mt-polygon-simplification/lib/psimpl/demo/RenderArea.cpp
2019-07-14 20:37:26 +02:00

124 lines
3.9 KiB
C++

/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is
* 'psimpl - generic n-dimensional polyline simplification'.
*
* The Initial Developer of the Original Code is
* Elmar de Koning.
* Portions created by the Initial Developer are Copyright (C) 2010-2011
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* ***** END LICENSE BLOCK ***** */
/*
psimpl - generic n-dimensional polyline simplification
Copyright (C) 2010-2011 Elmar de Koning, edekoning@gmail.com
This file is part of psimpl, and is hosted at SourceForge:
http://sourceforge.net/projects/psimpl/
*/
#include "RenderArea.h"
#include <QtGui/QPainter>
namespace psimpl {
RenderArea::RenderArea (QWidget *inParent, Qt::WindowFlags inFlags) :
QFrame (inParent, inFlags),
mDrawGeneratedPolyline (true),
mDrawSimplifiedPolyline (false),
mKeepAspectRatio (true)
{
}
void RenderArea::paintEvent(QPaintEvent * /*inEvent*/) {
if (!mGeneratedPolyline.elementCount ())
return;
QRectF rect = mGeneratedPolyline.boundingRect ();
if (!rect.isValid ())
return;
QPainter painter (this);
if (mKeepAspectRatio) {
qreal scale = qMin ((width () - 1) / rect.width (), (height () - 1) / rect.height ());
painter.translate ((width () - (rect.width () * scale)) / 2.0,
(height () - (rect.height () * scale)) / 2.0);
painter.scale (scale, scale);
painter.translate (-rect.left (), -rect.top ());
}
else {
painter.scale ((width () - 1) / rect.width (), (height () - 1) / rect.height ());
painter.translate (-rect.left (), -rect.top ());
}
if (mDrawGeneratedPolyline) {
painter.setPen (Qt::darkBlue);
painter.drawPath (mGeneratedPolyline);
}
if (!mSimplifiedPolyline.elementCount ())
return;
if (mDrawSimplifiedPolyline) {
painter.setPen (Qt::darkRed);
painter.drawPath (mSimplifiedPolyline);
}
}
QPainterPath RenderArea::Convert (QVector <qreal>& polyline)
{
// limit paths to max 100.000 points to speed up drawing
const int threshold = 100000;
QPainterPath path;
if (polyline.empty ()) {
return path;
}
int pointCount = polyline.size () / 2;
qreal skipStep = (qreal) (pointCount - threshold) / (qreal) threshold;
qreal skipValue = skipStep;
path.moveTo(polyline [0], polyline [1]);
for (int i=1; i<pointCount; i++) {
if (skipValue > 1.0) {
skipValue -= 1.0;
}
else {
path.lineTo (polyline [i*2], polyline [i*2+1]);
skipValue += skipStep;
}
}
int elemCount = path.elementCount ();
elemCount++;
return path;
}
void RenderArea::SetGeneratedPolyline (QVector <qreal>& polyline)
{
mSimplifiedPolyline = QPainterPath ();
mGeneratedPolyline = Convert (polyline);
}
void RenderArea::SetSimplifiedPolyline (QVector <qreal>& polyline)
{
mSimplifiedPolyline = Convert (polyline);
}
} // namespace psimpl