wpf 使用画布矩形裁剪图像
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时间：2020-09-13 11:36:52 来源:igfitidea点击:
Crop Image using Canvas Rectangle
提问by Jay
Cropping the image is not working properly. Where I'm wrong?
裁剪图像无法正常工作。我错在哪里？
My Xaml :
我的 Xml ：
<Grid x:Name="Gridimage1">
<Image Name="image1" Grid.Column="0" Height="317" HorizontalAlignment="Left" Margin="20,67,0,0" Stretch="Fill" VerticalAlignment="Top" Width="331"></Image>
<Canvas x:Name="BackPanel">
<Rectangle x:Name="selectionRectangle" Stroke="LightBlue" Fill="#220000FF" Visibility="Collapsed" />
</Canvas>
</Grid>
<Button Content=">>" Height="23" HorizontalAlignment="Left" Margin="357,201,0,0" Name="Go" VerticalAlignment="Top" Width="41" Click="Go_Click" FontWeight="Bold" Visibility="Hidden" />
<Image Grid.Column="1" Height="317" HorizontalAlignment="Left" Margin="408,67,0,0" Name="image2" Stretch="Fill" VerticalAlignment="Top" Width="331" />
C# :
C＃ ：
private bool isDragging = false;
private Point anchorPoint = new Point();
public MainWindow()
{
InitializeComponent();
Gridimage1.MouseLeftButtonDown += new MouseButtonEventHandler(image1_MouseLeftButtonDown);
Gridimage1.MouseMove += new MouseEventHandler(image1_MouseMove);
Gridimage1.MouseLeftButtonUp += new MouseButtonEventHandler(image1_MouseLeftButtonUp);
Go.IsEnabled = false;
image2.Source = null;
}
private void Go_Click(object sender, RoutedEventArgs e)
{
if (image1.Source != null)
{
Rect rect1 = new Rect(Canvas.GetLeft(selectionRectangle), Canvas.GetTop(selectionRectangle), selectionRectangle.Width, selectionRectangle.Height);
System.Windows.Int32Rect rcFrom = new System.Windows.Int32Rect();
rcFrom.X = (int)((rect1.X) * (image1.Source.Width) /(image1.Width));
rcFrom.Y = (int)((rect1.Y) *(image1.Source.Height) / (image1.Height));
rcFrom.Width = (int)((rect1.Width) * (image1.Source.Width) /(image1.Width));
rcFrom.Height = (int)((rect1.Height) * (image1.Source.Height) /(image1.Height));
BitmapSource bs = new CroppedBitmap(image1.Source as BitmapSource, rcFrom);
image2.Source = bs;
}
}
#region "Mouse events"
private void image1_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (isDragging == false)
{
anchorPoint.X = e.GetPosition(BackPanel).X;
anchorPoint.Y = e.GetPosition(BackPanel).Y;
isDragging = true;
}
}
private void image1_MouseMove(object sender, MouseEventArgs e)
{
if (isDragging)
{
double x = e.GetPosition(BackPanel).X;
double y = e.GetPosition(BackPanel).Y;
selectionRectangle.SetValue(Canvas.LeftProperty, Math.Min(x, anchorPoint.X));
selectionRectangle.SetValue(Canvas.TopProperty, Math.Min(y, anchorPoint.Y));
selectionRectangle.Width = Math.Abs(x - anchorPoint.X);
selectionRectangle.Height = Math.Abs(y - anchorPoint.Y);
if (selectionRectangle.Visibility != Visibility.Visible)
selectionRectangle.Visibility = Visibility.Visible;
}
}
private void image1_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
if (isDragging)
{
isDragging = false;
if(selectionRectangle.Width >0)
{
Go.Visibility = System.Windows.Visibility.Visible;
Go.IsEnabled = true;
}
if (selectionRectangle.Visibility != Visibility.Visible)
selectionRectangle.Visibility = Visibility.Visible;
}
}
private void RestRect()
{
selectionRectangle.Visibility = Visibility.Collapsed;
isDragging = false;
}
#endregion
It is cropping the wrong part.
它正在裁剪错误的部分。
回答by Jay
The Margin property was not set properly to the Canvas control. It should be the same as Image control's margin properly value. If we don't set Margin to Canvas, It will take the full window size.
Margin 属性未正确设置到 Canvas 控件。它应该与图像控件的边距正确值相同。如果我们不将 Margin 设置为 Canvas，它将占用整个窗口大小。
Xaml
xml
<Grid x:Name="Gridimage1" Margin="0,0,411,100">
<Image Name="image1" Grid.Column="0" Height="317" HorizontalAlignment="Left" Margin="20,67,0,0" Stretch="Fill" VerticalAlignment="Top" Width="331">
</Image>
<Canvas x:Name="BackPanel" Margin="20,67,0,0">
<Rectangle x:Name="selectionRectangle" Stroke="LightBlue" Fill="#220000FF" Visibility="Collapsed" />
</Canvas>
</Grid>
回答by amit
<Grid x:Name="other">
<Button Content=">>" Height="23" HorizontalAlignment="Left" Margin="341,152,0,0" Name="Go" VerticalAlignment="Top" Width="41" Click="Go_Click" FontWeight="Bold" />
<Image Height="317" HorizontalAlignment="Left" Margin="403,10,-217,-7" Name="image2" Stretch="Fill" VerticalAlignment="Top" Width="331" />
</Grid>
</Grid>
