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[FEATURE] allow starting/ending a gradient at a features centroid
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@nyalldawson
nyalldawson committed Nov 3, 2013
1 parent 8bdaf42 commit dfba26d
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Showing 13 changed files with 273 additions and 29 deletions.
8 changes: 6 additions & 2 deletions python/core/symbology-ng/qgsfillsymbollayerv2.sip
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Expand Up @@ -118,8 +118,6 @@ class QgsGradientFillSymbolLayerV2 : QgsFillSymbolLayerV2

QgsSymbolLayerV2* clone() const /Factory/;

//up to here

GradientType gradientType() const;
void setGradientType( GradientType gradientType );

Expand All @@ -140,9 +138,15 @@ class QgsGradientFillSymbolLayerV2 : QgsFillSymbolLayerV2

void setReferencePoint1( QPointF referencePoint );
QPointF referencePoint1() const;

void setReferencePoint1IsCentroid( bool isCentroid );
bool referencePoint1IsCentroid() const;

void setReferencePoint2( QPointF referencePoint );
QPointF referencePoint2() const;

void setReferencePoint2IsCentroid( bool isCentroid );
bool referencePoint2IsCentroid() const;

void setAngle( double angle );
double angle() const;
Expand Down
79 changes: 54 additions & 25 deletions src/core/symbology-ng/qgsfillsymbollayerv2.cpp
View file
Expand Up @@ -294,7 +294,9 @@ QgsGradientFillSymbolLayerV2::QgsGradientFillSymbolLayerV2( QColor color, QColor
mCoordinateMode( coordinateMode ),
mGradientSpread( spread ),
mReferencePoint1( QPointF( 0, 0 ) ),
mReferencePoint1IsCentroid( false ),
mReferencePoint2( QPointF( 1, 1 ) ),
mReferencePoint2IsCentroid( false ),
mAngle( 0 ),
mOffsetUnit( QgsSymbolV2::MM )
{
Expand All @@ -317,7 +319,9 @@ QgsSymbolLayerV2* QgsGradientFillSymbolLayerV2::create( const QgsStringMap& prop
//default to gradient from the default fill color to white
QColor color = DEFAULT_SIMPLEFILL_COLOR, color2 = Qt::white;
QPointF referencePoint1 = QPointF( 0, 0 );
bool refPoint1IsCentroid = false;
QPointF referencePoint2 = QPointF( 1, 1 );
bool refPoint2IsCentroid = false;
double angle = 0;
QPointF offset;

Expand All @@ -336,8 +340,12 @@ QgsSymbolLayerV2* QgsGradientFillSymbolLayerV2::create( const QgsStringMap& prop
color2 = QgsSymbolLayerV2Utils::decodeColor( props["gradient_color2"] );
if ( props.contains( "reference_point1" ) )
referencePoint1 = QgsSymbolLayerV2Utils::decodePoint( props["reference_point1"] );
if ( props.contains( "reference_point1_iscentroid" ) )
refPoint1IsCentroid = props["reference_point1_iscentroid"].toInt();
if ( props.contains( "reference_point2" ) )
referencePoint2 = QgsSymbolLayerV2Utils::decodePoint( props["reference_point2"] );
if ( props.contains( "reference_point2_iscentroid" ) )
refPoint2IsCentroid = props["reference_point2_iscentroid"].toInt();
if ( props.contains( "angle" ) )
angle = props["angle"].toDouble();
if ( props.contains( "offset" ) )
Expand All @@ -352,7 +360,9 @@ QgsSymbolLayerV2* QgsGradientFillSymbolLayerV2::create( const QgsStringMap& prop
if ( props.contains( "offset_unit" ) )
sl->setOffsetUnit( QgsSymbolLayerV2Utils::decodeOutputUnit( props["offset_unit"] ) );
sl->setReferencePoint1( referencePoint1 );
sl->setReferencePoint1IsCentroid( refPoint1IsCentroid );
sl->setReferencePoint2( referencePoint2 );
sl->setReferencePoint2IsCentroid( refPoint2IsCentroid );
sl->setAngle( angle );
if ( gradientRamp )
sl->setColorRamp( gradientRamp );
Expand All @@ -374,10 +384,14 @@ QgsSymbolLayerV2* QgsGradientFillSymbolLayerV2::create( const QgsStringMap& prop
sl->setDataDefinedProperty( "reference1_x", props["reference1_x_expression"] );
if ( props.contains( "reference1_y_expression" ) )
sl->setDataDefinedProperty( "reference1_y", props["reference1_y_expression"] );
if ( props.contains( "reference1_iscentroid_expression" ) )
sl->setDataDefinedProperty( "reference1_iscentroid", props["reference1_iscentroid_expression"] );
if ( props.contains( "reference2_x_expression" ) )
sl->setDataDefinedProperty( "reference2_x", props["reference2_x_expression"] );
if ( props.contains( "reference2_y_expression" ) )
sl->setDataDefinedProperty( "reference2_y", props["reference2_y_expression"] );
if ( props.contains( "reference2_iscentroid_expression" ) )
sl->setDataDefinedProperty( "reference2_iscentroid", props["reference2_iscentroid_expression"] );

return sl;
}
Expand All @@ -393,7 +407,7 @@ QString QgsGradientFillSymbolLayerV2::layerType() const
return "GradientFill";
}

void QgsGradientFillSymbolLayerV2::applyDataDefinedSymbology( QgsSymbolV2RenderContext& context )
void QgsGradientFillSymbolLayerV2::applyDataDefinedSymbology( QgsSymbolV2RenderContext& context, const QPolygonF& points )
{
//first gradient color
QgsExpression* colorExpression = expression( "color" );
Expand Down Expand Up @@ -493,6 +507,10 @@ void QgsGradientFillSymbolLayerV2::applyDataDefinedSymbology( QgsSymbolV2RenderC
double refPoint1Y = mReferencePoint1.y();
if ( ref1YExpression )
refPoint1Y = ref1YExpression->evaluate( const_cast<QgsFeature*>( context.feature() ) ).toDouble();
QgsExpression* ref1IsCentroidExpression = expression( "reference1_iscentroid" );
bool refPoint1IsCentroid = mReferencePoint1IsCentroid;
if ( ref1IsCentroidExpression )
refPoint1IsCentroid = ref1IsCentroidExpression->evaluate( const_cast<QgsFeature*>( context.feature() ) ).toBool();

//reference point 2 x & y
QgsExpression* ref2XExpression = expression( "reference2_x" );
Expand All @@ -503,6 +521,31 @@ void QgsGradientFillSymbolLayerV2::applyDataDefinedSymbology( QgsSymbolV2RenderC
double refPoint2Y = mReferencePoint2.y();
if ( ref2YExpression )
refPoint2Y = ref2YExpression->evaluate( const_cast<QgsFeature*>( context.feature() ) ).toDouble();
QgsExpression* ref2IsCentroidExpression = expression( "reference2_iscentroid" );
bool refPoint2IsCentroid = mReferencePoint2IsCentroid;
if ( ref2IsCentroidExpression )
refPoint2IsCentroid = ref2IsCentroidExpression->evaluate( const_cast<QgsFeature*>( context.feature() ) ).toBool();

if ( refPoint1IsCentroid || refPoint2IsCentroid )
{
//either the gradient is starting or ending at a centroid, so calculate it
QPointF centroid = QgsSymbolLayerV2Utils::polygonCentroid( points );
//centroid coordinates need to be scaled to a range [0, 1] relative to polygon bounds
QRectF bbox = points.boundingRect();
double centroidX = ( centroid.x() - bbox.left() ) / bbox.width();
double centroidY = ( centroid.y() - bbox.top() ) / bbox.height();

if ( refPoint1IsCentroid )
{
refPoint1X = centroidX;
refPoint1Y = centroidY;
}
if ( refPoint2IsCentroid )
{
refPoint2X = centroidX;
refPoint2Y = centroidY;
}
}

//update gradient with data defined values
applyGradient( context, mBrush, color, color2, mGradientColorType, mGradientRamp, gradientType, coordinateMode,
Expand Down Expand Up @@ -545,8 +588,8 @@ void QgsGradientFillSymbolLayerV2::applyGradient( const QgsSymbolV2RenderContext
fillColor2.setAlphaF( context.alpha() * fillColor2.alphaF() );

//rotate reference points
QPointF rotatedReferencePoint1 = rotateReferencePoint( referencePoint1, angle );
QPointF rotatedReferencePoint2 = rotateReferencePoint( referencePoint2, angle );
QPointF rotatedReferencePoint1 = angle != 0 ? rotateReferencePoint( referencePoint1, angle ) : referencePoint1;
QPointF rotatedReferencePoint2 = angle != 0 ? rotateReferencePoint( referencePoint2, angle ) : referencePoint2;

//create a QGradient with the desired properties
QGradient gradient;
Expand Down Expand Up @@ -604,14 +647,11 @@ void QgsGradientFillSymbolLayerV2::applyGradient( const QgsSymbolV2RenderContext

void QgsGradientFillSymbolLayerV2::startRender( QgsSymbolV2RenderContext& context )
{
//update mBrush to use a gradient fill with specified properties
applyGradient( context, mBrush, mColor, mColor2, mGradientColorType, mGradientRamp, mGradientType, mCoordinateMode,
mGradientSpread, mReferencePoint1, mReferencePoint2, mAngle );

QColor selColor = context.renderContext().selectionColor();
if ( ! selectionIsOpaque ) selColor.setAlphaF( context.alpha() );
mSelBrush = QBrush( selColor );

//update mBrush to use a gradient fill with specified properties
prepareExpressions( context.layer() );
}

Expand All @@ -629,7 +669,7 @@ void QgsGradientFillSymbolLayerV2::renderPolygon( const QPolygonF& points, QList
}

QPen mSelPen;
applyDataDefinedSymbology( context );
applyDataDefinedSymbology( context, points );

p->setBrush( context.selected() ? mSelBrush : mBrush );
p->setPen( QPen( Qt::NoPen ) );
Expand Down Expand Up @@ -660,7 +700,9 @@ QgsStringMap QgsGradientFillSymbolLayerV2::properties() const
map["coordinate_mode"] = QString::number( mCoordinateMode );
map["spread"] = QString::number( mGradientSpread );
map["reference_point1"] = QgsSymbolLayerV2Utils::encodePoint( mReferencePoint1 );
map["reference_point1_iscentroid"] = QString::number( mReferencePoint1IsCentroid );
map["reference_point2"] = QgsSymbolLayerV2Utils::encodePoint( mReferencePoint2 );
map["reference_point2_iscentroid"] = QString::number( mReferencePoint2IsCentroid );
map["angle"] = QString::number( mAngle );
map["offset"] = QgsSymbolLayerV2Utils::encodePoint( mOffset );
map["offset_unit"] = QgsSymbolLayerV2Utils::encodeOutputUnit( mOffsetUnit );
Expand All @@ -678,7 +720,9 @@ QgsSymbolLayerV2* QgsGradientFillSymbolLayerV2::clone() const
if ( mGradientRamp )
sl->setColorRamp( mGradientRamp->clone() );
sl->setReferencePoint1( mReferencePoint1 );
sl->setReferencePoint1IsCentroid( mReferencePoint1IsCentroid );
sl->setReferencePoint2( mReferencePoint2 );
sl->setReferencePoint2IsCentroid( mReferencePoint2IsCentroid );
sl->setAngle( mAngle );
sl->setOffset( mOffset );
sl->setOffsetUnit( mOffsetUnit );
Expand Down Expand Up @@ -2045,23 +2089,8 @@ void QgsCentroidFillSymbolLayerV2::renderPolygon( const QPolygonF& points, QList
{
Q_UNUSED( rings );

// calculate centroid
double cx = 0, cy = 0;
double area, sum = 0;
for ( int i = points.count() - 1, j = 0; j < points.count(); i = j++ )
{
const QPointF& p1 = points[i];
const QPointF& p2 = points[j];
area = p1.x() * p2.y() - p1.y() * p2.x();
sum += area;
cx += ( p1.x() + p2.x() ) * area;
cy += ( p1.y() + p2.y() ) * area;
}
sum *= 3.0;
cx /= sum;
cy /= sum;

mMarker->renderPoint( QPointF( cx, cy ), context.feature(), context.renderContext(), -1, context.selected() );
QPointF centroid = QgsSymbolLayerV2Utils::polygonCentroid( points );
mMarker->renderPoint( centroid, context.feature(), context.renderContext(), -1, context.selected() );
}

QgsStringMap QgsCentroidFillSymbolLayerV2::properties() const
Expand Down
12 changes: 11 additions & 1 deletion src/core/symbology-ng/qgsfillsymbollayerv2.h
View file
Expand Up @@ -188,10 +188,18 @@ class CORE_EXPORT QgsGradientFillSymbolLayerV2 : public QgsFillSymbolLayerV2
void setReferencePoint1( QPointF referencePoint ) { mReferencePoint1 = referencePoint; };
QPointF referencePoint1() const { return mReferencePoint1; };

/**Sets the starting point of the gradient to be the feature centroid*/
void setReferencePoint1IsCentroid( bool isCentroid ) { mReferencePoint1IsCentroid = isCentroid; };
bool referencePoint1IsCentroid() const { return mReferencePoint1IsCentroid; };

/**End point of gradient fill, in the range [0,0] - [1,1]*/
void setReferencePoint2( QPointF referencePoint ) { mReferencePoint2 = referencePoint; };
QPointF referencePoint2() const { return mReferencePoint2; };

/**Sets the end point of the gradient to be the feature centroid*/
void setReferencePoint2IsCentroid( bool isCentroid ) { mReferencePoint2IsCentroid = isCentroid; };
bool referencePoint2IsCentroid() const { return mReferencePoint2IsCentroid; };

/**Rotation angle for gradient fill. Can be used to rotate a gradient around its centre point*/
void setAngle( double angle ) { mAngle = angle; };
double angle() const { return mAngle; };
Expand All @@ -216,7 +224,9 @@ class CORE_EXPORT QgsGradientFillSymbolLayerV2 : public QgsFillSymbolLayerV2
GradientSpread mGradientSpread;

QPointF mReferencePoint1;
bool mReferencePoint1IsCentroid;
QPointF mReferencePoint2;
bool mReferencePoint2IsCentroid;
double mAngle;

QPointF mOffset;
Expand All @@ -225,7 +235,7 @@ class CORE_EXPORT QgsGradientFillSymbolLayerV2 : public QgsFillSymbolLayerV2
private:

//helper functions for data defined symbology
void applyDataDefinedSymbology( QgsSymbolV2RenderContext& context );
void applyDataDefinedSymbology( QgsSymbolV2RenderContext& context, const QPolygonF& points );

/**Applies the gradient to a brush*/
void applyGradient( const QgsSymbolV2RenderContext& context, QBrush& brush, const QColor& color, const QColor& color2,
Expand Down
22 changes: 22 additions & 0 deletions src/core/symbology-ng/qgssymbollayerv2utils.cpp
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Expand Up @@ -2925,3 +2925,25 @@ QString QgsSymbolLayerV2Utils::symbolPathToName( QString path )
return QgsProject::instance()->writePath( path );
}

QPointF QgsSymbolLayerV2Utils::polygonCentroid( const QPolygonF& points )
{
//Calculate the centroid of points
double cx = 0, cy = 0;
double area, sum = 0;
for ( int i = points.count() - 1, j = 0; j < points.count(); i = j++ )
{
const QPointF& p1 = points[i];
const QPointF& p2 = points[j];
area = p1.x() * p2.y() - p1.y() * p2.x();
sum += area;
cx += ( p1.x() + p2.x() ) * area;
cy += ( p1.y() + p2.y() ) * area;
}
sum *= 3.0;
cx /= sum;
cy /= sum;

return QPointF( cx, cy );
}


3 changes: 3 additions & 0 deletions src/core/symbology-ng/qgssymbollayerv2utils.h
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Expand Up @@ -243,6 +243,9 @@ class CORE_EXPORT QgsSymbolLayerV2Utils

//! Get symbols's name from its path
static QString symbolPathToName( QString path );

//! Calculate the centroid point of a QPolygonF
static QPointF polygonCentroid( const QPolygonF& points );
};

class QPolygonF;
Expand Down
5 changes: 5 additions & 0 deletions src/gui/symbology-ng/qgsdatadefinedsymboldialog.cpp
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Expand Up @@ -208,4 +208,9 @@ QString QgsDataDefinedSymbolDialog::gradientSpreadHelpText()
return tr( "'pad'|'repeat'|'reflect'" );
}

QString QgsDataDefinedSymbolDialog::boolHelpText()
{
return tr( "0 (false)|1 (true)" );
}


1 change: 1 addition & 0 deletions src/gui/symbology-ng/qgsdatadefinedsymboldialog.h
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Expand Up @@ -38,6 +38,7 @@ class GUI_EXPORT QgsDataDefinedSymbolDialog: public QDialog, private Ui::QgsData
static QString gradientTypeHelpText();
static QString gradientCoordModeHelpText();
static QString gradientSpreadHelpText();
static QString boolHelpText();

private slots:
void expressionButtonClicked();
Expand Down

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