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koffice/karbon/plugins/roundcorners/roundcornersplugin.cc

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/* This file is part of the KDE project
Copyright (C) 2002, The Karbon Developers
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "roundcornersplugin.h"
#include <karbon_view.h>
#include <karbon_part.h>
#include <core/vpath.h>
#include <core/vsegment.h>
#include <kgenericfactory.h>
#include <kdebug.h>
#include <qgroupbox.h>
#include <qlabel.h>
#include <knuminput.h>
typedef KGenericFactory<VRoundCornersPlugin, KarbonView> VRoundCornersPluginFactory;
K_EXPORT_COMPONENT_FACTORY( karbon_roundcornersplugin, VRoundCornersPluginFactory( "karbonroundcornersplugin" ) )
VRoundCornersPlugin::VRoundCornersPlugin( KarbonView *parent, const char* name, const QStringList & ) : Plugin( parent, name )
{
new KAction(
i18n( "&Round Corners..." ), "14_roundcorners", 0, this,
SLOT( slotRoundCorners() ), actionCollection(), "path_round_corners" );
m_roundCornersDlg = new VRoundCornersDlg();
m_roundCornersDlg->setRadius( 10.0 );
}
VRoundCornersPlugin::~VRoundCornersPlugin()
{
}
void
VRoundCornersPlugin::slotRoundCorners()
{
KarbonPart *part = ((KarbonView *)parent())->part();
if( part && m_roundCornersDlg->exec() )
part->addCommand( new VRoundCornersCmd( &part->document(), m_roundCornersDlg->radius() ), true );
}
VRoundCornersDlg::VRoundCornersDlg( QWidget* parent, const char* name )
: KDialogBase( parent, name, true, i18n( "Polygonize" ), Ok | Cancel )
{
// add input:
QGroupBox* group = new QGroupBox( 2, Qt::Horizontal, i18n( "Properties" ), this );
new QLabel( i18n( "Round corners:" ), group );
m_radius = new KDoubleNumInput( group );
group->setMinimumWidth( 300 );
// signals and slots:
connect( this, SIGNAL( okClicked() ), this, SLOT( accept() ) );
connect( this, SIGNAL( cancelClicked() ), this, SLOT( reject() ) );
setMainWidget( group );
setFixedSize( baseSize() );
}
double
VRoundCornersDlg::radius() const
{
return m_radius->value();
}
void
VRoundCornersDlg::setRadius( double value )
{
m_radius->setValue(value);
}
VRoundCornersCmd::VRoundCornersCmd( VDocument* doc, double radius )
: VReplacingCmd( doc, i18n( "Round Corners" ) )
{
// Set members.
m_radius = radius > 0.0 ? radius : 1.0;
}
void
VRoundCornersCmd::visitVSubpath( VSubpath& path )
{
// Optimize and avoid a crash.
if( path.isEmpty() )
return;
// Note: we modiy segments from path. that doesn't hurt, since we
// replace "path" with the temporary path "newPath" afterwards.
VSubpath newPath( 0L );
path.first();
// Skip "begin".
path.next();
/* This algorithm is worked out by <kudling AT kde DOT org> to produce similar results as
* the "round corners" algorithms found in other applications. Neither code nor
* algorithms from any 3rd party is used though.
*
* We want to replace all corners with round corners having "radius" m_radius.
* The algorithm doesn't really produce circular arcs, but that's ok since
* the algorithm achieves nice looking results and is generic enough to be applied
* to all kind of paths.
* Note also, that this algorithm doesn't touch smooth joins (in the sense of
* VSegment::isSmooth() ).
*
* We'll manipulate the input path for bookkeeping purposes and construct a new
* temporary path in parallel. We finally replace the input path with the new path.
*
*
* Without restricting generality, let's assume the input path is closed and
* contains segments which build a rectangle.
*
* 2
* O------------O
* | | Numbers reflect the segments' order
* 3| |1 in the path. We neglect the "begin"
* | | segment here.
* O------------O
* 0
*
* There are three unique steps to process. The second step is processed
* many times in a loop.
*
* 1) Begin
* -----
* Split the first segment of the input path (called "path[0]" here)
* at parameter t
*
* t = path[0]->param( m_radius )
*
* and move newPath to this new knot. If current segment is too small
* (smaller than 2 * m_radius), we always set t = 0.5 here and in the further
* steps as well.
*
* path: new path:
*
* 2
* O------------O
* | |
* 3 | | 1 The current segment is marked with "#"s.
* | |
* O##O#########O ...O
* 0 0
*
* 2) Loop
* ----
* The loop step is iterated over all segments. After each appliance the index n
* is incremented and the loop step is reapplied until no untouched segment is left.
*
* Split the current segment path[n] of the input path at parameter t
*
* t = path[n]->param( path[n]->length() - m_radius )
*
* and add the first subsegment of the curent segment to newPath.
*
* path: new path:
*
* 2
* O------------O
* | |
* 3 | | 1
* | |
* O--O######O##O O------O...
* 0 0
*
* Now make the second next segment (the original path[1] segment in our example)
* the current one. Split it at parameter t
*
* t = path[n]->param( m_radius )
*
* path: new path:
*
* 2
* O------------O
* | #
* 3 | O 1
* | #
* O--O------O--O O------O...
* 0 0
*
* Make the first subsegment of the current segment the current one.
*
* path: new path:
*
* 2
* O------------O
* | |
* 3 | O 1 O
* | # /.1
* O--O------O--O O------O...
* 0 0
*
* 3) End
* ---
*
* path: new path:
*
* 2 4
* O--O------O--O 5 .O------O. 3
* | | / \
* 3 O O 1 6 O O 2
* | | 7 .\ /
* O--O------O--O ...O------O. 1
* 0 0
*/
double length;
double param;
// "Begin" step.
// =============
// Convert flat beziers to lines.
if( path.current()->isFlat() )
path.current()->setDegree( 1 );
if( path.getLast()->isFlat() )
path.getLast()->setDegree( 1 );
if(
path.isClosed() &&
// Don't touch smooth joins.
!path.getLast()->isSmooth( *path.current() ) )
{
length = path.current()->length();
param = length > 2 * m_radius
? path.current()->lengthParam( m_radius )
: 0.5;
path.insert(
path.current()->splitAt( param ) );
newPath.moveTo(
path.current()->knot() );
path.next();
if( !success() )
setSuccess();
}
else
{
newPath.moveTo(
path.current()->prev()->knot() );
}
// "Loop" step.
// ============
while(
path.current() &&
path.current()->next() )
{
// Convert flat beziers to lines.
if( path.current()->isFlat() )
path.current()->setDegree( 1 );
if( path.current()->next()->isFlat() )
path.current()->next()->setDegree( 1 );
// Don't touch smooth joins.
if( path.current()->isSmooth() )
{
newPath.append( path.current()->clone() );
path.next();
continue;
}
// Split the current segment at param( m_radius ) counting
// from the end.
length = path.current()->length();
// If the current segment is too short to be split, just don't split it
// because it was split already a t=0.5 during the former step.
if( length > m_radius )
{
param = path.current()->lengthParam( length - m_radius );
path.insert(
path.current()->splitAt( param ) );
newPath.append(
path.current()->clone() );
path.next();
}
// Jump to the next untouched segment.
path.next();
// Split the current segment at param( m_radius ).
length = path.current()->length();
param = length > 2 * m_radius
? path.current()->lengthParam( m_radius )
: 0.5;
path.insert(
path.current()->splitAt( param ) );
// Round corner.
newPath.curveTo(
path.current()->prev()->pointAt( 0.5 ),
path.current()->pointAt( 0.5 ),
path.current()->knot() );
if( !success() )
setSuccess();
path.next();
}
// "End" step.
// ===========
if( path.isClosed() )
{
// Convert flat beziers to lines.
if( path.current()->isFlat() )
path.current()->setDegree( 1 );
if( path.getFirst()->next()->isFlat() )
path.getFirst()->next()->setDegree( 1 );
// Don't touch smooth joins.
if( !path.current()->isSmooth( *path.getFirst()->next() ) )
{
length = path.current()->length();
// If the current segment is too short to be split, just don't split it
// because it was split already at t=0.5 during the former step.
if( length > m_radius )
{
param = path.current()->lengthParam( length - m_radius );
path.insert(
path.current()->splitAt( param ) );
newPath.append(
path.current()->clone() );
path.next();
}
path.first();
path.next();
// Round corner.
newPath.curveTo(
path.getLast()->pointAt( 0.5 ),
path.current()->pointAt( 0.5 ),
path.current()->knot() );
if( !success() )
setSuccess();
}
else
newPath.append( path.current()->clone() );
newPath.close();
}
else
newPath.append( path.current()->clone() );
path = newPath;
// Invalidate bounding box once.
path.invalidateBoundingBox();
}
#include "roundcornersplugin.moc"