Silverlight 背景平铺——比较简单的实现方法
由于blend不够普及，图片平铺问题在所难免。以前写过如何在WPF中利用VisualBrush进行平铺。但是在silverlihgt中是没有VisualBrush的。那只能通过代码来控制图片平铺用了。
在google中找了一些实现方法，但总感觉太复杂。比较经典的当然是Elite.Silverlight3.PixelShaders这个项目中的平铺方法，但是过于复杂，并且不支持绝对的平铺即需要指明在X轴平铺数量和在Y轴的平铺数量。即便是使用宽度除以图片宽度来计算，也是稍显麻烦。后来就找到了一个继承于Panel的TitlePanel，这个是比较简单的实现方法，切不用修改以往的代码。贴上代码以及示例。/*
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using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Media.Imaging;
using System.Diagnostics;
namespace glPro.Common
{
public class TilePanel : Panel
{
#region DependencyProperty setup
// Dependency properties for Tile Width, Height and Image
public static readonly DependencyProperty TileWidthProperty =
DependencyProperty.Register("TileWidth", typeof(double), typeof(TilePanel),
new PropertyMetadata(double.NaN, new PropertyChangedCallback(TileWidthPropertyChanged)));
public static readonly DependencyProperty TileHeightProperty =
DependencyProperty.Register("TileHeight", typeof(double), typeof(TilePanel),
new PropertyMetadata(double.NaN, new PropertyChangedCallback(TileHeightPropertyChanged)));
public static readonly DependencyProperty ImageProperty =
DependencyProperty.Register("Image", typeof(ImageBrush), typeof(TilePanel), new PropertyMetadata(null,
new PropertyChangedCallback(ImagePropertyChanged)));
public double TileWidth
{
get { return (double)GetValue(TileWidthProperty); }
set { SetValue(TileWidthProperty, value); }
}
public double TileHeight
{
get { return (double)GetValue(TileHeightProperty); }
set { SetValue(TileHeightProperty, value); }
}
public ImageBrush Image
{
get { return (ImageBrush)GetValue(ImageProperty); }
set { SetValue(ImageProperty, value); }
}
#endregion
private Size _lastFinalSize;
private ImageBrush _imgBrush;
private bool _needsUpdate = false;
public TilePanel()
{
this.SizeChanged += new SizeChangedEventHandler(TilePanelSizeChanged);
}
/// <summary>
/// Called when the size of the panel changes.
/// </summary>
/// <param name="sender">This panel</param>
/// <param name="e">The new size information</param>
protected virtual void TilePanelSizeChanged(object sender, SizeChangedEventArgs e)
{
if (e.NewSize != _lastFinalSize)
{
_lastFinalSize = e.NewSize;
// adjust the clipping rectangle based on the new size
RectangleGeometry rg = new RectangleGeometry();
rg.Rect = new Rect(new Point(), _lastFinalSize);
this.Clip = rg;
TileAdjustmentNeededAsync();
}
}
/// <summary>
/// Signal that an adjustment to the tiles is needed,
/// then makes the call asynchronously.
/// By asynchronously making this call, it can help prevent
/// unnecessary work by the panel.
/// </summary>
protected void TileAdjustmentNeededAsync()
{
// by doing this sync, we can queue up several request
// but then really only handle the last one.
_needsUpdate = true;
// async call the adjust tiles
this.Dispatcher.BeginInvoke(delegate
{
AdjustTiles();
});
}
private static void TileHeightPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
TilePanel tilePanel = d as TilePanel;
if (tilePanel != null)
{
Debug.WriteLine("TileHeight Changed: {0}", e.NewValue);
double val = (double)e.NewValue;
if ( val == double.NaN || val <= 0.0)
{
throw new ArgumentOutOfRangeException("TileHeight");
}
tilePanel.TileAdjustmentNeededAsync();
}
}
private static void TileWidthPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
TilePanel tilePanel = d as TilePanel;
if (tilePanel != null)
{
Debug.WriteLine("TileWidth Changed: {0}", e.NewValue);
double val = (double)e.NewValue;
if (val == double.NaN || val <= 0.0)
{
throw new ArgumentOutOfRangeException("TileWidth");
}
tilePanel.TileAdjustmentNeededAsync();
}
}
private static void ImagePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
// put code here to handle the property changed for Image
TilePanel tilePanel = d as TilePanel;
if (tilePanel != null )
{
Debug.WriteLine("ImagePropertyChanged");
tilePanel._imgBrush = e.NewValue as ImageBrush;
// remove all of the existing tiles as they no longer are valid
tilePanel.Children.Clear();
tilePanel.TileAdjustmentNeededAsync();
}
}
/// <summary>
/// Perform the standard Arrange. Here though, all of the tiles
/// are placed based on the tilesize specified.
/// </summary>
/// <param name="finalSize">the actual size that the panel has been given</param>
/// <returns>The size taken (which is always what it was given).</returns>
protected override Size ArrangeOverride(Size finalSize)
{
UIElementCollection children = Children;
double tw = TileWidth;
double th = TileHeight;
double x = 0, y = 0;
foreach (UIElement uie in Children)
{
if (x >= finalSize.Width)
{
x = 0;
y += th;
}
uie.Arrange(new Rect(x, y, tw, th));
x += tw;
}
return finalSize;
}
/// <summary>
/// Adjusts the quantity of the tiles based on the
/// size of the panel and immediately calls
/// UpdateLayout so the new tiles can be properly
/// layed out.
/// </summary>
protected virtual void AdjustTiles()
{
Debug.WriteLine("AdjustTiles - Update Needed: {0}", _needsUpdate);
// seems that it was already done ...
if (!_needsUpdate) { return; }
_needsUpdate = false;
// if no image brush is set ... all the children are cleared!
if (_imgBrush == null)
{
this.Children.Clear();
return ;
}
double tw = TileWidth;
double th = TileHeight;
// determine how many we actually need
int totalNeededX = (int) Math.Ceiling(this.ActualWidth / tw);
int totalNeededY = (int) Math.Ceiling(this.ActualHeight / th);
int totalNeeded = totalNeededX * totalNeededY;
// there may be too many
if (totalNeeded < this.Children.Count)
{
while (this.Children.Count > totalNeeded)
{
this.Children.RemoveAt(this.Children.Count - 1);
}
}
// or too few ...
else if (this.Children.Count < totalNeeded)
{
while (this.Children.Count < totalNeeded)
{
Rectangle r = new Rectangle();
r.Width = tw;
r.Height = th;
r.Fill = _imgBrush;
this.Children.Add(r);
}
}
this.UpdateLayout();
}
}
}
在xaml页面中：引用此类： xmlns:local="clr-namespace:glPro.Common"
<Grid>
<local:TilePanel x:Name="pnlTile"
TileWidth="4"
TileHeight="61">
<local:TilePanel.Image>
<ImageBrush ImageSource="Images/2-1上平铺.png" />
</local:TilePanel.Image>
</local:TilePanel>
</Grid>
TileWidth是图片的宽度，TileHeight是图片的高度.其他的都是自动计算的。就这么简单。贴上找来的源码。靠，才发现CSDN不能上传源码。抱歉！不过基本上代码拷贝过去就能用。