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Article #16229: Adding hint windows to applications

 Question and Answer Database

FAQ1229D.txt   Adding hint windows to applications
Category   :Miscellaneous
Platform    :All
Product    :All 32 bit  

Question:
How can I pop up a hint window?

Answer:
You can either programmatically move the mouse pointer over 
the control with the hint, or you can display a hint window 
of your own;

Example # 1 - programmatically moving the mouse.

procedure TForm1.Button1Click(Sender: TObject);
var
  pt : TPoint;
begin
{Let the button repaint}
  Application.ProcessMessages;
{Get the screen coordinates of the center of the button}
  pt := ClientToScreen(Point(Button1.Left + Button1.Width div 2,
                             Button1.Top + Button1.Height div 2));
{Position the cursor at the center of the button}
  SetCursorPos(Pt.x, Pt.y);
end;


Example #2 - Creating you own hint window. For this example, you will
need a TPanel and a TTimer component. The Panel will be used as the
hint window, and will be invisible untill called. The timer will hide
the panel after a specified duration. 
procedure TForm1.FormCreate(Sender: TObject);
begin
  Timer1.Enabled := false;
  Panel1.Visible := false;
  Panel1.BevelInner := bvNone;
  Panel1.BevelOuter := bvNone;
  Panel1.BorderStyle := bsSingle;
  Panel1.Color := clWhite;
  Button1.Hint := 'Hint test';
end;

procedure TForm1.ShowAHint(x : integer;
                           y : integer;
                           Caption : string;
                           Duration : LongInt);
var
  dc : hdc;
  OldFont : hFont;
  pt : TSize;
  p : pChar;
begin
  if Timer1.Enabled <> false then
    Timer1.Enabled := false;
  Timer1.Enabled := false;
  if Panel1.Visible <> false then
    Panel1.Visible := false;
  if Caption = '' then exit;
  Panel1.Caption := caption;
 {Get the width of the caption string}
  GetMem(p, Length(Panel1.Caption) + 1);
  StrPCopy(p, Panel1.Caption);
  dc := GetDc(Panel1.Handle);
  OldFont := SelectObject(dc, Panel1.Font.Handle);
  GetTextExtentPoint32(dc, p, Length(Panel1.Caption), pt);
  SelectObject(dc, OldFont);
  ReleaseDc(Panel1.Handle, Dc);
  FreeMem(p, Length(Panel1.Caption) + 1);
 {Position and show the panel}
  Panel1.Left := x;
  Panel1.Top := y;
  Panel1.Width := pt.cx + 6;
  Panel1.Height := pt.cy + 2;
  Panel1.Visible := true;
 {Fire off the timer to hide the panel}
  Timer1.Interval := Duration;
  Timer1.Enabled := true;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  if Panel1.Visible <> false then
    Panel1.Visible := false;
  Timer1.Enabled := false;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  {Let the button repaint}
  Application.ProcessMessages;
  ShowAHint(Button1.Left,
            Button1.Top + Button1.Height + 6,
            Button1.Hint,
            2000);
end;




7/16/98 4:31:28 PM
 

Last Modified: 01-SEP-99