fix canvas error

app/javascript/draw.js

@@ -89,7 +89,7 @@ window.customElements.define('draw-signature', class extends HTMLElement {
   }
 
   redrawCanvas (oldWidth, oldHeight) {
-    if (this.pad && !this.pad.isEmpty() && oldWidth > 0 && oldHeight > 0) {
+    if (this.pad && !this.pad.isEmpty() && oldWidth > 0 && oldHeight > 0 && this.canvas.width > 0 && this.canvas.height > 0) {
       const sx = this.canvas.width / oldWidth
       const sy = this.canvas.height / oldHeight
 

app/javascript/elements/signature_form.js

@@ -80,7 +80,7 @@ export default targetable(class extends HTMLElement {
   }
 
   redrawCanvas (oldWidth, oldHeight) {
-    if (this.pad && !this.pad.isEmpty() && oldWidth > 0 && oldHeight > 0) {
+    if (this.pad && !this.pad.isEmpty() && oldWidth > 0 && oldHeight > 0 && this.canvas.width > 0 && this.canvas.height > 0) {
       const sx = this.canvas.width / oldWidth
       const sy = this.canvas.height / oldHeight
 

app/javascript/submission_form/signature_step.vue

@@ -586,7 +586,7 @@ export default {
     redrawCanvas (oldWidth, oldHeight) {
       const canvas = this.$refs.canvas
 
-      if (this.pad && !this.isTextSignature && !this.pad.isEmpty() && oldWidth > 0 && oldHeight > 0) {
+      if (this.pad && !this.isTextSignature && !this.pad.isEmpty() && oldWidth > 0 && oldHeight > 0 && canvas.width > 0 && canvas.height > 0) {
         const sx = canvas.width / oldWidth
         const sy = canvas.height / oldHeight