如何在wpf c#中的WritableBitmap中选择或突出显示鼠标移动事件中的文本

Question

我有WritableBitmap图像,我已在图像控制src中设置.当用户在选定的文本区域移动时,我正在创建矩形.我还使用PDFtron SDK从PDF文档中获取选定的文本.我们WritableBitmap从PDF 获取图像.我们必须在线选择文字.

我正在使用此代码绘制屏幕:

System.Drawing.Rectangle rectangle = new System.Drawing.Rectangle((int)Math.Min(_downX, x),
                             (int)Math.Min(_downY, y),
                             (int)Math.Abs(_downX - x),
                             (int)Math.Abs(_downY - y));

System.Drawing.Bitmap myBitmap = new System.Drawing.Bitmap(@"D:\PDF\ScreenDraw\WpfApplication1\WpfApplication1\Image\Capture.PNG");

using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(myBitmap))
{
    System.Drawing.Color customColor = System.Drawing.Color.FromArgb(50, System.Drawing.Color.Red);
    System.Drawing.SolidBrush shadowBrush = new System.Drawing.SolidBrush(customColor);
    g.FillRectangles(shadowBrush, new System.Drawing.Rectangle[] { rectangle });
}

//myBitmap.Save(@"D:\PDF\abc.png");
//bitmapSource = new BitmapImage(new Uri(@"D:\PDF\abc.png", UriKind.Absolute));

using (var memory = new System.IO.MemoryStream())
{
    myBitmap.Save(memory, System.Drawing.Imaging.ImageFormat.Png);
    memory.Position = 0;

    var bitmapImage = new BitmapImage();
    bitmapImage.BeginInit();
    bitmapImage.StreamSource = memory;
    bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
    bitmapImage.EndInit();
    Img.Source = bitmapImage;
}

我怎样才能用明智的Rect方式选择文字呢？

我必须选择上面图片中显示的文字.

Answer 1

你想要的东西是不可能的。你有一个位图，它并不能神奇地意识到其中的文本，并且没有什么可以改变这一点。虽然这并不是说你无能为力。我没有时间提供完整的解决方案，但我可以提供如何实现最佳解决方案的分步说明。

你能做的是：

1. 文本尺寸定义 - 使用覆盖在图像上的网格创建控件，并具有可编辑的 X 轴和 Y 轴步长和偏移量。然后您将能够使用文本行 (Y) 校准网格。和字符宽度 (X)。类似的事情应该做（我想你会明白的）：

   public int XGridStep
   {
       get { return (int)base.GetValue(XGridStepProperty); }
       set
       {
           base.SetValue(XGridStepProperty, value);
           RepaintGrid();
       }
   }
   
   public static readonly DependencyProperty XGridStepProperty = DependencyProperty.Register("XGridStepProperty", typeof(int), typeof(PlanLayout), new PropertyMetadata(100));
   
   public int XGridOffset
   {
       get { return (int)base.GetValue(XGridOffsetProperty); }
       set
       {
           base.SetValue(XGridOffsetProperty, value);
           RepaintGrid();
       }
   }
   
   public static readonly DependencyProperty XGridOffsetProperty = DependencyProperty.Register("XGridOffsetProperty", typeof(int), typeof(PlanLayout), new PropertyMetadata(0));
   
   public bool XGridVisible
   {
       get { return (bool)base.GetValue(XGridVisibleProperty); }
       set
       {
           base.SetValue(XGridVisibleProperty, value);
           RepaintGrid();
       }
   }
   
   public static readonly DependencyProperty XGridVisibleProperty = DependencyProperty.Register("XGridVisibleProperty", typeof(bool), typeof(PlanLayout), new PropertyMetadata(false));
   
   public int YGridStep
   {
       get { return (int)base.GetValue(YGridStepProperty); }
       set
       {
           base.SetValue(YGridStepProperty, value);
           RepaintGrid();
       }
   }
   
   public static readonly DependencyProperty YGridStepProperty = DependencyProperty.Register("YGridStepProperty", typeof(int), typeof(PlanLayout), new PropertyMetadata(100));
   
   public int YGridOffset
   {
       get { return (int)base.GetValue(YGridOffsetProperty); }
       set
       {
           base.SetValue(YGridOffsetProperty, value);
           RepaintGrid();
       }
   }
   
   public static readonly DependencyProperty YGridOffsetProperty = DependencyProperty.Register("YGridOffsetProperty", typeof(int), typeof(PlanLayout), new PropertyMetadata(0));
   
   public bool YGridVisible
   {
       get { return (bool)base.GetValue(YGridVisibleProperty); }
       set
       {
           base.SetValue(YGridVisibleProperty, value);
           RepaintGrid();
       }
   }
   
   public static readonly DependencyProperty YGridVisibleProperty = DependencyProperty.Register("YGridVisibleProperty", typeof(bool), typeof(PlanLayout), new PropertyMetadata(false));
   
   private void RepaintGrid()
   {
       if (!IsEditable)
           return;
   
       foreach (Line l in _gridXLines)
           content.Children.Remove(l);
       _gridXLines.Clear();
       if (XGridVisible)
           for (int i = XGridOffset; i < content.ActualWidth; i += XGridStep)
           {
               Line line = new Line();
               line.IsHitTestVisible = false;
               line.Stroke = Brushes.Black;
               line.Y1 = 0;
               line.Y2 = content.ActualHeight;
               line.X1 = line.X2 = i;
               if (Math.Abs(line.X1 - content.ActualWidth) < XGridStep * 0.5 || line.X1 < XGridStep * 0.5)
                   continue;
               _gridXLines.Add(line);
               content.Children.Add(line);
               Canvas.SetZIndex(line, 0);
           }
   
       foreach (Line l in _gridYLines)
           content.Children.Remove(l);
       _gridYLines.Clear();
       if (YGridVisible)
           for (int i = YGridOffset; i < content.ActualHeight; i += YGridStep)
           {
               Line line = new Line();
               line.IsHitTestVisible = false;
               line.Stroke = Brushes.Black;
               line.X1 = 0;
               line.X2 = content.ActualWidth;
               line.Y1 = line.Y2 = i;
               if (Math.Abs(line.Y1 - content.ActualHeight) < YGridStep * 0.5 || line.Y1 < YGridStep * 0.5)
                   continue;
               _gridYLines.Add(line);
               content.Children.Add(line);
               Canvas.SetZIndex(line, 0);
           }
   }
   

2. 文本选择- 现在您所要做的就是向您的控件添加“对齐网格”功能。再次强调一下，仅供参考：

   private void elementWrapper_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
   {
       if (_mouseHandlingMode != MouseHandlingMode.Dragging)
           return;
   
       SelectableElement element = (SelectableElement)sender;
   
       Point curContentPoint = e.GetPosition(content);
       //Vector elementDragVector = curContentPoint - _origContentMouseDownPoint;
   
       _origContentMouseDownPoint = curContentPoint;
   
       //double destinationLeft = Canvas.GetLeft(element) + elementDragVector.X;
       //double destinationTop = Canvas.GetTop(element) + elementDragVector.Y;
       double destinationLeft = curContentPoint.X - element.ActualWidth / 2;
       double destinationTop = curContentPoint.Y - element.ActualHeight / 2;
   
       if (SnapToGrid)
       {
           if (XGridVisible)
           {
               foreach (Line l in _gridXLines)
                   l.StrokeThickness = 1;
   
               Line nearest = GetNearestXGridLine((int)curContentPoint.X);
   
               if (Math.Abs(curContentPoint.X - nearest.X1) < XGridStep * 0.2)
               {
                   destinationLeft = nearest.X1 - element.ActualWidth / 2;
                   nearest.StrokeThickness = 3;
               }
           }
   
           if (YGridVisible)
           {
               foreach (Line l in _gridYLines)
                   l.StrokeThickness = 1;
   
               Line nearest = GetNearestYGridLine((int)curContentPoint.Y);
   
               if (Math.Abs(curContentPoint.Y - nearest.Y1) < YGridStep * 0.2)
               {
                   destinationTop = nearest.Y1 - element.ActualHeight / 2;
                   nearest.StrokeThickness = 3;
               }
           }
       }
   
       if (destinationLeft < 0)
           destinationLeft = 0;
   
       if (destinationLeft > content.ActualWidth - element.ActualWidth)
           destinationLeft = content.ActualWidth - element.ActualWidth;
   
       if (destinationTop < 0)
           destinationTop = 0;
   
       if (destinationTop > content.ActualHeight - element.ActualHeight)
           destinationTop = content.ActualHeight - element.ActualHeight;
   
       Canvas.SetLeft(element, destinationLeft);
       Canvas.SetTop(element, destinationTop);
   
       element.ElementContent.Position.X = curContentPoint.X;
       element.ElementContent.Position.Y = curContentPoint.Y;
   
       e.Handled = true;
   }
   
   private Line GetNearestXGridLine(int xpos)
   {
       return _gridXLines.OrderBy(gl => Math.Abs((int)gl.X1 - xpos)).First();
   }
   
   private Line GetNearestYGridLine(int Ypos)
   {
       return _gridYLines.OrderBy(gl => Math.Abs((int)gl.Y1 - Ypos)).First();
   }
   

3. 所选内容的图形表示- 现在绘制（最多）3 个矩形：从所选内容的左上角到相关文本行的右下角、下一行的左上角到最后一个所选行之前的行的右下角以及文本行的左上角所选内容右下角的最后一行

4. 获取文本- 从这些矩形中获取部分文本数据并连接。