回答MSDN问题所写。
使用Adorner+附加属性
图片类（来自这位博主的博客）
/// <summary>
/// 用于获取位图像素的类
/// </summary>
public class Imghelper
{
/// <summary>
/// 位图宽度
/// </summary>
public int Width { get; protected set; }
/// <summary>
/// 位图高度
/// </summary>
public int Height { get; protected set; }
/// <summary>
/// 像素
/// </summary>
public Color[][] Pixels { get; protected set; }
/// <summary>
/// 根据指定的位图生成BitmapPixelHelper类的新实例。
/// </summary>
/// <param name="bitmap">指定的位图</param>
public Imghelper(BitmapSource bitmap)
{
FormatConvertedBitmap newBitmap = new FormatConvertedBitmap(bitmap, PixelFormats.Bgra32, BitmapPalettes.WebPaletteTransparent, 0);
const int bytesPerPixel = 4;
Height = newBitmap.PixelHeight;
Width = newBitmap.PixelWidth;
byte[] data = new byte[Height * Width * bytesPerPixel];
newBitmap.CopyPixels(data, Width * bytesPerPixel, 0);
Pixels = new Color[Height][];
for (int i = 0; i < Height; ++i)
{
Pixels[i] = new Color[Width];
for (int j = 0; j < Width; ++j)
{
Pixels[i][j] = Color.FromArgb(
data[(i * Width + j) * bytesPerPixel + 3],
data[(i * Width + j) * bytesPerPixel + 2],
data[(i * Width + j) * bytesPerPixel + 1],
data[(i * Width + j) * bytesPerPixel + 0]);
}
}
}
/// <summary>
/// 获取图片的平均色
/// </summary>
public Color GetAverageColor()
{
int a = 0, r = 0, g = 0, b = 0;
for (int i = 0; i < Height; ++i)
{
for (int j = 0; j < Width; ++j)
{
a += Pixels[i][j].A;
r += Pixels[i][j].R;
g += Pixels[i][j].G;
b += Pixels[i][j].B;
}
}
a = a / Height / Width;
r = r / Height / Width;
g = g / Height / Width;
b = b / Height / Width;
return Color.FromArgb((byte)a, (byte)r, (byte)g, (byte)b);
}
} adorner代码
public class ShowImagePixelsPopup : Adorner
{
private TextBlock GetTextBlock;
private VisualCollection collection;
private UIElement _UIElement;
private Border GetBorder;
public ShowImagePixelsPopup(UIElement adornedElement) : base(adornedElement)
{
collection = new VisualCollection(this);
GetTextBlock = new TextBlock();
GetTextBlock.Height = 20;
GetTextBlock.Width = 120;
GetTextBlock.Background = new SolidColorBrush(Colors.Wheat);
GetTextBlock.HorizontalAlignment = HorizontalAlignment.Left;
GetTextBlock.VerticalAlignment = VerticalAlignment.Top;
GetBorder = new Border();
GetBorder.Height = 15;
GetBorder.Width = 15;
GetBorder.HorizontalAlignment = HorizontalAlignment.Left;
GetBorder.VerticalAlignment = VerticalAlignment.Top;
collection.Add(GetTextBlock);
collection.Add(GetBorder);
_UIElement = adornedElement;
}
protected override int VisualChildrenCount => collection.Count;
protected override Visual GetVisualChild(int index) => collection[index];
protected override Size MeasureOverride(Size constraint) => base.MeasureOverride(constraint);
public void SetData(Point MousePoint, String Pixels,Color color)
{
GetTextBlock.Margin = new Thickness(MousePoint.X+7.5, MousePoint.Y-15, 0,0);
GetBorder.Margin = new Thickness(MousePoint.X-7.5 , MousePoint.Y-7.5 , 0, 0);
GetBorder.Background = new SolidColorBrush(color);
GetTextBlock.Text = Pixels;
}
protected override Size ArrangeOverride(Size finalSize)
{
GetTextBlock.Arrange(new Rect(finalSize));
GetBorder.Arrange(new Rect(finalSize));
return base.ArrangeOverride(finalSize);
}
}
附加属性类
public class IsShowImagePixels
{
public static readonly DependencyProperty IsShowImagePixelsProperty = DependencyProperty.RegisterAttached("IsShowImagePixels", typeof(bool), typeof(IsShowImagePixels), new PropertyMetadata(false, new PropertyChangedCallback(OnIsShowImagePixelsChanged)));
public static void SetIsShowImagePixels(DependencyObject d, bool value) => d.SetValue(IsShowImagePixelsProperty, value);
public static bool GetIsShowImagePixels(DependencyObject d) => (bool)d.GetValue(IsShowImagePixelsProperty);
public static readonly DependencyProperty ShowImagePixelsPointProperty = DependencyProperty.RegisterAttached("ShowImagePixelsPoint", typeof(Point), typeof(IsShowImagePixels), new PropertyMetadata(new Point(0, 0),new PropertyChangedCallback(OnShowImagePixelsPointChanged)));
public static void SetIsShowImagePixelsPoint(DependencyObject d, Point value) => d.SetValue(ShowImagePixelsPointProperty, value);
public static Point GetShowImagePixelsPoint(DependencyObject d) => (Point)d.GetValue(ShowImagePixelsPointProperty);
private static void OnShowImagePixelsPointChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var c =(Point)e.NewValue;
popup.SetData(c, $"X={(((int)c.X ) < 0 ? 0 : (int)c.X )},Y={(((int)c.Y ) < 0 ? 0 : (int)c.Y )}", imghelper.Pixels[((int)c.Y - 1) < 0 ? 0 : (int)c.Y - 1][((int)c.X - 1) < 0 ? 0 : (int)c.X - 1]);
}
private static AdornerLayer layer;
private static Imghelper imghelper;
private static ShowImagePixelsPopup popup;
private static void OnIsShowImagePixelsChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var NewValue = (bool)e.NewValue;
UIElement element = d as UIElement;
if (!NewValue)
{
AdornerLayer l = AdornerLayer.GetAdornerLayer(element);
var ado = l.GetAdorners(element);
for (var o = 0; o < ado.Length; o++)
l.Remove(ado[o]);
element.MouseMove -= Element_MouseMove;
imghelper = null;
popup = null;
layer = null;
element = null;
}
if (element == null)
return;
layer = AdornerLayer.GetAdornerLayer(element);
popup = new ShowImagePixelsPopup(element);
layer.Add(popup);
imghelper = new Imghelper((element as Image).Source as BitmapSource);
//显示鼠标位置
element.MouseMove += Element_MouseMove;
}
private static void Element_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
{
var c = e.GetPosition(sender as FrameworkElement);
//此处只是用了鼠标位置，也可以用ShowImagePixelsPoint直接指定位置
popup.SetData(c, $"X={(((int)c.X - 1) < 0 ? 0 : (int)c.X - 1)},Y={(((int)c.Y - 1) < 0 ? 0 : (int)c.Y - 1)}", imghelper.Pixels[((int)c.Y - 1) < 0 ? 0 : (int)c.Y - 1][((int)c.X - 1) < 0 ? 0 : (int)c.X - 1]);
}
} xaml代码
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="auto"/>
</Grid.RowDefinitions>
<AdornerDecorator Grid.Row="0">
<Image x:Name="img" />
</AdornerDecorator>
<Button Click="Button_Click" Grid.Row="1" Height="40" Content="ShowOrNot"/>
</Grid> cs页面代码
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var b = new BitmapImage(new Uri("timg.jpg", UriKind.RelativeOrAbsolute));
Imghelper imghelper = new Imghelper(b);
img.Source = b;
img.SetValue(IsShowImagePixels.IsShowImagePixelsProperty, true);
Set = true;
}
private bool Set = false;
private void Button_Click(object sender, RoutedEventArgs e)
{
if (Set)
Set = false;
else
Set = true;
img.SetValue(IsShowImagePixels.IsShowImagePixelsProperty, Set);
return;
}
}