如何在wpf画布上绘制自由形状(随机)和文本打印

Question

我正在开发一个涂料应用程序.我使用Canvas控件作为白板.

我想在WPF画布中使用InkCanvas类功能,意味着我想在Canvas上绘制一个自由形状.我怎样才能做到这一点 ？我也想保存为*.JPG

第二个问题是像我们在MS Paint中那样绘制字体？我可以在其中集成FontDialogBox吗？如果是,怎么样？

感谢您 !!!

Answer 1

这是一个在画布上绘制线条以及如何添加textBlock对象的简单示例.

例:

    <StackPanel>
      <Canvas MouseLeftButtonDown="myCanvas_MouseLeftButtonDown" MouseMove="myCanvas_MouseMove"
x:Name="inkCanvas" Width="400" Height="200"> </Canvas>
      <Button Height="20" Width="30" x:Name="AddTextBtn" Click="AddTextBtn_Click">AddText</Button>
    </StackPanel>

代码背后:

private Point _startPoint;
private Polyline _line;

private void myCanvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
  _startPoint = e.GetPosition(myCanvas);
  _line = new Polyline();
  _line.Stroke = new SolidColorBrush(Colors.Black);
  _line.StrokeThickness = 2.0;

  myCanvas.Children.Add(_line);
}

private void myCanvas_MouseMove(object sender, MouseEventArgs e)
{
  if (e.LeftButton == MouseButtonState.Pressed)
  {
    Point currentPoint = e.GetPosition(myCanvas);
    if (_startPoint != currentPoint)
    {
        _line.Points.Add(currentPoint);
    }
  } 
}

private void AddTextBtn_Click(object sender, RoutedEventArgs e)
{
  // Show Font Dialog Box

  TextBlock tb = new TextBlock();
  tb.FontFamily = new FontFamily("Arial");
  tb.FontSize = 14;
  tb.Text = "SampleText";

  // Set position on canvas:
  Canvas.SetTop(tb,100);
  Canvas.SetLeft(tb, 50);

  myCanvas.Children.Add(tb);
}

但是没有纯WPF字体选择器.您既可以使用WinForms中的那个,也可以查看有很多纯Xaml实现.例如链接

另存为jpg:使用RenderTargetBitmap或CroppedBitmap; 请参阅SO上的链接