Unity3D Editor Tool to convert Unity GUI Text objects to Text Mesh Pro Text Objects

UGuiTextToTextMeshPro.cs

using UnityEngine;
using UnityEditor;
using UnityEngine.UI;
using TMPro;
using TMPro.EditorUtilities;

public class UGuiTextToTextMeshPro : Editor
{
	[MenuItem("GameObject/UI/Convert To Text Mesh Pro", false, 4000)]
	static void DoIt()
	{
		Text uiText = Selection.activeGameObject.GetComponent<Text>();
		if (uiText == null)
		{
			EditorUtility.DisplayDialog(
				"ERROR!", "You must select a Unity UI Text Object to convert.", "OK", "");
			return;
		}

		MenuCommand command = new MenuCommand(uiText);

		// If you have an error due to this line then go to TMPro_CreateObjectMenu.cs
		// and make this method public.
		TMPro_CreateObjectMenu.CreateTextMeshProGuiObjectPerform(command);

		TextMeshProUGUI tmp = Selection.activeGameObject.GetComponent<TextMeshProUGUI>();

		if (tmp == null)
		{
			EditorUtility.DisplayDialog(
				"ERROR!",
				"Something went wrong! Text Mesh Pro did not select the newly created object.",
				"OK",
				"");
			return;
		}

		tmp.fontStyle = GetTmpFontStyle(uiText.fontStyle);

		tmp.fontSize = uiText.fontSize;
		tmp.fontSizeMin = uiText.resizeTextMinSize;
		tmp.fontSizeMax = uiText.resizeTextMaxSize;
		tmp.enableAutoSizing = uiText.resizeTextForBestFit;
		tmp.alignment = GetTmpAlignment(uiText.alignment);
		tmp.text = uiText.text;
		tmp.color = uiText.color;

		tmp.transform.SetParent(uiText.transform.parent);
		tmp.name = uiText.name;

		tmp.rectTransform.anchoredPosition3D = uiText.rectTransform.anchoredPosition3D;
		tmp.rectTransform.anchorMax = uiText.rectTransform.anchorMax;
		tmp.rectTransform.anchorMin = uiText.rectTransform.anchorMin;
		tmp.rectTransform.localPosition = uiText.rectTransform.localPosition;
		tmp.rectTransform.localRotation = uiText.rectTransform.localRotation;
		tmp.rectTransform.localScale = uiText.rectTransform.localScale;
		tmp.rectTransform.pivot = uiText.rectTransform.pivot;
		tmp.rectTransform.sizeDelta = uiText.rectTransform.sizeDelta;

		tmp.transform.SetSiblingIndex(uiText.transform.GetSiblingIndex());

		// Copy all other components
		Component[] components = uiText.GetComponents<Component>();
		int componentsCopied = 0;
		for (int i = 0; i < components.Length; i++)
		{
			var thisType = components[i].GetType();
			if (thisType == typeof(Text) || 
				thisType == typeof(RectTransform) || 
				thisType == typeof(Transform) ||
				thisType == typeof(CanvasRenderer))
				continue;

			UnityEditorInternal.ComponentUtility.CopyComponent(components[i]);
			UnityEditorInternal.ComponentUtility.PasteComponentAsNew(tmp.gameObject);

			componentsCopied++;
		}

		if (componentsCopied == 0)
			Undo.DestroyObjectImmediate((Object)uiText.gameObject);
		else
		{
			EditorUtility.DisplayDialog(
				"uGUI to TextMesh Pro",
				string.Format(
					"{0} components copied. Please check for accuracy as some references may not transfer properly.", 
					componentsCopied),
				"OK",
				"");
			uiText.name += " OLD";
			uiText.gameObject.SetActive(false);
		}
	}


	private static FontStyles GetTmpFontStyle(FontStyle uGuiFontStyle)
	{
		FontStyles tmp = FontStyles.Normal;
		switch (uGuiFontStyle)
		{
			case FontStyle.Normal:
			default:
				tmp = FontStyles.Normal;
				break;
			case FontStyle.Bold:
				tmp = FontStyles.Bold;
				break;
			case FontStyle.Italic:
				tmp = FontStyles.Italic;
				break;
			case FontStyle.BoldAndItalic:
				tmp = FontStyles.Bold | FontStyles.Italic;
				break;
		}

		return tmp;
	}


	private static TextAlignmentOptions GetTmpAlignment(TextAnchor uGuiAlignment)
	{
		TextAlignmentOptions alignment = TextAlignmentOptions.TopLeft;

		switch (uGuiAlignment)
		{
			default:
			case TextAnchor.UpperLeft:
				alignment = TextAlignmentOptions.TopLeft;
				break;
			case TextAnchor.UpperCenter:
				alignment = TextAlignmentOptions.Top;
				break;
			case TextAnchor.UpperRight:
				alignment = TextAlignmentOptions.TopRight;
				break;
			case TextAnchor.MiddleLeft:
				alignment = TextAlignmentOptions.MidlineLeft;
				break;
			case TextAnchor.MiddleCenter:
				alignment = TextAlignmentOptions.Midline;
				break;
			case TextAnchor.MiddleRight:
				alignment = TextAlignmentOptions.MidlineRight;
				break;
			case TextAnchor.LowerLeft:
				alignment = TextAlignmentOptions.BottomLeft;
				break;
			case TextAnchor.LowerCenter:
				alignment = TextAlignmentOptions.Bottom;
				break;
			case TextAnchor.LowerRight:
				alignment = TextAlignmentOptions.BottomRight;
				break;
		}

		return alignment;
	}
}

Thanks to Naphier it was very helpful!

I forked a new version which includes levilansing's update and added a missing Using that was needed when compiling under VS 2017 for Unity 2019.4.