另一种方法实现silverlight图片局部放大效果

  今天看到這篇文章,即模仿京東(360buy)浏览产品图片的效果:

  silverlight图片局部放大效果

  一時技痒于是也打算做一个出来。因为功能简单不如索性用纯xaml做,不写一行代码。当然,MouseDragElementBehavior这种东西也是要用到的,但这也不算是“我”写了代码吧。
  原以为会很简单,结果失败了。MouseDragElementBehavior有一个属性是ConstrainToParentBounds,即是否只在父容器的范围中拖动。这个属性理所当然地应该设置为True,但实际上只要鼠标一移出父容器被拖动的控件就完全不动了。实际效果如下,为了方便比较做了 ConstrainToParentBounds="False" 和 ConstrainToParentBounds="True"两种。 这个东西做出来的效果不是很理想,难登大雅之堂,如果需要实际使用还是老老实实地用上面那篇文章介绍的方法吧。

获取 Microsoft Silverlight

  稍微解释一下:放大区域的位移量应该和那块半透明方块的位移量成反比的,因为不想写代码,所以将放大区域反转再反转,然后再将半透明方块的位移量和放大区域的位移量绑定。MouseDragElementBehavior是通过改变半透明方块的RenderTransform来改变它的位移量,所以应该绑定RenderTransform:


  RenderTransform="{Binding RenderTransform,Mode=TwoWay,ElementName=image}"


  另外,要遮挡图片的其它部分,我倾向于直接使用ScrollViewer,不过放大区域是圆形或其它形状那就另当别论了。
  下面是全部源代码

 

 

xaml
 <Grid x:Name="LayoutRoot">
        
<Grid.Background>
            
<LinearGradientBrush EndPoint="0.189,0.967" StartPoint="0.181,0.075">
                
<GradientStop Color="#FFB3B3B3" Offset="0"/>
                
<GradientStop Color="#FFD2D2D2" Offset="1"/>
            
</LinearGradientBrush>
        
</Grid.Background>
        
<Grid.ColumnDefinitions>
            
<ColumnDefinition Width="Auto"/>
            
<ColumnDefinition/>
        
</Grid.ColumnDefinitions>
        
<StackPanel>
            
<StackPanel Orientation="Horizontal">
                
<TextBlock Text="width:" Margin="5,0" Width="40"/>
                
<Slider  Maximum="1024" x:Name="sliderX" Value="500" Width="200"
                         ToolTipService.ToolTip
="{Binding Value,ElementName=sliderX}"/>
            
</StackPanel>
            
<StackPanel Orientation="Horizontal">
                
<TextBlock Text="height:" Margin="5,0" Width="40"/>
                
<Slider  Maximum="768" x:Name="sliderY" Value="400" Width="200"  
                         ToolTipService.ToolTip
="{Binding Value,ElementName=sliderY}"/>
            
</StackPanel>
            
<TextBlock Margin="5,0" Text="ConstrainToParentBounds='False'"/>
            
<controlsToolkit:Viewbox HorizontalAlignment="Left" Margin="5,0,5,5"
                    Width
="250" >
                
<Grid HorizontalAlignment="Center" VerticalAlignment="Center">
                    
<Image Source="Penguins.jpg"/>
                    
<Rectangle Height="{Binding Value,Mode=OneWay,ElementName=sliderY}"
                               Width
="{Binding Value,Mode=OneWay,ElementName=sliderX}" 
                               x:Name
="rec" RenderTransform="{Binding RenderTransform,Mode=TwoWay,ElementName=image}"
                                   HorizontalAlignment
="Left" VerticalAlignment="Top"
                               Fill
="#66FFFFFF" Stroke="Red" StrokeThickness="2" 
                               RenderTransformOrigin
="0.5,0.5">
                        
<i:Interaction.Behaviors>
                            
<il:MouseDragElementBehavior  ConstrainToParentBounds="False" />
                        
</i:Interaction.Behaviors>

                    
</Rectangle>
                
</Grid>
            
</controlsToolkit:Viewbox>

            
<TextBlock Margin="5,0" Text="ConstrainToParentBounds='True'"/>
            
<controlsToolkit:Viewbox HorizontalAlignment="Left" Margin="5"
                    Width
="250" >
                
<Grid HorizontalAlignment="Center" VerticalAlignment="Center">
                    
<Image Source="Penguins.jpg"/>


                    
<Rectangle  RenderTransform="{Binding RenderTransform,Mode=TwoWay,ElementName=image}"
                           Height
="{Binding Value,Mode=OneWay,ElementName=sliderY}"
                                Width
="{Binding Value,Mode=OneWay,ElementName=sliderX}" x:Name="rec2"
                                HorizontalAlignment
="Left" VerticalAlignment="Top" Fill="#66FFFFFF" Stroke="Red"
                                StrokeThickness
="2" RenderTransformOrigin="0.5,0.5">
                        
<i:Interaction.Behaviors>
                            
<il:MouseDragElementBehavior ConstrainToParentBounds="True" />
                        
</i:Interaction.Behaviors>
                    
</Rectangle>
                
</Grid>
            
</controlsToolkit:Viewbox>
        
</StackPanel>

        
<controlsToolkit:Viewbox Margin="5" Padding="0" Grid.Column="1">
            
<ScrollViewer  Height="{Binding Value,Mode=OneWay,ElementName=sliderY}"
                           Width
="{Binding Value,Mode=OneWay,ElementName=sliderX}"  
                           Padding
="0" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden">
                
<Grid  HorizontalAlignment="Left" VerticalAlignment="Top" RenderTransformOrigin="0,0" Margin="0">
                    
<Grid.RenderTransform>
                        
<TransformGroup>
                            
<ScaleTransform ScaleX="-1" ScaleY="-1"/>
                            
<SkewTransform AngleX="0" AngleY="0"/>
                            
<RotateTransform Angle="0"/>
                            
<TranslateTransform/>
                        
</TransformGroup>
                    
</Grid.RenderTransform>
                    
<Image x:Name="image" Source="Penguins.jpg"    RenderTransformOrigin="0,0" Margin="0">
                        
<Image.Projection>
                            
<PlaneProjection CenterOfRotationX="0" CenterOfRotationY="0" RotationY="180" RotationX="180"/>
                        
</Image.Projection>
                    
</Image>
                
</Grid>
            
</ScrollViewer>
        
</controlsToolkit:Viewbox>
    
</Grid>

 

 

posted @ 2009-12-03 15:37 dino.c 阅读(...) 评论(...) 编辑 收藏