Index: src/common/Makefile
==================================================================
--- src/common/Makefile
+++ src/common/Makefile
@@ -1,11 +1,12 @@
 include ../../extra.mk
 
 STATIC_PIC_LIB_NOINST = ${COMMON_LIB_A}
 STATIC_LIB_NOINST = ${COMMON_A}
 
-SRCS = OFData+QByteArray.mm	\
+SRCS = OFColor+QColor.mm	\
+       OFData+QByteArray.mm	\
        OFString+QString.mm
 
 include ../../buildsys.mk
 
 CPPFLAGS += -I. -I../QtCore

ADDED   src/common/OFColor+QColor.h
Index: src/common/OFColor+QColor.h
==================================================================
--- /dev/null
+++ src/common/OFColor+QColor.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2018, Jonathan Schleifer <js@heap.zone>
+ *
+ * https://heap.zone/git/objqt.git
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#import <ObjFW/ObjFW.h>
+
+#include <QColor>
+
+@interface OFColor (QColor)
++ (instancetype)colorWithQColor: (const QColor &)qColor;
+- (instancetype)initWithQColor: (const QColor &)qColor;
+- (QColor)qColor;
+@end
+
+namespace ObjQt {
+
+static OF_INLINE OFColor *
+toOF(const QColor &qColor)
+{
+	if (!qColor.isValid())
+		return nil;
+
+	return [OFColor colorWithQColor: qColor];
+}
+
+static OF_INLINE QColor
+toQt(OFColor *color)
+{
+	if (color == nil)
+		return QColor();
+
+	return [color qColor];
+}
+
+}

ADDED   src/common/OFColor+QColor.mm
Index: src/common/OFColor+QColor.mm
==================================================================
--- /dev/null
+++ src/common/OFColor+QColor.mm
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2018, Jonathan Schleifer <js@heap.zone>
+ *
+ * https://heap.zone/git/objqt.git
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#import "OFColor+QColor.h"
+
+@implementation OFColor (QColor)
++ (instancetype)colorWithQColor: (const QColor &)qColor
+{
+	return [[[self alloc] initWithQColor: qColor] autorelease];
+}
+
+- (instancetype)initWithQColor: (const QColor &)qColor
+{
+	return [self initWithRed: qColor.redF()
+			   green: qColor.greenF()
+			    blue: qColor.blueF()
+			   alpha: qColor.alphaF()];
+}
+
+- (QColor)qColor
+{
+	QColor qColor;
+	float red, green, blue, alpha;
+
+	[self getRed: &red
+	       green: &green
+		blue: &blue
+	       alpha: &alpha];
+
+	qColor.setRedF(red);
+	qColor.setGreenF(green);
+	qColor.setBlueF(blue);
+	qColor.setAlphaF(alpha);
+
+	return qColor;
+}
+@end

Index: src/common/OFData+QByteArray.h
==================================================================
--- src/common/OFData+QByteArray.h
+++ src/common/OFData+QByteArray.h
@@ -24,10 +24,11 @@
 
 #include <QByteArray>
 
 @interface OFData (QByteArray)
 + (instancetype)dataWithQByteArray: (const QByteArray &)qByteArray;
+- (instancetype)initWithQByteArray: (const QByteArray &)qByteArray;
 - (QByteArray)qByteArray;
 @end
 
 namespace ObjQt {
 

Index: src/common/OFData+QByteArray.mm
==================================================================
--- src/common/OFData+QByteArray.mm
+++ src/common/OFData+QByteArray.mm
@@ -23,12 +23,17 @@
 #import "OFData+QByteArray.h"
 
 @implementation OFData (QByteArray)
 + (instancetype)dataWithQByteArray: (const QByteArray &)qByteArray
 {
-	return [OFData dataWithItems: qByteArray.data()
-			       count: qByteArray.count()];
+	return [[[self alloc] initWithQByteArray: qByteArray] autorelease];
+}
+
+- (instancetype)initWithQByteArray: (const QByteArray &)qByteArray
+{
+	return [self initWithItems: qByteArray.data()
+			     count: qByteArray.count()];
 }
 
 - (QByteArray)qByteArray
 {
 	return QByteArray((const char *)[self items],

Index: src/common/OFString+QString.h
==================================================================
--- src/common/OFString+QString.h
+++ src/common/OFString+QString.h
@@ -24,11 +24,11 @@
 
 #include <QString>
 
 @interface OFString (QString)
 + (instancetype)stringWithQString: (const QString &)qString;
-- initWithQString: (const QString &)qString;
+- (instancetype)initWithQString: (const QString &)qString;
 - (QString)qString;
 @end
 
 namespace ObjQt {
 

Index: src/common/OFString+QString.mm
==================================================================
--- src/common/OFString+QString.mm
+++ src/common/OFString+QString.mm
@@ -21,16 +21,16 @@
  */
 
 #import "OFString+QString.h"
 
 @implementation OFString (QString)
-+ stringWithQString: (const QString &)qString
++ (instancetype)stringWithQString: (const QString &)qString
 {
 	return [[[self alloc] initWithQString: qString] autorelease];
 }
 
-- initWithQString: (const QString &)qString
+- (instancetype)initWithQString: (const QString &)qString
 {
 	static_assert(sizeof(QChar) == sizeof(char16_t),
 	    "QChar and char16_t have a different size!");
 
 	return [self initWithUTF16String: (char16_t *)qString.data()