subsurface/stats/statsaxis.h
Berthold Stoeger e7907c494f statistics: convert chart to QQuickItem
It turns out that the wrong base class was used for the chart.
QQuickWidget can only be used on desktop, not in a mobile UI.

Therefore, turn this into a QQuickItem and move the container
QQuickWidget into desktop-only code.

Currently, this code is insane: The chart is rendered onto a
QGraphicsScene (as it was before), which is then rendered into
a QImage, which is transformed into a QSGTexture, which is then
projected onto the device. This is performed on every mouse
move event, since these events in general change the position
of the info-box.

The plan is to slowly convert elements such as the info-box into
QQuickItems. Browsing the QtQuick documentation, this will
not be much fun.

Also note that the rendering currently tears, flickers and has
antialiasing artifacts, most likely owing to integer (QImage)
to floating point (QGraphicsScene, QQuickItem) conversion
problems. The data flow is
QGraphicsScene (float) -> QImage (int) -> QQuickItem (float).

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2021-01-10 15:16:52 -08:00

113 lines
3.1 KiB
C++

// SPDX-License-Identifier: GPL-2.0
#ifndef STATS_AXIS_H
#define STATS_AXIS_H
#include <memory>
#include <vector>
#include <QBarCategoryAxis>
#include <QCategoryAxis>
#include <QFont>
#include <QGraphicsSimpleTextItem>
#include <QGraphicsLineItem>
#include <QValueAxis>
class QGraphicsScene;
class StatsAxis : public QGraphicsLineItem {
public:
virtual ~StatsAxis();
// Returns minimum and maximum of shown range, not of data points.
std::pair<double, double> minMax() const;
std::pair<double, double> minMaxScreen() const; // minimum and maximum in screen coordinates
double width() const; // Only supported by vertical axes. Only valid after setSize().
double height() const; // Only supported for horizontal axes. Always valid.
void setSize(double size); // Width for horizontal and height for vertical.
void setPos(QPointF pos); // Must be called after setSize().
void setRange(double, double);
// Map x (horizontal) or y (vertical) coordinate to or from screen coordinate
double toScreen(double) const;
double toValue(double) const;
std::vector<double> ticksPositions() const; // Positions in screen coordinates
protected:
StatsAxis(const QString &title, bool horizontal, bool labelsBetweenTicks);
struct Label {
std::unique_ptr<QGraphicsSimpleTextItem> label;
double pos;
Label(const QString &name, double pos, QGraphicsScene *scene, const QFont &font);
};
std::vector<Label> labels;
void addLabel(const QString &label, double pos);
virtual void updateLabels() = 0;
struct Tick {
std::unique_ptr<QGraphicsLineItem> item;
double pos;
Tick(double pos, QGraphicsScene *scene);
};
std::vector<Tick> ticks;
void addTick(double pos);
int guessNumTicks(const std::vector<QString> &strings) const;
bool horizontal;
bool labelsBetweenTicks; // When labels are between ticks, they can be moved closer to the axis
QFont labelFont, titleFont;
std::unique_ptr<QGraphicsSimpleTextItem> title;
double size; // width for horizontal, height for vertical
double zeroOnScreen;
double min, max;
double labelWidth; // Maximum width of labels
private:
double titleSpace() const; // Space needed for title
};
class ValueAxis : public StatsAxis {
public:
ValueAxis(const QString &title, double min, double max, int decimals, bool horizontal);
private:
double min, max;
int decimals;
void updateLabels() override;
};
class CountAxis : public ValueAxis {
public:
CountAxis(const QString &title, int count, bool horizontal);
private:
int count;
void updateLabels() override;
};
class CategoryAxis : public StatsAxis {
public:
CategoryAxis(const QString &title, const std::vector<QString> &labels, bool horizontal);
private:
std::vector<QString> labelsText;
void updateLabels();
};
struct HistogramAxisEntry {
QString name;
double value;
bool recommended;
};
class HistogramAxis : public StatsAxis {
public:
HistogramAxis(const QString &title, std::vector<HistogramAxisEntry> bin_values, bool horizontal);
private:
void updateLabels() override;
std::vector<HistogramAxisEntry> bin_values;
int preferred_step;
};
class DateAxis : public HistogramAxis {
public:
DateAxis(const QString &title, double from, double to, bool horizontal);
};
#endif