Qt-interest Archive, July 2005
RE: Drawing an arrow
Message 1 in thread
try something like this
void EdgeItem::drawArrow( const doublePoint& pt, const doublePoint& ppt, double sze, const QPen& pen )
{
doublePoint pd, pa, pb;
double tangent;
/* in order to get the arrowhead the correct way round,
* we reverse the gradient.
* This is equivalent to reversing the geometry below...
*/
pd.x = ppt.x - pt.x, pd.y = ppt.y - pt.y;
if (pd.x == 0 && pd.y == 0)
return;
tangent = atan2 ((double) pd.y, (double) pd.x);
pa.x = sze * cos (tangent + M_PI / 7) + pt.x;
pa.y = sze * sin (tangent + M_PI / 7) + pt.y;
pb.x = sze * cos (tangent - M_PI / 7) + pt.x;
pb.y = sze * sin (tangent - M_PI / 7) + pt.y;
//-- connect the dots...
CanvasLine* lhs = new CanvasLine( canvas );
lhs->setPoints( pa.x, pa.y, pt.x, pt.y );
lhs->setPen( pen );
lhs->setZ( 1 );
lhs->show();
SimpleCanvasLine* rhs = new SimpleCanvasLine( canvas, this );
rhs->setPoints( pb.x, pb.y, pt.x, pt.y );
rhs->setPen( pen );
lhs->setZ( 1 );
rhs->show();
}
-----Original Message-----
From: François-Xavier Payet [mailto:mailing-lists@xxxxxxxx]
Sent: 06 July 2005 08:56
To: qt-interest@xxxxxxxxxxxxx
Subject: Drawing an arrow
Hi,
Has anyone got a source code for drawing an arrow?
Thanks,
FX
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Message 2 in thread
On Mer 6 juillet 2005 9:54, Alistair MacArthur a écrit :
> try something like this
> void EdgeItem::drawArrow( const doublePoint& pt, const doublePoint& ppt,
> double sze, const QPen& pen )
> {
> doublePoint pd, pa, pb;
> double tangent;
> /* in order to get the arrowhead the correct way round,
> * we reverse the gradient.
> * This is equivalent to reversing the geometry below...
> */
> pd.x = ppt.x - pt.x, pd.y = ppt.y - pt.y;
> if (pd.x == 0 && pd.y == 0)
> return;
> tangent = atan2 ((double) pd.y, (double) pd.x);
> pa.x = sze * cos (tangent + M_PI / 7) + pt.x;
> pa.y = sze * sin (tangent + M_PI / 7) + pt.y;
> pb.x = sze * cos (tangent - M_PI / 7) + pt.x;
> pb.y = sze * sin (tangent - M_PI / 7) + pt.y;
> //-- connect the dots...
> CanvasLine* lhs = new CanvasLine( canvas );
> lhs->setPoints( pa.x, pa.y, pt.x, pt.y );
> lhs->setPen( pen );
> lhs->setZ( 1 );
> lhs->show();
> SimpleCanvasLine* rhs = new SimpleCanvasLine( canvas, this );
> rhs->setPoints( pb.x, pb.y, pt.x, pt.y );
> rhs->setPen( pen );
> lhs->setZ( 1 );
> rhs->show();
> }
>
It worked great. Thanks a lot
FX
> -----Original Message-----
> From: François-Xavier Payet [mailto:mailing-lists@xxxxxxxx]
> Sent: 06 July 2005 08:56
> To: qt-interest@xxxxxxxxxxxxx
> Subject: Drawing an arrow
>
>
> Hi,
>
> Has anyone got a source code for drawing an arrow?
>
> Thanks,
>
> FX
>
>
> _____________________________________________________________________
> This incoming message has been checked for all known viruses by Star
> Internet, on behalf of Celoxica, delivered through the MessageLabs Virus
> Scanning Service.
>
> _____________________________________________________________________
> This message has been checked for all known viruses by Star Internet
> delivered on behalf of Celoxica Ltd through the MessageLabs Virus Scanning
> Service.
>
> This email and any files transmitted with it are confidential and
> may be legally privileged. It is intended solely for the use of the
> individual or entity to whom it is addressed. If you have received
> this in error, please contact the sender and delete the material
> immediately. Whilst this email has been swept for viruses, you
> should carry out your own virus check before opening any
> attachment. Celoxica Ltd accepts no liability for any loss or
> damage which may be caused by software viruses or interception
> or interruption of this email.
>
>
Message 3 in thread
Hi,
Has anyone got a source code for drawing an arrow?
Thanks,
FX
