Added converter to improve object serialization

Author: FlorianRappl

src/ElectronNET.API/API/Entities/PageSize.cs

@@ -0,0 +1,20 @@
+namespace ElectronNET.API.Entities;
+
+public class PageSize
+{
+    private readonly string _value;
+
+    public PageSize()
+    {
+    }
+
+    private PageSize(string value) : this() => _value = value;
+
+    public double Height { get; set; }
+
+    public double Width { get; set; }
+
+    public static implicit operator string(PageSize pageSize) => pageSize?._value;
+
+    public static implicit operator PageSize(string value) => new(value);
+}

src/ElectronNET.API/API/Entities/PrintToPDFOptions.cs

@@ -1,4 +1,7 @@
-namespace ElectronNET.API.Entities;
+using ElectronNET.Converter;
+using Newtonsoft.Json;
+
+namespace ElectronNET.API.Entities;
 
 /// <summary>
 /// 
@@ -30,7 +33,8 @@ public class PrintToPDFOptions
     /// `A5`, `A6`, `Legal`, `Letter`, `Tabloid`, `Ledger`, or an Object containing
     /// `height` and `width` in inches. Defaults to `Letter`.
     /// </summary>
-    public object PageSize { get; set; } = "Letter";
+    [JsonConverter(typeof(PageSizeConverter))]
+    public PageSize PageSize { get; set; } = "Letter";
 
     /// <summary>
     /// Paper ranges to print, e.g., '1-5, 8, 11-13'. Defaults to the empty string,

src/ElectronNET.API/Converter/PageSizeConverter.cs

@@ -0,0 +1,43 @@
+using ElectronNET.API.Entities;
+using Newtonsoft.Json;
+using System;
+
+namespace ElectronNET.Converter;
+
+public class PageSizeConverter : JsonConverter<PageSize>
+{
+    public override PageSize ReadJson(JsonReader reader, Type objectType, PageSize existingValue, bool hasExistingValue, JsonSerializer serializer)
+    {
+        if (reader.TokenType == JsonToken.String)
+        {
+            return (string)reader.Value;
+        }
+        else if (reader.TokenType == JsonToken.StartObject)
+        {
+            return serializer.Deserialize<PageSize>(reader);
+        }
+        else
+        {
+            throw new JsonSerializationException("Invalid value for PageSize. Expected true, false, or an object.");
+        }
+    }
+
+    public override void WriteJson(JsonWriter writer, PageSize value, JsonSerializer serializer)
+    {
+        if (value is null)
+        {
+            writer.WriteUndefined();
+        }
+
+        var str = (string)value;
+
+        if (str is not null)
+        {
+            writer.WriteValue(str);
+        }
+        else
+        {
+            serializer.Serialize(writer, value);
+        }
+    }
+}