Methode zum zeichnen eines Auswahlrechtecks

Methode zum zeichnen eines Auswahlrechtecks:

      /// <summary>
      /// This method draws a selection box.
      /// </summary>
      /// <param name="grfx">The Graphics</param>
      /// <param name="start">The start point</param>
      /// <param name="vDeltaX">The x-value of the vector</param>
      /// <param name="vDeltaY">The y-value of the vector</param>
      /// <param name="pen">The pen which is used to draw</param>
      /// <param name="fill">A brush or null</param>
      protected virtual RectangleF DrawSelectionBox(Graphics grfx, PointF start, float vDeltaX, float vDeltaY, Pen pen, Brush fill)
      {
         RectangleF selectionBox = new RectangleF();

         #region Determine correct position and size

         if (vDeltaX > 0 && vDeltaY > 0)
         {
            //RightDown
            selectionBox.X = start.X;
            selectionBox.Y = start.Y;

            selectionBox.Width = vDeltaX;
            selectionBox.Height = vDeltaY;
         }
         else if (vDeltaX < 0 && vDeltaY < 0)
         {
            //LeftUp
            selectionBox.X = start.X + vDeltaX;
            selectionBox.Y = start.Y + vDeltaY;

            selectionBox.Width = (float)Math.Abs(vDeltaX);
            selectionBox.Height = (float)Math.Abs(vDeltaY);
         }
         else if (vDeltaX > 0 && vDeltaY < 0)
         {
            //RightUp
            selectionBox.X = start.X;
            selectionBox.Y = start.Y + vDeltaY;

            selectionBox.Width = vDeltaX;
            selectionBox.Height = (float)Math.Abs(vDeltaY);
         }
         else if (vDeltaX < 0 && vDeltaY > 0)
         {
            //LeftDown
            selectionBox.X = start.X + vDeltaX;
            selectionBox.Y = start.Y;

            selectionBox.Width = (float)Math.Abs(vDeltaX);
            selectionBox.Height = vDeltaY;
         }

         #endregion

         if (fill != null)
         {
            grfx.FillRectangle(fill, selectionBox);
         }
         grfx.DrawRectangle(pen, selectionBox.X, selectionBox.Y, selectionBox.Width, selectionBox.Height);

         return selectionBox;
      }

Schlagwörter: Auswahlrechteck, Auswahlbox, SelectionBox, GDI

Hallo!

Passend zu meinem Vorposter hier noch zwei Links, die sich die gleiche Aufgaube gestellt haben:

How to draw a rubber band rectangle

Drawing a selection rubber band

Gruß, DaMoe