charts: Clamp gradient color x between 0 and 1

Author: codeling

libs/charts/iAChartFunctionTransfer.cpp

@@ -63,7 +63,7 @@ void iAChartTransferFunction::draw(QPainter &painter, QColor color, int lineWidt
 	int y1 = opacity2PixelY(opacityTFValue[1]);
 
 	QColor c; c.setRgbF(colorTFValue[1], colorTFValue[2], colorTFValue[3], 0.588);
-	m_gradient.setColorAt(static_cast<double>(x1) / gradientWidth, c);
+	m_gradient.setColorAt(std::clamp(static_cast<double>(x1) / gradientWidth, 0.0, 1.0), c);
 
 	int lastX = x1;
 	for ( int i = 1; i < m_tf->opacityTF()->GetSize(); i++)
@@ -108,7 +108,7 @@ void iAChartTransferFunction::draw(QPainter &painter, QColor color, int lineWidt
 
 		painter.setPen(pen);
 		c.setRgbF(colorTFValue[1], colorTFValue[2], colorTFValue[3], 0.588);
-		m_gradient.setColorAt(static_cast<double>(x2) / gradientWidth, c);
+		m_gradient.setColorAt(std::clamp(static_cast<double>(x2) / gradientWidth, 0.0, 1.0), c);
 		x1 = x2;
 		y1 = y2;
 	}