使用图像透明度过滤鼠标事件

时间：2018-07-10 01:38:48

标签： c# wpf opacitymask ismouseover

我整天都在研究示例，教程和论坛，但似乎无法将自己笼罩在一个简单的概念上。

基本上，我正在创建一个色轮颜色选择工具。该工具为环形，因此除非鼠标悬停在工具形状本身上，否则我不希望鼠标执行功能。

色轮是简单的图像。我试图找到利用不透明度贴图的方法，画出椭圆形来检测鼠标（这是可行的，但是我不能单击它下面的物理滚轮）。

我在这里空白。

我想要实现的目标（不可避免）是：鼠标移至色轮的域，将光标更改为滴管。当用户单击xPos / yPos处的像素时，我们要获取该位置的像素的RGB值。在纸上看起来很简单，对吧？

有人想协助吗？也许有些吐痰？非常感谢您提供的任何帮助，也感谢您抽出宝贵的时间至少看看我的问题！

以下是当前用于色轮的图像：

Color Wheel PNG

更新：我有一个叠加层，并且正在成功传递click事件。好像我可能走对了路。接下来只需要弄清楚如何获取像素数据即可。

XAML：

<Window x:Name="frmMain" x:Class="MouseImageTest.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:MouseImageTest"
    mc:Ignorable="d"
    Title="Color Picker Example" Height="423.41" Width="572.61">
<Window.Resources>
    <Style x:Key="EllipseStyle1" TargetType="{x:Type Ellipse}"/>
</Window.Resources>
<Grid>
    <Label x:Name="lblOpacity" Content="Update:" HorizontalAlignment="Left" VerticalAlignment="Top" Width="59" HorizontalContentAlignment="Right"/>
    <Label x:Name="lblNumbers" Content="" HorizontalAlignment="Left" Margin="64,0,0,0" VerticalAlignment="Top" Width="149"/>
    <Grid x:Name="grdBleh">
        <Image x:Name="image" HorizontalAlignment="Left" Height="331" Margin="118,29,0,0" VerticalAlignment="Top" Width="323" Source="physicswheel.png" StretchDirection="DownOnly" MouseDown="image_MouseDown">
            <Image.OpacityMask>
                <ImageBrush ImageSource="physicswheel.png" Stretch="Uniform" Opacity="0.99"/>
            </Image.OpacityMask>
        </Image>
        <Ellipse x:Name="swatchOuterBounds" HorizontalAlignment="Left" Height="291" Margin="127,38,0,0" VerticalAlignment="Top" Width="290" Stroke="#FDFF0000" StrokeThickness="50" Style="{DynamicResource EllipseStyle1}" Opacity="0" MouseEnter="ellipse_MouseEnter" MouseLeave="ellipse_MouseLeave" PreviewMouseDown="ellipse_MouseDown"/>
        <Border x:Name="brdrRed1" BorderBrush="Black" BorderThickness="2,2,1,2" Width="29" Height="25" Margin="446,106,89,256" VerticalAlignment="Center" HorizontalAlignment="Center" CornerRadius="4,0,0,4" Background="#FF959595">
            <Label x:Name="lblRed" Content="R:" Margin="0,0,5,0" Background="{x:Null}" Foreground="Black" BorderThickness="0" Padding="0" VerticalContentAlignment="Center" HorizontalContentAlignment="Right"/>
        </Border>
        <Border x:Name="brdrRed2" BorderBrush="Black" BorderThickness="1,2,2,2" Width="29" Height="25" Margin="475,106,61,256" VerticalAlignment="Center" HorizontalAlignment="Center" CornerRadius="0,4,4,0" Background="#FF959595">
            <Label x:Name="lblRed2" Content="" Margin="5,0,0,0" Background="{x:Null}" Foreground="Black" BorderThickness="0" Padding="0" VerticalContentAlignment="Center" HorizontalContentAlignment="Right"/>
        </Border>
        <Border x:Name="brdrGreen1" BorderBrush="Black" BorderThickness="2,2,1,2" Width="29" Height="25" Margin="446,135,89,229" VerticalAlignment="Center" HorizontalAlignment="Center" CornerRadius="4,0,0,4" Background="#FF959595">
            <Label x:Name="lblGreen" Content="G:" Margin="0,0,5,0" Background="{x:Null}" Foreground="Black" BorderThickness="0" Padding="0" VerticalContentAlignment="Center" HorizontalContentAlignment="Right"/>
        </Border>
        <Border x:Name="brdrGreen2" BorderBrush="Black" BorderThickness="1,2,2,2" Width="29" Height="25" Margin="475,135,61,229" VerticalAlignment="Center" HorizontalAlignment="Center" CornerRadius="0,4,4,0" Background="#FF959595">
            <Label x:Name="lblGreen2" Content="" Margin="5,0,0,0" Background="{x:Null}" Foreground="Black" BorderThickness="0" Padding="0" VerticalContentAlignment="Center" HorizontalContentAlignment="Right"/>
        </Border>
        <Border x:Name="brdrBlue1" BorderBrush="Black" BorderThickness="2,2,1,2" Width="29" Height="25" Margin="446,162,89,200" VerticalAlignment="Center" HorizontalAlignment="Center" CornerRadius="4,0,0,4" Background="#FF959595">
            <Label x:Name="lblBlue" Content="B:" Margin="0,0,5,0" Background="{x:Null}" Foreground="Black" BorderThickness="0" Padding="0" VerticalContentAlignment="Center" HorizontalContentAlignment="Right"/>
        </Border>
        <Border x:Name="brdrBlue2" BorderBrush="Black" BorderThickness="1,2,2,2" Width="29" Height="25" Margin="475,162,61,200" VerticalAlignment="Center" HorizontalAlignment="Center" CornerRadius="0,4,4,0" Background="#FF959595">
            <Label x:Name="lblBlue2" Content="" Margin="5,0,0,0" Background="{x:Null}" Foreground="Black" BorderThickness="0" Padding="0" VerticalContentAlignment="Center" HorizontalContentAlignment="Right"/>
        </Border>
    </Grid>

</Grid>

C＃：

public partial class MainWindow : Window
{
     public MainWindow()
     {
         InitializeComponent();
     }

     private void ellipse_MouseEnter(object sender, MouseEventArgs e)
     {
         Cursor = Cursors.Hand;
     }

     private void ellipse_MouseLeave(object sender, MouseEventArgs e)
     {
         Cursor = Cursors.Arrow;
     }

     private void image_MouseDown(object sender, MouseButtonEventArgs e)
     {
         if (swatchOuterBounds.IsMouseOver)
         {
             lblNumbers.Content = "Clicked the color wheel!";

             // Insert mouseclick evaluation here and grab Pixel Data. 
             // Write to R/G/B labels.
         }
     }

     private void ellipse_MouseDown(object sender, MouseButtonEventArgs e)
     {
         image_MouseDown(sender, e);
     }
 }

2 个答案:

答案 0 :(得分：1)

您可以使用Path元素来绘制叠加层。在这种情况下，我将两个EllipseGeometry组合成路径，第一个是外圆，然后排除内圆。 

<Path Fill="#CCCCFF" Margin="127,38,0,0" 
    MouseEnter="ellipse_MouseEnter" 
    MouseLeave="ellipse_MouseLeave" 
    PreviewMouseDown="ellipse_MouseDown">
    <Path.Data>                    
        <CombinedGeometry GeometryCombineMode="Exclude">
            <CombinedGeometry.Geometry1>
                <EllipseGeometry RadiusX="150" RadiusY="150" Center="150,150" />
            </CombinedGeometry.Geometry1>
            <CombinedGeometry.Geometry2>
                <EllipseGeometry RadiusX="100" RadiusY="100" Center="150,150" />
            </CombinedGeometry.Geometry2>
        </CombinedGeometry>
    </Path.Data>
</Path>

我使用紫色突出显示此Path元素，并且为事件处理程序使用了相同的名称，只是为了向您展示我只是将Ellipse替换为Path-自己重命名。

enter image description here

您无需将事件传递给下面的图像，所有操作都在叠加层的MouseDown事件中完成。

private void ellipse_MouseDown(object sender, MouseButtonEventArgs e)
{
    //Get the x,y position as relative to the upper-left corner of the overlay
    var point = e.GetPosition(sender as IInputElement); 

    //Or, relative to the wheel
    var point2 = e.GetPosition(image);
}

答案 1 :(得分：0)

所以，我不得不给它加翅膀。我控制了透明椭圆上的单击，并从Mouse坐标处的图像控件中收集了像素数据。因此，一切正常。 （对不起，我不喜欢XAML，所以这是我想到的：

Image swatcher = new Image();
        swatcher.Source = new BitmapImage(new Uri("/Icons/physicswheel.png", UriKind.Relative));
        swatcher.Stretch = Stretch.Uniform;
        swatcher.Height = 100;
        swatcher.Width = 100;
        swatcher.Margin = new Thickness(5, 5, 5, 5);
        swatcher.SetValue(Grid.RowProperty, 0);
        swatcher.SetValue(Grid.ColumnProperty, 0);
        swatcher.HorizontalAlignment = HorizontalAlignment.Center;
        columns.Children.Add(swatcher);

        Ellipse bumper = new Ellipse();
        bumper.Height = 95;
        bumper.Width = 95;
        bumper.SetValue(Grid.RowProperty, 0);
        bumper.SetValue(Grid.ColumnProperty, 0);
        bumper.Stroke = new SolidColorBrush(Color.FromArgb(0, 12, 12, 255));
        bumper.StrokeThickness = 17;
        bumper.MouseEnter += delegate (object source, MouseEventArgs e)
        {
                //Change Mouse Cursor to custom dropper.
                Uri curDropper = new Uri("/Cursors/eyedropper.cur", UriKind.Relative);
            bumper.Cursor = new Cursor(App.GetResourceStream(curDropper).Stream);
        };
        bumper.MouseDown += delegate (object source, MouseButtonEventArgs e)
        {
                //Get Mouse position and then grab pixel data.
                int xPos = Convert.ToInt32(e.GetPosition(swatcher).X);
            int yPos = Convert.ToInt32(e.GetPosition(swatcher).Y);

            CroppedBitmap dropper = new CroppedBitmap(swatcher.Source as BitmapSource, new Int32Rect(xPos, yPos, 1, 1));

            byte[] pixel = new byte[4];
            dropper.CopyPixels(pixel, 4, 0);

                //Change Swatch Preview and RGB fields.

                redUpDown.Text = pixel[2].ToString();
            greenUpDown.Text = pixel[1].ToString();
            blueUpDown.Text = pixel[0].ToString();

        };
        columns.Children.Add(bumper);

我真的希望这可以帮助任何走同一条道路的人。 ：）

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