Fabric.js中loadFromJSON无法加载自定义textAnchor属性问题

Hey there! I’ve run into similar hiccups when adding custom properties to Fabric.js objects, so let’s get this sorted out for your textAnchor property.

Here’s exactly what you need to do:

1. Understand the stateProperties Role #

Fabric.js uses the stateProperties array on each object class to decide which properties get included during serialization (toJSON) and deserialization (loadFromJSON). Since you added textAnchor but didn’t add it to this list, Fabric ignores the property entirely when loading your JSON data.

2. Add textAnchor to the Relevant Class’s stateProperties #

You have two solid options here—extend the class in your own code (the safer choice to avoid breaking future library updates) or modify the Fabric.js source directly:

Option A: Extend in Your Own Code (Recommended)

Add this snippet before you call loadFromJSON:

// Add textAnchor to fabric.Text's state properties
fabric.Text.prototype.stateProperties.push('textAnchor');

// Optional: Set a default value for objects that might not define textAnchor
if (!fabric.Text.prototype.textAnchor) {
  fabric.Text.prototype.textAnchor = 'left'; // Adjust to your preferred default
}

If you’re using other text-based classes like fabric.IText, repeat the same logic for those:

fabric.IText.prototype.stateProperties.push('textAnchor');

Option B: Modify Fabric.js Source

If you prefer editing the core library, locate the fabric.Text definition (usually in the unminified fabric.js source). Find the stateProperties array and add 'textAnchor' to its list:

stateProperties: [
  // ... existing properties like 'fontSize', 'fill', 'stroke'
  'textAnchor'
]

3. Double-Check Your Property Setup #

Make sure your textAnchor property is properly defined on text objects with working getters/setters. For example, if you added a custom method to handle textAnchor, ensure that setting object.textAnchor = 'center' correctly updates the object’s rendering behavior.

Once you’ve completed these steps, calling canvas.loadFromJSON() will automatically apply the textAnchor value from your JSON to the corresponding text objects.

内容的提问来源于stack exchange，提问作者DS9