feat: add barcode scanner plugin (#536)

examples/api/src/views/Scanner.svelte

@@ -0,0 +1,155 @@
+<script>
+  import { scan, checkPermissions, requestPermissions, Format, cancel } from "@tauri-apps/plugin-barcode-scanner";
+
+  export let onMessage;
+
+  let scanning = false;
+  let windowed = true;
+  let formats = [Format.QRCode];
+  const supportedFormats = [Format.QRCode, Format.EAN13];
+
+  async function startScan() {
+    let permission = await checkPermissions();
+    if (permission === 'prompt') {
+      permission = await requestPermissions();
+    }
+    if (permission === 'granted') {
+      scanning = true;
+      scan({ windowed, formats })
+        .then((res) => {
+          scanning = false;
+          onMessage(res);
+        })
+        .catch((error) => {
+          scanning = false;
+          onMessage(error);
+        });
+    } else {
+      onMessage('Permission denied')
+    }
+  }
+
+  async function cancelScan() {
+    await cancel();
+    scanning = false;
+    onMessage("cancelled");
+  }
+</script>
+
+<div class="full-height">
+  <div class:invisible={scanning}>
+    <div>
+      <input type="checkbox" id="scanner-windowed" bind:checked={windowed} />
+      <label for="scanner-windowed">Windowed</label>
+    </div>
+    <div>
+      <select class="input" id="format" multiple bind:value={formats}>
+        {#each supportedFormats as f}
+          <option value={f}>{f}</option>
+        {/each}
+      </select>
+    </div>
+    <button class="btn" type="button" on:click={startScan}>Scan</button>
+  </div>
+  <div class="scanning full-height" class:invisible={!scanning}>
+    <div class="scanner-background">
+      <!-- this background simulates the camera view -->
+    </div>
+    <div class="container full-height">
+      <div class="barcode-scanner--area--container">
+        <div class="relative">
+          <p>Aim your camera at a QR code</p>
+          <button class="btn" type="button" on:click={cancelScan}>Cancel</button>
+        </div>
+        <div class="square surround-cover">
+          <div class="barcode-scanner--area--outer surround-cover">
+            <div class="barcode-scanner--area--inner" />
+          </div>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+
+<style>
+  .invisible {
+    display: none;
+  }
+
+  .full-height {
+    height: 100%;
+  }
+
+  p {
+    color: #fff;
+    font-family: sans-serif;
+    text-align: center;
+    font-weight: 600;
+  }
+
+  .container {
+    width: 100%;
+    height: 100%;
+    overflow: hidden;
+  }
+  .container {
+    display: flex;
+  }
+
+  .relative {
+    position: relative;
+    display: flex;
+    flex-direction: row;
+    justify-content: space-between;
+    z-index: 1;
+  }
+
+  .square {
+    width: 100%;
+    position: relative;
+    overflow: hidden;
+    transition: 0.3s;
+  }
+  .square:after {
+    content: "";
+    top: 0;
+    display: block;
+    padding-bottom: 100%;
+  }
+  .square > div {
+    position: absolute;
+    top: 0;
+    left: 0;
+    bottom: 0;
+    right: 0;
+  }
+
+  .surround-cover {
+    box-shadow: 0 0 0 99999px rgba(0, 0, 0, 0.5);
+  }
+
+  .barcode-scanner--area--container {
+    width: 80%;
+    max-width: min(500px, 80vh);
+    margin: auto;
+  }
+  .barcode-scanner--area--outer {
+    display: flex;
+    border-radius: 1em;
+  }
+  .barcode-scanner--area--inner {
+    width: 100%;
+    margin: 1rem;
+    border: 2px solid #fff;
+    box-shadow: 0px 0px 2px 1px rgb(0 0 0 / 0.5),
+      inset 0px 0px 2px 1px rgb(0 0 0 / 0.5);
+    border-radius: 1rem;
+  }
+
+  .scanner-background {
+    background: linear-gradient(45deg, #673ab7, transparent);
+    background-position: 45% 50%;
+    background-size: cover;
+    background-repeat: no-repeat;
+  }
+</style>