QGIS API Documentation  3.23.0-Master (c716e02dd3)
qgshollowscalebarrenderer.cpp
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1 /***************************************************************************
2  qgshollowscalebarrenderer.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 "qgsfillsymbollayer.h"
22 #include "qgstextrenderer.h"
23 #include "qgslinesymbol.h"
24 #include "qgsfillsymbol.h"
25 #include <QList>
26 #include <QPainter>
27 
29 {
30  return QStringLiteral( "hollow" );
31 }
32 
34 {
35  return QObject::tr( "Hollow" );
36 }
37 
38 QgsScaleBarRenderer::Flags QgsHollowScaleBarRenderer::flags() const
39 {
50 }
51 
53 {
54  return 8;
55 }
56 
58 {
59  return new QgsHollowScaleBarRenderer( *this );
60 }
61 
62 void QgsHollowScaleBarRenderer::draw( QgsRenderContext &context, const QgsScaleBarSettings &settings, const ScaleBarContext &scaleContext ) const
63 {
64  if ( !context.painter() )
65  {
66  return;
67  }
68  QPainter *painter = context.painter();
69 
70  const double scaledLabelBarSpace = context.convertToPainterUnits( settings.labelBarSpace(), QgsUnitTypes::RenderMillimeters );
71  const double scaledBoxContentSpace = context.convertToPainterUnits( settings.boxContentSpace(), QgsUnitTypes::RenderMillimeters );
72  const QFontMetricsF fontMetrics = QgsTextRenderer::fontMetrics( context, settings.textFormat() );
73  const double barTopPosition = scaledBoxContentSpace + ( settings.labelVerticalPlacement() == QgsScaleBarSettings::LabelAboveSegment ? fontMetrics.ascent() + scaledLabelBarSpace : 0 );
74  const double barHeight = context.convertToPainterUnits( settings.height(), QgsUnitTypes::RenderMillimeters );
75 
76  painter->save();
77  context.setPainterFlagsUsingContext( painter );
78 
79  std::unique_ptr< QgsLineSymbol > lineSymbol( settings.lineSymbol()->clone() );
80  lineSymbol->startRender( context );
81 
82  std::unique_ptr< QgsFillSymbol > fillSymbol1( settings.fillSymbol()->clone() );
83  fillSymbol1->startRender( context );
84 
85  std::unique_ptr< QgsFillSymbol > fillSymbol2( settings.alternateFillSymbol()->clone() );
86  fillSymbol2->startRender( context );
87 
88  painter->setPen( Qt::NoPen );
89  painter->setBrush( Qt::NoBrush );
90 
91  bool useColor = true; //alternate brush color/white
92  const double xOffset = firstLabelXOffset( settings, context, scaleContext );
93 
94  const QList<double> positions = segmentPositions( context, scaleContext, settings );
95  const QList<double> widths = segmentWidths( scaleContext, settings );
96 
97  // draw the fill
98  double minX = 0;
99  double maxX = 0;
100  QgsFillSymbol *currentSymbol = nullptr;
101  for ( int i = 0; i < positions.size(); ++i )
102  {
103  if ( useColor ) //alternating colors
104  {
105  currentSymbol = fillSymbol1.get();
106  }
107  else //secondary fill
108  {
109  currentSymbol = fillSymbol2.get();
110  }
111 
112  const double thisX = context.convertToPainterUnits( positions.at( i ), QgsUnitTypes::RenderMillimeters ) + xOffset;
113  const double thisWidth = context.convertToPainterUnits( widths.at( i ), QgsUnitTypes::RenderMillimeters );
114 
115  if ( i == 0 )
116  minX = thisX;
117  if ( i == positions.size() - 1 )
118  maxX = thisX + thisWidth;
119 
120  const QRectF segmentRect( thisX, barTopPosition, thisWidth, barHeight );
121  currentSymbol->renderPolygon( QPolygonF()
122  << segmentRect.topLeft()
123  << segmentRect.topRight()
124  << segmentRect.bottomRight()
125  << segmentRect.bottomLeft()
126  << segmentRect.topLeft(), nullptr, nullptr, context );
127  useColor = !useColor;
128  }
129 
130  // and then the lines
131  // note that we do this layer-by-layer, to avoid ugliness where the lines touch the outer rect
132  for ( int layer = 0; layer < lineSymbol->symbolLayerCount(); ++layer )
133  {
134  // horizontal lines
135  bool drawLine = false;
136  for ( int i = 0; i < positions.size(); ++i )
137  {
138  drawLine = !drawLine;
139  if ( !drawLine )
140  continue;
141 
142  const double lineX = context.convertToPainterUnits( positions.at( i ), QgsUnitTypes::RenderMillimeters ) + xOffset;
143  const double lineLength = context.convertToPainterUnits( widths.at( i ), QgsUnitTypes::RenderMillimeters );
144  lineSymbol->renderPolyline( QPolygonF()
145  << QPointF( lineX, barTopPosition + barHeight / 2.0 )
146  << QPointF( lineX + lineLength, barTopPosition + barHeight / 2.0 ),
147  nullptr, context, layer );
148  }
149 
150  // vertical lines
151  for ( int i = 1; i < positions.size(); ++i )
152  {
153  const double lineX = context.convertToPainterUnits( positions.at( i ), QgsUnitTypes::RenderMillimeters ) + xOffset;
154  lineSymbol->renderPolyline( QPolygonF()
155  << QPointF( lineX, barTopPosition )
156  << QPointF( lineX, barTopPosition + barHeight ),
157  nullptr, context, layer );
158  }
159 
160  // outside line
161  lineSymbol->renderPolyline( QPolygonF()
162  << QPointF( minX, barTopPosition )
163  << QPointF( maxX, barTopPosition )
164  << QPointF( maxX, barTopPosition + barHeight )
165  << QPointF( minX, barTopPosition + barHeight )
166  << QPointF( minX, barTopPosition ),
167  nullptr, context, layer );
168  }
169 
170  lineSymbol->stopRender( context );
171  fillSymbol1->stopRender( context );
172  fillSymbol2->stopRender( context );
173  painter->restore();
174 
175  //draw labels using the default method
176  drawDefaultLabels( context, settings, scaleContext );
177 }
178 
180 {
181  // null the fill symbols by default
182  std::unique_ptr< QgsFillSymbol > fillSymbol = std::make_unique< QgsFillSymbol >();
183  std::unique_ptr< QgsSimpleFillSymbolLayer > fillSymbolLayer = std::make_unique< QgsSimpleFillSymbolLayer >();
184  fillSymbolLayer->setColor( QColor( 0, 0, 0 ) );
185  fillSymbolLayer->setBrushStyle( Qt::NoBrush );
186  fillSymbolLayer->setStrokeStyle( Qt::NoPen );
187  fillSymbol->changeSymbolLayer( 0, fillSymbolLayer->clone() );
188  settings.setFillSymbol( fillSymbol.release() );
189 
190  fillSymbol = std::make_unique< QgsFillSymbol >();
191  fillSymbolLayer->setColor( QColor( 255, 255, 255 ) );
192  fillSymbol->changeSymbolLayer( 0, fillSymbolLayer.release() );
193  settings.setAlternateFillSymbol( fillSymbol.release() );
194 
195  return true;
196 }
197 
198 
199 
A fill symbol type, for rendering Polygon and MultiPolygon geometries.
Definition: qgsfillsymbol.h:30
void renderPolygon(const QPolygonF &points, const QVector< QPolygonF > *rings, const QgsFeature *f, QgsRenderContext &context, int layer=-1, bool selected=false)
Renders the symbol using the given render context.
QgsFillSymbol * clone() const override
Returns a deep copy of this symbol.
Scalebar style that draws a single box with alternating color for the segments, with horizontal lines...
int sortKey() const override
Returns a sorting key value, where renderers with a lower sort key will be shown earlier in lists.
bool applyDefaultSettings(QgsScaleBarSettings &settings) const override
Applies any default settings relating to the scalebar to the passed settings object.
QgsHollowScaleBarRenderer * clone() const override
Returns a clone of the renderer.
QString visibleName() const override
Returns the user friendly, translated name for the renderer.
QgsHollowScaleBarRenderer()=default
Constructor for QgsHollowScaleBarRenderer.
Flags flags() const override
Returns the scalebar rendering flags, which dictates the renderer's behavior.
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.
QString id() const override
Returns the unique ID for this renderer.
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.
@ FlagUsesFillSymbol
Renderer utilizes the scalebar fill symbol (see QgsScaleBarSettings::fillSymbol() )
@ FlagRespectsMapUnitsPerScaleBarUnit
Renderer respects the QgsScaleBarSettings::mapUnitsPerScaleBarUnit() setting.
@ FlagRespectsUnits
Renderer respects the QgsScaleBarSettings::units() setting.
@ FlagUsesAlternateFillSymbol
Renderer utilizes the alternate scalebar fill symbol (see QgsScaleBarSettings::alternateFillSymbol() ...
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).
void setAlternateFillSymbol(QgsFillSymbol *symbol)
Sets the secondary fill symbol used to render the scalebar (only used for some scalebar types).
void setFillSymbol(QgsFillSymbol *symbol)
Sets the primary fill 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.
QgsFillSymbol * alternateFillSymbol() const
Returns the secondary fill symbol used to render the scalebar (only used for some scalebar types).
QgsFillSymbol * fillSymbol() const
Returns the primary fill symbol used to render the scalebar (only used for some scalebar types).
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).
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.