From 146894583bfe0b221fed717b90baaf2562054ff0 Mon Sep 17 00:00:00 2001
From: Mike Lynch <m.lynch@sydney.edu.au>
Date: Sat, 11 Jan 2025 17:18:43 +1100
Subject: [PATCH] First working version of wasm svg->png generator

---
 src/components/download.js | 21 +++++++++------
 src/index.md               | 52 +++++++++++++++++++++++++++++++++++---
 2 files changed, 61 insertions(+), 12 deletions(-)

diff --git a/src/components/download.js b/src/components/download.js
index d0ce83b..6c45b79 100644
--- a/src/components/download.js
+++ b/src/components/download.js
@@ -1,14 +1,16 @@
-// adapted from the DOM.download method as per this issue:
 
-// https://github.com/observablehq/framework/issues/906
+
 
 const xmlns = "http://www.w3.org/2000/xmlns/";
 const xlinkns = "http://www.w3.org/1999/xlink";
 const svgns = "http://www.w3.org/2000/svg";
 
+// adapted from the DOM.download method as per this issue:
+
+// https://github.com/observablehq/framework/issues/906
+
 
 export function download(value, name = "untitled", label = "Save") {
-  console.log("in download");
   const a = document.createElement("a");
   const b = a.appendChild(document.createElement("button"));
   b.textContent = label;
@@ -32,8 +34,6 @@ export function download(value, name = "untitled", label = "Save") {
     b.textContent = "Saving…";
     try {
       const object = await (typeof value === "function" ? value() : value);
-      console.log("svg object:");
-      console.log(object);
       b.textContent = "Download";
       a.href = URL.createObjectURL(object); // eslint-disable-line require-atomic-updates
       console.log(`url = ${a.href}`);
@@ -48,11 +48,16 @@ export function download(value, name = "untitled", label = "Save") {
 }
 
 
-export function serialize_svg(svg) {
+export function svg_to_string(svg) {
   svg = svg.cloneNode(true);
   svg.setAttributeNS(xmlns, "xmlns", svgns);
   svg.setAttributeNS(xmlns, "xmlns:xlink", xlinkns);
   const serializer = new window.XMLSerializer;
-  const string = serializer.serializeToString(svg);
-  return new Blob([string], {type: "image/svg+xml"});
+  return serializer.serializeToString(svg);
+}
+
+
+export function svg_to_blob(svg) {
+  const str = svg_to_string(svg);
+  return new Blob([string], {type: "image/svg+xml"})
 }
diff --git a/src/index.md b/src/index.md
index bec9ffc..6d72f4c 100644
--- a/src/index.md
+++ b/src/index.md
@@ -2,6 +2,8 @@
 toc: false
 ---
 
+
+
 <h1>poptimal</h1>
 
 <p>v1.1.0 | by <a href="https://mikelynch.org">mike lynch</a> | <a href="https://aus.social/@mikelynch">@mikelynch@aus.social</a> | <a href="https://git.tilde.town/bombinans/poptimal">source</a></p>
@@ -14,9 +16,13 @@ toc: false
 
 import {RADIUS_OPTS, DotMaker} from './components/dots.js';
 import {PALETTES, DotControls} from './components/controls.js';
-import {download, serialize_svg} from './components/download.js';
+import {download, svg_to_string, svg_to_blob} from './components/download.js';
 import random from "npm:random";
 
+import * as resvg from 'npm:@resvg/resvg-wasm';
+
+await resvg.initWasm(fetch('https://unpkg.com/@resvg/resvg-wasm/index_bg.wasm'));
+
 const CELL = 10;
 const MAG = 2;
 const WIDTH = 20;
@@ -154,14 +160,52 @@ display(svg.node());
 
 ```js
 
-display(download(() => serialize_svg(svg.node()), "poptimal.svg", "Save as SVG"));
+display(download(() => svg_to_blob(svg.node()), "poptimal.svg", "Save as SVG"));
 
 ```
 
-</p>
-</div>
+```js
+
+const png_img = document.createElement("img");
+
+async function svg_to_png (svg) {
+  // The Wasm must be initialized first
+
+  const svgstr = svg_to_string(svg.node());
+
+  const opts = {
+      background: 'rgba(238, 235, 230, .9)',
+      fitTo: {
+        mode: 'width', // If you need to change the size
+        value: 400,
+      }
+    };
+  const resvgJS = new resvg.Resvg(svgstr, opts)
+  console.log(resvgJS);
+  const pngData = resvgJS.render(svgstr, opts) // Output PNG data, Uint8Array
+  console.log(`pngData = ${pngData}`);
+  const pngBuffer = pngData.asPng();
+  const pngURL = URL.createObjectURL(new Blob([pngBuffer], { type: 'image/png' }))
+  console.log(`url = ${pngURL}`);
+  png_img.src = pngURL
+}
+
+display(png_img);
+
+const made_png = view(Inputs.button("Make PNG"));
+
+```
+
+```js
+made_png;
+console.log(made_png);
+if( made_png > 0 ) {
+  console.log("Trying to make png");
+  await svg_to_png(svg);
+}
 
 
+```
 
 </div>