
        .attr('class', 'box');
		}
	}
}

Did you figure out what this plugin does? It provides a box macro that draws a box on our pattern in a given location with a give size.

We can use it like this:

points.boxAnchor = new Point(100, 100);
macro('box', {
  anchor: points.boxAnchor
  size: 25
}); 

Obviously, you can expect to learn how to call a macro in its documentation, rather than have to comb through its code.

Macros take only 1 argument

When writing a macro, keep in mind that all information that needs to be passed to a macro needs to be contained in a single argument.

Typically, you use a single plain object to configure the macro.