Signature capture in Windows Phone 8.1 - xaml

Question

I'm surprised that I'm unable to find any solution for capturing signature in Windows Phone 8.1. So far I found only one in StackOverflow here... but it complains that WriteableBitmap.DrawLine method isn't available.
Code from the above link:
using Windows.Foundation;
using Windows.UI;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Media.Imaging;
namespace ProofOfConcept.App.Controls
{
public class SignatureCaptureControl : Canvas
{
private WriteableBitmap _writeableBitmap;
private Point _currentPoint;
private Point _oldPoint;
public SignatureCaptureControl()
{
_writeableBitmap = new WriteableBitmap(300, 130);
PointerPressed += SignatureCaptureControl_PointerPressed;
PointerMoved += SignatureCaptureControl_PointerMoved;
}
private void SignatureCaptureControl_PointerPressed(object sender, PointerRoutedEventArgs e)
{
_currentPoint = e.GetCurrentPoint(this).Position;
_oldPoint = _currentPoint;
}
void SignatureCaptureControl_PointerMoved(object sender, PointerRoutedEventArgs e)
{
_currentPoint = e.GetCurrentPoint(this).Position;
_writeableBitmap.DrawLine((int)_currentPoint.X, (int)_currentPoint.Y, (int)_oldPoint.X, (int)_oldPoint.Y, PenColor);
this.InvalidateArrange();
_oldPoint = _currentPoint;
}
public void ClearSignature()
{
_writeableBitmap.Clear();
}
}
}

Answer 1

This code sample requires the WriteableBitmapEx library, the DrawLine method is defined as an extension method in that library.
You can install this package in NuGet package manager.

Answer 2

Finally I found a sample code that does exactly what I was looking for. It does let the user scribble their signature or whatever on the canvas, I'm yet to figure out how to save the image and upload it to a webservice. I'll get to that later. But here is the code to create a drawing pad.
Link to the website where I found the code.
I made it as a UserControl.
This is how I used the UserControl:
<Grid x:Name="inkPanel">
<Controls:SignatureCaptureControl/>
</Grid>
UserControl Xaml:
<UserControl
x:Class="MyApp.Controls.SignatureCaptureControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MyApp.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="170"></RowDefinition>
<RowDefinition Height="60"></RowDefinition>
<RowDefinition Height="50"></RowDefinition>
</Grid.RowDefinitions>
<Canvas x:Name="inkCanvas" Grid.Row="0">
<Rectangle x:Name="rect" VerticalAlignment="Top" Height="150" Width="360" Fill="#FFF4F4F5" Stroke="Black" />
</Canvas>
<PasswordBox x:Name="txtPin" Grid.Row="1" Width="360" PlaceholderText="Enter Pin">
</PasswordBox>
<StackPanel Orientation="Horizontal" Grid.Row="2" Margin="0,10,0,0" HorizontalAlignment="Center">
<Button Name="btnAccept" Content="Accept" Click="btnAccept_Click"></Button>
<Button Name="btnClear" Content="Clear" Click="btnClear_Click"></Button>
</StackPanel>
</Grid>
</UserControl>
Code Behind:
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Media.Imaging;
using Windows.UI.Xaml.Navigation;
using Windows.UI;
// The User Control item template is documented at http://go.microsoft.com/fwlink/?LinkId=234236
namespace MyApp.Controls
{
public sealed partial class SignatureCaptureControl : UserControl
{
Windows.UI.Xaml.Shapes.Path _Current;
public SignatureCaptureControl()
{
this.InitializeComponent();
inkCanvas.PointerPressed += inkCanvas_PointerPressed;
inkCanvas.PointerMoved += inkCanvas_PointerMoved;
inkCanvas.PointerReleased += inkCanvas_PointerReleased;
inkCanvas.PointerExited += inkCanvas_PointerReleased;
}
void inkCanvas_PointerReleased(object sender, PointerRoutedEventArgs e)
{
_Current = null;
}
void inkCanvas_PointerMoved(object sender, PointerRoutedEventArgs e)
{
var pointer = e.GetCurrentPoint(inkCanvas);
if (!pointer.Properties.IsLeftButtonPressed || _Current == null)
return;
var segments = (_Current.Data as PathGeometry).Figures.First().Segments.First() as PolyLineSegment;
segments.Points.Add(pointer.Position);
}
void inkCanvas_PointerPressed(object sender, PointerRoutedEventArgs e)
{
var pointer = e.GetCurrentPoint(inkCanvas);
if (!pointer.Properties.IsLeftButtonPressed)
return;
_Current = new Windows.UI.Xaml.Shapes.Path
{
Data = new PathGeometry
{
Figures = { new PathFigure { StartPoint = pointer.Position, Segments = { new PolyLineSegment() } } }
},
Stroke = new SolidColorBrush(Colors.Black),
StrokeThickness = 4d,
};
inkCanvas.Children.Add(_Current);
}
private void btnClear_Click(object sender, RoutedEventArgs e)
{
inkCanvas.Children.Clear();
inkCanvas.Children.Add(rect);
txtPin.Password = "";
}
private void btnAccept_Click(object sender, RoutedEventArgs e)
{
}
}
}