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