[breaking]: FreeSewing v4 (#7297)

Refer to the CHANGELOG for all info.

---------

Co-authored-by: Wouter van Wageningen <wouter.vdub@yahoo.com>
Co-authored-by: Josh Munic <jpmunic@gmail.com>
Co-authored-by: Jonathan Haas <haasjona@gmail.com>

packages/react/components/Editor/lib/export/pdf.mjs

@@ -0,0 +1,59 @@
+import PDFDocument from 'pdfkit/js/pdfkit.standalone.js'
+
+/**
+ * PdfKit, the library we're using for pdf generation, uses points as a unit,
+ * so when we tell it things like where to put the svg and how big the svg is,
+ * we need those numbers to be in points. The svg uses mm internally, so when
+ * we do spatial reasoning inside the svg, we need to know values in mm
+ * */
+export const mmToPoints = 2.834645669291339
+
+/**
+ * A PDFKit PDF instance
+ */
+export const Pdf = ({ size, layout }) => {
+  const pdf = new PDFDocument({
+    size,
+    layout,
+  })
+
+  /*
+   * PdfKit wants to flush the buffer on each new page.
+   * We can't save directly from inside a worker, so we have to manage the
+   * buffers ourselves so we can return a blob
+   */
+  const buffers = []
+
+  /*
+   * Use a listener to add new data to our buffer storage
+   */
+  pdf.on('data', buffers.push.bind(buffers))
+
+  /*
+   * Convert the pdf to a blob
+   */
+  pdf.toBlob = function () {
+    return new Promise((resolve) => {
+      /*
+       * We have to do it this way so that the document flushes everything to buffers
+       */
+      pdf.on('end', () => {
+        /*
+         * Convert buffers to a blob
+         */
+        resolve(
+          new Blob(buffers, {
+            type: 'application/pdf',
+          })
+        )
+      })
+
+      /*
+       * End the stream
+       */
+      pdf.end()
+    })
+  }
+
+  return pdf
+}