Implement XEP-0392: Consisten Color Generation

LICENSES/MIT.txt

@@ -0,0 +1,18 @@
+MIT License
+
+Copyright (c) <year> <copyright holders>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and 
+associated documentation files (the "Software"), to deal in the Software without restriction, including 
+without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
+copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the 
+following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial 
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT 
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO 
+EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 
+USE OR OTHER DEALINGS IN THE SOFTWARE.

doc/doap.xml

@@ -611,6 +611,14 @@ SPDX-License-Identifier: CC0-1.0
         <xmpp:since>1.7</xmpp:since>
       </xmpp:SupportedXep>
     </implements>
+    <implements>
+      <xmpp:SupportedXep>
+        <xmpp:xep rdf:resource='https://xmpp.org/extensions/xep-0392.html'/>
+        <xmpp:status>complete</xmpp:status>
+        <xmpp:version>1.0.0</xmpp:version>
+        <xmpp:since>1.10</xmpp:since>
+      </xmpp:SupportedXep>
+    </implements>
     <implements>
       <xmpp:SupportedXep>
         <xmpp:xep rdf:resource='https://xmpp.org/extensions/xep-0405.html'/>

src/CMakeLists.txt

@@ -19,6 +19,7 @@ set(INSTALL_HEADER_FILES
     base/QXmppBitsOfBinaryIq.h
     base/QXmppBookmarkSet.h
     base/QXmppByteStreamIq.h
+    base/QXmppColorGeneration.h
     base/QXmppDataForm.h
     base/QXmppDataFormBase.h
     base/QXmppDiscoveryIq.h
@@ -174,6 +175,7 @@ set(SOURCE_FILES
     base/QXmppBitsOfBinaryIq.cpp
     base/QXmppBookmarkSet.cpp
     base/QXmppByteStreamIq.cpp
+    base/QXmppColorGeneration.cpp
     base/QXmppDataForm.cpp
     base/QXmppDataFormBase.cpp
     base/QXmppDiscoveryIq.cpp
@@ -237,6 +239,7 @@ set(SOURCE_FILES
     base/QXmppVCardIq.cpp
     base/QXmppVersionIq.cpp
     base/compat/removed_api.cpp
+    base/hsluv/hsluv.c
     # to trigger MOC
     base/XmppSocket.h
 

src/base/QXmppColorGeneration.cpp

@@ -0,0 +1,60 @@
+// SPDX-FileCopyrightText: 2019 Linus Jahn <[email protected]>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "QXmppColorGeneration.h"
+
+#include "hsluv/hsluv.h"
+
+#include <QCryptographicHash>
+
+using namespace QXmpp::Private;
+
+///
+/// \class QXmppColorGeneration
+///
+/// \brief Generates colors from strings as defined in \xep{0392, Consistent Color Generation}.
+///
+/// This way the colors are unique between different clients.
+///
+/// \since QXmpp 1.10
+///
+
+///
+/// Generates an RGB color triple for a string.
+///
+QXmppColorGeneration::Rgb QXmppColorGeneration::generateRgb(QStringView str)
+{
+    double hue = generateColorAngle(str);
+    double saturation = 100.0;
+    double lightness = 50.0;
+
+    // convert to rgb values (values are between 0.0 and 1.0)
+    double red, green, blue = 0.0;
+    hsluv2rgb(hue, saturation, lightness, &red, &green, &blue);
+
+    return Rgb { quint8(red * 255.0), quint8(green * 255.0), quint8(blue * 255.0) };
+}
+
+///
+/// \fn QXmppColorGeneration::generateColor
+///
+/// Generates a QColor for a string.
+///
+/// \note This is a header-only function and it is only available when building the application
+/// using QXmpp with the Qt GUI module.
+///
+
+double QXmpp::Private::generateColorAngle(QStringView str)
+{
+    QByteArray input = str.toUtf8();
+
+    // hash input through SHA-1
+    auto hashValue = QCryptographicHash::hash(str.toUtf8(), QCryptographicHash::Sha1);
+
+    // the first two bytes are used to calculate the angle/hue
+    auto hashData = reinterpret_cast<quint8 *>(hashValue.data());
+    int angle = hashData[0] + hashData[1] * 256;
+
+    return double(angle) / 65536.0 * 360.0;
+}

src/base/QXmppColorGeneration.h

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2019 Linus Jahn <[email protected]>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#ifndef QXMPPCOLORGENERATION_H
+#define QXMPPCOLORGENERATION_H
+
+#include "QXmppGlobal.h"
+
+#ifdef QT_GUI_LIB
+#include <QColor>
+#endif
+
+class QXMPP_EXPORT QXmppColorGeneration
+{
+public:
+    struct Rgb {
+        quint8 red;
+        quint8 green;
+        quint8 blue;
+    };
+
+    static Rgb generateRgb(QStringView str);
+
+#if defined(QT_GUI_LIB) || defined(QXMPP_DOC)
+    static QColor generateColor(QStringView str)
+    {
+        auto rgb = generateRgb(str);
+        return QColor(rgb.red, rgb.green, rgb.blue);
+    }
+#endif
+};
+
+namespace QXmpp::Private {
+double generateColorAngle(QStringView str);
+}
+
+#endif  // QXMPPCOLORGENERATION_H