Graphics in Silverlight 5 - Part II

This article continues from Graphics in Silverlight 5 - Part I.

In the second part of this series, we shall see how to create other Shape elements. But before we do so, you may have some questions. You may feel this article is just dealing with controls/elements in a very trivial manner. You may feel, why should I spend the effort to learn just a few shapes when I can easily drag and drop various controls from Expression Blend and create fancy pages or user controls. The answer to this can be given through an analogy. When you look at a house, you don't see the elements that went into building it. You don't see the bricks, the cement, the paints, the wood, and other elements that have gone into building the house. If you take an individual brick, by itself it may hardly seem a useful item. It may even seem useless all by itself (unless you want to hit someone over the head with it! Just kidding.) But when you put together a few hundred or thousand bricks, throw in some cement, some fancy paints, wood, glass or whatever elements you need to build a good house, place them all in an appropriate manner (the placing may take years even) then the outcome will be a good one. Likewise, instead of looking at an Ellipse or any other shape element by itself, if you put together a bunch of shapes, add some fancy animations, storyboards, triggers, and even styles, you can have a spectacular outcome.

Enough of the analogy, now let's move on. In this part of the series, we shall take a look at the Rectangle element.

The Rectangle element is used to draw outlines or filled regions of a rectangular shape.

The following XAML markup snippet demonstrates how to draw an outline of a rectangle.

<Rectangle Width="100" Height="40" Stroke="Magenta" Margin="142,31,328,365"></Rectangle>

When you build and execute, the output will be as displayed in Figure 
below.



The following markup fills the rectangle with Magenta color instead of just drawing an outline

<Rectangle Width="100" Height="40" Fill="Magenta" Margin="142,31,328,365"></Rectangle>

When you build and execute, the output will be as displayed in Figure 
below.



You can further customize the properties of the Rectangle such as Stroke, StrokeThickness, RadiusX, and RadiusY.

<Rectangle Fill="PaleTurquoise" Margin="142,31,310,346" Stroke="Navy"  StrokeThickness="4" RadiusX="20" RadiusY="140">

When you build and execute, the output will be as displayed in Figure 
below.



Now have a look at a fancy rectangle created with a LinearGradientBrush for its Fill property.

<Rectangle Margin="142,31,310,346">
    <
Rectangle.Fill>
        <
LinearGradientBrush StartPoint="0.5,0" EndPoint="0.5,1">
            <
GradientStop Color="Wheat" Offset="0.1" />
            <
GradientStop Color="Tomato"  Offset="0.5" />
            <
GradientStop Color="Wheat"  Offset="0.66" />
            <
GradientStop Color="Blue" Offset="1" />
        </
LinearGradientBrush>
    </
Rectangle.Fill>
</
Rectangle>

When you build and execute, the output will be as displayed in Figure 
below.



The following example dynamically adds three rectangle on top of one another based on a button click.

<Grid x:Name="LayoutRoot" Background="White">
    <
Grid.RowDefinitions>
        <
RowDefinition Height="Auto" />
        <
RowDefinition Height="*" />
    </
Grid.RowDefinitions>
        <
Button Content="Add Rectangle" Click="btnAdd_Click" x:Name="btnAdd" Width="100" Height="40"/>
        <
StackPanel x:Name="stkp1" Grid.Row="1" VerticalAlignment="Bottom"/>
</
Grid>

In the code-behind, add:

int i = 0;
private void btnAdd_Click(object sender, RoutedEventArgs e)
{
    i++;
    // check if 3 rectangles are added
    if (i == 3)
    {
        btnAdd.IsEnabled =
false;
    }
    Rectangle rect = new Rectangle();
    rect.Height = 50;
    rect.Width = 100;
    rect.Fill=
new SolidColorBrush(Colors.Green);
    rect.Stroke =
new SolidColorBrush(Colors.Purple);
    rect.StrokeThickness = 2;
    stkp1.Children.Insert(0, rect);
}

The final outcome after the three rectangles are added one by one is shown in Figure below.



Conclusion: The second part of this series introduced the Rectangle element.