asked on

Moving a borderless window

Hi

I have a window creted with:

procedure TOknoAbout.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
with Params do
Style := (Style or WS_POPUP) and (not WS_DLGFRAME);
end;

and a window move procedures that take care of it:

procedure TOknoAbout.FormMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
myszX := X;
myszY := Y;
end;

procedure TOknoAbout.FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
begin
if shift = [ssLeft] then
begin
OknoAbout.Left := OknoAbout.Left + (X - myszX);
OknoAbout.Top := OknoAbout.Top + (Y - myszY);
end;
end;

how to modify the formmousemove procedure for it not to let the windows get out of the screen.workarea ??

thanks for any advice

ASKER CERTIFIED SOLUTION

TheRealLoki

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abrakadabra1

ASKER

thank you for your help

abrakadabra1

ASKER

@TheRealLoki

i have a problem with this. the answer that you gave wasn'e working if the mouse was moved to fat to the screen side. i've modified the procedure to this:

procedure TOknoAbout.FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
var
NewTop, NewLeft : integer;

begin
if shift = [ssLeft] then
begin
NewLeft := OknoAbout.Left + (X - myszX);
NewTop := OknoAbout.Top + (Y - myszY);
if ((NewLeft >= 0) and ((NewLeft + OknoAbout.Width) < Screen.WorkAreaWidth)) then
OknoAbout.Left := NewLeft;
if ((NewTop >= 0) and ((NewTop + OknoAbout.Height) < Screen.WorkAreaHeight)) then
OknoAbout.Top := NewTop;
if (X < 10) then
OknoAbout.Left := 0;
if (Y < 10) then
OknoAbout.Top := 0;
if (X > (Screen.WorkAreaWidth - 10)) then
OknoAbout.Left := Screen.WorkAreaWidth - OknoAbout.Width;
if (Y > (Screen.WorkAreaHeight - 10)) then
OknoAbout.Top := Screen.WorkAreaHeight - OknoAbout.Height;
end;
end;

and now the top and left screen side work ok but there is some kind of a problem with this part of the code:

if (X > (Screen.WorkAreaWidth - 10)) then
OknoAbout.Left := Screen.WorkAreaWidth - OknoAbout.Width;
if (Y > (Screen.WorkAreaHeight - 10)) then
OknoAbout.Top := Screen.WorkAreaHeight - OknoAbout.Height;

now if the mouse is moved to fast to the right or bottom side of the screen the window still stays far on the screen... http://spisik.szm.sk/img.jpg ... any idea how to correct this ??

TheRealLoki

hmmm, not sure what is happening.
I've simplified the procedure a bit, maybe this will help

uses math;

procedure TOknoAbout.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
myszX := X;
myszY := Y;
end;

procedure TOknoAbout.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
var
NewTop, NewLeft : integer;
begin
if shift = [ssLeft] then
begin
NewLeft := OknoAbout.Left + (X - myszX);
NewTop := OknoAbout.Top + (Y - myszY);

NewLeft := Max(0, NewLeft);
NewLeft := Min(Screen.WorkAreaWidth - OknoAbout.Width, NewLeft);
NewTop := Max(0, NewTop);
NewTop := Min(Screen.WorkAreaHeight - OknoAbout.Height, NewTop);

OknoAbout.Left := NewLeft;
OknoAbout.Top := NewTop;
end;
end;

btw, another way to move the form is to make it act as a titlebar, eg.
pubic
procedure WMNCHitTest(var M: TWMNCHitTest); message wm_NCHitTest;

procedure TOknoAbout.WMNCHitTest(var M: TWMNCHitTest);
begin
inherited; { call the inherited message handler }
if M.Result = htClient then { is the click in the client area? }
M.Result := htCaption; { if so, make Windows think it's }
{ on the caption bar. }
end;
just doing the above code, you can move the form around now.

and you can check the position being moved to with
procedure WMPosChange(var Message: TWMWINDOWPOSCHANGING); message WM_WINDOWPOSCHANGING;
Message.WindowPos.x and Message.WindowPos.y, although I had trouble checking the left bounds, so didn't look into it.