我可以在禁用的按钮中,通过一种方式对图像进行去饱和度处理吗?例如:ICommand.CanExecute = false
?还是我需要使用不同的图像+样式/触发器?
我使用了一种特殊的样式,当按钮被禁用时,它会降低图像的不透明度(是的,即使按钮绑定到命令也有效)。从技术上讲,这不是去饱和度,但它看起来很相似,这可能会帮助您自己得出解决方案:
<Style x:Key="buttonImage">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType={x:Type Button}, AncestorLevel=1}, Path=IsEnabled}" Value="False">
<Setter Property="Image.Opacity" Value="0.25"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
这里有一个去色调的着色器(Desaturate.fx):
sampler2D inputSampler : register(S0);
/// <summary>The strength of the effect.</summary>
/// <minValue>0</minValue>
/// <maxValue>1</maxValue>
/// <defaultValue>0</defaultValue>
float Strength : register(C0);
float4 main(float2 uv : TEXCOORD) : COLOR
{
float4 srcColor = tex2D(inputSampler, uv);
float3 rgb = srcColor.rgb;
float3 c = (1 - Strength)*rgb + Strength* dot(rgb, float3(0.30, 0.59, 0.11));
return float4(c, srcColor.a);
}
public class Desaturate : ShaderEffect
{
public static readonly DependencyProperty InputProperty = ShaderEffect.RegisterPixelShaderSamplerProperty(
"Input",
typeof(Desaturate),
0);
public static readonly DependencyProperty StrengthProperty = DependencyProperty.Register(
"Strength",
typeof(double),
typeof(Desaturate),
new UIPropertyMetadata(((double)(0D)), PixelShaderConstantCallback(0)));
public Desaturate()
{
PixelShader pixelShader = new PixelShader();
pixelShader.UriSource = new Uri("/So.Wpf;component/Effects/Desaturate.ps", UriKind.Relative);
this.PixelShader = pixelShader;
this.UpdateShaderValue(InputProperty);
this.UpdateShaderValue(StrengthProperty);
}
public Brush Input
{
get
{
return ((Brush)(this.GetValue(InputProperty)));
}
set
{
this.SetValue(InputProperty, value);
}
}
/// <summary>The strength of the effect. 0 is unchanged and 1 is monochrome</summary>
public double Strength
{
get
{
return ((double)(this.GetValue(StrengthProperty)));
}
set
{
this.SetValue(StrengthProperty, value);
}
}
}
那么你可以像这样在Xaml中使用它,强度是可绑定的,所以不需要通过触发器连接到启用状态:
<Grid>
<Image Source="http://i.imgur.com/CN63KcN.jpg">
<Image.Effect>
<effects:Desaturate Strength="{Binding ElementName=SaturationSlider, Path=Value}"/>
</Image.Effect>
</Image>
<Slider x:Name="SaturationSlider" Minimum="0" Maximum="1" VerticalAlignment="Bottom"/>
</Grid>