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QWT API (中文) 7.3.0
Qt绘图库 - 中文API文档
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A class for drawing scales 更多...
#include <qwt_scale_draw.h>
类 | |
| class | PrivateData |
Public 类型 | |
| enum | Alignment { BottomScale , TopScale , LeftScale , RightScale } |
| Alignment of the scale draw 更多... | |
Public 类型 继承自 QwtAbstractScaleDraw | |
| enum | ScaleComponent { Backbone = 0x01 , Ticks = 0x02 , Labels = 0x04 } |
| Components of a scale 更多... | |
Public 成员函数 | |
| QwtScaleDraw () | |
| Constructor | |
| void | getBorderDistHint (const QFont &, int &start, int &end) const |
| Get the border distance hint | |
| int | minLabelDist (const QFont &) const |
| Get the minimum label distance | |
| int | minLength (const QFont &) const |
| Get the minimum length | |
| virtual double | extent (const QFont &) const override |
| Calculate the width/height that is needed for a vertical/horizontal scale | |
| void | move (double x, double y) |
| Move the position of the scale | |
| void | move (const QPointF &) |
| Move the position of the scale | |
| void | setLength (double length) |
| Set the length of the backbone | |
| Alignment | alignment () const |
| Return alignment of the scale | |
| void | setAlignment (Alignment) |
| Set the alignment | |
| Qt::Orientation | orientation () const |
| Return the orientation | |
| QPointF | pos () const |
| Get origin of the scale | |
| double | length () const |
| Get the length of the backbone | |
| void | setLabelAlignment (Qt::Alignment) |
| Set the label alignment | |
| Qt::Alignment | labelAlignment () const |
| Get the label flags | |
| void | setLabelRotation (double rotation) |
| Set the label rotation | |
| double | labelRotation () const |
| Get the label rotation | |
| int | maxLabelHeight (const QFont &) const |
| Get the maximum label height | |
| int | maxLabelWidth (const QFont &) const |
| Get the maximum label width | |
| QPointF | labelPosition (double value) const |
| Get the label position for a value | |
| QRectF | labelRect (const QFont &, double value) const |
| Get the label rectangle for a value | |
| QSizeF | labelSize (const QFont &, double value) const |
| Get the label size for a value | |
| QRect | boundingLabelRect (const QFont &, double value) const |
| Get the bounding label rectangle | |
Public 成员函数 继承自 QwtAbstractScaleDraw | |
| QwtAbstractScaleDraw () | |
| Constructor for QwtAbstractScaleDraw | |
| void | setScaleDiv (const QwtScaleDiv &) |
| Set the scale division | |
| const QwtScaleDiv & | scaleDiv () const |
| Return the scale division | |
| void | setTransformation (QwtTransform *) |
| Set the scale transformation | |
| const QwtScaleMap & | scaleMap () const |
| Return the scale map (const version) | |
| QwtScaleMap & | scaleMap () |
| Return the scale map (non-const version) | |
| void | enableComponent (ScaleComponent, bool enable=true) |
| Enable or disable a scale component | |
| bool | hasComponent (ScaleComponent) const |
| Check if a component is enabled | |
| void | setTickLength (QwtScaleDiv::TickType, double length) |
| Set the length of the ticks | |
| double | tickLength (QwtScaleDiv::TickType) const |
| Get the length of the ticks | |
| double | maxTickLength () const |
| Get the length of the longest tick | |
| void | setSpacing (double) |
| Set the spacing between tick and labels | |
| double | spacing () const |
| Get the spacing | |
| void | setPenWidthF (qreal width) |
| Specify the width of the scale pen | |
| qreal | penWidthF () const |
| Get the scale pen width | |
| void | setSelected (bool on) |
| Set whether the scale draw is selected | |
| bool | isSelected () const |
| Check if the scale draw is selected | |
| void | setSelectedPenWidthOffset (qreal offset=1) |
| Set the pen width offset for the axis when it is in selected state | |
| qreal | selectedPenWidthOffset () const |
| Get the current pen width offset for the axis when it is in selected state | |
| virtual void | draw (QPainter *, const QPalette &) const |
| Draw the scale | |
| virtual QwtText | label (double) const |
| Convert a value into its representing label | |
| void | setMinimumExtent (double) |
| Set a minimum for the extent | |
| double | minimumExtent () const |
| Get the minimum extent | |
| void | invalidateCache () |
| Invalidate the cache used by tickLabel() | |
Protected 成员函数 | |
| QTransform | labelTransformation (const QPointF &, const QSizeF &) const |
| Calculate the transformation that is needed to paint a label | |
| virtual void | drawTick (QPainter *, double value, double len) const override |
| Draw a tick | |
| virtual void | drawBackbone (QPainter *) const override |
| Draws the baseline of the scale | |
| virtual void | drawLabel (QPainter *, double value) const override |
| Draws the label for a major scale tick | |
Protected 成员函数 继承自 QwtAbstractScaleDraw | |
| const QwtText & | tickLabel (const QFont &, double value) const |
| Convert a value into its representing label and cache it | |
A class for drawing scales
QwtScaleDraw can be used to draw linear or logarithmic scales. A scale has a position, an alignment and a length, which can be specified. The labels can be rotated and aligned to the ticks using setLabelRotation() and setLabelAlignment().
After a scale division has been specified as a QwtScaleDiv object using QwtAbstractScaleDraw::setScaleDiv(const QwtScaleDiv &s), the scale can be drawn with the QwtAbstractScaleDraw::draw() member.
| QwtScaleDraw::QwtScaleDraw | ( | ) |
Constructor
The range of the scale is initialized to [0, 100], the position is at (0, 0) with a length of 100. The orientation is QwtAbstractScaleDraw::Bottom.
| QwtScaleDraw::Alignment QwtScaleDraw::alignment | ( | ) | const |
| QRect QwtScaleDraw::boundingLabelRect | ( | const QFont & | font, |
| double | value | ||
| ) | const |
Get the bounding label rectangle
Find the bounding rectangle for the label
The coordinates of the rectangle are absolute ( calculated from pos() ) in direction of the tick.
| font | Font used for painting |
| value | Value |
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overrideprotectedvirtual |
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overrideprotectedvirtual |
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overrideprotectedvirtual |
Draw a tick
| painter | Painter |
| value | Value of the tick |
| len | Length of the tick |
实现了 QwtAbstractScaleDraw.
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overridevirtual |
Calculate the width/height that is needed for a vertical/horizontal scale
The extent is calculated from the pen width of the backbone, the major tick length, the spacing and the maximum width/height of the labels.
| font | Font used for painting the labels |
实现了 QwtAbstractScaleDraw.
| void QwtScaleDraw::getBorderDistHint | ( | const QFont & | font, |
| int & | start, | ||
| int & | end | ||
| ) | const |
Get the border distance hint
Determine the minimum border distance
This member function returns the minimum space needed to draw the mark labels at the scale's endpoints.
| font | Font |
| start | Start border distance |
| end | End border distance |
| Qt::Alignment QwtScaleDraw::labelAlignment | ( | ) | const |
| QPointF QwtScaleDraw::labelPosition | ( | double | value | ) | const |
Get the label position for a value
Find the position, where to paint a label
The position has a distance that depends on the length of the ticks in direction of the alignment().
| value | Value |
| QRectF QwtScaleDraw::labelRect | ( | const QFont & | font, |
| double | value | ||
| ) | const |
Get the label rectangle for a value
Find the bounding rectangle for the label
The coordinates of the rectangle are relative to spacing + tick length from the backbone in direction of the tick.
| font | Font used for painting |
| value | Value |
| double QwtScaleDraw::labelRotation | ( | ) | const |
Get the label rotation
| QSizeF QwtScaleDraw::labelSize | ( | const QFont & | font, |
| double | value | ||
| ) | const |
Get the label size for a value
Calculate the size that is needed to draw a label
| font | Label font |
| value | Value |
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protected |
Calculate the transformation that is needed to paint a label
Calculate the transformation that is needed to paint a label depending on its alignment and rotation.
| pos | Position where to paint the label |
| size | Size of the label |
| double QwtScaleDraw::length | ( | ) | const |
| int QwtScaleDraw::maxLabelHeight | ( | const QFont & | font | ) | const |
Get the maximum label height
Get the maximum height of a label
| font | Font |
| int QwtScaleDraw::maxLabelWidth | ( | const QFont & | font | ) | const |
Get the maximum label width
Get the maximum width of a label
| font | Font |
| int QwtScaleDraw::minLabelDist | ( | const QFont & | font | ) | const |
Get the minimum label distance
Determine the minimum distance between two labels
Determine the minimum distance between two labels, that is necessary that the texts don't overlap.
| font | Font |
| int QwtScaleDraw::minLength | ( | const QFont & | font | ) | const |
Get the minimum length
Calculate the minimum length that is needed to draw the scale
| font | Font used for painting the labels |
| void QwtScaleDraw::move | ( | const QPointF & | pos | ) |
Move the position of the scale
The meaning of the parameter pos depends on the alignment:
| pos | Origin of the scale |
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| Qt::Orientation QwtScaleDraw::orientation | ( | ) | const |
Return the orientation
TopScale, BottomScale are horizontal (Qt::Horizontal) scales, LeftScale, RightScale are vertical (Qt::Vertical) scales.
| QPointF QwtScaleDraw::pos | ( | ) | const |
| void QwtScaleDraw::setAlignment | ( | Alignment | align | ) |
Set the alignment
Set the alignment of the scale
| align | Alignment of the scale |
The default alignment is QwtScaleDraw::BottomScale
| void QwtScaleDraw::setLabelAlignment | ( | Qt::Alignment | alignment | ) |
Set the label alignment
Change the label flags
Labels are aligned to the point tick length + spacing away from the backbone.
The alignment is relative to the orientation of the label text. In case of an flags of 0 the label will be aligned depending on the orientation of the scale:
Changing the alignment is often necessary for rotated labels.
| alignment | Or'd Qt::AlignmentFlags see <qnamespace.h> |
| void QwtScaleDraw::setLabelRotation | ( | double | rotation | ) |
Set the label rotation
Rotate all labels
When changing the rotation, it might be necessary to adjust the label flags too. Finding a useful combination is often the result of try and error.
| rotation | Angle in degrees. When changing the label rotation, the label flags often needs to be adjusted too. |
| void QwtScaleDraw::setLength | ( | double | length | ) |
Set the length of the backbone
The length doesn't include the space needed for overlapping labels.
| length | Length of the backbone |