Add dither algorithm option

showbits-thermal-printer/static/image.html

@@ -13,6 +13,13 @@
         <li>
           <label><input type="checkbox" name="bright" checked /> Bright</label>
         </li>
+        <li>
+          Dithering algorithm:
+          <select name="algo">
+            <option value="floyd-steinberg">Floyd-Steinberg</option>
+            <option value="stucki">Stucki</option>
+          </select>
+        </li>
         <li><button>Print!</button></li>
       </ol>
     </form>