Well, I have got close but I am not sure how to make the Drawn rectangle
transparent or how to dispose of the DC after I am through.. Any help
would be greatly appreciated.
You'll be glad to know, that the solution is straightforward:) It's
probably worth explaining a few things for the benifit of other readers.
In a normal situation you would have a Win32::GUI DC object and you would
call methods upon it such as $dc->Rectangle($left,$top,$right,$bottom).
You can also call the Rectangle function in procedural form, you just need
to pass a DC object or a valid handle:
$dc->Rectangle($left,$top,$right,$bottom);
Win32::GUI::DC::Rectangle($dc,$left,$top,$right,$bottom);
The above two calls are equivalent. But you don't need to pass an object
at all:
Win32::GUI::DC::Rectangle(18947123,$left,$top,$right,$bottom);
If 18947123 is a valid DC, then you'll get a rectangle drawn. So you can
use all the DC 'methods', as function calls passing in your handles.
As the rectangle function draws with the current pen and fills with the
current brush, one way would be:
sub drawRectangle{
#usage: my $ok=drawRectangle($hdc,$left,$top,$right,$bottom);
#info: returns the handle of a device context for the specified window.
my $hdc=shift || return;
my $left=shift || 0;
my $top=shift || 0;
my $right=shift || 0;
my $bottom=shift || 0;
#my $Rectangle = new Win32::API("gdi32", "Rectangle",
['N','I','I','I','I'], 'N') || return $^E;
Win32::GUI::DC::Line($hdc,$left,$top,$right,$top);
Win32::GUI::DC::Line($hdc,$right,$top,$right,$bottom);
Win32::GUI::DC::Line($hdc,$right,$bottom,$left,$bottom);
Win32::GUI::DC::Line($hdc,$left,$bottom,$left,$top);
#my $ok=$Rectangle->Call($hdc,$left,$top,$right,$bottom);
return $hdc;
}
Perhaps the better solution in this case would be to use the FrameRect
function (notice how you can mix and match real Win32::GUI objects and
handles):
sub drawRectangle{
#usage: my $ok=drawRectangle($hdc,$left,$top,$right,$bottom);
#info: returns the handle of a device context for the specified window.
my $hdc=shift || return;
my $left=shift || 0;
my $top=shift || 0;
my $right=shift || 0;
my $bottom=shift || 0;
#my $Rectangle = new Win32::API("gdi32", "Rectangle",
['N','I','I','I','I'], 'N') || return $^E;
my $brush = new Win32::GUI::Brush([255,0,0]);
Win32::GUI::DC::FrameRect($hdc,$left,$top,$right,$bottom,$brush);
#my $ok=$Rectangle->Call($hdc,$left,$top,$right,$bottom);
return $hdc;
}
As for releasing the DC, you could use the ReleaseDC function - but you'll
have to pass the window handle and well as the DC handle:
Win32::GUI::DC::ReleaseDC($windowhandle,$hdc);
Cheers,
jez.
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