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/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
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* Copyright (C) 1997 Josef Wilgen
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* Copyright (C) 2002 Uwe Rathmann
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the Qwt License, Version 1.0
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*****************************************************************************/
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#include "qwt_raster_data.h"
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class QwtRasterData::Contour3DPoint
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inline void setPos(double x, double y)
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inline QwtDoublePoint pos() const
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return QwtDoublePoint(d_x, d_y);
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inline void setX(double x) { d_x = x; }
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inline void setY(double y) { d_y = y; }
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inline void setZ(double z) { d_z = z; }
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inline double x() const { return d_x; }
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inline double y() const { return d_y; }
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inline double z() const { return d_z; }
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class QwtRasterData::ContourPlane
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inline ContourPlane(double z):
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inline bool intersect(const Contour3DPoint vertex[3],
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QwtDoublePoint line[2], bool ignoreOnPlane) const;
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inline double z() const { return d_z; }
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inline int compare(double z) const;
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inline QwtDoublePoint intersection(
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const Contour3DPoint& p1, const Contour3DPoint &p2) const;
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inline bool QwtRasterData::ContourPlane::intersect(
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const Contour3DPoint vertex[3], QwtDoublePoint line[2],
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bool ignoreOnPlane) const
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// Are the vertices below (-1), on (0) or above (1) the plan ?
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const int eq1 = compare(vertex[0].z());
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const int eq2 = compare(vertex[1].z());
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const int eq3 = compare(vertex[2].z());
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(a) All the vertices lie below the contour level.
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(b) Two vertices lie below and one on the contour level.
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(c) Two vertices lie below and one above the contour level.
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(d) One vertex lies below and two on the contour level.
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(e) One vertex lies below, one on and one above the contour level.
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(f) One vertex lies below and two above the contour level.
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(g) Three vertices lie on the contour level.
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(h) Two vertices lie on and one above the contour level.
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(i) One vertex lies on and two above the contour level.
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(j) All the vertices lie above the contour level.
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static const int tab[3][3][3] =
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// jump table to avoid nested case statements
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{ { 0, 0, 8 }, { 0, 2, 5 }, { 7, 6, 9 } },
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{ { 0, 3, 4 }, { 1, 10, 1 }, { 4, 3, 0 } },
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{ { 9, 6, 7 }, { 5, 2, 0 }, { 8, 0, 0 } }
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const int edgeType = tab[eq1+1][eq2+1][eq3+1];
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// d(0,0,-1), h(0,0,1)
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line[0] = vertex[0].pos();
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line[1] = vertex[1].pos();
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// d(-1,0,0), h(1,0,0)
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line[0] = vertex[1].pos();
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line[1] = vertex[2].pos();
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// d(0,-1,0), h(0,1,0)
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line[0] = vertex[2].pos();
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line[1] = vertex[0].pos();
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// e(0,-1,1), e(0,1,-1)
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line[0] = vertex[0].pos();
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line[1] = intersection(vertex[1], vertex[2]);
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// e(-1,0,1), e(1,0,-1)
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line[0] = vertex[1].pos();
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line[1] = intersection(vertex[2], vertex[0]);
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// e(-1,1,0), e(1,0,-1)
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line[0] = vertex[1].pos();
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line[1] = intersection(vertex[0], vertex[1]);
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// c(-1,1,-1), f(1,1,-1)
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line[0] = intersection(vertex[0], vertex[1]);
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line[1] = intersection(vertex[1], vertex[2]);
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// c(-1,-1,1), f(1,1,-1)
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line[0] = intersection(vertex[1], vertex[2]);
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line[1] = intersection(vertex[2], vertex[0]);
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// f(-1,1,1), c(1,-1,-1)
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line[0] = intersection(vertex[2], vertex[0]);
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line[1] = intersection(vertex[0], vertex[1]);
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// The CONREC algorithm has no satisfying solution for
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// what to do, when all vertices are on the plane.
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line[0] = vertex[2].pos();
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line[1] = vertex[0].pos();
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inline int QwtRasterData::ContourPlane::compare(double z) const
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inline QwtDoublePoint QwtRasterData::ContourPlane::intersection(
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const Contour3DPoint& p1, const Contour3DPoint &p2) const
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const double h1 = p1.z() - d_z;
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const double h2 = p2.z() - d_z;
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const double x = (h2 * p1.x() - h1 * p2.x()) / (h2 - h1);
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const double y = (h2 * p1.y() - h1 * p2.y()) / (h2 - h1);
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return QwtDoublePoint(x, y);
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QwtRasterData::QwtRasterData()
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QwtRasterData::QwtRasterData(const QwtDoubleRect &boundingRect):
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d_boundingRect(boundingRect)
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QwtRasterData::~QwtRasterData()
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void QwtRasterData::setBoundingRect(const QwtDoubleRect &boundingRect)
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d_boundingRect = boundingRect;
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QwtDoubleRect QwtRasterData::boundingRect() const
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return d_boundingRect;
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\brief Initialize a raster
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Before the composition of an image QwtPlotSpectrogram calls initRaster,
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announcing the area and its resolution that will be requested.
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The default implementation does nothing, but for data sets that
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are stored in files, it might be good idea to reimplement initRaster,
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where the data is resampled and loaded into memory.
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\param rect Area of the raster
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\param raster Number of horizontal and vertical pixels
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\sa initRaster(), value()
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void QwtRasterData::initRaster(const QwtDoubleRect &, const QSize&)
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\brief Discard a raster
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After the composition of an image QwtPlotSpectrogram calls discardRaster().
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The default implementation does nothing, but if data has been loaded
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in initRaster(), it could deleted now.
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\sa initRaster(), value()
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void QwtRasterData::discardRaster()
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\brief Find the raster of the data for an area
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The resolution is the number of horizontal and vertical pixels
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that the data can return for an area. An invalid resolution
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indicates that the data can return values for any detail level.
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The resolution will limit the size of the image that is rendered
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from the data. F.e. this might be important when printing a spectrogram
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to a A0 printer with 600 dpi.
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The default implementation returns an invalid resolution (size)
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\param rect In most implementations the resolution of the data doesn't
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depend on the requested rectangle.
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\return Resolution, as number of horizontal and vertical pixels
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QSize QwtRasterData::rasterHint(const QwtDoubleRect &) const
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return QSize(); // use screen resolution
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Calculate contour lines
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An adaption of CONREC, a simple contouring algorithm.
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http://local.wasp.uwa.edu.au/~pbourke/papers/conrec/
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#if QT_VERSION >= 0x040000
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QwtRasterData::ContourLines QwtRasterData::contourLines(
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const QwtDoubleRect &rect, const QSize &raster,
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const QList<double> &levels, int flags) const
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QwtRasterData::ContourLines QwtRasterData::contourLines(
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const QwtDoubleRect &rect, const QSize &raster,
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const QValueList<double> &levels, int flags) const
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ContourLines contourLines;
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if ( levels.size() == 0 || !rect.isValid() || !raster.isValid() )
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const double dx = rect.width() / raster.width();
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const double dy = rect.height() / raster.height();
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const bool ignoreOnPlane =
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flags & QwtRasterData::IgnoreAllVerticesOnLevel;
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const QwtDoubleInterval range = this->range();
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bool ignoreOutOfRange = false;
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if ( range.isValid() )
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ignoreOutOfRange = flags & IgnoreOutOfRange;
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((QwtRasterData*)this)->initRaster(rect, raster);
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for ( int y = 0; y < raster.height() - 1; y++ )
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Contour3DPoint xy[NumPositions];
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for ( int x = 0; x < raster.width() - 1; x++ )
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const QwtDoublePoint pos(rect.x() + x * dx, rect.y() + y * dy);
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xy[TopRight].setPos(pos.x(), pos.y());
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value( xy[TopRight].x(), xy[TopRight].y())
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xy[BottomRight].setPos(pos.x(), pos.y() + dy);
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xy[BottomRight].setZ(
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value(xy[BottomRight].x(), xy[BottomRight].y())
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xy[TopLeft] = xy[TopRight];
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xy[BottomLeft] = xy[BottomRight];
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xy[TopRight].setPos(pos.x() + dx, pos.y());
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xy[BottomRight].setPos(pos.x() + dx, pos.y() + dy);
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value(xy[TopRight].x(), xy[TopRight].y())
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xy[BottomRight].setZ(
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value(xy[BottomRight].x(), xy[BottomRight].y())
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double zMin = xy[TopLeft].z();
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for ( int i = TopRight; i <= BottomLeft; i++ )
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const double z = xy[i].z();
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if ( ignoreOutOfRange )
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if ( !range.contains(zMin) || !range.contains(zMax) )
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if ( zMax < levels[0] ||
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zMin > levels[levels.size() - 1] )
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xy[Center].setPos(pos.x() + 0.5 * dx, pos.y() + 0.5 * dy);
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xy[Center].setZ(0.25 * zSum);
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const int numLevels = (int)levels.size();
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for (int l = 0; l < numLevels; l++)
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const double level = levels[l];
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if ( level < zMin || level > zMax )
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#if QT_VERSION >= 0x040000
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QPolygonF &lines = contourLines[level];
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QwtArray<QwtDoublePoint> &lines = contourLines[level];
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const ContourPlane plane(level);
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QwtDoublePoint line[2];
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Contour3DPoint vertex[3];
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for (int m = TopLeft; m < NumPositions; m++)
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vertex[2] = xy[m != BottomLeft ? m + 1 : TopLeft];
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const bool intersects =
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plane.intersect(vertex, line, ignoreOnPlane);
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#if QT_VERSION >= 0x040000
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const int index = lines.size();
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lines.resize(lines.size() + 2, QGArray::SpeedOptim);
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lines[index] = line[0];
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lines[index+1] = line[1];
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((QwtRasterData*)this)->discardRaster();
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removed
qwt-5.1.2/src/qwt_raster_data.cpp
