OnMouseMove (C++)

Description

The following example requires a form with a four-paneled status bar. (Set the Width of the status panels to 150 before running this example). When you press a mouse button, move the mouse, and release the mouse button, a rectangle is drawn on the form. When the mouse button is released, the rectangle appears on the form's canvas. Its top-left and bottom-right corners are defined by the location of the mouse pointer when you pressed and released the mouse button. While you drag the mouse, the location of the top, left, bottom, and right sides of the rectangle are displayed in the status bar.

Code

int StartX, StartY;  // Declare at the top of the form's unit.

// Use this code as the OnMouseDown event handler of the form:
void __fastcall TForm1::FormMouseDown(TObject *Sender, TMouseButton Button, TShiftState Shift, int X, int Y)
{
  StartX = X;
  StartY = Y;
}

// Use this code as the OnMouseUp event handler of the form:
void __fastcall TForm1::FormMouseUp(TObject *Sender, TMouseButton Button, TShiftState Shift, int X, int Y)
{
  Form1->Canvas->Rectangle(StartX, StartY, X, Y);
  StatusBar1->Panels->Items[0]->Text = "";
  StatusBar1->Panels->Items[1]->Text = "";
  StatusBar1->Panels->Items[2]->Text = "";
  StatusBar1->Panels->Items[3]->Text = "";
}

// Use this code as the OnMouseMove event handler of the form:
void __fastcall TForm1::FormMouseMove(TObject *Sender, TShiftState Shift, int X, int Y)
{
  if (Shift.Contains(ssLeft)) // make sure button is down
  {
    if (Y > StartY)
    {
	  StatusBar1->Panels->Items[0]->Text = "Top: " + IntToStr(StartY);
      StatusBar1->Panels->Items[2]->Text = "Bottom: " + IntToStr(Y);
    }
	else
    {
      StatusBar1->Panels->Items[0]->Text = "Top: " + IntToStr(Y);
      StatusBar1->Panels->Items[2]->Text = "Bottom: " + IntToStr(StartY);
    }
    if (X > StartX)
    {
      StatusBar1->Panels->Items[1]->Text = "Left: " + IntToStr(StartX);
      StatusBar1->Panels->Items[3]->Text = "Right: " + IntToStr(X);
    }
    else
    {
      StatusBar1->Panels->Items[1]->Text = "Left: " + IntToStr(X);
      StatusBar1->Panels->Items[3]->Text = "Right: " + IntToStr(StartX);
    }
  }
}

Uses

• Vcl.Controls.TControl.OnMouseDown ( fr | de | ja )
• Vcl.Controls.TControl.OnMouseMove ( fr | de | ja )
• Vcl.Controls.TControl.OnMouseUp ( fr | de | ja )
• Vcl.ComCtrls.TCustomStatusBar.Panels ( fr | de | ja )
• Vcl.ComCtrls.TStatusPanel.Text ( fr | de | ja )