| 1 | // Copyright (C) 2024 The Qt Company Ltd. |
|---|---|
| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only |
| 3 | |
| 4 | #include "qcolorutil_p.h" |
| 5 | |
| 6 | #include <QtGui/qcolor.h> |
| 7 | #include <QtGui/qvector3d.h> |
| 8 | #include <cmath> |
| 9 | |
| 10 | QT_BEGIN_NAMESPACE |
| 11 | |
| 12 | namespace { |
| 13 | |
| 14 | // Poor man's RGB to YUV conversion with BT.709 coefficients |
| 15 | // from https://en.wikipedia.org/wiki/Y%E2%80%B2UV |
| 16 | QVector3D RGBToYUV(const QColor &c) |
| 17 | { |
| 18 | const float R = c.redF(); |
| 19 | const float G = c.greenF(); |
| 20 | const float B = c.blueF(); |
| 21 | QVector3D yuv; |
| 22 | yuv[0] = 0.2126f * R + 0.7152f * G + 0.0722f * B; |
| 23 | yuv[1] = -0.09991f * R - 0.33609f * G + 0.436f * B; |
| 24 | yuv[2] = 0.615f * R - 0.55861f * G - 0.05639f * B; |
| 25 | return yuv; |
| 26 | } |
| 27 | |
| 28 | } // namespace |
| 29 | |
| 30 | bool fuzzyCompare(const QColor &lhs, const QColor &rhs, float tol) |
| 31 | { |
| 32 | const QVector3D lhsYuv = RGBToYUV(c: lhs); |
| 33 | const QVector3D rhsYuv = RGBToYUV(c: rhs); |
| 34 | const float relativeLumaDiff = |
| 35 | 0.5f * std::abs(x: (lhsYuv[0] - rhsYuv[0]) / (lhsYuv[0] + rhsYuv[0])); |
| 36 | const float colorDiff = QVector3D::crossProduct(v1: lhsYuv, v2: rhsYuv).length(); |
| 37 | return colorDiff < tol && relativeLumaDiff < tol; |
| 38 | } |
| 39 | |
| 40 | QT_END_NAMESPACE |
| 41 |