Dynamic Transforms
Applying transforms to elements in XAML is fairly straight forward, for example the following will rotate some text:
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Obviously this is fine for static rotation values, and animations using a Storyboard, however what if you want to specify the rotation in C#? Or perhaps a Scale Transform in C#?
This simple example allows you to specify Rotation and Scale values and the image is rotated to reflect the current settings.
<UserControl x:Class="DynamicTransforms.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">
<Grid x:Name="LayoutRoot">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Image x:Name="image" Grid.Column="0" Source="assets/sign.jpg" Stretch="None" />
<StackPanel Grid.Column="1" Orientation="Vertical">
<TextBlock Text="Scale X" />
<TextBox x:Name="scaleX" Width="50" Text="1.0" TextChanged="TextBox_TextChanged" />
<TextBlock Text="Scale Y" />
<TextBox x:Name="scaleY" Width="50" Text="1.0" TextChanged="TextBox_TextChanged" />
<TextBlock Text="Rotation Angle" />
<TextBox x:Name="rotate" Width="50" Text="0.0" TextChanged="TextBox_TextChanged" />
</StackPanel>
</Grid>
</UserControl>
Here we have 3 textboxes that allow you to specify the Rotation angle and the Scale X/Y values.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Threading;
namespace DynamicTransforms
{
public partial class MainPage : UserControl
{
TransformGroup _tg = new TransformGroup();
ScaleTransform _st = new ScaleTransform();
RotateTransform _rt = new RotateTransform();
private DispatcherTimer _timer = new DispatcherTimer();
public MainPage()
{
InitializeComponent();
Setup();
}
private void Setup()
{
_st.ScaleX = 1;
_st.ScaleY = 1;
_tg.Children.Add(_st);
_tg.Children.Add(_rt);
image.RenderTransform = _tg;
}
private void ValueChanged()
{
_st.ScaleX = double.Parse(scaleX.Text);
_st.ScaleY = double.Parse(scaleY.Text);
_rt.Angle = double.Parse(rotate.Text);
_rt.CenterX = image.ActualWidth * 0.5;
_rt.CenterY = image.ActualHeight * 0.5;
}
private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
ValueChanged();
}
}
}
obviously you will need to the alter the image source in the XAML above.
