Month: December 2014

Drawing a heart using Path in WPF / WinRT

Standard

While writing a shape matching app for my daughter I’ve been generating several different shapes. While most were straightforward, creating a heart took a little bit of work and research that I thought I would share to possibly save someone time in the future.

<Canvas>
    <Path Stroke="Red" StrokeThickness="3" 
        Data="M 241,200 
              A 20,20 0 0 0 200,240
              C 210,250 240,270 240,270
              C 240,270 260,260 280,240
              A 20,20 0 0 0 239,200
              " />
</Canvas>

This is making use of 2 arcs and 2 Bezier curves.
M – moves start position to designated location (x, y)
A – specify line size & draw an arc from current to a new position
C – draw cubic Bezier to X, with control points at Y and Z

There are a few different mathematical equations for drawing a heart shape including the following:

x = 16sin^3(t)
y = 13cos(t) - 5cos(2t) - 2cos(3t) - cos(4t)

and 

((x^2 + y^2 - 1)^3) - (x^2 * y^3) = 0

Hopefully this saves you some time if you are trying to draw a heart!  Good coding!

WPF – Advanced Animation Effects

Standard

When designing an application there are many reasons to use an Animation Effect to an element in order to draw attention to it. My specific implementation was for monitoring application but the effects can be leveraged in many scenarios. Here are 5 common variations of requested animation effects.

GIF Example of Output

The XAML

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions" x:Class="MainWindow"
    Title="MainWindow" Height="450" Width="250">
    <Window.Resources>

        <!-- Marching Ants -->
        <Storyboard x:Key="MarchingAnts">
                <DoubleAnimation BeginTime="00:00:00"
                                Storyboard.TargetName="AlertBox"
                                Storyboard.TargetProperty="StrokeThickness"
                                To="4"
                                Duration="0:0:0.25" />
                           <!-- If you want to run counter-clockwise, just swap the 'From' and 'To' values. -->
                <DoubleAnimation BeginTime="00:00:00" RepeatBehavior="Forever" Storyboard.TargetName="AlertBox" Storyboard.TargetProperty="StrokeDashOffset" 
                                Duration="0:3:0" From="1000" To="0"/>
        </Storyboard>

        <!-- Pulse -->
        <Storyboard x:Key="Pulse" RepeatBehavior="Forever">
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)" Storyboard.TargetName="PulseBox">
                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="1.15"/>
                <EasingDoubleKeyFrame KeyTime="0:0:1" Value="1"/>
            </DoubleAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)" Storyboard.TargetName="PulseBox">
                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="1.15"/>
                <EasingDoubleKeyFrame KeyTime="0:0:1" Value="1"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>

        <!-- Flipper -->
        <Storyboard x:Key="Flipper" RepeatBehavior="Forever">
            <PointAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransformOrigin)" Storyboard.TargetName="FlipperBox">
                <EasingPointKeyFrame KeyTime="0:0:1" Value="0.5,0.5"/>
                <EasingPointKeyFrame KeyTime="0:0:2" Value="0.5,0.5"/>
            </PointAnimationUsingKeyFrames>
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)" Storyboard.TargetName="FlipperBox">
                <EasingDoubleKeyFrame KeyTime="0:0:1" Value="-1"/>
                <EasingDoubleKeyFrame KeyTime="0:0:2" Value="1"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>


        <!-- Elasic Lines -->
        <Storyboard x:Key="ElasticLines" RepeatBehavior="Forever" AutoReverse="True">
            <PointAnimationUsingKeyFrames Storyboard.TargetProperty="(Shape.Fill).(LinearGradientBrush.EndPoint)" Storyboard.TargetName="ElasticBox">
                <EasingPointKeyFrame KeyTime="0:0:4" Value="12,8"/>
            </PointAnimationUsingKeyFrames>
        </Storyboard>

        <!-- Knight Rider -->
        <Storyboard x:Key="KnightRider" RepeatBehavior="Forever" AutoReverse="True">
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.X)" Storyboard.TargetName="KRBox">
                <EasingDoubleKeyFrame KeyTime="0:0:1" Value="-50"/>
                <EasingDoubleKeyFrame KeyTime="0:0:2" Value="50"/>
                <EasingDoubleKeyFrame KeyTime="0:0:3" Value="0"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>

    </Window.Resources>
    <Window.Triggers>
        <EventTrigger RoutedEvent="FrameworkElement.Loaded">
            <BeginStoryboard Storyboard="{StaticResource Pulse}"/>
            <BeginStoryboard Storyboard="{StaticResource MarchingAnts}"/>
            <BeginStoryboard Storyboard="{StaticResource Flipper}"/>
            <BeginStoryboard Storyboard="{StaticResource ElasticLines}"/>
            <BeginStoryboard Storyboard="{StaticResource KnightRider}"/>
        </EventTrigger>
    </Window.Triggers>

    <Grid HorizontalAlignment="Center" VerticalAlignment="Center">
        <Grid.Resources>
            <Style TargetType="{x:Type TextBlock}">
                <Setter Property="Foreground" Value="White"/>
                <Setter Property="FontWeight" Value="Bold"/>
                <Setter Property="FontSize" Value="35"/>
                <Setter Property="HorizontalAlignment" Value="Center"/>
                <Setter Property="VerticalAlignment" Value="Center"/>
                <Setter Property="Text" Value="ALERT"/>
            </Style>
            <Style TargetType="{x:Type Grid}">
                <Setter Property="Margin" Value="0,10"/>                
            </Style>
            <Style TargetType="{x:Type Rectangle}">
                <Setter Property="Height" Value="50"/>
                <Setter Property="Width" Value="150"/>
            </Style>
        </Grid.Resources>

        <StackPanel>

        <!-- Marching Ants -->
        <Grid>

            <Rectangle x:Name="AlertBox"
                      Stroke="Red" 
                       StrokeDashOffset="2" StrokeDashArray="5" Margin="5">
                <Rectangle.Fill>
                    <LinearGradientBrush StartPoint="0,0" EndPoint="6,4" MappingMode="Absolute" SpreadMethod="Repeat">
                        <GradientStop Color="Red" Offset="0.25"/>
                        <GradientStop Color="#00000000" Offset="0.15"/>
                    </LinearGradientBrush>
                </Rectangle.Fill>
            </Rectangle>

            <TextBlock/>

        </Grid>
        <!-- End Marching Ants -->


        <!-- Pulse : Will not skew other elements location like width/height animations would. -->
        <Grid>
            <Border x:Name="PulseBox"
                        Background="Red" RenderTransformOrigin="0.5,0.5">
                <Border.RenderTransform>
                    <TransformGroup>
                        <ScaleTransform/>
                        <SkewTransform/>
                        <RotateTransform/>
                        <TranslateTransform/>
                    </TransformGroup>
                </Border.RenderTransform>

                <TextBlock/>

            </Border>
        </Grid>
        <!-- End Pulse -->


        <!-- Flipper -->
        <Grid>
            <Border x:Name="FlipperBox"
                        Background="Red">
                <Border.RenderTransform>
                    <TransformGroup>
                        <ScaleTransform/>
                        <SkewTransform/>
                        <RotateTransform/>
                        <TranslateTransform/>
                    </TransformGroup>
                </Border.RenderTransform>

                <TextBlock/>

            </Border>
        </Grid>
        <!-- End Flipper -->


        <!-- Elastic Lines -->
        <Grid>
            <Rectangle x:Name="ElasticBox"
                      Stroke="Red" StrokeThickness="5" Margin="5">
                <Rectangle.Fill>
                    <LinearGradientBrush StartPoint="0,0" EndPoint="6,4" MappingMode="Absolute" SpreadMethod="Repeat">
                        <GradientStop Color="Red" Offset="0.25"/>
                        <GradientStop Color="#00000000" Offset="0.15"/>
                    </LinearGradientBrush>
                </Rectangle.Fill>
            </Rectangle>

            <TextBlock/>

        </Grid>
        <!-- End Elastic Box -->


        <!-- Knight Rider -->
        <Grid>
            <Rectangle Fill="Red"/>
            <Rectangle x:Name="KRBox" Width="50" Fill="White" RenderTransformOrigin="0.5,0.5">
                <Rectangle.RenderTransform>
                    <TransformGroup>
                        <ScaleTransform/>
                        <SkewTransform/>
                        <RotateTransform/>
                        <TranslateTransform/>
                    </TransformGroup>
                </Rectangle.RenderTransform>
            </Rectangle>

            <TextBlock Foreground="Red"/>

        </Grid>
        <!-- End Knight Rider -->

        </StackPanel>

    </Grid>
</Window>

Hopefully this helps you with your animation needs!