KisScreentoneScreentoneFunctions::DotsEllipseLinearEqualized Class Reference

#include <KisScreentoneScreentoneFunctions.h>

Inheritance diagram for KisScreentoneScreentoneFunctions::DotsEllipseLinearEqualized:

Public Member Functions
qreal	operator() (qreal x, qreal y) const
Public Member Functions inherited from KisScreentoneScreentoneFunctions::DotsEllipseLinear
qreal	operator() (qreal x, qreal y) const

Detailed Description

Definition at line 101 of file KisScreentoneScreentoneFunctions.h.

Member Function Documentation

operator()()

qreal KisScreentoneScreentoneFunctions::DotsEllipseLinearEqualized::operator()	(	qreal	x,
		qreal	y ) const

Definition at line 93 of file KisScreentoneScreentoneFunctions.cpp.

{
    // In theory, the cumulative function for this spot function is:
    // "coverage = area of the intersection between the elliptical disk formed
    // by the value, and the screen cell".
    // This uses a piecewise cumulative function obtained analytically. First,
    // the area of the elliptical disk is obtained. If the value is greater than
    // "0.625" (value at which the elliptical disk touches the left and right
    // screen cell borders) then the area of the left and right elliptical
    // chords is subtracted; and if the value is greater than "0.78125" then the
    // area of the top and bottom elliptical chords is also subtracted
    const qreal z = DotsEllipseLinear::operator()(x, y);
    constexpr qreal factor = 0.625;
    constexpr qreal factorTimes2 = factor * 2.0;
    const qreal zOverFactorTimes2 = z / factorTimes2;
    const qreal zTimesPoint8OverFactorTimes2 = 0.8 * zOverFactorTimes2;
    qreal result = M_PI * zOverFactorTimes2 * zTimesPoint8OverFactorTimes2;
    if (z > 0.625) {
        const qreal zOverFactorTimes2Squared = zOverFactorTimes2 * zOverFactorTimes2;
        result -= 2.0 * (zOverFactorTimes2Squared * std::acos(factor / z) -
                         0.5 * std::sqrt(zOverFactorTimes2Squared - 0.25)) * 0.8;
    }
    if (z > 0.78125) {
        const qreal zTimesPoint8OverFactorTimes2Squared =
            zTimesPoint8OverFactorTimes2 * zTimesPoint8OverFactorTimes2;
        result -= 2.0 * (zTimesPoint8OverFactorTimes2Squared * std::acos(factor / (0.8 * z)) -
                         0.5 * std::sqrt(zTimesPoint8OverFactorTimes2Squared - 0.25)) / 0.8;
    }
    return result;
}

References M_PI, and KisScreentoneScreentoneFunctions::DotsEllipseLinear::operator()().

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The documentation for this class was generated from the following files:

• plugins/generators/screentone/KisScreentoneScreentoneFunctions.h
• plugins/generators/screentone/KisScreentoneScreentoneFunctions.cpp