initial creation of mirror plugin

packages/plugin-mirror/src/index.js

@@ -0,0 +1,83 @@
+import { name, version } from '../package.json'
+
+export const lineValues = (start, end) => {
+  const { x: x1, y: y1 } = end
+  const { x: x2, y: y2 } = start
+  const c = x1 * y2 - x2 * y1
+  return [-(x1 - x2), y1 - y2, c]
+}
+
+export const mirrorGen = (start, end) => {
+  const [A, B, C] = lineValues(start, end)
+  return (point) => {
+    const { x, y } = point
+    const uNom = (B ** 2 - A ** 2) * x - 2 * A * B * y - 2 * A * C
+    const vNom = (A ** 2 - B ** 2) * y - 2 * A * B * x - 2 * B * C
+    const denom = A ** 2 + B ** 2
+    return [uNom / denom, vNom / denom]
+  }
+}
+
+export default {
+  name: name,
+  version: version,
+  hooks: {
+    preRender: function (svg) {
+      if (svg.attributes.get('freesewing:plugin-mirror') === false)
+        svg.attributes.set('freesewing:plugin-mirror', version)
+    }
+  },
+  macros: {
+    macros: {
+      mirror: function ({
+        mirror,
+        clone = true,
+        points = null,
+        paths = null,
+        prefix = 'mirrored',
+        nameFormat // unimplemented
+      }) {
+        const [start, end] = mirror
+        const mirrorPoint = mirrorGen(start, end)
+        const ops = ['from', 'to', 'cp1', 'cp2']
+
+        if (paths !== null) {
+          paths.forEach((path) => {
+            // find existing path id
+            // Find point name from path by looking in the list of all points?
+            let foundId = null
+            for (let id of Object.keys(this.paths)) {
+              if (this.paths[id] === path) {
+                foundId = id
+                break
+              }
+            }
+            if (clone && foundId !== null) {
+              path = clone ? path.clone() : path
+              this.paths[`${prefix}${foundId}`] = path
+            }
+            for (let op in path.ops) {
+              for (let type of ops) {
+                // Iterate over all possible path op points and clone/move point
+                const pathOp = path.ops[op][type]
+                if (typeof pathOp !== 'undefined') {
+                  ;[pathOp.x, pathOp.y] = mirrorPoint(pathOp)
+                  pathOp.attributes.set('mirrored', true)
+                }
+              }
+            }
+          })
+        }
+        if (points !== null) {
+          points.forEach((point) => {
+            if (clone) {
+              point = point.clone()
+            }
+            ;[point.x, point.y] = mirrorPoint(point)
+            point.attributes.set('mirrored', true)
+          })
+        }
+      }
+    }
+  }
+}