QGIS API Documentation 3.28.0-Firenze (ed3ad0430f)
qgshistogramdiagram.cpp
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1/***************************************************************************
2 qgshistogramdiagram.cpp
3 ---------------------
4 begin : August 2012
5 copyright : (C) 2012 by Matthias Kuhn
6 email : matthias at opengis dot ch
7 ***************************************************************************
8 * *
9 * This program is free software; you can redistribute it and/or modify *
10 * it under the terms of the GNU General Public License as published by *
11 * the Free Software Foundation; either version 2 of the License, or *
12 * (at your option) any later version. *
13 * *
14 ***************************************************************************/
15#include "qgshistogramdiagram.h"
16#include "qgsdiagramrenderer.h"
17#include "qgsrendercontext.h"
18#include "qgsexpression.h"
19#include "qgssymbollayerutils.h"
20#include "qgslinesymbol.h"
21
22#include <QPainter>
23
25{
26 mCategoryBrush.setStyle( Qt::SolidPattern );
27 mPen.setStyle( Qt::SolidLine );
28 mScaleFactor = 0;
29}
30
32{
33 return new QgsHistogramDiagram( *this );
34}
35
37{
38 QSizeF size;
39 if ( feature.attributes().isEmpty() )
40 {
41 return size; //zero size if no attributes
42 }
43
44 if ( qgsDoubleNear( is.upperValue, is.lowerValue ) )
45 return size; // invalid value range => zero size
46
47 double maxValue = 0;
48
49 QgsExpressionContext expressionContext = c.expressionContext();
50 expressionContext.setFeature( feature );
51 if ( !feature.fields().isEmpty() )
52 expressionContext.setFields( feature.fields() );
53
54 for ( const QString &cat : std::as_const( s.categoryAttributes ) )
55 {
56 QgsExpression *expression = getExpression( cat, expressionContext );
57 maxValue = std::max( expression->evaluate( &expressionContext ).toDouble(), maxValue );
58 }
59
60 // Scale, if extension is smaller than the specified minimum
61 if ( maxValue < s.minimumSize )
62 {
63 maxValue = s.minimumSize;
64 }
65
66 // eh - this method returns size in unknown units ...! We'll have to fake it and use a rough estimation of
67 // a conversion factor to painter units...
68 // TODO QGIS 4.0 -- these methods should all use painter units, dependent on the render context scaling...
69 double painterUnitConversionScale = c.convertToPainterUnits( 1, s.sizeType );
70
71 const double spacing = c.convertToPainterUnits( s.spacing(), s.spacingUnit(), s.spacingMapUnitScale() ) / painterUnitConversionScale;
72
73 switch ( s.diagramOrientation )
74 {
77 mScaleFactor = ( ( is.upperSize.width() - is.lowerSize.height() ) / ( is.upperValue - is.lowerValue ) );
78 size.scale( s.barWidth * s.categoryAttributes.size() + spacing * std::max( 0, static_cast<int>( s.categoryAttributes.size() ) - 1 ), maxValue * mScaleFactor, Qt::IgnoreAspectRatio );
79 break;
80
83 mScaleFactor = ( ( is.upperSize.width() - is.lowerSize.width() ) / ( is.upperValue - is.lowerValue ) );
84 size.scale( maxValue * mScaleFactor, s.barWidth * s.categoryAttributes.size() + spacing * std::max( 0, static_cast<int>( s.categoryAttributes.size() ) - 1 ), Qt::IgnoreAspectRatio );
85 break;
86 }
87
88 if ( s.showAxis() && s.axisLineSymbol() )
89 {
90 const double maxBleed = QgsSymbolLayerUtils::estimateMaxSymbolBleed( s.axisLineSymbol(), c ) / painterUnitConversionScale;
91 size.setWidth( size.width() + 2 * maxBleed );
92 size.setHeight( size.height() + 2 * maxBleed );
93 }
94
95 return size;
96}
97
99{
100 if ( qgsDoubleNear( is.upperValue, is.lowerValue ) )
101 return s.minimumSize; // invalid value range => zero size
102
103 // Scale, if extension is smaller than the specified minimum
104 if ( value < s.minimumSize )
105 {
106 value = s.minimumSize;
107 }
108
109 double scaleFactor = ( ( is.upperSize.width() - is.lowerSize.width() ) / ( is.upperValue - is.lowerValue ) );
110 return value * scaleFactor;
111}
112
114{
116}
117
119{
120 Q_UNUSED( c )
121 QSizeF size;
122
123 if ( attributes.isEmpty() )
124 {
125 return QSizeF(); //zero size if no attributes
126 }
127
128 double maxValue = attributes.at( 0 ).toDouble();
129
130 for ( int i = 0; i < attributes.count(); ++i )
131 {
132 maxValue = std::max( attributes.at( i ).toDouble(), maxValue );
133 }
134
135 // eh - this method returns size in unknown units ...! We'll have to fake it and use a rough estimation of
136 // a conversion factor to painter units...
137 // TODO QGIS 4.0 -- these methods should all use painter units, dependent on the render context scaling...
138 double painterUnitConversionScale = c.convertToPainterUnits( 1, s.sizeType );
139
140 const double spacing = c.convertToPainterUnits( s.spacing(), s.spacingUnit(), s.spacingMapUnitScale() ) / painterUnitConversionScale;
141
142 switch ( s.diagramOrientation )
143 {
146 mScaleFactor = maxValue / s.size.height();
147 size.scale( s.barWidth * s.categoryColors.size() + spacing * std::max( 0, static_cast<int>( s.categoryAttributes.size() ) - 1 ), s.size.height(), Qt::IgnoreAspectRatio );
148 break;
149
152 mScaleFactor = maxValue / s.size.width();
153 size.scale( s.size.width(), s.barWidth * s.categoryColors.size() + spacing * std::max( 0, static_cast<int>( s.categoryAttributes.size() ) - 1 ), Qt::IgnoreAspectRatio );
154 break;
155 }
156
157 if ( s.showAxis() && s.axisLineSymbol() )
158 {
159 const double maxBleed = QgsSymbolLayerUtils::estimateMaxSymbolBleed( s.axisLineSymbol(), c ) / painterUnitConversionScale;
160 size.setWidth( size.width() + 2 * maxBleed );
161 size.setHeight( size.height() + 2 * maxBleed );
162 }
163
164 return size;
165}
166
167void QgsHistogramDiagram::renderDiagram( const QgsFeature &feature, QgsRenderContext &c, const QgsDiagramSettings &s, QPointF position )
168{
169 QPainter *p = c.painter();
170 if ( !p )
171 {
172 return;
173 }
174
175 QList<double> values;
176 double maxValue = 0;
177
178 QgsExpressionContext expressionContext = c.expressionContext();
179 expressionContext.setFeature( feature );
180 if ( !feature.fields().isEmpty() )
181 expressionContext.setFields( feature.fields() );
182
183 values.reserve( s.categoryAttributes.size() );
184 for ( const QString &cat : std::as_const( s.categoryAttributes ) )
185 {
186 QgsExpression *expression = getExpression( cat, expressionContext );
187 double currentVal = expression->evaluate( &expressionContext ).toDouble();
188 values.push_back( currentVal );
189 maxValue = std::max( currentVal, maxValue );
190 }
191
192 double scaledMaxVal = sizePainterUnits( maxValue * mScaleFactor, s, c );
193
194 double currentOffset = 0;
195 double scaledWidth = sizePainterUnits( s.barWidth, s, c );
196
197 const double spacing = c.convertToPainterUnits( s.spacing(), s.spacingUnit(), s.spacingMapUnitScale() );
198
199 double baseX = position.x();
200 double baseY = position.y();
201
202 if ( s.showAxis() && s.axisLineSymbol() )
203 {
204 // if showing axis, the diagram position needs shifting from the default base x so that the axis
205 // line stroke sits within the desired label engine rect (otherwise we risk overlaps of the axis line stroke)
206 const double maxBleed = QgsSymbolLayerUtils::estimateMaxSymbolBleed( s.axisLineSymbol(), c );
207 baseX += maxBleed;
208 baseY -= maxBleed;
209 }
210
211
212 mPen.setColor( s.penColor );
213 setPenWidth( mPen, s, c );
214 p->setPen( mPen );
215
216 QList<double>::const_iterator valIt = values.constBegin();
217 QList< QColor >::const_iterator colIt = s.categoryColors.constBegin();
218 for ( ; valIt != values.constEnd(); ++valIt, ++colIt )
219 {
220 double length = sizePainterUnits( *valIt * mScaleFactor, s, c );
221
222 QColor brushColor( *colIt );
223 brushColor.setAlphaF( brushColor.alphaF() * s.opacity );
224 mCategoryBrush.setColor( brushColor );
225 p->setBrush( mCategoryBrush );
226
227 switch ( s.diagramOrientation )
228 {
230 p->drawRect( QRectF( baseX + currentOffset, baseY, scaledWidth, length * -1 ) );
231 break;
232
234 p->drawRect( QRectF( baseX + currentOffset, baseY - scaledMaxVal, scaledWidth, length ) );
235 break;
236
238 p->drawRect( QRectF( baseX, baseY - scaledWidth * values.size() - spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ) + currentOffset, length, scaledWidth ) );
239 break;
240
242 p->drawRect( QRectF( baseX + scaledMaxVal, baseY - scaledWidth * values.size() - spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ) + currentOffset, 0 - length, scaledWidth ) );
243 break;
244 }
245
246 currentOffset += scaledWidth + spacing;
247 }
248
249 if ( s.showAxis() && s.axisLineSymbol() )
250 {
252 QPolygonF axisPoints;
253 switch ( s.diagramOrientation )
254 {
256 axisPoints << QPointF( baseX, baseY - scaledMaxVal ) << QPointF( baseX, baseY ) << QPointF( baseX + scaledWidth * values.size() + spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ), baseY );
257 break;
258
260 axisPoints << QPointF( baseX, baseY ) << QPointF( baseX, baseY - scaledMaxVal ) << QPointF( baseX + scaledWidth * values.size() + spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ), baseY - scaledMaxVal );
261 break;
262
264 axisPoints << QPointF( baseX + scaledMaxVal, baseY - scaledWidth * values.size() - spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ) )
265 << QPointF( baseX, baseY - scaledWidth * values.size() - spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ) )
266 << QPointF( baseX, baseY );
267 break;
268
270 axisPoints << QPointF( baseX, baseY - scaledWidth * values.size() - spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ) )
271 << QPointF( baseX + scaledMaxVal, baseY - scaledWidth * values.size() - spacing * std::max( 0, static_cast<int>( values.size() ) - 1 ) )
272 << QPointF( baseX + scaledMaxVal, baseY );
273 break;
274 }
275
276 s.axisLineSymbol()->renderPolyline( axisPoints, nullptr, c );
278 }
279}
A vector of attributes.
Definition: qgsattributes.h:59
Additional diagram settings for interpolated size rendering.
Stores the settings for rendering a single diagram.
QgsUnitTypes::RenderUnit spacingUnit() const
Returns the units for the content spacing.
QgsUnitTypes::RenderUnit sizeType
Diagram size unit.
bool showAxis() const
Returns true if the diagram axis should be shown.
double opacity
Opacity, from 0 (transparent) to 1.0 (opaque)
QgsLineSymbol * axisLineSymbol() const
Returns the line symbol to use for rendering axis in diagrams.
QList< QString > categoryAttributes
DiagramOrientation diagramOrientation
double spacing() const
Returns the spacing between diagram contents.
QList< QColor > categoryColors
const QgsMapUnitScale & spacingMapUnitScale() const
Returns the map unit scale for the content spacing.
double minimumSize
Scale diagrams smaller than mMinimumSize to mMinimumSize.
void setPenWidth(QPen &pen, const QgsDiagramSettings &s, const QgsRenderContext &c)
Changes the pen width to match the current settings and rendering context.
Definition: qgsdiagram.cpp:49
QSizeF sizePainterUnits(QSizeF size, const QgsDiagramSettings &s, const QgsRenderContext &c)
Calculates a size to match the current settings and rendering context.
Definition: qgsdiagram.cpp:55
QgsExpression * getExpression(const QString &expression, const QgsExpressionContext &context)
Returns a prepared expression for the specified context.
Definition: qgsdiagram.cpp:38
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
void setFeature(const QgsFeature &feature)
Convenience function for setting a feature for the context.
void setFields(const QgsFields &fields)
Convenience function for setting a fields for the context.
Class for parsing and evaluation of expressions (formerly called "search strings").
QVariant evaluate()
Evaluate the feature and return the result.
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition: qgsfeature.h:56
QgsAttributes attributes
Definition: qgsfeature.h:65
QgsFields fields
Definition: qgsfeature.h:66
bool isEmpty() const
Checks whether the container is empty.
Definition: qgsfields.cpp:128
A histogram style diagram.
double legendSize(double value, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is) const override
Returns the size of the legend item for the diagram corresponding to a specified value.
QSizeF diagramSize(const QgsAttributes &attributes, const QgsRenderContext &c, const QgsDiagramSettings &s) override
Returns the size in map units the diagram will use to render.
QString diagramName() const override
Gets a descriptive name for this diagram type.
void renderDiagram(const QgsFeature &feature, QgsRenderContext &c, const QgsDiagramSettings &s, QPointF position) override
Draws the diagram at the given position (in pixel coordinates)
QgsHistogramDiagram * clone() const override
Returns an instance that is equivalent to this one.
void renderPolyline(const QPolygonF &points, const QgsFeature *f, QgsRenderContext &context, int layer=-1, bool selected=false)
Renders the symbol along the line joining points, using the given render context.
Contains information about the context of a rendering operation.
static double estimateMaxSymbolBleed(QgsSymbol *symbol, const QgsRenderContext &context)
Returns the maximum estimated bleed for the symbol.
void stopRender(QgsRenderContext &context)
Ends the rendering process.
Definition: qgssymbol.cpp:873
void startRender(QgsRenderContext &context, const QgsFields &fields=QgsFields())
Begins the rendering process for the symbol.
Definition: qgssymbol.cpp:825
As part of the API refactoring and improvements which landed in the Processing API was substantially reworked from the x version This was done in order to allow much of the underlying Processing framework to be ported into c
bool qgsDoubleNear(double a, double b, double epsilon=4 *std::numeric_limits< double >::epsilon())
Compare two doubles (but allow some difference)
Definition: qgis.h:2527
#define DIAGRAM_NAME_HISTOGRAM