Re: [win32gui] Re: [perl-win32-gui-users] How to do "While MouseDown, Move Window" ?

[Robert May]

Jason P. wrote:
kortyzon wrote:
I'm a french win32 gui user and i search how to move the window
whitout the dragbar.

you will need 3 things.

mouseDown, mouseMove, mouseUp (these are generic names, the specifcs are 
up to you in OEM/NEM)

inside the mouseDown event, set a state flag (like $mouseIsDown)

when the mouseMove event is fired, check the status of $mouseIsDown, and 
then move the window accordingly.

when mouseUp is fired, set $mouseIsDown to 0/-1/undef/your version of 
false.

viola.

there may be some other slightly more specfic, but unmentioned code 
realting to the exact method by which you know how and where to move the 
window to, but these are the basics.

Here's a (C++) article describing what you're looking for (see the 
second part of the article):
http://msdn.microsoft.com/msdnmag/issues/02/12/CQA/default.aspx

And because I wanted to understand the difference between then, here's 
Win32::GUI implementations of both methods:

(1) Using mouse down/move/up:

#!perl -w
use strict;
use warnings;

use Win32::GUI;

my $down   = 0; # Flag to indcate if we are dragging or not
my $msx;       # last known position of mouse in screen co-ordinates
my $msy;       # last known position of mouse in screen co-ordinates

my $mw = Win32::GUI::Window->new(
        -title => "Click anywhere to move",
        -pos   => [100,100],
        -size  => [400,300],
        -onMouseDown => \&down,
        -onMouseUp   => \&up,
        -onMouseMove => \&move,
);

$mw->Show();
Win32::GUI::Dialog();
exit(0);

sub down
{
        my ($object, $x, $y) = @_;

        # we're dragging
        $down = 1;

        # record mouse position
        ($msx, $msy) = $object->ClientToScreen($x, $y);

        # capture mouse
        $object->SetCapture();

        return 1;
}

sub up
{
        my ($object) = @_;

        # not dragging any more
        $down = 0;

        # release mouse capture
        $object->ReleaseCapture();

        return 1;
}

sub move
{
        my ($object, $x, $y) = @_;  # x/y in client co-ordinates

        # don't do anything unless the left button is down
        return unless $down;

        # how much have we moved?
        my ($sx, $sy) = $object->ClientToScreen($x, $y);
        my $xshift = $sx - $msx;
        my $yshift = $sy - $msy;

        # record the new mouse position
        ($msx, $msy) = ($sx, $sy);

        # move the window
        $object->Move($object->Left() + $xshift, $object->Top() + $yshift);

        return 1;
}
__END__

(2) using WM_NCHITTEST:

#!perl -w
use strict;
use warnings;

use Win32::GUI;

sub WM_NCHITTEST() {132}
sub HTCAPTION()    {2}

my $mw = Win32::GUI::Window->new(
        -title => "Click anywhere to move",
        -pos   => [100,100],
        -size  => [400,300],
);

$mw->Hook(WM_NCHITTEST, \&hittest);

$mw->Show();
Win32::GUI::Dialog();
exit(0);

sub hittest
{
        my ($object, $wParam, $lParam, $type, $msgcode) = @_;

        return unless $type == 0;
        return unless $msgcode == WM_NCHITTEST;

        # get mouse position from $lParam (screen co-ordinates)
        my $sx = $lParam & 0xFFFF;
        my $sy = ($lParam >> 16) & 0xFFFF;

        # convert to client co-ordinates:
        my ($cx, $cy) = $object->ScreenToClient($sx, $sy);

        # See if we're in the client area ...
        my ($cl, $ct, $cr, $cb) = $object->GetClientRect();

        if (    $cx < $cl or $cx > $cr
             or $cy < $ct or $cy > $cb ) {
                # not in client area, pass to defwindowproc
                return 1;
        }

        # In client area, return HTCAPTION
        $object->Result(HTCAPTION);
        return 0;
}
__END__

Regards,
Rob.