WPF之效果

模糊效果：

<Button Content="Blurred (Radius=2)" Padding="5" Margin="3">
<Button.Effect>
<BlurEffect Radius="2"></BlurEffect>
</Button.Effect>
</Button>

<Button Content="Blurred (Radius=5)" Padding="5" Margin="3">
<Button.Effect>
<BlurEffect Radius="5"></BlurEffect>
</Button.Effect>
</Button>

<Button Content="Blurred (Radius=20)" Padding="5" Margin="3">
<Button.Effect>
<BlurEffect Radius="20"></BlurEffect>
</Button.Effect>
</Button>灰色效果：
<StackPanel>
<Image Name="img" Margin="5" Source="harpsichord.jpg">
<Image.Effect>
<local:GrayscaleEffect></local:GrayscaleEffect>
</Image.Effect>
</Image>
<CheckBox Name="chkEffect" Margin="5" Content="Effect enabled" IsChecked="True" Click="chkEffect_Click"></CheckBox>

</StackPanel>

public GrayscaleEffect()
{
Uri pixelShaderUri = new Uri("Grayscale_Compiled.ps",
UriKind.Relative);

// Load the information from the .ps file.
PixelShader = new PixelShader();
PixelShader.UriSource = pixelShaderUri;
UpdateShaderValue(InputProperty);
}

public static readonly DependencyProperty InputProperty =
ShaderEffect.RegisterPixelShaderSamplerProperty("Input", typeof(GrayscaleEffect), 0 /* assigned to sampler register S0 */);

public Brush Input
{
get { return (Brush)GetValue(InputProperty); }
set { SetValue(InputProperty, value); }
}

阴影效果：
<StackPanel>
<TextBlock FontSize="20" Margin="5">
<TextBlock.Effect>
<DropShadowEffect></DropShadowEffect>
</TextBlock.Effect>
<TextBlock.Text>Basic dropshadow</TextBlock.Text>
</TextBlock>

<TextBlock FontSize="20" Margin="5">
<TextBlock.Effect>
<DropShadowEffect Color="SlateBlue"></DropShadowEffect>
</TextBlock.Effect>
<TextBlock.Text>Light blue dropshadow</TextBlock.Text>
</TextBlock>

<TextBlock FontSize="20" Foreground="White" Margin="5">
<TextBlock.Effect>
<DropShadowEffect BlurRadius="15"></DropShadowEffect>
</TextBlock.Effect>
<TextBlock.Text>Blurred dropshadow with white text</TextBlock.Text>
</TextBlock>

<TextBlock FontSize="20" Foreground="Magenta" Margin="5">
<TextBlock.Effect>
<DropShadowEffect ShadowDepth="0"></DropShadowEffect>
</TextBlock.Effect>
<TextBlock.Text>Close dropshadow</TextBlock.Text>
</TextBlock>

<TextBlock FontSize="20" Foreground="LimeGreen" Margin="5">
<TextBlock.Effect>
<DropShadowEffect ShadowDepth="25"></DropShadowEffect>
</TextBlock.Effect>
<TextBlock.Text>Distant dropshadow</TextBlock.Text>
</TextBlock>

</StackPanel>生成位图：
<Grid x:Name="LayoutRoot" Background="White">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition></RowDefinition>
</Grid.RowDefinitions>
<Button Content="Button" Grid.Row="1" Height="81" HorizontalAlignment="Left" Margin="106,90,0,0" Name="button1" VerticalAlignment="Top" Width="193" />
<Button Content="Generate Bitmap" Width="120" Margin="5" Padding="10" Click="cmdGenerate_Click" HorizontalAlignment="Center"></Button>
<Image Grid.Row="1" x:Name="img" Margin="5" Width="400" Height="300" IsHitTestVisible="False"></Image>
</Grid>

private void cmdGenerate_Click(object sender, RoutedEventArgs e)
{
// Create the bitmap, with the dimensions of the image placeholder.
WriteableBitmap wb = new WriteableBitmap((int)img.Width,
(int)img.Height, 96, 96, PixelFormats.Bgra32, null);

// Define the update square (which is as big as the entire image).
Int32Rect rect = new Int32Rect(0, 0, (int)img.Width, (int)img.Height);

byte[] pixels = new byte[(int)img.Width * (int)img.Height * wb.Format.BitsPerPixel / 8];
Random rand = new Random();
for (int y = 0; y < wb.PixelHeight; y++)
{
for (int x = 0; x < wb.PixelWidth; x++)
{
int alpha = 0;
int red = 0;
int green = 0;
int blue = 0;

// Determine the pixel's color.
if ((x % 5 == 0) || (y % 7 == 0))
{
red = (int)((double)y / wb.PixelHeight * 255);
green = rand.Next(100, 255);
blue = (int)((double)x / wb.PixelWidth * 255);
alpha = 255;
}
else
{
red = (int)((double)x / wb.PixelWidth * 255);
green = rand.Next(100, 255);
blue = (int)((double)y / wb.PixelHeight * 255);
alpha = 50;
}

int pixelOffset = (x + y * wb.PixelWidth) * wb.Format.BitsPerPixel/8;
pixels[pixelOffset] = (byte)blue;
pixels[pixelOffset + 1] = (byte)green;
pixels[pixelOffset + 2] = (byte)red;
pixels[pixelOffset + 3] = (byte)alpha;

}

int stride = (wb.PixelWidth * wb.Format.BitsPerPixel) / 8;

wb.WritePixels(rect, pixels, stride, 0);
}

// Show the bitmap in an Image element.
img.Source = wb;
}

private void cmdGenerate2_Click(object sender, RoutedEventArgs e)
{

// Create the bitmap, with the dimensions of the image placeholder.
WriteableBitmap wb = new WriteableBitmap((int)img.Width,
(int)img.Height, 96, 96, PixelFormats.Bgra32, null);

Random rand = new Random();
for (int x = 0; x < wb.PixelWidth; x++)
{
for (int y = 0; y < wb.PixelHeight; y++)
{
int alpha = 0;
int red = 0;
int green = 0;
int blue = 0;

// Determine the pixel's color.
if ((x % 5 == 0) || (y % 7 == 0))
{
red = (int)((double)y / wb.PixelHeight * 255);
green = rand.Next(100, 255);
blue = (int)((double)x / wb.PixelWidth * 255);
alpha = 255;
}
else
{
red = (int)((double)x / wb.PixelWidth * 255);
green = rand.Next(100, 255);
blue = (int)((double)y / wb.PixelHeight * 255);
alpha = 50;
}

// Set the pixel value.
byte[] colorData = { (byte)blue, (byte)green, (byte)red, (byte)alpha }; // B G R

Int32Rect rect = new Int32Rect(x,y, 1, 1);
int stride = (wb.PixelWidth * wb.Format.BitsPerPixel) / 8;
wb.WritePixels(rect, colorData, stride, 0);

//wb.WritePixels(.[y * wb.PixelWidth + x] = pixelColorValue;
}
}
4000

// Show the bitmap in an Image element.
img.Source = wb;
}

可视化层：
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<ToolBarTray Orientation="Vertical">
<ToolBar>
<RadioButton Margin="0,3" Name="cmdSelectMove">
<StackPanel>
<Image Source="pointer.png" Width="35" Height="35"></Image>
<TextBlock>Select/Move</TextBlock>
</StackPanel>
</RadioButton>
<RadioButton Margin="0,3" IsChecked="True" Name="cmdAdd">
<StackPanel>
<Rectangle Width="30" Height="30" Stroke="SteelBlue" StrokeThickness="3" Fill="AliceBlue"></Rectangle>
<TextBlock>Add Square</TextBlock>
</StackPanel>
</RadioButton>
<RadioButton Margin="0,3" Name="cmdDelete">
<StackPanel>
<Path Stroke="SteelBlue" StrokeThickness="4" StrokeEndLineCap="Round" StrokeStartLineCap="Round"
Fill="Red" HorizontalAlignment="Center">
<Path.Data>
<GeometryGroup>
<PathGeometry>
<PathFigure StartPoint="0,0">
<LineSegment Point="18,18"></LineSegment>
</PathFigure>
<PathFigure StartPoint="0,18">
<LineSegment Point="18,0"></LineSegment>
</PathFigure>
</PathGeometry>
</GeometryGroup>
</Path.Data>
</Path>
<TextBlock>Delete Square</TextBlock>
</StackPanel>
</RadioButton>
<RadioButton Margin="0,3" Name="cmdSelectMultiple">
<StackPanel>
<Image Source="pointer.png" Width="35" Height="35"></Image>
<TextBlock>Select Multiple</TextBlock>
</StackPanel>
</RadioButton>
</ToolBar>
</ToolBarTray>
<Border Grid.Column="1" Margin="3" BorderBrush="SteelBlue" BorderThickness="1">

<local:DrawingCanvas x:Name="drawingSurface" Background="White" ClipToBounds="True"
MouseLeftButtonDown="drawingSurface_MouseLeftButtonDown"
MouseLeftButtonUp="drawingSurface_MouseLeftButtonUp"
MouseMove="drawingSurface_MouseMove">
</local:DrawingCanvas>
</Border>
</Grid>

public VisualLayer()
{
InitializeComponent();
DrawingVisual v = new DrawingVisual();
DrawSquare(v, new Point(10, 10), false);
}

// Variables for dragging shapes.
private bool isDragging = false;
private Vector clickOffset;
private DrawingVisual selectedVisual;

// Variables for drawing the selection square.
private bool isMultiSelecting = false;
private Point selectionSquareTopLeft;

private void drawingSurface_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
Point pointClicked = e.GetPosition(drawingSurface);

if (cmdAdd.IsChecked == true)
{
DrawingVisual visual = new DrawingVisual();
DrawSquare(visual, pointClicked, false);
drawingSurface.AddVisual(visual);
}
else if (cmdDelete.IsChecked == true)
{
DrawingVisual visual = drawingSurface.GetVisual(pointClicked);
if (visual != null) drawingSurface.DeleteVisual(visual);
}
else if (cmdSelectMove.IsChecked == true)
{
DrawingVisual visual = drawingSurface.GetVisual(pointClicked);
if (visual != null)
{
// Calculate the top-left corner of the square.
// This is done by looking at the current bounds and
// removing half the border (pen thickness).
// An alternate solution would be to store the top-left
// point of every visual in a collection in the
// DrawingCanvas, and provide this point when hit testing.
Point topLeftCorner = new Point(
visual.ContentBounds.TopLeft.X + drawingPen.Thickness / 2,
visual.ContentBounds.TopLeft.Y + drawingPen.Thickness / 2);
DrawSquare(visual, topLeftCorner, true);

clickOffset = topLeftCorner - pointClicked;
isDragging = true;

if (selectedVisual != null && selectedVisual != visual)
{
// The selection has changed. Clear the previous selection.
ClearSelection();
}
selectedVisual = visual;
}
}
else if (cmdSelectMultiple.IsChecked == true)
{

selectionSquare = new DrawingVisual();

drawingSurface.AddVisual(selectionSquare);

selectionSquareTopLeft = pointClicked;
isMultiSelecting = true;

// Make sure we get the MouseLeftButtonUp event even if the user
// moves off the Canvas. Otherwise, two selection squares could be drawn at once.
drawingSurface.CaptureMouse();
}
}

// Drawing constants.
private Brush drawingBrush = Brushes.AliceBlue;
private Brush selectedDrawingBrush = Brushes.LightGoldenrodYellow;
private Pen drawingPen = new Pen(Brushes.SteelBlue, 3);
private Size squareSize = new Size(30, 30);
private DrawingVisual selectionSquare;

// Rendering the square.
private void DrawSquare(DrawingVisual visual, Point topLeftCorner, bool isSelected)
{
using (DrawingContext dc = visual.RenderOpen())
{
Brush brush = drawingBrush;
if (isSelected) brush = selectedDrawingBrush;

dc.DrawRectangle(brush, drawingPen,
new Rect(topLeftCorner, squareSize));
}
}

private void drawingSurface_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
isDragging = false;

if (isMultiSelecting)
{
// Display all the squares in this region.
RectangleGeometry geometry = new RectangleGeometry(
new Rect(selectionSquareTopLeft, e.GetPosition(drawingSurface)));
List<DrawingVisual> visualsInRegion =
drawingSurface.GetVisuals(geometry);
MessageBox.Show(String.Format("You selected {0} square(s).", visualsInRegion.Count));

isMultiSelecting = false;
drawingSurface.DeleteVisual(selectionSquare);
drawingSurface.ReleaseMouseCapture();
}
}

private void ClearSelection()
{
Point topLeftCorner = new Point(
selectedVisual.ContentBounds.TopLeft.X + drawingPen.Thickness / 2,
selectedVisual.ContentBounds.TopLeft.Y + drawingPen.Thickness / 2);
DrawSquare(selectedVisual, topLeftCorner, false);
selectedVisual = null;
}

private void drawingSurface_MouseMove(object sender, MouseEventArgs e)
{
if (isDragging)
{
Point pointDragged = e.GetPosition(drawingSurface) + clickOffset;
DrawSquare(selectedVisual, pointDragged, true);
}
else if (isMultiSelecting)
{
Point pointDragged = e.GetPosition(drawingSurface);
DrawSelectionSquare(selectionSquareTopLeft, pointDragged);
}
}

private Brush selectionSquareBrush = Brushes.Transparent;
private Pen selectionSquarePen = new Pen(Brushes.Black, 2);

private void DrawSelectionSquare(Point point1, Point point2)
{
selectionSquarePen.DashStyle = DashStyles.Dash;

using (DrawingContext dc = selectionSquare.RenderOpen())
{
dc.DrawRectangle(selectionSquareBrush, selectionSquarePen,
new Rect(point1, point2));
}
}

public class DrawingCanvas : Panel
{
private List<Visual> visuals = new List<Visual>();

protected override Visual GetVisualChild(int index)
{
return visuals[index];
}
protected override int VisualChildrenCount
{
get
{
return visuals.Count;
}
}

public void AddVisual(Visual visual)
{
visuals.Add(visual);

base.AddVisualChild(visual);
base.AddLogicalChild(visual);
}

public void DeleteVisual(Visual visual)
{
visuals.Remove(visual);

base.RemoveVisualChild(visual);
base.RemoveLogicalChild(visual);
}

public DrawingVisual GetVisual(Point point)
{
HitTestResult hitResult = VisualTreeHelper.HitTest(this, point);
return hitResult.VisualHit as DrawingVisual;
}

private List<DrawingVisual> hits = new List<DrawingVisual>();
public List<DrawingVisual> GetVisuals(Geometry region)
{
hits.Clear();
GeometryHitTestParameters parameters = new GeometryHitTestParameters(region);
HitTestResultCallback callback = new HitTestResultCallback(this.HitTestCallback);
VisualTreeHelper.HitTest(this, null, callback, parameters);
return hits;
}

private HitTestResultBehavior HitTestCallback(HitTestResult result)
{
GeometryHitTestResult geometryResult = (GeometryHitTestResult)result;
DrawingVisual visual = result.VisualHit as DrawingVisual;
if (visual != null &&
geometryResult.IntersectionDetail == IntersectionDetail.FullyInside)
{
hits.Add(visual);
}
return HitTestResultBehavior.Continue;
}

}