add: open files from local disk

src/base/dom/file-picker.ts

@@ -0,0 +1,50 @@
+/*
+    Copyright (c) 2025 Xiang Yang.
+    Published under the standard MIT License.
+    Full text available at: https://opensource.org/licenses/MIT
+*/
+
+import { LocalFileSystem } from "../../kicanvas/services/vfs";
+
+export class FilePicker {
+    /**
+     * Open file picker and call callback with the selected files.
+     */
+    static async pick(callback: (vfs: LocalFileSystem) => Promise<void>) {
+        const files = await FilePicker.open_picker();
+        if (files.length > 0) {
+            await callback(new LocalFileSystem(files));
+        }
+    }
+
+    /**
+     * Open the file picker
+     */
+    private static open_picker(): Promise<File[]> {
+        return new Promise((resolve) => {
+            // because the Window:showOpenFilePicker() method is experimental
+            // so we use the traditional technique
+            const input = document.createElement("input");
+
+            input.type = "file";
+            input.style.display = "none";
+            input.multiple = true;
+            input.accept = ".kicad_pcb,.kicad_pro,.kicad_sch";
+
+            input.onchange = (event) => {
+                const files = (event.target as HTMLInputElement).files;
+                if (files && files.length > 0) {
+                    resolve(Array.from(files));
+                } else {
+                    resolve([]);
+                }
+            };
+
+            input.oncancel = () => {
+                resolve([]);
+            };
+
+            input.click();
+        });
+    }
+}

src/kicanvas/elements/kicanvas-shell.css

@@ -84,6 +84,26 @@ section.overlay input::placeholder {
     color: var(--fg);
 }
 
+section.overlay .link_button {
+    color: #81eeff;
+    background: transparent;
+    font-size: 1em;
+    font-weight: normal;
+    text-decoration: underline;
+    outline: none;
+    border: none;
+    box-sizing: border-box;
+    transition: color var(--transition-time-medium) ease;
+}
+
+section.overlay .link_button:focus {
+    border: var(--button-focus-outline);
+}
+
+section.overlay .link_button:hover {
+    color: var(--fg);
+}
+
 section.overlay p.note {
     color: var(--input-placeholder);
     font-size: 1em;

src/kicanvas/elements/kicanvas-shell.ts

@@ -6,6 +6,7 @@
 
 import { later } from "../../base/async";
 import { DropTarget } from "../../base/dom/drag-drop";
+import { FilePicker } from "../../base/dom/file-picker";
 import { CSS, attribute, html, query } from "../../base/web-components";
 import { KCUIElement, KCUIIconElement } from "../../kc-ui";
 import { sprites_url } from "../icons/sprites";
@@ -76,6 +77,9 @@ class KiCanvasShellElement extends KCUIElement {
     @query(`input[name="link"]`, true)
     public link_input: HTMLInputElement;
 
+    @query(`button[name="open_local"]`, true)
+    public open_file_button: HTMLButtonElement;
+
     override initialContentCallback() {
         const url_params = new URLSearchParams(document.location.search);
         const github_paths = url_params.getAll("github");
@@ -111,6 +115,12 @@ class KiCanvasShellElement extends KCUIElement {
             location.searchParams.set("github", link);
             window.history.pushState(null, "", location);
         });
+
+        this.open_file_button.addEventListener("click", async (e) => {
+            FilePicker.pick(async (vfs) => {
+                await this.setup_project(vfs);
+            });
+        });
     }
 
     private async setup_project(vfs: VirtualFileSystem) {
@@ -166,7 +176,13 @@ class KiCanvasShellElement extends KCUIElement {
                         type="text"
                         placeholder="Paste a GitHub link..."
                         autofocus />
-                    <p>or drag & drop your KiCAD files</p>
+                    <p>
+                        or drag & drop your KiCAD files, or<button
+                            name="open_local"
+                            class="link_button">
+                            open from local
+                        </button>
+                    </p>
                     <p class="note">
                         KiCanvas is
                         <a

src/kicanvas/services/vfs.ts

@@ -197,3 +197,35 @@ export class DragAndDropFileSystem extends VirtualFileSystem {
         initiate_download(await this.get(name));
     }
 }
+
+/**
+ * Virtual file system for local files
+ */
+export class LocalFileSystem extends VirtualFileSystem {
+    constructor(private files: File[]) {
+        super();
+    }
+
+    override *list() {
+        for (const entry of this.files) {
+            yield entry.name;
+        }
+    }
+
+    override async has(name: string): Promise<boolean> {
+        return this.files.find((f) => f.name == name) !== undefined;
+    }
+
+    override async get(name: string): Promise<File> {
+        const file = this.files.find((f) => f.name == name);
+        if (file) {
+            return file;
+        } else {
+            throw new Error(`File ${name} not found`);
+        }
+    }
+
+    override async download(name: string) {
+        initiate_download(await this.get(name));
+    }
+}