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| |
| #ifndef QCOLORTRANSFERTABLE_P_H |
| #define QCOLORTRANSFERTABLE_P_H |
| |
| // |
| // W A R N I N G |
| // ------------- |
| // |
| // This file is not part of the Qt API. It exists purely as an |
| // implementation detail. This header file may change from version to |
| // version without notice, or even be removed. |
| // |
| // We mean it. |
| // |
| |
| #include <QtGui/private/qtguiglobal_p.h> |
| #include "qcolortransferfunction_p.h" |
| |
| #include <QVector> |
| #include <cmath> |
| |
| QT_BEGIN_NAMESPACE |
| |
| // Defines either an ICC TRC 'curve' or a lut8/lut16 A or B table |
| class Q_GUI_EXPORT QColorTransferTable |
| { |
| public: |
| QColorTransferTable() noexcept |
| : m_tableSize(0) |
| { } |
| QColorTransferTable(uint32_t size, const QVector<uint8_t> &table) noexcept |
| : m_tableSize(size) |
| , m_table8(table) |
| { } |
| QColorTransferTable(uint32_t size, const QVector<uint16_t> &table) noexcept |
| : m_tableSize(size) |
| , m_table16(table) |
| { } |
| |
| bool isValid() const |
| { |
| if (m_tableSize < 2) |
| return false; |
| |
| #if !defined(QT_NO_DEBUG) |
| // The table must describe an injective curve: |
| if (!m_table8.isEmpty()) { |
| uint8_t val = 0; |
| for (uint i = 0; i < m_tableSize; ++i) { |
| Q_ASSERT(m_table8[i] >= val); |
| val = m_table8[i]; |
| } |
| } |
| if (!m_table16.isEmpty()) { |
| uint16_t val = 0; |
| for (uint i = 0; i < m_tableSize; ++i) { |
| Q_ASSERT(m_table16[i] >= val); |
| val = m_table16[i]; |
| } |
| } |
| #endif |
| return !m_table8.isEmpty() || !m_table16.isEmpty(); |
| } |
| |
| float apply(float x) const |
| { |
| x = std::min(std::max(x, 0.0f), 1.0f); |
| x *= m_tableSize - 1; |
| uint32_t lo = (int)std::floor(x); |
| uint32_t hi = std::min(lo + 1, m_tableSize); |
| float frac = x - lo; |
| if (!m_table16.isEmpty()) |
| return (m_table16[lo] * (1.0f - frac) + m_table16[hi] * frac) * (1.0f/65535.0f); |
| if (!m_table8.isEmpty()) |
| return (m_table8[lo] * (1.0f - frac) + m_table8[hi] * frac) * (1.0f/255.0f); |
| return x; |
| } |
| |
| // Apply inverse, optimized by giving a previous result a value < x. |
| float applyInverse(float x, float resultLargerThan = 0.0f) const |
| { |
| Q_ASSERT(resultLargerThan >= 0.0f && resultLargerThan <= 1.0f); |
| if (x <= 0.0f) |
| return 0.0f; |
| if (x >= 1.0f) |
| return 1.0f; |
| if (!m_table16.isEmpty()) { |
| float v = x * 65535.0f; |
| uint i = std::floor(resultLargerThan * (m_tableSize - 1)) + 1; |
| for ( ; i < m_tableSize; ++i) { |
| if (m_table16[i] > v) |
| break; |
| } |
| if (i >= m_tableSize - 1) |
| return 1.0f; |
| float y1 = m_table16[i - 1]; |
| float y2 = m_table16[i]; |
| Q_ASSERT(x >= y1 && x < y2); |
| float fr = (v - y1) / (y2 - y1); |
| return (i + fr) * (1.0f / (m_tableSize - 1)); |
| |
| } |
| if (!m_table8.isEmpty()) { |
| float v = x * 255.0f; |
| uint i = std::floor(resultLargerThan * (m_tableSize - 1)) + 1; |
| for ( ; i < m_tableSize; ++i) { |
| if (m_table8[i] > v) |
| break; |
| } |
| if (i >= m_tableSize - 1) |
| return 1.0f; |
| float y1 = m_table8[i - 1]; |
| float y2 = m_table8[i]; |
| Q_ASSERT(x >= y1 && x < y2); |
| float fr = (v - y1) / (y2 - y1); |
| return (i + fr) * (1.0f / (m_tableSize - 1)); |
| } |
| return x; |
| } |
| |
| bool asColorTransferFunction(QColorTransferFunction *transferFn) |
| { |
| Q_ASSERT(isValid()); |
| Q_ASSERT(transferFn); |
| if (!m_table8.isEmpty() && (m_table8[0] != 0 || m_table8[m_tableSize - 1] != 255)) |
| return false; |
| if (!m_table16.isEmpty() && (m_table16[0] != 0 || m_table16[m_tableSize - 1] != 65535)) |
| return false; |
| if (m_tableSize == 2) { |
| *transferFn = QColorTransferFunction(); // Linear |
| return true; |
| } |
| // The following heuristics are based on those from Skia: |
| if (m_tableSize == 26 && !m_table16.isEmpty()) { |
| // code.facebook.com/posts/411525055626587/under-the-hood-improving-facebook-photos |
| if (m_table16[6] != 3062) |
| return false; |
| if (m_table16[12] != 12824) |
| return false; |
| if (m_table16[18] != 31237) |
| return false; |
| *transferFn = QColorTransferFunction::fromSRgb(); |
| return true; |
| } |
| if (m_tableSize == 1024 && !m_table16.isEmpty()) { |
| // HP and Canon sRGB gamma tables: |
| if (m_table16[257] != 3366) |
| return false; |
| if (m_table16[513] != 14116) |
| return false; |
| if (m_table16[768] != 34318) |
| return false; |
| *transferFn = QColorTransferFunction::fromSRgb(); |
| return true; |
| } |
| if (m_tableSize == 4096 && !m_table16.isEmpty()) { |
| // Nikon, Epson, and lcms2 sRGB gamma tables: |
| if (m_table16[515] != 960) |
| return false; |
| if (m_table16[1025] != 3342) |
| return false; |
| if (m_table16[2051] != 14079) |
| return false; |
| *transferFn = QColorTransferFunction::fromSRgb(); |
| return true; |
| } |
| return false; |
| } |
| friend inline bool operator!=(const QColorTransferTable &t1, const QColorTransferTable &t2); |
| friend inline bool operator==(const QColorTransferTable &t1, const QColorTransferTable &t2); |
| |
| uint32_t m_tableSize; |
| QVector<uint8_t> m_table8; |
| QVector<uint16_t> m_table16; |
| }; |
| |
| inline bool operator!=(const QColorTransferTable &t1, const QColorTransferTable &t2) |
| { |
| if (t1.m_tableSize != t2.m_tableSize) |
| return true; |
| if (t1.m_table8.isEmpty() != t2.m_table8.isEmpty()) |
| return true; |
| if (t1.m_table16.isEmpty() != t2.m_table16.isEmpty()) |
| return true; |
| if (!t1.m_table8.isEmpty()) { |
| for (quint32 i = 0; i < t1.m_tableSize; ++i) { |
| if (t1.m_table8[i] != t2.m_table8[i]) |
| return true; |
| } |
| } |
| if (!t1.m_table16.isEmpty()) { |
| for (quint32 i = 0; i < t1.m_tableSize; ++i) { |
| if (t1.m_table16[i] != t2.m_table16[i]) |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| inline bool operator==(const QColorTransferTable &t1, const QColorTransferTable &t2) |
| { |
| return !(t1 != t2); |
| } |
| |
| QT_END_NAMESPACE |
| |
| #endif // QCOLORTRANSFERTABLE_P_H |
