Scales¶
QwtScaleWidget¶
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class
qwt.scale_widget.QwtScaleWidget(*args)[source]¶ A Widget which contains a scale
This Widget can be used to decorate composite widgets with a scale.
Layout flags:
- QwtScaleWidget.TitleInverted: The title of vertical scales is painted from top to bottom. Otherwise it is painted from bottom to top.
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class
QwtScaleWidget([parent=None])¶ Alignment default is QwtScaleDraw.LeftScale.
Parameters: parent (QWidget or None) – Parent widget
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class
qwt.scale_widget.QwtScaleWidget(align, parent)[source] Parameters: - align (int) – Alignment
- parent (QWidget) – Parent widget
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QwtScaleWidget.setLayoutFlag(flag, on=True)[source]¶ Toggle an layout flag
Parameters: - flag (int) – Layout flag
- on (bool) – True/False
See also
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QwtScaleWidget.testLayoutFlag(flag)[source]¶ Test a layout flag
Parameters: flag (int) – Layout flag Returns: True/False See also
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QwtScaleWidget.setTitle(title)[source]¶ Give title new text contents
Parameters: title (qwt.text.QwtText or str) – New title See also
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QwtScaleWidget.setAlignment(alignment)[source]¶ Change the alignment
Parameters: alignment (int) – New alignment Valid alignment values: see
qwt.scale_draw.QwtScaleDrawSee also
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QwtScaleWidget.setBorderDist(dist1, dist2)[source]¶ Specify distances of the scale’s endpoints from the widget’s borders. The actual borders will never be less than minimum border distance.
Parameters: - dist1 (int) – Left or top Distance
- dist2 (int) – Right or bottom distance
See also
borderDist()
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QwtScaleWidget.setMargin(margin)[source]¶ Specify the margin to the colorBar/base line.
Parameters: margin (int) – Margin See also
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QwtScaleWidget.setSpacing(spacing)[source]¶ Specify the distance between color bar, scale and title
Parameters: spacing (int) – Spacing See also
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QwtScaleWidget.setLabelAlignment(alignment)[source]¶ Change the alignment for the labels.
Parameters: spacing (int) – Spacing See also
QwtScaleDraw.setLabelAlignment(),setLabelRotation()
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QwtScaleWidget.setLabelRotation(rotation)[source]¶ Change the rotation for the labels.
Parameters: rotation (float) – Rotation See also
QwtScaleDraw.setLabelRotation(),setLabelFlags()
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QwtScaleWidget.setScaleDraw(scaleDraw)[source]¶ Set a scale draw
scaleDraw has to be created with new and will be deleted in class destructor or the next call of setScaleDraw(). scaleDraw will be initialized with the attributes of the previous scaleDraw object.
Parameters: scaleDraw (qwt.scale_draw.QwtScaleDraw) – ScaleDraw object See also
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QwtScaleWidget.scaleDraw()[source]¶ Returns: scaleDraw of this scale See also
QwtScaleDraw.setScaleDraw()
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QwtScaleWidget.colorBarRect(rect)[source]¶ Calculate the the rectangle for the color bar
Parameters: rect (QRectF) – Bounding rectangle for all components of the scale Returns: Rectangle for the color bar
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QwtScaleWidget.layoutScale(update_geometry=True)[source]¶ Recalculate the scale’s geometry and layout based on the current geometry and fonts.
Parameters: update_geometry (bool) – Notify the layout system and call update to redraw the scale
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QwtScaleWidget.drawColorBar(painter, rect)[source]¶ Draw the color bar of the scale widget
Parameters: - painter (QPainter) – Painter
- rect (QRectF) – Bounding rectangle for the color bar
See also
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QwtScaleWidget.drawTitle(painter, align, rect)[source]¶ Rotate and paint a title according to its position into a given rectangle.
Parameters: - painter (QPainter) – Painter
- align (int) – Alignment
- rect (QRectF) – Bounding rectangle
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QwtScaleWidget.scaleChange()[source]¶ Notify a change of the scale
This method can be overloaded by derived classes. The default implementation updates the geometry and repaints the widget.
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QwtScaleWidget.titleHeightForWidth(width)[source]¶ Find the height of the title for a given width.
Parameters: width (int) – Width Returns: Height
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QwtScaleWidget.dimForLength(length, scaleFont)[source]¶ Find the minimum dimension for a given length. dim is the height, length the width seen in direction of the title.
Parameters: - length (int) – width for horizontal, height for vertical scales
- scaleFont (QFont) – Font of the scale
Returns: height for horizontal, width for vertical scales
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QwtScaleWidget.getBorderDistHint()[source]¶ Calculate a hint for the border distances.
This member function calculates the distance of the scale’s endpoints from the widget borders which is required for the mark labels to fit into the widget. The maximum of this distance an the minimum border distance is returned.
Parameters: - start (int) – Return parameter for the border width at the beginning of the scale
- end (int) – Return parameter for the border width at the end of the scale
Warning
The minimum border distance depends on the font.
See also
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QwtScaleWidget.setMinBorderDist(start, end)[source]¶ Set a minimum value for the distances of the scale’s endpoints from the widget borders. This is useful to avoid that the scales are “jumping”, when the tick labels or their positions change often.
Parameters: - start (int) – Minimum for the start border
- end (int) – Minimum for the end border
See also
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QwtScaleWidget.getMinBorderDist()[source]¶ Get the minimum value for the distances of the scale’s endpoints from the widget borders.
Parameters: - start (int) – Return parameter for the border width at the beginning of the scale
- end (int) – Return parameter for the border width at the end of the scale
See also
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QwtScaleWidget.setScaleDiv(scaleDiv)[source]¶ Assign a scale division
The scale division determines where to set the tick marks.
Parameters: scaleDiv (qwt.scale_div.QwtScaleDiv) – Scale Division See also
For more information about scale divisions, see
qwt.scale_div.QwtScaleDiv.
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QwtScaleWidget.setTransformation(transformation)[source]¶ Set the transformation
Parameters: transformation (qwt.transform.Transform) – Transformation See also
qwt.scale_draw.QwtAbstractScaleDraw.scaleDraw(),qwt.scale_map.QwtScaleMap
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QwtScaleWidget.setColorBarEnabled(on)[source]¶ En/disable a color bar associated to the scale
Parameters: on (bool) – On/Off See also
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QwtScaleWidget.setColorBarWidth(width)[source]¶ Set the width of the color bar
Parameters: width (int) – Width See also
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QwtScaleWidget.setColorMap(interval, colorMap)[source]¶ Set the color map and value interval, that are used for displaying the color bar.
Parameters: - interval (qwt.interval.QwtInterval) – Value interval
- colorMap (qwt.color_map.QwtColorMap) – Color map
See also
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class
qwt.scale_widget.QwtScaleWidget(*args)[source] A Widget which contains a scale
This Widget can be used to decorate composite widgets with a scale.
Layout flags:
- QwtScaleWidget.TitleInverted: The title of vertical scales is painted from top to bottom. Otherwise it is painted from bottom to top.
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class
QwtScaleWidget([parent=None]) Alignment default is QwtScaleDraw.LeftScale.
Parameters: parent (QWidget or None) – Parent widget
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class
qwt.scale_widget.QwtScaleWidget(align, parent)[source] Parameters: - align (int) – Alignment
- parent (QWidget) – Parent widget
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QwtScaleWidget.initScale(align)[source] Initialize the scale
Parameters: align (int) – Alignment
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QwtScaleWidget.setLayoutFlag(flag, on=True)[source] Toggle an layout flag
Parameters: - flag (int) – Layout flag
- on (bool) – True/False
See also
-
QwtScaleWidget.testLayoutFlag(flag)[source] Test a layout flag
Parameters: flag (int) – Layout flag Returns: True/False See also
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QwtScaleWidget.setTitle(title)[source] Give title new text contents
Parameters: title (qwt.text.QwtText or str) – New title See also
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QwtScaleWidget.setAlignment(alignment)[source] Change the alignment
Parameters: alignment (int) – New alignment Valid alignment values: see
qwt.scale_draw.QwtScaleDrawSee also
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QwtScaleWidget.alignment()[source] Returns: position See also
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QwtScaleWidget.setBorderDist(dist1, dist2)[source] Specify distances of the scale’s endpoints from the widget’s borders. The actual borders will never be less than minimum border distance.
Parameters: - dist1 (int) – Left or top Distance
- dist2 (int) – Right or bottom distance
See also
borderDist()
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QwtScaleWidget.setMargin(margin)[source] Specify the margin to the colorBar/base line.
Parameters: margin (int) – Margin See also
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QwtScaleWidget.setSpacing(spacing)[source] Specify the distance between color bar, scale and title
Parameters: spacing (int) – Spacing See also
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QwtScaleWidget.setLabelAlignment(alignment)[source] Change the alignment for the labels.
Parameters: spacing (int) – Spacing See also
QwtScaleDraw.setLabelAlignment(),setLabelRotation()
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QwtScaleWidget.setLabelRotation(rotation)[source] Change the rotation for the labels.
Parameters: rotation (float) – Rotation See also
QwtScaleDraw.setLabelRotation(),setLabelFlags()
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QwtScaleWidget.setScaleDraw(scaleDraw)[source] Set a scale draw
scaleDraw has to be created with new and will be deleted in class destructor or the next call of setScaleDraw(). scaleDraw will be initialized with the attributes of the previous scaleDraw object.
Parameters: scaleDraw (qwt.scale_draw.QwtScaleDraw) – ScaleDraw object See also
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QwtScaleWidget.scaleDraw()[source] Returns: scaleDraw of this scale See also
QwtScaleDraw.setScaleDraw()
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QwtScaleWidget.title()[source] Returns: title See also
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QwtScaleWidget.startBorderDist()[source] Returns: start border distance See also
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QwtScaleWidget.endBorderDist()[source] Returns: end border distance See also
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QwtScaleWidget.margin()[source] Returns: margin See also
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QwtScaleWidget.spacing()[source] Returns: distance between scale and title See also
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QwtScaleWidget.draw(painter)[source] Draw the scale
Parameters: painter (QPainter) – Painter
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QwtScaleWidget.colorBarRect(rect)[source] Calculate the the rectangle for the color bar
Parameters: rect (QRectF) – Bounding rectangle for all components of the scale Returns: Rectangle for the color bar
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QwtScaleWidget.layoutScale(update_geometry=True)[source] Recalculate the scale’s geometry and layout based on the current geometry and fonts.
Parameters: update_geometry (bool) – Notify the layout system and call update to redraw the scale
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QwtScaleWidget.drawColorBar(painter, rect)[source] Draw the color bar of the scale widget
Parameters: - painter (QPainter) – Painter
- rect (QRectF) – Bounding rectangle for the color bar
See also
-
QwtScaleWidget.drawTitle(painter, align, rect)[source] Rotate and paint a title according to its position into a given rectangle.
Parameters: - painter (QPainter) – Painter
- align (int) – Alignment
- rect (QRectF) – Bounding rectangle
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QwtScaleWidget.scaleChange()[source] Notify a change of the scale
This method can be overloaded by derived classes. The default implementation updates the geometry and repaints the widget.
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QwtScaleWidget.titleHeightForWidth(width)[source] Find the height of the title for a given width.
Parameters: width (int) – Width Returns: Height
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QwtScaleWidget.dimForLength(length, scaleFont)[source] Find the minimum dimension for a given length. dim is the height, length the width seen in direction of the title.
Parameters: - length (int) – width for horizontal, height for vertical scales
- scaleFont (QFont) – Font of the scale
Returns: height for horizontal, width for vertical scales
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QwtScaleWidget.getBorderDistHint()[source] Calculate a hint for the border distances.
This member function calculates the distance of the scale’s endpoints from the widget borders which is required for the mark labels to fit into the widget. The maximum of this distance an the minimum border distance is returned.
Parameters: - start (int) – Return parameter for the border width at the beginning of the scale
- end (int) – Return parameter for the border width at the end of the scale
Warning
The minimum border distance depends on the font.
See also
-
QwtScaleWidget.setMinBorderDist(start, end)[source] Set a minimum value for the distances of the scale’s endpoints from the widget borders. This is useful to avoid that the scales are “jumping”, when the tick labels or their positions change often.
Parameters: - start (int) – Minimum for the start border
- end (int) – Minimum for the end border
See also
-
QwtScaleWidget.getMinBorderDist()[source] Get the minimum value for the distances of the scale’s endpoints from the widget borders.
Parameters: - start (int) – Return parameter for the border width at the beginning of the scale
- end (int) – Return parameter for the border width at the end of the scale
See also
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QwtScaleWidget.setScaleDiv(scaleDiv)[source] Assign a scale division
The scale division determines where to set the tick marks.
Parameters: scaleDiv (qwt.scale_div.QwtScaleDiv) – Scale Division See also
For more information about scale divisions, see
qwt.scale_div.QwtScaleDiv.
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QwtScaleWidget.setTransformation(transformation)[source] Set the transformation
Parameters: transformation (qwt.transform.Transform) – Transformation See also
qwt.scale_draw.QwtAbstractScaleDraw.scaleDraw(),qwt.scale_map.QwtScaleMap
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QwtScaleWidget.setColorBarEnabled(on)[source] En/disable a color bar associated to the scale
Parameters: on (bool) – On/Off See also
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QwtScaleWidget.isColorBarEnabled()[source] Returns: True, when the color bar is enabled See also
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QwtScaleWidget.setColorBarWidth(width)[source] Set the width of the color bar
Parameters: width (int) – Width See also
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QwtScaleWidget.colorBarWidth()[source] Returns: Width of the color bar See also
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QwtScaleWidget.colorBarInterval()[source] Returns: Value interval for the color bar See also
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QwtScaleWidget.setColorMap(interval, colorMap)[source] Set the color map and value interval, that are used for displaying the color bar.
Parameters: - interval (qwt.interval.QwtInterval) – Value interval
- colorMap (qwt.color_map.QwtColorMap) – Color map
See also
-
QwtScaleWidget.colorMap()[source] Returns: Color map See also
QwtScaleDiv¶
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class
qwt.scale_div.QwtScaleDiv(*args)[source]¶ A class representing a scale division
A Qwt scale is defined by its boundaries and 3 list for the positions of the major, medium and minor ticks.
The upperLimit() might be smaller than the lowerLimit() to indicate inverted scales.
Scale divisions can be calculated from a QwtScaleEngine.
Scale tick types:
- QwtScaleDiv.NoTick: No ticks
- QwtScaleDiv.MinorTick: Minor ticks
- QwtScaleDiv.MediumTick: Medium ticks
- QwtScaleDiv.MajorTick: Major ticks
- QwtScaleDiv.NTickTypes: Number of valid tick types
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class
QwtScaleDiv¶ Basic constructor. Lower bound = Upper bound = 0.
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class
qwt.scale_div.QwtScaleDiv(interval, ticks)[source] Parameters: - interval (qwt.interval.QwtInterval) – Interval
- ticks (list) – list of major, medium and minor ticks
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class
qwt.scale_div.QwtScaleDiv(lowerBound, upperBound)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
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class
qwt.scale_div.QwtScaleDiv(lowerBound, upperBound, ticks)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
- ticks (list) – list of major, medium and minor ticks
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class
qwt.scale_div.QwtScaleDiv(lowerBound, upperBound, minorTicks, mediumTicks, majorTicks)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
- minorTicks (list) – list of minor ticks
- mediumTicks (list) – list of medium ticks
- majorTicks (list) – list of major ticks
Note
lowerBound might be greater than upperBound for inverted scales
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QwtScaleDiv.setInterval(*args)[source]¶ Change the interval
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setInterval(lowerBound, upperBound)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
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setInterval(interval)[source] Parameters: interval (qwt.interval.QwtInterval) – Interval
Note
lowerBound might be greater than upperBound for inverted scales
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QwtScaleDiv.setLowerBound(lowerBound)[source]¶ Set the first boundary
Parameters: lowerBound (float) – First boundary See also
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QwtScaleDiv.setUpperBound(upperBound)[source]¶ Set the second boundary
Parameters: lowerBound (float) – Second boundary See also
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QwtScaleDiv.isIncreasing()[source]¶ Check if the scale division is increasing( lowerBound() <= upperBound() )
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QwtScaleDiv.contains(value)[source]¶ Return if a value is between lowerBound() and upperBound()
Parameters: value (float) – Value Returns: True/False
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QwtScaleDiv.inverted()[source]¶ Returns: A scale division with inverted boundaries and ticks See also
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QwtScaleDiv.bounded(lowerBound, upperBound)[source]¶ Return a scale division with an interval [lowerBound, upperBound] where all ticks outside this interval are removed
Parameters: - lowerBound (float) – First boundary
- lowerBound – Second boundary
Returns: Scale division with all ticks inside of the given interval
Note
lowerBound might be greater than upperBound for inverted scales
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class
qwt.scale_div.QwtScaleDiv(*args)[source] A class representing a scale division
A Qwt scale is defined by its boundaries and 3 list for the positions of the major, medium and minor ticks.
The upperLimit() might be smaller than the lowerLimit() to indicate inverted scales.
Scale divisions can be calculated from a QwtScaleEngine.
Scale tick types:
- QwtScaleDiv.NoTick: No ticks
- QwtScaleDiv.MinorTick: Minor ticks
- QwtScaleDiv.MediumTick: Medium ticks
- QwtScaleDiv.MajorTick: Major ticks
- QwtScaleDiv.NTickTypes: Number of valid tick types
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class
QwtScaleDiv Basic constructor. Lower bound = Upper bound = 0.
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class
qwt.scale_div.QwtScaleDiv(interval, ticks)[source] Parameters: - interval (qwt.interval.QwtInterval) – Interval
- ticks (list) – list of major, medium and minor ticks
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class
qwt.scale_div.QwtScaleDiv(lowerBound, upperBound)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
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class
qwt.scale_div.QwtScaleDiv(lowerBound, upperBound, ticks)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
- ticks (list) – list of major, medium and minor ticks
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class
qwt.scale_div.QwtScaleDiv(lowerBound, upperBound, minorTicks, mediumTicks, majorTicks)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
- minorTicks (list) – list of minor ticks
- mediumTicks (list) – list of medium ticks
- majorTicks (list) – list of major ticks
Note
lowerBound might be greater than upperBound for inverted scales
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QwtScaleDiv.setInterval(*args)[source] Change the interval
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setInterval(lowerBound, upperBound)[source] Parameters: - lowerBound (float) – First boundary
- upperBound (float) – Second boundary
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setInterval(interval)[source] Parameters: interval (qwt.interval.QwtInterval) – Interval
Note
lowerBound might be greater than upperBound for inverted scales
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QwtScaleDiv.interval()[source] Returns: Interval
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QwtScaleDiv.setLowerBound(lowerBound)[source] Set the first boundary
Parameters: lowerBound (float) – First boundary See also
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QwtScaleDiv.lowerBound()[source] Returns: the first boundary See also
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QwtScaleDiv.setUpperBound(upperBound)[source] Set the second boundary
Parameters: lowerBound (float) – Second boundary See also
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QwtScaleDiv.upperBound()[source] Returns: the second boundary See also
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QwtScaleDiv.range()[source] Returns: upperBound() - lowerBound()
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QwtScaleDiv.isEmpty()[source] Check if the scale division is empty( lowerBound() == upperBound() )
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QwtScaleDiv.isIncreasing()[source] Check if the scale division is increasing( lowerBound() <= upperBound() )
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QwtScaleDiv.contains(value)[source] Return if a value is between lowerBound() and upperBound()
Parameters: value (float) – Value Returns: True/False
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QwtScaleDiv.invert()[source] Invert the scale division
See also
-
QwtScaleDiv.inverted()[source] Returns: A scale division with inverted boundaries and ticks See also
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QwtScaleDiv.bounded(lowerBound, upperBound)[source] Return a scale division with an interval [lowerBound, upperBound] where all ticks outside this interval are removed
Parameters: - lowerBound (float) – First boundary
- lowerBound – Second boundary
Returns: Scale division with all ticks inside of the given interval
Note
lowerBound might be greater than upperBound for inverted scales
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QwtScaleDiv.setTicks(tickType, ticks)[source] Assign ticks
Parameters: - type (int) – MinorTick, MediumTick or MajorTick
- ticks (list) – Values of the tick positions
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QwtScaleDiv.ticks(tickType)[source] Return a list of ticks
Parameters: type (int) – MinorTick, MediumTick or MajorTick Returns: Tick list
QwtScaleEngine¶
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class
qwt.scale_engine.QwtScaleEngine(base=10)[source]¶ Base class for scale engines.
A scale engine tries to find “reasonable” ranges and step sizes for scales.
The layout of the scale can be varied with setAttribute().
python-qwt offers implementations for logarithmic and linear scales.
Layout attributes:
- QwtScaleEngine.NoAttribute: No attributes
- QwtScaleEngine.IncludeReference: Build a scale which includes the reference() value
- QwtScaleEngine.Symmetric: Build a scale which is symmetric to the reference() value
- QwtScaleEngine.Floating: The endpoints of the scale are supposed to be equal the outmost included values plus the specified margins (see setMargins()). If this attribute is not set, the endpoints of the scale will be integer multiples of the step size.
- QwtScaleEngine.Inverted: Turn the scale upside down
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autoScale(maxNumSteps, x1, x2, stepSize)[source]¶ Align and divide an interval
Parameters: - maxNumSteps (int) – Max. number of steps
- x1 (float) – First limit of the interval (In/Out)
- x2 (float) – Second limit of the interval (In/Out)
- stepSize (float) – Step size
Returns: tuple (x1, x2, stepSize)
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divideScale(x1, x2, maxMajorSteps, maxMinorSteps, stepSize=0.0)[source]¶ Calculate a scale division
Parameters: - x1 (float) – First interval limit
- x2 (float) – Second interval limit
- maxMajorSteps (int) – Maximum for the number of major steps
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size. If stepSize == 0.0, the scaleEngine calculates one
Returns: Calculated scale division
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setTransformation(transform)[source]¶ Assign a transformation
Parameters: transform (qwt.transform.QwtTransform) – Transformation The transformation object is used as factory for clones that are returned by transformation()
The scale engine takes ownership of the transformation.
See also
QwtTransform.copy(),transformation()
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transformation()[source]¶ Create and return a clone of the transformation of the engine. When the engine has no special transformation None is returned, indicating no transformation.
Returns: A clone of the transfomation See also
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lowerMargin()[source]¶ Returns: the margin at the lower end of the scale The default margin is 0.
See also
-
upperMargin()[source]¶ Returns: the margin at the upper end of the scale The default margin is 0.
See also
-
setMargins(lower, upper)[source]¶ Specify margins at the scale’s endpoints
Parameters: - lower (float) – minimum distance between the scale’s lower boundary and the smallest enclosed value
- upper (float) – minimum distance between the scale’s upper boundary and the greatest enclosed value
Returns: A clone of the transfomation
Margins can be used to leave a minimum amount of space between the enclosed intervals and the boundaries of the scale.
Warning
QwtLogScaleEngine measures the margins in decades.
See also
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divideInterval(intervalSize, numSteps)[source]¶ Calculate a step size for a given interval
Parameters: - intervalSize (float) – Interval size
- numSteps (float) – Number of steps
Returns: Step size
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contains(interval, value)[source]¶ Check if an interval “contains” a value
Parameters: - intervalSize (float) – Interval size
- value (float) – Value
Returns: True, when the value is inside the interval
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strip(ticks, interval)[source]¶ Remove ticks from a list, that are not inside an interval
Parameters: - ticks (list) – Tick list
- interval (qwt.interval.QwtInterval) – Interval
Returns: Stripped tick list
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buildInterval(value)[source]¶ Build an interval around a value
In case of v == 0.0 the interval is [-0.5, 0.5], otherwide it is [0.5 * v, 1.5 * v]
Parameters: value (float) – Initial value Returns: Calculated interval
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setAttribute(attribute, on=True)[source]¶ Change a scale attribute
Parameters: - attribute (int) – Attribute to change
- on (bool) – On/Off
Returns: Calculated interval
See also
-
testAttribute(attribute)[source]¶ Parameters: attribute (int) – Attribute to be tested Returns: True, if attribute is enabled See also
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setAttributes(attributes)[source]¶ Change the scale attribute
Parameters: attributes – Set scale attributes See also
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setReference(r)[source]¶ Specify a reference point
Parameters: r (float) – new reference value The reference point is needed if options IncludeReference or Symmetric are active. Its default value is 0.0.
QwtLinearScaleEngine¶
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class
qwt.scale_engine.QwtLinearScaleEngine(base=10)[source]¶ A scale engine for linear scales
The step size will fit into the pattern
$left{ 1,2,5 ight} cdot 10^{n} $, where n is an integer.
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autoScale(maxNumSteps, x1, x2, stepSize)[source]¶ Align and divide an interval
Parameters: - maxNumSteps (int) – Max. number of steps
- x1 (float) – First limit of the interval (In/Out)
- x2 (float) – Second limit of the interval (In/Out)
- stepSize (float) – Step size
Returns: tuple (x1, x2, stepSize)
See also
setAttribute()
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divideScale(x1, x2, maxMajorSteps, maxMinorSteps, stepSize=0.0)[source]¶ Calculate a scale division for an interval
Parameters: - x1 (float) – First interval limit
- x2 (float) – Second interval limit
- maxMajorSteps (int) – Maximum for the number of major steps
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size. If stepSize == 0.0, the scaleEngine calculates one
Returns: Calculated scale division
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buildTicks(interval, stepSize, maxMinorSteps)[source]¶ Calculate ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
- maxMinorSteps (int) – Maximum number of minor steps
Returns: Calculated ticks
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buildMajorTicks(interval, stepSize)[source]¶ Calculate major ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Calculated ticks
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buildMinorTicks(ticks, maxMinorSteps, stepSize)[source]¶ Calculate minor ticks for an interval
Parameters: - ticks (list) – Major ticks (returned)
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size
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align(interval, stepSize)[source]¶ Align an interval to a step size
The limits of an interval are aligned that both are integer multiples of the step size.
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Aligned interval
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QwtLogScaleEngine¶
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class
qwt.scale_engine.QwtLogScaleEngine(base=10)[source]¶ A scale engine for logarithmic scales
The step size is measured in decades and the major step size will be adjusted to fit the pattern {1,2,3,5}.10**n, where n is a natural number including zero.
Warning
The step size as well as the margins are measured in decades.
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autoScale(maxNumSteps, x1, x2, stepSize)[source]¶ Align and divide an interval
Parameters: - maxNumSteps (int) – Max. number of steps
- x1 (float) – First limit of the interval (In/Out)
- x2 (float) – Second limit of the interval (In/Out)
- stepSize (float) – Step size
Returns: tuple (x1, x2, stepSize)
See also
setAttribute()
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divideScale(x1, x2, maxMajorSteps, maxMinorSteps, stepSize=0.0)[source]¶ Calculate a scale division for an interval
Parameters: - x1 (float) – First interval limit
- x2 (float) – Second interval limit
- maxMajorSteps (int) – Maximum for the number of major steps
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size. If stepSize == 0.0, the scaleEngine calculates one
Returns: Calculated scale division
-
buildTicks(interval, stepSize, maxMinorSteps)[source]¶ Calculate ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
- maxMinorSteps (int) – Maximum number of minor steps
Returns: Calculated ticks
-
buildMajorTicks(interval, stepSize)[source]¶ Calculate major ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Calculated ticks
-
buildMinorTicks(ticks, maxMinorSteps, stepSize)[source]¶ Calculate minor ticks for an interval
Parameters: - ticks (list) – Major ticks (returned)
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size
-
align(interval, stepSize)[source]¶ Align an interval to a step size
The limits of an interval are aligned that both are integer multiples of the step size.
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Aligned interval
-
-
qwt.scale_engine.qwtStepSize(intervalSize, maxSteps, base)[source]¶ this version often doesn’t find the best ticks: f.e for 15: 5, 10
-
qwt.scale_engine.ceilEps(value, intervalSize)[source]¶ Ceil a value, relative to an interval
Parameters: - value (float) – Value to be ceiled
- intervalSize (float) – Interval size
Returns: Rounded value
See also
-
qwt.scale_engine.floorEps(value, intervalSize)[source]¶ Floor a value, relative to an interval
Parameters: - value (float) – Value to be floored
- intervalSize (float) – Interval size
Returns: Rounded value
See also
-
qwt.scale_engine.divideEps(intervalSize, numSteps)[source]¶ Divide an interval into steps
stepSize = (intervalSize - intervalSize * 10**-6) / numSteps
Parameters: - intervalSize (float) – Interval size
- numSteps (float) – Number of steps
Returns: Step size
-
qwt.scale_engine.divideInterval(intervalSize, numSteps, base)[source]¶ Calculate a step size for a given interval
Parameters: - intervalSize (float) – Interval size
- numSteps (float) – Number of steps
- base (int) – Base for the division (usually 10)
Returns: Calculated step size
-
class
qwt.scale_engine.QwtScaleEngine(base=10)[source] Base class for scale engines.
A scale engine tries to find “reasonable” ranges and step sizes for scales.
The layout of the scale can be varied with setAttribute().
python-qwt offers implementations for logarithmic and linear scales.
Layout attributes:
- QwtScaleEngine.NoAttribute: No attributes
- QwtScaleEngine.IncludeReference: Build a scale which includes the reference() value
- QwtScaleEngine.Symmetric: Build a scale which is symmetric to the reference() value
- QwtScaleEngine.Floating: The endpoints of the scale are supposed to be equal the outmost included values plus the specified margins (see setMargins()). If this attribute is not set, the endpoints of the scale will be integer multiples of the step size.
- QwtScaleEngine.Inverted: Turn the scale upside down
-
autoScale(maxNumSteps, x1, x2, stepSize)[source] Align and divide an interval
Parameters: - maxNumSteps (int) – Max. number of steps
- x1 (float) – First limit of the interval (In/Out)
- x2 (float) – Second limit of the interval (In/Out)
- stepSize (float) – Step size
Returns: tuple (x1, x2, stepSize)
-
divideScale(x1, x2, maxMajorSteps, maxMinorSteps, stepSize=0.0)[source] Calculate a scale division
Parameters: - x1 (float) – First interval limit
- x2 (float) – Second interval limit
- maxMajorSteps (int) – Maximum for the number of major steps
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size. If stepSize == 0.0, the scaleEngine calculates one
Returns: Calculated scale division
-
setTransformation(transform)[source] Assign a transformation
Parameters: transform (qwt.transform.QwtTransform) – Transformation The transformation object is used as factory for clones that are returned by transformation()
The scale engine takes ownership of the transformation.
See also
QwtTransform.copy(),transformation()
-
transformation()[source] Create and return a clone of the transformation of the engine. When the engine has no special transformation None is returned, indicating no transformation.
Returns: A clone of the transfomation See also
-
lowerMargin()[source] Returns: the margin at the lower end of the scale The default margin is 0.
See also
-
upperMargin()[source] Returns: the margin at the upper end of the scale The default margin is 0.
See also
-
setMargins(lower, upper)[source] Specify margins at the scale’s endpoints
Parameters: - lower (float) – minimum distance between the scale’s lower boundary and the smallest enclosed value
- upper (float) – minimum distance between the scale’s upper boundary and the greatest enclosed value
Returns: A clone of the transfomation
Margins can be used to leave a minimum amount of space between the enclosed intervals and the boundaries of the scale.
Warning
QwtLogScaleEngine measures the margins in decades.
See also
-
divideInterval(intervalSize, numSteps)[source] Calculate a step size for a given interval
Parameters: - intervalSize (float) – Interval size
- numSteps (float) – Number of steps
Returns: Step size
-
contains(interval, value)[source] Check if an interval “contains” a value
Parameters: - intervalSize (float) – Interval size
- value (float) – Value
Returns: True, when the value is inside the interval
-
strip(ticks, interval)[source] Remove ticks from a list, that are not inside an interval
Parameters: - ticks (list) – Tick list
- interval (qwt.interval.QwtInterval) – Interval
Returns: Stripped tick list
-
buildInterval(value)[source] Build an interval around a value
In case of v == 0.0 the interval is [-0.5, 0.5], otherwide it is [0.5 * v, 1.5 * v]
Parameters: value (float) – Initial value Returns: Calculated interval
-
setAttribute(attribute, on=True)[source] Change a scale attribute
Parameters: - attribute (int) – Attribute to change
- on (bool) – On/Off
Returns: Calculated interval
See also
-
testAttribute(attribute)[source] Parameters: attribute (int) – Attribute to be tested Returns: True, if attribute is enabled See also
-
setAttributes(attributes)[source] Change the scale attribute
Parameters: attributes – Set scale attributes See also
-
attributes()[source] Returns: Scale attributes See also
-
setReference(r)[source] Specify a reference point
Parameters: r (float) – new reference value The reference point is needed if options IncludeReference or Symmetric are active. Its default value is 0.0.
-
reference()[source] Returns: the reference value See also
-
setBase(base)[source] Set the base of the scale engine
While a base of 10 is what 99.9% of all applications need certain scales might need a different base: f.e 2
The default setting is 10
Parameters: base (int) – Base of the engine See also
-
class
qwt.scale_engine.QwtLinearScaleEngine(base=10)[source] A scale engine for linear scales
The step size will fit into the pattern
$left{ 1,2,5 ight} cdot 10^{n} $, where n is an integer.
-
autoScale(maxNumSteps, x1, x2, stepSize)[source] Align and divide an interval
Parameters: - maxNumSteps (int) – Max. number of steps
- x1 (float) – First limit of the interval (In/Out)
- x2 (float) – Second limit of the interval (In/Out)
- stepSize (float) – Step size
Returns: tuple (x1, x2, stepSize)
See also
setAttribute()
-
divideScale(x1, x2, maxMajorSteps, maxMinorSteps, stepSize=0.0)[source] Calculate a scale division for an interval
Parameters: - x1 (float) – First interval limit
- x2 (float) – Second interval limit
- maxMajorSteps (int) – Maximum for the number of major steps
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size. If stepSize == 0.0, the scaleEngine calculates one
Returns: Calculated scale division
-
buildTicks(interval, stepSize, maxMinorSteps)[source] Calculate ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
- maxMinorSteps (int) – Maximum number of minor steps
Returns: Calculated ticks
-
buildMajorTicks(interval, stepSize)[source] Calculate major ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Calculated ticks
-
buildMinorTicks(ticks, maxMinorSteps, stepSize)[source] Calculate minor ticks for an interval
Parameters: - ticks (list) – Major ticks (returned)
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size
-
align(interval, stepSize)[source] Align an interval to a step size
The limits of an interval are aligned that both are integer multiples of the step size.
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Aligned interval
-
-
class
qwt.scale_engine.QwtLogScaleEngine(base=10)[source] A scale engine for logarithmic scales
The step size is measured in decades and the major step size will be adjusted to fit the pattern {1,2,3,5}.10**n, where n is a natural number including zero.
Warning
The step size as well as the margins are measured in decades.
-
autoScale(maxNumSteps, x1, x2, stepSize)[source] Align and divide an interval
Parameters: - maxNumSteps (int) – Max. number of steps
- x1 (float) – First limit of the interval (In/Out)
- x2 (float) – Second limit of the interval (In/Out)
- stepSize (float) – Step size
Returns: tuple (x1, x2, stepSize)
See also
setAttribute()
-
divideScale(x1, x2, maxMajorSteps, maxMinorSteps, stepSize=0.0)[source] Calculate a scale division for an interval
Parameters: - x1 (float) – First interval limit
- x2 (float) – Second interval limit
- maxMajorSteps (int) – Maximum for the number of major steps
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size. If stepSize == 0.0, the scaleEngine calculates one
Returns: Calculated scale division
-
buildTicks(interval, stepSize, maxMinorSteps)[source] Calculate ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
- maxMinorSteps (int) – Maximum number of minor steps
Returns: Calculated ticks
-
buildMajorTicks(interval, stepSize)[source] Calculate major ticks for an interval
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Calculated ticks
-
buildMinorTicks(ticks, maxMinorSteps, stepSize)[source] Calculate minor ticks for an interval
Parameters: - ticks (list) – Major ticks (returned)
- maxMinorSteps (int) – Maximum number of minor steps
- stepSize (float) – Step size
-
align(interval, stepSize)[source] Align an interval to a step size
The limits of an interval are aligned that both are integer multiples of the step size.
Parameters: - interval (qwt.interval.QwtInterval) – Interval
- stepSize (float) – Step size
Returns: Aligned interval
-
QwtAbstractScaleDraw¶
-
class
qwt.scale_draw.QwtAbstractScaleDraw[source]¶ A abstract base class for drawing scales
QwtAbstractScaleDraw can be used to draw linear or logarithmic scales.
After a scale division has been specified as a QwtScaleDiv object using setScaleDiv(), the scale can be drawn with the draw() member.
Scale components:
- QwtAbstractScaleDraw.Backbone: Backbone = the line where the ticks are located
- QwtAbstractScaleDraw.Ticks: Ticks
- QwtAbstractScaleDraw.Labels: Labels
-
class
QwtAbstractScaleDraw¶ The range of the scale is initialized to [0, 100], The spacing (distance between ticks and labels) is set to 4, the tick lengths are set to 4,6 and 8 pixels
-
QwtAbstractScaleDraw.extent(font)[source]¶ Calculate the extent
The extent is the distance from the baseline to the outermost pixel of the scale draw in opposite to its orientation. It is at least minimumExtent() pixels.
Parameters: font (QFont) – Font used for drawing the tick labels Returns: Number of pixels See also
-
QwtAbstractScaleDraw.drawTick(painter, value, len_)[source]¶ Draw a tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value of the tick
- len (float) – Length of the tick
See also
-
QwtAbstractScaleDraw.drawBackbone(painter)[source]¶ Draws the baseline of the scale
Parameters: painter (QPainter) – Painter See also
-
QwtAbstractScaleDraw.drawLabel(painter, value)[source]¶ Draws the label for a major scale tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value
See also
-
QwtAbstractScaleDraw.enableComponent(component, enable)[source]¶ En/Disable a component of the scale
Parameters: - component (int) – Scale component
- enable (bool) – On/Off
See also
-
QwtAbstractScaleDraw.hasComponent(component)[source]¶ Check if a component is enabled
Parameters: component (int) – Component type Returns: True, when component is enabled See also
-
QwtAbstractScaleDraw.setScaleDiv(scaleDiv)[source]¶ Change the scale division
Parameters: scaleDiv (qwt.scale_div.QwtScaleDiv) – New scale division
-
QwtAbstractScaleDraw.setTransformation(transformation)[source]¶ Change the transformation of the scale
Parameters: transformation (qwt.transform.QwtTransform) – New scale transformation
-
QwtAbstractScaleDraw.scaleMap()[source]¶ Returns: Map how to translate between scale and pixel values
-
QwtAbstractScaleDraw.setPenWidth(width)[source]¶ Specify the width of the scale pen
Parameters: width (int) – Pen width See also
-
QwtAbstractScaleDraw.draw(painter, palette)[source]¶ Draw the scale
Parameters: - painter (QPainter) – The painter
- palette (QPalette) – Palette, text color is used for the labels, foreground color for ticks and backbone
-
QwtAbstractScaleDraw.setSpacing(spacing)[source]¶ Set the spacing between tick and labels
The spacing is the distance between ticks and labels. The default spacing is 4 pixels.
Parameters: spacing (float) – Spacing See also
-
QwtAbstractScaleDraw.spacing()[source]¶ Get the spacing
The spacing is the distance between ticks and labels. The default spacing is 4 pixels.
Returns: Spacing See also
-
QwtAbstractScaleDraw.setMinimumExtent(minExtent)[source]¶ Set a minimum for the extent
The extent is calculated from the components of the scale draw. In situations, where the labels are changing and the layout depends on the extent (f.e scrolling a scale), setting an upper limit as minimum extent will avoid jumps of the layout.
Parameters: minExtent (float) – Minimum extent See also
-
QwtAbstractScaleDraw.minimumExtent()[source]¶ Get the minimum extent
Returns: Minimum extent See also
-
QwtAbstractScaleDraw.setTickLength(tickType, length)[source]¶ Set the length of the ticks
Parameters: - tickType (int) – Tick type
- length (float) – New length
Warning
the length is limited to [0..1000]
-
QwtAbstractScaleDraw.maxTickLength()[source]¶ Returns: Length of the longest tick Useful for layout calculations
See also
-
QwtAbstractScaleDraw.label(value)[source]¶ Convert a value into its representing label
The value is converted to a plain text using QLocale().toString(value). This method is often overloaded by applications to have individual labels.
Parameters: value (float) – Value Returns: Label string
-
QwtAbstractScaleDraw.tickLabel(font, value)[source]¶ Convert a value into its representing label and cache it.
The conversion between value and label is called very often in the layout and painting code. Unfortunately the calculation of the label sizes might be slow (really slow for rich text in Qt4), so it’s necessary to cache the labels.
Parameters: - font (QFont) – Font
- value (float) – Value
Returns: Tick label
QwtScaleDraw¶
-
class
qwt.scale_draw.QwtScaleDraw[source]¶ 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(scaleDiv), the scale can be drawn with the QwtAbstractScaleDraw.draw() member.
Alignment of the scale draw:
- QwtScaleDraw.BottomScale: The scale is below
- QwtScaleDraw.TopScale: The scale is above
- QwtScaleDraw.LeftScale: The scale is left
- QwtScaleDraw.RightScale: The scale is right
-
class
QwtAbstractScaleDraw¶ 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.setAlignment(align)[source]¶ Set the alignment of the scale
Parameters: align (int) – Alignment of the scale Alignment of the scale draw:
- QwtScaleDraw.BottomScale: The scale is below
- QwtScaleDraw.TopScale: The scale is above
- QwtScaleDraw.LeftScale: The scale is left
- QwtScaleDraw.RightScale: The scale is right
The default alignment is QwtScaleDraw.BottomScale
See also
-
QwtScaleDraw.orientation()[source]¶ Return the orientation
TopScale, BottomScale are horizontal (Qt.Horizontal) scales, LeftScale, RightScale are vertical (Qt.Vertical) scales.
Returns: Orientation of the scale See also
-
QwtScaleDraw.getBorderDistHint(font)[source]¶ Determine the minimum border distance
This member function returns the minimum space needed to draw the mark labels at the scale’s endpoints.
Parameters: font (QFont) – Font Returns: tuple (start, end) Returned tuple:
- start: Start border distance
- end: End border distance
-
QwtScaleDraw.minLabelDist(font)[source]¶ Determine the minimum distance between two labels, that is necessary that the texts don’t overlap.
Parameters: font (QFont) – Font Returns: The maximum width of a label See also
-
QwtScaleDraw.extent(font)[source]¶ 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.
Parameters: font (QFont) – Font used for painting the labels Returns: Extent See also
-
QwtScaleDraw.minLength(font)[source]¶ Calculate the minimum length that is needed to draw the scale
Parameters: font (QFont) – Font used for painting the labels Returns: Minimum length that is needed to draw the scale See also
-
QwtScaleDraw.labelPosition(value)[source]¶ 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().
Parameters: value (float) – Value Returns: Position, where to paint a label
-
QwtScaleDraw.drawTick(painter, value, len_)[source]¶ Draw a tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value of the tick
- len (float) – Length of the tick
See also
-
QwtScaleDraw.drawBackbone(painter)[source]¶ Draws the baseline of the scale
Parameters: painter (QPainter) – Painter See also
-
QwtScaleDraw.move(*args)[source]¶ Move the position of the scale
The meaning of the parameter pos depends on the alignment:
QwtScaleDraw.LeftScale:
The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the left of the backbone.
QwtScaleDraw.RightScale:
The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the right of the backbone.
QwtScaleDraw.TopScale:
The origin is the leftmost point of the backbone. The backbone is a horizontal line. Scale marks and labels are drawn above the backbone.
QwtScaleDraw.BottomScale:
The origin is the leftmost point of the backbone. The backbone is a horizontal line Scale marks and labels are drawn below the backbone.
-
move(x, y)[source] Parameters: - x (float) – X coordinate
- y (float) – Y coordinate
-
move(pos)[source] Parameters: pos (QPointF) – position
See also
-
QwtScaleDraw.setLength(length)[source]¶ Set the length of the backbone.
The length doesn’t include the space needed for overlapping labels.
Parameters: length (float) – Length of the backbone See also
-
QwtScaleDraw.drawLabel(painter, value)[source]¶ Draws the label for a major scale tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value
See also
-
QwtScaleDraw.boundingLabelRect(font, value)[source]¶ Find the bounding rectangle for the label.
The coordinates of the rectangle are absolute (calculated from pos()) in direction of the tick.
Parameters: - font (QFont) – Font used for painting
- value (float) – Value
Returns: Bounding rectangle
See also
-
QwtScaleDraw.labelTransformation(pos, size)[source]¶ Calculate the transformation that is needed to paint a label depending on its alignment and rotation.
Parameters: - pos (QPointF) – Position where to paint the label
- size (QSizeF) – Size of the label
Returns: Transformation matrix
See also
-
QwtScaleDraw.labelRect(font, value)[source]¶ 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.
Parameters: - font (QFont) – Font used for painting
- value (float) – Value
Returns: Bounding rectangle that is needed to draw a label
-
QwtScaleDraw.labelSize(font, value)[source]¶ Calculate the size that is needed to draw a label
Parameters: - font (QFont) – Label font
- value (float) – Value
Returns: Size that is needed to draw a label
-
QwtScaleDraw.setLabelRotation(rotation)[source]¶ 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.
Parameters: rotation (float) – Angle in degrees. When changing the label rotation, the label flags often needs to be adjusted too. See also
-
QwtScaleDraw.setLabelAlignment(alignment)[source]¶ 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:
- QwtScaleDraw.TopScale: Qt.AlignHCenter | Qt.AlignTop
- QwtScaleDraw.BottomScale: Qt.AlignHCenter | Qt.AlignBottom
- QwtScaleDraw.LeftScale: Qt.AlignLeft | Qt.AlignVCenter
- QwtScaleDraw.RightScale: Qt.AlignRight | Qt.AlignVCenter
Changing the alignment is often necessary for rotated labels.
:param Qt.Alignment alignment Or’d Qt.AlignmentFlags
See also
Warning
The various alignments might be confusing. The alignment of the label is not the alignment of the scale and is not the alignment of the flags (QwtText.flags()) returned from QwtAbstractScaleDraw.label().
-
class
qwt.scale_draw.QwtAbstractScaleDraw[source] A abstract base class for drawing scales
QwtAbstractScaleDraw can be used to draw linear or logarithmic scales.
After a scale division has been specified as a QwtScaleDiv object using setScaleDiv(), the scale can be drawn with the draw() member.
Scale components:
- QwtAbstractScaleDraw.Backbone: Backbone = the line where the ticks are located
- QwtAbstractScaleDraw.Ticks: Ticks
- QwtAbstractScaleDraw.Labels: Labels
-
class
QwtAbstractScaleDraw The range of the scale is initialized to [0, 100], The spacing (distance between ticks and labels) is set to 4, the tick lengths are set to 4,6 and 8 pixels
-
QwtAbstractScaleDraw.extent(font)[source] Calculate the extent
The extent is the distance from the baseline to the outermost pixel of the scale draw in opposite to its orientation. It is at least minimumExtent() pixels.
Parameters: font (QFont) – Font used for drawing the tick labels Returns: Number of pixels See also
-
QwtAbstractScaleDraw.drawTick(painter, value, len_)[source] Draw a tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value of the tick
- len (float) – Length of the tick
See also
-
QwtAbstractScaleDraw.drawBackbone(painter)[source] Draws the baseline of the scale
Parameters: painter (QPainter) – Painter See also
-
QwtAbstractScaleDraw.drawLabel(painter, value)[source] Draws the label for a major scale tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value
See also
-
QwtAbstractScaleDraw.enableComponent(component, enable)[source] En/Disable a component of the scale
Parameters: - component (int) – Scale component
- enable (bool) – On/Off
See also
-
QwtAbstractScaleDraw.hasComponent(component)[source] Check if a component is enabled
Parameters: component (int) – Component type Returns: True, when component is enabled See also
-
QwtAbstractScaleDraw.setScaleDiv(scaleDiv)[source] Change the scale division
Parameters: scaleDiv (qwt.scale_div.QwtScaleDiv) – New scale division
-
QwtAbstractScaleDraw.setTransformation(transformation)[source] Change the transformation of the scale
Parameters: transformation (qwt.transform.QwtTransform) – New scale transformation
-
QwtAbstractScaleDraw.scaleMap()[source] Returns: Map how to translate between scale and pixel values
-
QwtAbstractScaleDraw.scaleDiv()[source] Returns: scale division
-
QwtAbstractScaleDraw.setPenWidth(width)[source] Specify the width of the scale pen
Parameters: width (int) – Pen width See also
-
QwtAbstractScaleDraw.penWidth()[source] Returns: Scale pen width See also
-
QwtAbstractScaleDraw.draw(painter, palette)[source] Draw the scale
Parameters: - painter (QPainter) – The painter
- palette (QPalette) – Palette, text color is used for the labels, foreground color for ticks and backbone
-
QwtAbstractScaleDraw.setSpacing(spacing)[source] Set the spacing between tick and labels
The spacing is the distance between ticks and labels. The default spacing is 4 pixels.
Parameters: spacing (float) – Spacing See also
-
QwtAbstractScaleDraw.spacing()[source] Get the spacing
The spacing is the distance between ticks and labels. The default spacing is 4 pixels.
Returns: Spacing See also
-
QwtAbstractScaleDraw.setMinimumExtent(minExtent)[source] Set a minimum for the extent
The extent is calculated from the components of the scale draw. In situations, where the labels are changing and the layout depends on the extent (f.e scrolling a scale), setting an upper limit as minimum extent will avoid jumps of the layout.
Parameters: minExtent (float) – Minimum extent See also
-
QwtAbstractScaleDraw.minimumExtent()[source] Get the minimum extent
Returns: Minimum extent See also
-
QwtAbstractScaleDraw.setTickLength(tickType, length)[source] Set the length of the ticks
Parameters: - tickType (int) – Tick type
- length (float) – New length
Warning
the length is limited to [0..1000]
-
QwtAbstractScaleDraw.tickLength(tickType)[source] Returns: Length of the ticks See also
-
QwtAbstractScaleDraw.maxTickLength()[source] Returns: Length of the longest tick Useful for layout calculations
See also
-
QwtAbstractScaleDraw.label(value)[source] Convert a value into its representing label
The value is converted to a plain text using QLocale().toString(value). This method is often overloaded by applications to have individual labels.
Parameters: value (float) – Value Returns: Label string
-
QwtAbstractScaleDraw.tickLabel(font, value)[source] Convert a value into its representing label and cache it.
The conversion between value and label is called very often in the layout and painting code. Unfortunately the calculation of the label sizes might be slow (really slow for rich text in Qt4), so it’s necessary to cache the labels.
Parameters: - font (QFont) – Font
- value (float) – Value
Returns: Tick label
-
QwtAbstractScaleDraw.invalidateCache()[source] Invalidate the cache used by tickLabel()
The cache is invalidated, when a new QwtScaleDiv is set. If the labels need to be changed. while the same QwtScaleDiv is set, invalidateCache() needs to be called manually.
-
class
qwt.scale_draw.QwtScaleDraw[source] 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(scaleDiv), the scale can be drawn with the QwtAbstractScaleDraw.draw() member.
Alignment of the scale draw:
- QwtScaleDraw.BottomScale: The scale is below
- QwtScaleDraw.TopScale: The scale is above
- QwtScaleDraw.LeftScale: The scale is left
- QwtScaleDraw.RightScale: The scale is right
-
class
QwtAbstractScaleDraw 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()[source] Returns: Alignment of the scale See also
-
QwtScaleDraw.setAlignment(align)[source] Set the alignment of the scale
Parameters: align (int) – Alignment of the scale Alignment of the scale draw:
- QwtScaleDraw.BottomScale: The scale is below
- QwtScaleDraw.TopScale: The scale is above
- QwtScaleDraw.LeftScale: The scale is left
- QwtScaleDraw.RightScale: The scale is right
The default alignment is QwtScaleDraw.BottomScale
See also
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QwtScaleDraw.orientation()[source] Return the orientation
TopScale, BottomScale are horizontal (Qt.Horizontal) scales, LeftScale, RightScale are vertical (Qt.Vertical) scales.
Returns: Orientation of the scale See also
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QwtScaleDraw.getBorderDistHint(font)[source] Determine the minimum border distance
This member function returns the minimum space needed to draw the mark labels at the scale’s endpoints.
Parameters: font (QFont) – Font Returns: tuple (start, end) Returned tuple:
- start: Start border distance
- end: End border distance
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QwtScaleDraw.minLabelDist(font)[source] Determine the minimum distance between two labels, that is necessary that the texts don’t overlap.
Parameters: font (QFont) – Font Returns: The maximum width of a label See also
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QwtScaleDraw.extent(font)[source] 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.
Parameters: font (QFont) – Font used for painting the labels Returns: Extent See also
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QwtScaleDraw.minLength(font)[source] Calculate the minimum length that is needed to draw the scale
Parameters: font (QFont) – Font used for painting the labels Returns: Minimum length that is needed to draw the scale See also
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QwtScaleDraw.labelPosition(value)[source] 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().
Parameters: value (float) – Value Returns: Position, where to paint a label
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QwtScaleDraw.drawTick(painter, value, len_)[source] Draw a tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value of the tick
- len (float) – Length of the tick
See also
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QwtScaleDraw.drawBackbone(painter)[source] Draws the baseline of the scale
Parameters: painter (QPainter) – Painter See also
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QwtScaleDraw.move(*args)[source] Move the position of the scale
The meaning of the parameter pos depends on the alignment:
QwtScaleDraw.LeftScale:
The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the left of the backbone.
QwtScaleDraw.RightScale:
The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the right of the backbone.
QwtScaleDraw.TopScale:
The origin is the leftmost point of the backbone. The backbone is a horizontal line. Scale marks and labels are drawn above the backbone.
QwtScaleDraw.BottomScale:
The origin is the leftmost point of the backbone. The backbone is a horizontal line Scale marks and labels are drawn below the backbone.
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move(x, y)[source] Parameters: - x (float) – X coordinate
- y (float) – Y coordinate
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move(pos)[source] Parameters: pos (QPointF) – position
See also
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QwtScaleDraw.pos()[source] Returns: Origin of the scale See also
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QwtScaleDraw.setLength(length)[source] Set the length of the backbone.
The length doesn’t include the space needed for overlapping labels.
Parameters: length (float) – Length of the backbone See also
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QwtScaleDraw.length()[source] Returns: the length of the backbone See also
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QwtScaleDraw.drawLabel(painter, value)[source] Draws the label for a major scale tick
Parameters: - painter (QPainter) – Painter
- value (float) – Value
See also
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QwtScaleDraw.boundingLabelRect(font, value)[source] Find the bounding rectangle for the label.
The coordinates of the rectangle are absolute (calculated from pos()) in direction of the tick.
Parameters: - font (QFont) – Font used for painting
- value (float) – Value
Returns: Bounding rectangle
See also
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QwtScaleDraw.labelTransformation(pos, size)[source] Calculate the transformation that is needed to paint a label depending on its alignment and rotation.
Parameters: - pos (QPointF) – Position where to paint the label
- size (QSizeF) – Size of the label
Returns: Transformation matrix
See also
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QwtScaleDraw.labelRect(font, value)[source] 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.
Parameters: - font (QFont) – Font used for painting
- value (float) – Value
Returns: Bounding rectangle that is needed to draw a label
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QwtScaleDraw.labelSize(font, value)[source] Calculate the size that is needed to draw a label
Parameters: - font (QFont) – Label font
- value (float) – Value
Returns: Size that is needed to draw a label
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QwtScaleDraw.setLabelRotation(rotation)[source] 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.
Parameters: rotation (float) – Angle in degrees. When changing the label rotation, the label flags often needs to be adjusted too. See also
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QwtScaleDraw.labelRotation()[source] Returns: the label rotation See also
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QwtScaleDraw.setLabelAlignment(alignment)[source] 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:
- QwtScaleDraw.TopScale: Qt.AlignHCenter | Qt.AlignTop
- QwtScaleDraw.BottomScale: Qt.AlignHCenter | Qt.AlignBottom
- QwtScaleDraw.LeftScale: Qt.AlignLeft | Qt.AlignVCenter
- QwtScaleDraw.RightScale: Qt.AlignRight | Qt.AlignVCenter
Changing the alignment is often necessary for rotated labels.
:param Qt.Alignment alignment Or’d Qt.AlignmentFlags
See also
Warning
The various alignments might be confusing. The alignment of the label is not the alignment of the scale and is not the alignment of the flags (QwtText.flags()) returned from QwtAbstractScaleDraw.label().
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QwtScaleDraw.labelAlignment()[source] Returns: the label flags See also
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QwtScaleDraw.maxLabelWidth(font)[source] Parameters: font (QFont) – Font Returns: the maximum width of a label
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QwtScaleDraw.maxLabelHeight(font)[source] Parameters: font (QFont) – Font Returns: the maximum height of a label