Felipe Monteiro de Carvalho wrote 19 lines
Hello,
I am investigating how to make a component act like the title bar, in
the sense that it can be used to drag the window around.
We have 2 solutions at the moment:
1 - Use MouseMove, MouseUp, MouseDown to emulate this, but in my Mac
it sometimes looses track of MouseMove because the mouse was faster
then the window, so not 100% good
2 - Use platform-specific APIs. It's easy in Windows and we already
have an idea in X11, but nothing yet in Carbon.
Has anyone tryed this before and knows if option 1 is good enough or
how to implement 2 well?
thanks,
This may be of help:
http://forum.lazarus.freepascal.org/index.php/topic,7962.msg38255.html#msg38255
Create a new project.
Create a blank form.
Change border type to none.
For this example, I will leave the default name of 'Form1'. //for this example
Save all your files.
Goto the global var section for Form1.
Add:
Code:
MouseX, MouseY: Integer;
Using the object inspector on Form1, create an event handler for 'OnMouseDown'.
The purpose of this event handler is to record the mouse position on the form for use later.
Code:
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
if [ssLeft] <= Shift then begin //only interested in left mouse button...
//using <= as we are dealing with SETS.
MouseX := X; //used later as an offset for the move
MouseY := Y; //used later as an offset for the move
end;
end;
Now for the actual movement.
We will respond the OnMouseMove event, as the setbounds sets the upper left corner of the mainform, we have to subtract out the form relative position of the mouse pointer from the new screen position so that the top left corner stays relative to the mouse during the move. Code:
procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
var P : TPoint;
begin
if [ssLeft] <= Shift then begin //only left mouse button again.
//using <= as we are dealing with SETS.
P := ClientToScreen(Point(X, Y)); //convert to screen relative numbers instead of form relative numbers.
SetBounds(P.X-MouseX, P.Y-MouseY, Width, Height); //Move form to new location.
//Note that we subtract the mouse's relative position in regards to the upper left of the form.
end;
end;
