user details dialog fixes

src/utils.h

@@ -3,9 +3,14 @@
 
 #pragma once
 
+#include <QColor>
+#include <QGuiApplication>
+#include <QPalette>
 #include <QQmlEngine>
 #include <QRegularExpression>
 
+#include <Quotient/user.h>
+
 class QmlUtils : public QObject
 {
     Q_OBJECT
@@ -26,11 +31,30 @@ public:
     }
 
     Q_INVOKABLE bool isValidJson(const QByteArray &json);
+    Q_INVOKABLE QString escapeString(const QString &string);
+    Q_INVOKABLE QColor getUserColor(qreal hueF);
 
 private:
     QmlUtils() = default;
 };
 
+namespace Utils
+{
+
+/**
+ * @brief Get a color for a user from a hueF value.
+ *
+ * The lightness of the color will be modified depending on the current palette in
+ * order to maintain contrast.
+ */
+inline QColor getUserColor(qreal hueF)
+{
+    const auto lightness = static_cast<QGuiApplication *>(QGuiApplication::instance())->palette().color(QPalette::Active, QPalette::Window).lightnessF();
+    // https://github.com/quotient-im/libQuotient/wiki/User-color-coding-standard-draft-proposal
+    return QColor::fromHslF(hueF, 1, -0.7 * lightness + 0.9, 1);
+}
+}
+
 namespace TextRegex
 {
 static const QRegularExpression endTagType{QStringLiteral("(>| )")};