QGIS API Documentation  3.27.0-Master (e113457133)
qgssteppedlinescalebarrenderer.cpp
Go to the documentation of this file.
1 /***************************************************************************
2  qgssteppedlinescalebarrenderer.cpp
3  --------------------------------
4  begin : March 2020
5  copyright : (C) 2020 by Nyall Dawson
6  email : nyall dot dawson at gmail dot com
7  ***************************************************************************/
8 /***************************************************************************
9  * *
10  * This program is free software; you can redistribute it and/or modify *
11  * it under the terms of the GNU General Public License as published by *
12  * the Free Software Foundation; either version 2 of the License, or *
13  * (at your option) any later version. *
14  * *
15  ***************************************************************************/
16 
18 #include "qgsscalebarsettings.h"
19 #include "qgslayoututils.h"
20 #include "qgssymbol.h"
21 #include "qgstextrenderer.h"
22 #include "qgslinesymbol.h"
23 #include <QList>
24 #include <QPainter>
25 
27 {
28  return QStringLiteral( "stepped" );
29 }
30 
32 {
33  return QObject::tr( "Stepped Line" );
34 }
35 
37 {
38  return 7;
39 }
40 
41 QgsScaleBarRenderer::Flags QgsSteppedLineScaleBarRenderer::flags() const
42 {
51 }
52 
54 {
55  return new QgsSteppedLineScaleBarRenderer( *this );
56 }
57 
58 void QgsSteppedLineScaleBarRenderer::draw( QgsRenderContext &context, const QgsScaleBarSettings &settings, const ScaleBarContext &scaleContext ) const
59 {
60  if ( !context.painter() )
61  {
62  return;
63  }
64  QPainter *painter = context.painter();
65 
66  std::unique_ptr< QgsLineSymbol > sym( settings.lineSymbol()->clone() );
67  sym->startRender( context ) ;
68 
69  const double scaledLabelBarSpace = context.convertToPainterUnits( settings.labelBarSpace(), QgsUnitTypes::RenderMillimeters );
70  const double scaledBoxContentSpace = context.convertToPainterUnits( settings.boxContentSpace(), QgsUnitTypes::RenderMillimeters );
71  const QFontMetricsF fontMetrics = QgsTextRenderer::fontMetrics( context, settings.textFormat() );
72  const double barTopPosition = scaledBoxContentSpace + ( settings.labelVerticalPlacement() == QgsScaleBarSettings::LabelAboveSegment ? fontMetrics.ascent() + scaledLabelBarSpace : 0 );
73  const double barBottomPosition = barTopPosition + context.convertToPainterUnits( settings.height(), QgsUnitTypes::RenderMillimeters );
74 
75  painter->save();
76  context.setPainterFlagsUsingContext( painter );
77 
78  painter->setPen( Qt::NoPen );
79 
80  const double xOffset = firstLabelXOffset( settings, context, scaleContext );
81 
82  const QList<double> positions = segmentPositions( context, scaleContext, settings );
83  const QList<double> widths = segmentWidths( scaleContext, settings );
84 
85  QPolygonF points;
86 
87  for ( int i = 0; i < positions.size() + 1; ++i )
88  {
89  // we render one extra place, corresponding to the final position + width (i.e. the "end" of the bar)
90  const double x = i < positions.size() ? context.convertToPainterUnits( positions.at( i ), QgsUnitTypes::RenderMillimeters ) + xOffset
91  : context.convertToPainterUnits( positions.at( i - 1 ), QgsUnitTypes::RenderMillimeters ) + xOffset + context.convertToPainterUnits( widths.at( i - 1 ), QgsUnitTypes::RenderMillimeters );
92  if ( i % 2 == 0 )
93  {
94  points << QPointF( x, barBottomPosition ) << QPointF( x, barTopPosition );
95  }
96  else
97  {
98  points << QPointF( x, barTopPosition ) << QPointF( x, barBottomPosition ) ;
99  }
100  }
101 
102  sym->renderPolyline( points, nullptr, context );
103 
104  painter->restore();
105 
106  sym->stopRender( context );
107 
108  //draw labels using the default method
109  drawDefaultLabels( context, settings, scaleContext );
110 }
111 
112 
113 
QgsLineSymbol * clone() const override
Returns a deep copy of this symbol.
Contains information about the context of a rendering operation.
QPainter * painter()
Returns the destination QPainter for the render operation.
void setPainterFlagsUsingContext(QPainter *painter=nullptr) const
Sets relevant flags on a destination painter, using the flags and settings currently defined for the ...
double convertToPainterUnits(double size, QgsUnitTypes::RenderUnit unit, const QgsMapUnitScale &scale=QgsMapUnitScale(), Qgis::RenderSubcomponentProperty property=Qgis::RenderSubcomponentProperty::Generic) const
Converts a size from the specified units to painter units (pixels).
@ FlagUsesLabelVerticalPlacement
Renderer uses the QgsScaleBarSettings::labelVerticalPlacement() setting.
@ FlagUsesLabelHorizontalPlacement
Renderer uses the QgsScaleBarSettings::labelHorizontalPlacement() setting.
@ FlagUsesLineSymbol
Renderer utilizes the scalebar line symbol (see QgsScaleBarSettings::lineSymbol() )
@ FlagUsesUnitLabel
Renderer uses the QgsScaleBarSettings::unitLabel() setting.
@ FlagUsesSegments
Renderer uses the scalebar segments.
@ FlagUsesLabelBarSpace
Renderer uses the QgsScaleBarSettings::labelBarSpace() setting.
@ FlagRespectsMapUnitsPerScaleBarUnit
Renderer respects the QgsScaleBarSettings::mapUnitsPerScaleBarUnit() setting.
@ FlagRespectsUnits
Renderer respects the QgsScaleBarSettings::units() setting.
void drawDefaultLabels(QgsRenderContext &context, const QgsScaleBarSettings &settings, const QgsScaleBarRenderer::ScaleBarContext &scaleContext) const
Draws default scalebar labels using the specified settings and scaleContext to a destination render c...
QList< double > segmentWidths(const QgsScaleBarRenderer::ScaleBarContext &scaleContext, const QgsScaleBarSettings &settings) const
Returns a list of widths of each segment of the scalebar.
Q_DECL_DEPRECATED QList< double > segmentPositions(const QgsScaleBarRenderer::ScaleBarContext &scaleContext, const QgsScaleBarSettings &settings) const
Returns a list of positions for each segment within the scalebar.
Q_DECL_DEPRECATED double firstLabelXOffset(const QgsScaleBarSettings &settings) const
Returns the x-offset (in millimeters) used for the first label in the scalebar.
The QgsScaleBarSettings class stores the appearance and layout settings for scalebar drawing with Qgs...
QgsLineSymbol * lineSymbol() const
Returns the line symbol used to render the scalebar (only used for some scalebar types).
double boxContentSpace() const
Returns the spacing (margin) between the scalebar box and content in millimeters.
LabelVerticalPlacement labelVerticalPlacement() const
Returns the vertical placement of text labels.
@ LabelAboveSegment
Labels are drawn above the scalebar.
double labelBarSpace() const
Returns the spacing (in millimeters) between labels and the scalebar.
QgsTextFormat & textFormat()
Returns the text format used for drawing text in the scalebar.
double height() const
Returns the scalebar height (in millimeters).
Scalebar style that draws a stepped line representation of a scalebar.
void draw(QgsRenderContext &context, const QgsScaleBarSettings &settings, const QgsScaleBarRenderer::ScaleBarContext &scaleContext) const override
Draws the scalebar using the specified settings and scaleContext to a destination render context.
int sortKey() const override
Returns a sorting key value, where renderers with a lower sort key will be shown earlier in lists.
QgsSteppedLineScaleBarRenderer()=default
Constructor for QgsSteppedLineScaleBarRenderer.
Flags flags() const override
Returns the scalebar rendering flags, which dictates the renderer's behavior.
QgsSteppedLineScaleBarRenderer * clone() const override
Returns a clone of the renderer.
QString visibleName() const override
Returns the user friendly, translated name for the renderer.
QString id() const override
Returns the unique ID for this renderer.
static QFontMetricsF fontMetrics(QgsRenderContext &context, const QgsTextFormat &format, double scaleFactor=1.0)
Returns the font metrics for the given text format, when rendered in the specified render context.
@ RenderMillimeters
Millimeters.
Definition: qgsunittypes.h:169
Contains parameters regarding scalebar calculations.