1 files changed, 126 insertions, 0 deletions
diff --git a/src/gui/painting/qrgbafloat.h b/src/gui/painting/qrgbafloat.h
new file mode 100644
index 0000000000..da74328f71
--- /dev/null
+++ b/src/gui/painting/qrgbafloat.h
@@ -0,0 +1,126 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef QRGBAFLOAT_H
+#define QRGBAFLOAT_H
+
+#include <QtGui/qtguiglobal.h>
+#include <QtCore/qfloat16.h>
+
+#include <algorithm>
+#include <cmath>
+#include <type_traits>
+
+QT_BEGIN_NAMESPACE
+
+template<typename F>
+class alignas(sizeof(F) * 4) QRgbaFloat
+{
+    static_assert(std::is_same<F, qfloat16>::value || std::is_same<F, float>::value);
+public:
+    using Type = F;
+#if defined(__AVX512FP16__) && QFLOAT16_IS_NATIVE
+    // AVX512FP16 has multiplication instructions
+    using FastType = F;
+#else
+    // use FP32 for multiplications
+    using FastType = float;
+#endif
+    F r;
+    F g;
+    F b;
+    F a;
+
+    static constexpr
+    QRgbaFloat fromRgba64(quint16 red, quint16 green, quint16 blue, quint16 alpha)
+    {
+        constexpr FastType scale = FastType(1.0f / 65535.0f);
+        return QRgbaFloat{
+            F(red    * scale),
+            F(green  * scale),
+            F(blue   * scale),
+            F(alpha  * scale) };
+    }
+
+    static constexpr
+    QRgbaFloat fromRgba(quint8 red, quint8 green, quint8 blue, quint8 alpha)
+    {
+        constexpr FastType scale = FastType(1.0f / 255.0f);
+        return QRgbaFloat{
+            F(red    * scale),
+            F(green  * scale),
+            F(blue   * scale),
+            F(alpha  * scale) };
+    }
+    static constexpr
+    QRgbaFloat fromArgb32(uint rgb)
+    {
+        return fromRgba(quint8(rgb >> 16), quint8(rgb >> 8), quint8(rgb), quint8(rgb >> 24));
+    }
+
+    constexpr bool isOpaque() const { return a >= FastType(1.0f); }
+    constexpr bool isTransparent() const { return a <= FastType(0.0f); }
+
+    constexpr float red()   const { return r; }
+    constexpr float green() const { return g; }
+    constexpr float blue()  const { return b; }
+    constexpr float alpha() const { return a; }
+    void setRed(float _red)     { r = F(_red); }
+    void setGreen(float _green) { g = F(_green); }
+    void setBlue(float _blue)   { b = F(_blue); }
+    void setAlpha(float _alpha) { a = F(_alpha); }
+
+    constexpr float redNormalized()   const { return clamp01(r); }
+    constexpr float greenNormalized() const { return clamp01(g); }
+    constexpr float blueNormalized()  const { return clamp01(b); }
+    constexpr float alphaNormalized() const { return clamp01(a); }
+
+    constexpr quint8 red8()   const { return qRound(redNormalized()   * FastType(255.0f)); }
+    constexpr quint8 green8() const { return qRound(greenNormalized() * FastType(255.0f)); }
+    constexpr quint8 blue8()  const { return qRound(blueNormalized()  * FastType(255.0f)); }
+    constexpr quint8 alpha8() const { return qRound(alphaNormalized() * FastType(255.0f)); }
+    constexpr uint toArgb32() const
+    {
+       return uint((alpha8() << 24) | (red8() << 16) | (green8() << 8) | blue8());
+    }
+
+    constexpr quint16 red16()   const { return qRound(redNormalized()   * FastType(65535.0f)); }
+    constexpr quint16 green16() const { return qRound(greenNormalized() * FastType(65535.0f)); }
+    constexpr quint16 blue16()  const { return qRound(blueNormalized()  * FastType(65535.0f)); }
+    constexpr quint16 alpha16() const { return qRound(alphaNormalized() * FastType(65535.0f)); }
+
+    constexpr Q_ALWAYS_INLINE QRgbaFloat premultiplied() const
+    {
+        return QRgbaFloat{r * a, g * a, b * a, a};
+    }
+    constexpr Q_ALWAYS_INLINE QRgbaFloat unpremultiplied() const
+    {
+        if (a <= F{0.0f})
+            return QRgbaFloat{};    // default-initialization: zeroes
+        if (a >= F{1.0f})
+            return *this;
+        const FastType ia = 1.0f / a;
+        return QRgbaFloat{F(r * ia), F(g * ia), F(b * ia), F(a)};
+    }
+    constexpr bool operator==(QRgbaFloat f) const
+    {
+        return r == f.r && g == f.g && b == f.b && a == f.a;
+    }
+    constexpr bool operator!=(QRgbaFloat f) const
+    {
+        return !(*this == f);
+    }
+
+private:
+    constexpr static FastType clamp01(Type f)
+    {
+        return std::clamp(FastType(f), FastType(0.0f), FastType(1.0f));
+    }
+};
+
+typedef QRgbaFloat<qfloat16> QRgbaFloat16;
+typedef QRgbaFloat<float> QRgbaFloat32;
+
+QT_END_NAMESPACE
+
+#endif // QRGBAFLOAT_H