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filling with gradients seems to work

This commit is contained in:
Uwe Rathmann 2024-06-04 18:17:07 +02:00
parent bf7fe7c8f3
commit 1a08de914a
2 changed files with 103 additions and 123 deletions
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11
playground/shadows/ShadowedArc.cpp
View File

@ -103,8 +103,15 @@ ShadowedArc::ShadowedArc( QQuickItem* parent )
//setFillColor( Qt::darkRed );
const QskGradient gradient( Qt::darkRed, Qt::darkYellow );
setGradientHint( Arc, gradient );
const QskGradientStops stops =
{
{ 0.1, Qt::darkRed },
{ 0.5, Qt::darkYellow },
{ 0.75, Qt::darkBlue },
{ 1.0, Qt::darkRed }
};
setGradientHint( Arc, stops );
setBorderWidth( 0 );
setBorderColor( Qt::gray );

169
src/nodes/QskArcRenderer.cpp
View File

@ -26,73 +26,6 @@ static inline QskVertex::ColoredLine* qskAllocateColoredLines(
return reinterpret_cast< QskVertex::ColoredLine* >( geometry.vertexData() );
}
namespace
{
/*
QskVertex::ArcIterator is slightly more efficient as it increments
cos/sin instead of doing the table lookups that are behind qFastCos/qFastSin.
For the moment we go with qFastCos/qFastSin, maybe later: TODO ...
*/
class AngleIterator
{
public:
AngleIterator( qreal radians1, qreal radians2, int stepCount );
inline void operator++() { increment(); }
void increment();
inline qreal cos() const { return m_cos; }
inline qreal sin() const { return m_sin; }
inline int step() const { return m_stepIndex; }
inline int stepCount() const { return m_stepCount; }
inline bool isDone() const { return m_stepIndex >= m_stepCount; }
inline qreal progress() const { return qreal( m_stepIndex ) / m_stepCount; }
private:
qreal m_cos;
qreal m_sin;
int m_stepIndex;
int m_stepCount;
const qreal m_radians1;
const qreal m_radians2;
const qreal m_radiansStep;
};
inline AngleIterator::AngleIterator( qreal radians1, qreal radians2, int stepCount )
: m_stepIndex( 0 )
, m_stepCount( stepCount )
, m_radians1( radians1 )
, m_radians2( radians2 )
, m_radiansStep( ( radians2 - radians1 ) / ( stepCount - 1 ) )
{
m_cos = qFastCos( radians1 );
m_sin = qFastSin( radians1 );
}
inline void AngleIterator::increment()
{
if ( ++m_stepIndex >= m_stepCount )
{
if ( m_stepIndex == m_stepCount )
{
m_cos = qFastCos( m_radians2 );
m_sin = qFastSin( m_radians2 );
}
}
else
{
const auto radians = m_radians1 + m_stepIndex * m_radiansStep;
m_cos = qFastCos( radians );
m_sin = qFastSin( radians );
}
}
}
namespace
{
class EllipseStroker
@ -109,6 +42,12 @@ namespace
private:
int arcLineCount() const;
qreal radiansAt( qreal progress ) const;
void setFillLine( const qreal radians,
const QskVertex::Color, QskVertex::ColoredLine& ) const;
const qreal m_extent;
// radius
const qreal m_rx;
@ -121,34 +60,33 @@ namespace
const qreal m_radians1;
const qreal m_radians2;
const qreal m_extent;
const QskGradient& m_gradient;
};
EllipseStroker::EllipseStroker( const QRectF& rect,
const QskArcMetrics& m, qreal borderWidth, const QskGradient& gradient )
: m_rx( 0.5 * rect.width() )
, m_ry( 0.5 * rect.height() )
, m_cx( rect.x() + m_rx )
, m_cy( rect.y() + m_ry )
: m_extent( 0.5 * ( m.thickness() - borderWidth ) )
, m_rx( 0.5 * rect.width() - m_extent )
, m_ry( 0.5 * rect.height() - m_extent )
, m_cx( rect.center().x() )
, m_cy( rect.center().y() )
, m_radians1( qDegreesToRadians( m.startAngle() ) )
, m_radians2( qDegreesToRadians( m.endAngle() ) )
, m_extent( 0.5 * ( m.thickness() - borderWidth ) )
, m_gradient( gradient )
{
}
int EllipseStroker::fillCount() const
{
return arcLineCount();
return arcLineCount() + m_gradient.stepCount() - 1;
}
int EllipseStroker::arcLineCount() const
{
// not very sophisticated - TODO ...
const auto radius = qMax( m_rx, m_ry );
const auto radius = qMax( m_rx, m_ry ) + m_extent; // outer border
const auto radians = qAbs( m_radians2 - m_radians1 );
const auto count = qCeil( ( radius * radians ) / 3.0 );
@ -169,19 +107,12 @@ namespace
return 0;
}
int EllipseStroker::setFillLines( QskVertex::ColoredLine* lines ) const
inline void EllipseStroker::setFillLine( const qreal radians,
const QskVertex::Color color, QskVertex::ColoredLine& line ) const
{
const auto w = m_rx - m_extent;
const auto h = m_ry - m_extent;
const auto aspectRatio = w / h;
const auto cos = qFastCos( radians );
const auto sin = qFastSin( radians );
auto l = lines;
const QskVertex::Color color1 = m_gradient.rgbStart();
const QskVertex::Color color2 = m_gradient.rgbEnd();
for ( AngleIterator it( m_radians1, m_radians2, arcLineCount() ); !it.isDone(); ++it )
{
/*
The inner/outer points are found by shifting orthogonally along the
ellipse tangent:
@ -200,32 +131,62 @@ namespace
qreal dx, dy;
if ( qFuzzyIsNull( it.cos() ) )
if ( qFuzzyIsNull( cos ) )
{
dx = 0.0;
dy = ( it.sin() > 0.0 ) ? m_extent : -m_extent;
dy = ( sin > 0.0 ) ? m_extent : -m_extent;
}
else
{
const qreal m = aspectRatio * ( it.sin() / it.cos() );
const qreal m = ( m_rx / m_ry ) * ( sin / cos );
const qreal t = m_extent / qSqrt( 1.0 + m * m );
dx = ( it.cos() >= 0.0 ) ? t : -t;
dx = ( cos >= 0.0 ) ? t : -t;
dy = m * dx;
}
const auto x = m_cx + w * it.cos();
const auto y = m_cy - h * it.sin();
const auto x = m_cx + m_rx * cos;
const auto y = m_cy - m_ry * sin;
auto color = color1;
if ( color1 != color2 )
color = color.interpolatedTo( color2, it.progress() );
line.setLine( x + dx, y - dy, x - dx, y + dy, color );
}
l++->setLine( x + dx, y - dy, x - dx, y + dy, color );
int EllipseStroker::setFillLines( QskVertex::ColoredLine* lines ) const
{
auto l = lines;
QskBoxRenderer::GradientIterator it;
if ( m_gradient.stepCount() <= 1 )
{
it.reset( m_gradient.rgbStart(), m_gradient.rgbEnd() );
}
else
{
it.reset( m_gradient.stops() );
it.advance(); // the first stop is always covered by the contour
}
const auto stepCount = arcLineCount();
const auto stepSize = ( m_radians2 - m_radians1 ) / ( stepCount - 1 );
for ( int i = 0; i < stepCount; i++ )
{
const auto progress = qreal( i ) / stepCount;
for ( ; it.position() < progress; it.advance() )
setFillLine( radiansAt( it.position() ), it.color(), *l++ );
const auto color = it.colorAt( progress );
setFillLine( m_radians1 + i * stepSize, color, *l++ );
}
return l - lines;
}
inline qreal EllipseStroker::radiansAt( qreal progress ) const
{
return m_radians1 + progress * ( m_radians2 - m_radians1 );
}
}
bool QskArcRenderer::isGradientSupported( const QskGradient& gradient )
@ -250,9 +211,21 @@ void QskArcRenderer::renderFillGeometry( const QRectF& rect,
if ( lines )
{
const auto effectiveCount = stroker.setFillLines( lines );
if ( lineCount != effectiveCount )
if ( effectiveCount > lineCount )
{
qWarning() << lineCount << effectiveCount;
qFatal( "geometry: allocated memory exceeded: %d vs. %d",
effectiveCount, lineCount );
}
if ( effectiveCount < lineCount )
{
/*
Gradient or contour lines might be at the same position
and we end up with less lines, than expected.
*/
for ( int i = effectiveCount; i < lineCount; i++ )
lines[i] = lines[i - 1];
}
}
}