Customizing the Annotation Toolbar in Our Flutter Viewer

The annotation toolbar in PSPDFKit is designed to be flexible and highly configurable. This guide details how to customize the annotation toolbar.


You can show or hide the annotation toolbar using the annotation button in the main toolbar.


Using Custom Buttons

To add a custom button to the annotation toolbar, please refer to our video tutorial and blog post about how to bridge native iOS code to Flutter.

Annotation Preset Customization

You can customize the default properties of annotation tools using the PspdfkitViewController.setAnnotationConfigurations method. The example below shows how to set default properties for the ink and free text annotation tools:

                AnnotationTool.inkPen: InkAnnotationConfiguration(
                  thickness: 10,
                  fillColor: Colors.white,
                  alpha: 0.5,
                AnnotationTool.freeText: FreeTextAnnotationConfiguration(
                  fontSize: 40,
                  fillColor: Colors.white,
                  alpha: 0.5,

Available Preset Configuration Options

The table below shows the configuration options available for each annotation type and platform.

Annotation Type Configuration Options Android iOS
Ink color, fillColor, alpha, thickness, blendMode
Free Text color, fillColor, alpha, fontSize, fontName, fillColor, alpha
Shape color, fillColor, alpha, thickness, borderStyle, borderEffect, blendMode
Line color, alpha, thickness, borderStyle, borderEffect, blendMode, lineEndStyle
Markup color, alpha, blendMode, thickness,
Stamp alpha, blendMode
Note color, alpha, iconName
Redaction color, fillColor, overlayText, repeatOverlayText, outlineColor
Image alpha, blendMode
Measurements color, alpha, thickness, blendMode, scale, precision

Options Available for Specific Platforms

Option Description Android iOS
blendMode The blend mode of the annotation.
borderEffect The border effect of the annotation.
maximumThickness Maximum annotation thickness.
minimumThickness Minimum annotation thickness.
maximumAlpha Maximum possible opacity of the annotation.
minimumAlpha Minimum possible opacity of the annotation.
minimumFontSize Minimum font size of the free text annotation.
maximumFontSize Maximum font size of the free text annotation.
availableFonts Available fonts for the free text annotation.
showColorPicker Whether to show the color picker.
forceDefaults Whether to show the opacity slider.
availableProperties Available annotation properties to be displayed in the inspector.