set fullscreen padding to the proper width

Author: thestinger

app/src/main/assets/viewer.css

@@ -4,6 +4,7 @@ body, canvas, #padding {
 }
 
 #padding {
+    min-width: 100%;
     background: black;
 }
 

app/src/main/assets/viewer.js

@@ -1,5 +1,6 @@
 "use strict";
 
+const padding = document.getElementById("padding");
 let pdfDoc = null;
 let pageRendering = false;
 let renderPending = false;
@@ -54,6 +55,7 @@ function display(newCanvas) {
     canvas.width = newCanvas.width;
     canvas.style.height = newCanvas.style.height;
     canvas.style.width = newCanvas.style.width;
+    padding.style.width = canvas.style.width;
     canvas.getContext("2d", { alpha: false }).drawImage(newCanvas, 0, 0);
     scrollTo(0, 0);
 }
@@ -190,7 +192,6 @@ function isTextSelected() {
 }
 
 function updateInset() {
-    const padding = document.getElementById("padding");
     const windowInsetTop = channel.getWindowInsetTop() / window.devicePixelRatio + "px";
     padding.style.paddingTop = windowInsetTop;
     textLayerDiv.style.top = windowInsetTop;