diff --git a/lib/zin/wg/think3c/js/v1.js b/lib/zin/wg/think3c/js/v1.js
index d77e057297..da70a71906 100644
--- a/lib/zin/wg/think3c/js/v1.js
+++ b/lib/zin/wg/think3c/js/v1.js
@@ -61,3 +61,20 @@ function binarizeImage(imageData)
     imageData.data = pixels;
     return imageData;
 }
+
+/**
+ * 获取画布尺寸。
+ * Get canvas size.
+ *
+ * @param  number width
+ * @param  number height
+ * @access public
+ * @return object
+ */
+function getCanvasSize(width = 0, height = 0)
+{
+    const maxWidth  = $('.think-model-content').length ? ($('.think-model-content').width() - 50) : 400;
+    const maxHeight = maxWidth;
+
+    return {width, height};
+}