fix svg hmi prop parsing

Author: jogibear9988

src/SvgHmi.ts

@@ -55,13 +55,13 @@ export class SvgHmi extends BaseCustomWebComponentConstructorAppend {
 
                     if (attributeName == 'src')
                         this.src = this.getAttribute('src');
-                    else {
-                        const prp = this._svgHmiProperties.get(attributeName);
-                        if (prp != null) {
-                            this['__' + prp.name] = SvgHmi.parseValue(this.getAttribute(attributeName), prp.type);
-                        }
-                    }
-                }
+                    else {
+                        const prp = this._svgHmiProperties.get(attributeName);
+                        if (prp != null) {
+                            this['__' + prp.name] = this._readPropertyAttribute(attributeName, prp.type, prp.default);
+                        }
+                    }
+                }
             }
             this._evaluateSvgBindings();
         });
@@ -108,13 +108,12 @@ export class SvgHmi extends BaseCustomWebComponentConstructorAppend {
                 let d = SvgHmi.parseValue(n.getAttribute('default') ?? "", tp);
                 this._svgHmiProperties.set(nm, { name: name, type: tp, default: d });
 
-                let val = this.getAttribute(nm);
-                this['__' + name] = val == null ? d : SvgHmi.parseValue(val, tp);
-
-                if (this[name]) {
-                    this['__' + name] = SvgHmi.parseValue(this[name], tp);
-                    delete this[name];
-                }
+                this['__' + name] = this._readPropertyAttribute(nm, tp, d);
+
+                if (Object.prototype.hasOwnProperty.call(this, name)) {
+                    this['__' + name] = SvgHmi.parseValue(this[name], tp);
+                    delete this[name];
+                }
 
                 Object.defineProperty(this, name, {
                     get() {
@@ -162,9 +161,16 @@ export class SvgHmi extends BaseCustomWebComponentConstructorAppend {
 
 
             this._evaluateSvgBindings();
-            this.shadowRoot!.appendChild(svgNode);
-        }
-    }
+            this.shadowRoot!.appendChild(svgNode);
+        }
+    }
+
+    private _readPropertyAttribute(attributeName: string, type: string, defaultValue: unknown) {
+        if (this.hasAttribute(attributeName))
+            return SvgHmi.parseValue(this.getAttribute(attributeName) ?? "", type);
+
+        return defaultValue;
+    }
 
     public static camelToDashCase(text: string) {
         return text[0].toLowerCase() + text.substring(1).replace(/([A-Z])/g, (g) => `-${g[0].toLowerCase()}`);
@@ -181,8 +187,8 @@ export class SvgHmi extends BaseCustomWebComponentConstructorAppend {
         switch (type) {
             case "number":
                 return typeof value == "number" ? value : Number(value);
-            case "boolean":
-                return typeof value == "boolean" ? value : String(value).toLowerCase() == "true";
+            case "boolean":
+                return typeof value == "boolean" ? value : value === "" || String(value).toLowerCase() == "true";
             case "string":
                 return String(value);
             case "HmiColor":