Add text tool (close #5)

src/index.html

@@ -131,19 +131,20 @@ file, You can obtain one at http://mozilla.org/MPL/2.0/.
         </div>
         <div class="d-inline-block"><span id="lockstatus" title="Private key locked"><i class="fas fa-lock"></i></span> <span id="statustext"></span></div>
         <div class="btn-toolbar" role="toolbar">
-            <div class="btn-group me-2 mb-2" role="group" aria-label="First group">
+            <div class="btn-group me-2 mb-2" role="group" aria-label="Second group">
                 <div class="btn btn-primary" onclick="pdfZoom('fitheight');"><i class="fas fa-arrows-alt-v"></i> Fit Height</div>
                 <div class="btn btn-primary" onclick="pdfZoom('fitwidth');"><i class="fas fa-arrows-alt-h"></i> Fit Width</div>
                 <div class="btn btn-primary" onclick="pdfZoom('out');"><i class="fas fa-search-minus"></i> Zoom Out</div>
                 <div class="btn btn-primary" onclick="pdfZoom('in');"><i class="fas fa-search-plus"></i> Zoom In</div>
             </div>
-            <div class="btn-group me-2 mb-2" role="group" aria-label="Second group">
+            <div class="btn-group me-2 mb-2" role="group" aria-label="Third group">
                 <div class="btn btn-primary" onclick="activateStampDrawTool()"><i class="fas fa-stamp"></i> Stamp/Seal</div>
                 <div class="btn btn-primary" onclick="activateClientSignaturePad()"><i class="fas fa-file-signature"></i> Sign (Client)</div>
                 <div class="btn btn-primary" onclick="activateNotarySignatureTool()"><i class="fas fa-file-signature"></i> Sign (Notary)</div>
+                <div class="btn btn-primary" onclick="activateTextTool()"><i class="fas fa-font"></i> Add Text</div>
                 <div class="btn btn-primary" onclick="disableGuideBox()">Cancel</div>
             </div>
-            <div class="btn-group mb-2" role="group" aria-label="Third group">
+            <div class="btn-group mb-2" role="group" aria-label="Fourth group">
                 <div class="btn btn-primary" onclick="addPage()"><i class="fas fa-plus"></i> Append Blank Page</div>
             </div>
         </div>

src/js/drawtools.js

@@ -43,6 +43,31 @@ function makeStampImage(callback) {
     });
 }
 
+function activateTextTool() {
+    var text = prompt("");
+    if (text == "") {
+        return;
+    }
+    var canvas = document.createElement('canvas');
+    canvas.width = 2000;
+    canvas.height = 400;
+    var ctx = canvas.getContext('2d');
+
+    ctx.font = "50px sans-serif";
+    ctx.fillText(text, 0, 50);
+
+    const image = new Image();
+    image.src = canvas.toDataURL();
+    image.width = 500;
+    image.height = 100;
+
+    activeDrawImage = image;
+
+    image.onload = function () {
+        enableGuideBox(activeDrawImage);
+    };
+}
+
 function activateStampDrawTool() {
     makeStampImage(function (image) {
         activeDrawImage = image;