SignaturePad

A signature capture control that opens in a FloatingPanel overlay (MAUI) or SheetView (Blazor). Users draw on a canvas and tap Sign to export the signature as a PNG image. The Sign button is disabled until the user actually draws something. A Clear button lets users erase and start over.

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Frameworks

.NET MAUI

Blazor

Important: Placement Requirement (MAUI)

SignaturePad uses a FloatingPanel internally, so it must be placed inside an OverlayHost or ShinyContentPage.Panels — just like a standalone FloatingPanel. Placing it outside an overlay host will not display correctly.

Basic Usage

Using ShinyContentPage (recommended)

<shiny:ShinyContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
                         xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                         xmlns:shiny="http://shiny.net/maui/controls"
                         x:Class="MyApp.SignaturePage">
    <shiny:ShinyContentPage.PageContent>
        <VerticalStackLayout Padding="20" Spacing="10">
            <Button Text="Capture Signature" Command="{Binding OpenSignatureCommand}" />
            <Border StrokeShape="RoundRectangle 12"
                    Stroke="LightGray"
                    StrokeThickness="1"
                    Padding="10"
                    IsVisible="{Binding HasSignature}">
                <Image Source="{Binding SignatureImage}"
                       HeightRequest="150"
                       Aspect="AspectFit" />
            </Border>
        </VerticalStackLayout>
    </shiny:ShinyContentPage.PageContent>
    <shiny:ShinyContentPage.Panels>
        <shiny:SignaturePad IsOpen="{Binding IsSignatureOpen}"
                            StrokeColor="Black"
                            SignatureBackgroundColor="#F8F8F8"
                            StrokeWidth="3"
                            SignButtonColor="#6C63FF"
                            CancelButtonColor="#94A3B8"
                            SignCommand="{Binding HandleSignedCommand}"
                            CancelCommand="{Binding HandleCancelledCommand}" />
    </shiny:ShinyContentPage.Panels>
</shiny:ShinyContentPage>

Using OverlayHost (manual)

<ContentPage>
    <Grid>
        <ScrollView>
            <VerticalStackLayout Padding="20" Spacing="10">
                <Button Text="Capture Signature" Command="{Binding OpenSignatureCommand}" />
            </VerticalStackLayout>
        </ScrollView>

        <shiny:OverlayHost>
            <shiny:SignaturePad IsOpen="{Binding IsSignatureOpen}"
                                StrokeColor="Black"
                                SignCommand="{Binding HandleSignedCommand}" />
        </shiny:OverlayHost>
    </Grid>
</ContentPage>

Properties (MAUI)

Property	Type	Default	Description
IsOpen	bool	false	Opens/closes the signature panel (TwoWay)
Position	FloatingPanelPosition	Bottom	Panel slide direction (Bottom, BottomTabs, Top)
IsLocked	bool	true	Prevents drag dismiss of the panel
Detent	DetentValue	Half	Panel snap position
StrokeColor	Color	Black	Drawing stroke color
SignatureBackgroundColor	Color	White	Canvas background color
StrokeWidth	double	3.0	Drawing stroke width
SignButtonText	string	"Sign"	Sign button label
CancelButtonText	string	"Cancel"	Cancel button label
SignButtonColor	Color	Blue	Sign button background color
CancelButtonColor	Color	Gray	Cancel button background color
ShowCancelButton	bool	true	Show/hide the cancel button
PanelBackgroundColor	Color	White	Panel background color
PanelCornerRadius	double	16	Panel corner radius
HasBackdrop	bool	true	Show backdrop behind the panel
ExportWidth	int	600	Exported PNG width in pixels
ExportHeight	int	200	Exported PNG height in pixels
SignCommand	ICommand?	null	Command invoked on sign with SignatureImageEventArgs
CancelCommand	ICommand?	null	Command invoked on cancel

Events (MAUI)

Event	Args	Description
Signed	SignatureImageEventArgs	Fires when the user taps Sign; ImageStream contains the PNG
Cancelled	EventArgs	Fires when the user taps Cancel

SignatureImageEventArgs

Property	Type	Description
ImageStream	Stream	PNG image stream of the captured signature

ViewModel Pattern (MAUI)

public partial class SignatureViewModel : ObservableObject
{
    [ObservableProperty]
    bool isSignatureOpen;

    [ObservableProperty]
    ImageSource? signatureImage;

    public bool HasSignature => SignatureImage != null;

    [RelayCommand]
    void OpenSignature() => IsSignatureOpen = true;

    [RelayCommand]
    void HandleSigned(SignatureImageEventArgs args)
    {
        var ms = new MemoryStream();
        args.ImageStream.CopyTo(ms);
        ms.Position = 0;
        SignatureImage = ImageSource.FromStream(() => ms);
        OnPropertyChanged(nameof(HasSignature));
    }

    [RelayCommand]
    void HandleCancelled() { }

    [RelayCommand]
    void ClearSignature()
    {
        SignatureImage = null;
        OnPropertyChanged(nameof(HasSignature));
    }
}

Blazor Usage

<button @onclick="() => isOpen = true">Capture Signature</button>

@if (signatureDataUrl != null)
{
    <img src="@signatureDataUrl" alt="Captured signature"
         style="max-width:100%;border:1px solid #E5E7EB;border-radius:8px;" />
    <button style="background:#EF4444;color:white;" @onclick="ClearSignature">Clear</button>
}

<SignaturePad @bind-IsOpen="isOpen"
              StrokeColor="#000000"
              SignatureBackgroundColor="#F8F8F8"
              StrokeWidth="3"
              SignButtonColor="#6C63FF"
              CancelButtonColor="#94A3B8"
              Signed="OnSigned"
              Cancelled="OnCancelled" />

@code {
    bool isOpen;
    string? signatureDataUrl;

    void OnSigned(byte[] pngBytes)
    {
        var base64 = Convert.ToBase64String(pngBytes);
        signatureDataUrl = $"data:image/png;base64,{base64}";
    }

    void OnCancelled() { }

    void ClearSignature() => signatureDataUrl = null;
}

Properties (Blazor)

Parameter	Type	Default	Description
IsOpen	bool	false	Opens/closes the sheet (two-way via @bind-IsOpen)
Direction	SheetDirection	Bottom	Sheet slide direction
IsLocked	bool	true	Prevents drag dismiss
Detent	DetentValue	Half	Sheet snap position
StrokeColor	string	"#000000"	CSS stroke color
SignatureBackgroundColor	string	"#FFFFFF"	CSS canvas background
StrokeWidth	double	3	Stroke width
SignButtonText	string	"Sign"	Sign button label
CancelButtonText	string	"Cancel"	Cancel button label
SignButtonColor	string	"#6C63FF"	CSS sign button color
CancelButtonColor	string	"#94A3B8"	CSS cancel button color
ShowCancelButton	bool	true	Show/hide cancel button
PanelBackgroundColor	string	"#FFFFFF"	CSS panel background
PanelCornerRadius	double	16	Panel corner radius
HasBackdrop	bool	true	Show backdrop
ExportWidth	int	600	Exported PNG width
ExportHeight	int	200	Exported PNG height

Events (Blazor)

Event	Type	Description
Signed	EventCallback<byte[]>	Fires with raw PNG bytes when the user signs
Cancelled	EventCallback	Fires when the user cancels

Note

On Blazor, colors are CSS strings. IsOpen supports two-way binding via @bind-IsOpen. Direction replaces MAUI’s Position (SheetDirection vs FloatingPanelPosition). The Signed callback provides raw byte[] PNG data instead of SignatureImageEventArgs.

Features

• Canvas drawing — Touch/pointer-based freehand drawing on a canvas surface
• Sign button gating — The Sign button is disabled until the user draws something
• Clear button — Erase the canvas and start over without closing the panel
• PNG export — Signature is exported as a PNG image at configurable resolution (ExportWidth x ExportHeight). The drawn strokes are scaled uniformly to fit and centered within those dimensions, so the full signature is preserved without clipping or aspect-ratio distortion when the canvas and export sizes differ (differing aspect ratios are letterboxed with the background color)
• FloatingPanel integration — Opens as a bottom/top panel overlay with configurable detent, backdrop, and corner radius
• Auto-reset — Canvas resets automatically after signing or cancelling
• Auto-close — Panel closes automatically after sign or cancel
• iOS edge-swipe protection — While the pad is open, the navigation controller’s interactive “swipe back” gesture is automatically suppressed (and restored on close) so strokes that start near the left screen edge are drawn instead of triggering back-navigation
• Customizable buttons — Configure text, colors, and visibility of the Sign and Cancel buttons

AI Skill

Claude Code GitHub Copilot

Step 1 — Add the marketplace:

claude plugin marketplace add shinyorg/skills

Step 2 — Install the plugin:

claude plugin install controls@shiny

Step 1 — Add the marketplace:

copilot plugin marketplace add https://github.com/shinyorg/skills

Step 2 — Install the plugin:

copilot plugin install controls@shiny

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