Flatten Form Fields

Updated on Jun 5, 2026

Environment

Product Version	Product	Author
2020.1.316	RadPdfProcessing	Martin Velikov

Description

This article demonstrates how to flatten Form Fields.

Solution

Starting with R2 2021, you can achieve this with a single method of the AcroForm. Check the Flatten Form Fields topic for more details.

To flatten form fields, iterate the RadFixedPage Annotations and check whether the annotation type is Widget. If it is, flatten its appearance.

csharp

	public static void FlattenFormFields(RadFixedDocument document)
	{
		if (document.AcroForm.FormFields.Count == 0)
		{
			return;
		}
		
		foreach (RadFixedPage page in document.Pages)
		{
			List<Widget> widgetsToRemove = new List<Widget>();
			FixedContentEditor pageEditor = new FixedContentEditor(page);

			foreach (Annotation annotation in page.Annotations)
			{
				if (annotation.Type == AnnotationType.Widget)
				{
					Widget widget = (Widget)annotation;
					FlattenWidgetAppearance(pageEditor, widget);
					widgetsToRemove.Add(widget);
				}
			}

			foreach (Widget widget in widgetsToRemove)
			{
				page.Annotations.Remove(widget);
			}
		}

		foreach (FormField field in document.AcroForm.FormFields.ToArray())
		{
			document.AcroForm.FormFields.Remove(field);
		}
	}

	private static void FlattenWidgetAppearance(FixedContentEditor pageEditor, Widget widget)
	{
		FormSource widgetAppearance = GetWidgetNormalAppearance(widget);
		pageEditor.Position.Translate(widget.Rect.Left, widget.Rect.Top);
		pageEditor.DrawForm(widgetAppearance, widget.Rect.Width, widget.Rect.Height);
	}

	private static FormSource GetWidgetNormalAppearance(Widget widget)
	{
		FormSource widgetAppearance;
		switch (widget.WidgetContentType)
		{
			case WidgetContentType.PushButtonContent:
				widgetAppearance = ((PushButtonWidget)widget).Content.NormalContentSource;
				break;
			case WidgetContentType.SignatureContent:
				widgetAppearance = ((SignatureWidget)widget).Content.NormalContentSource;
				break;
			case WidgetContentType.VariableContent:
				widgetAppearance = ((VariableContentWidget)widget).Content.NormalContentSource;
				break;
			case WidgetContentType.TwoStatesContent:
				TwoStatesButtonWidget twoStatesWidget = (TwoStatesButtonWidget)widget;
				widgetAppearance = GetTwoStatesWidgetNormalAppearance(twoStatesWidget);
				break;
			default:
				throw new NotSupportedException(string.Format("Not supported widget content type {0}", widget.WidgetContentType));
		}

		return widgetAppearance;
	}

	private static FormSource GetTwoStatesWidgetNormalAppearance(TwoStatesButtonWidget twoStatesWidget)
	{
		FormField field = twoStatesWidget.Field;
		bool isOnState;

		switch (field.FieldType)
		{
			case FormFieldType.CheckBox:
				CheckBoxField checkBox = (CheckBoxField)field;
				isOnState = checkBox.IsChecked;
				break;
			case FormFieldType.RadioButton:
				RadioButtonField radio = (RadioButtonField)field;
				RadioButtonWidget radioWidget = (RadioButtonWidget)twoStatesWidget;

				if (radio.ShouldUpdateRadiosInUnison)
				{
					isOnState = radio.Value != null && radio.Value.Value.Equals(radioWidget.Option.Value);
				}
				else
				{
					isOnState = radio.Value == radioWidget.Option;
				}
				break;
			default:
				throw new NotSupportedException(string.Format("Not supported field type {0} for TwoStateButtonWidget", field.FieldType));
		}

		FormSource widgetAppearance = (isOnState ? twoStatesWidget.OnStateContent : twoStatesWidget.OffStateContent).NormalContentSource;

		return widgetAppearance;
	}

See Also

• Flatten Form Fields
• RadPdfProcessing Overview