Add simple to/from xml methods to KoColor

This uses an undocumented extension to the format in which
KoColor saves to store/restore the channel depth.

libs/pigment/KoColor.cpp

@@ -304,13 +304,13 @@ qreal KoColor::opacityF() const
     return m_colorSpace->opacityF(m_data);
 }
 
-KoColor KoColor::fromXML(const QDomElement& elt, const QString& bitDepthId)
+KoColor KoColor::fromXML(const QDomElement& elt, const QString& channelDepthId)
 {
     bool ok;
-    return fromXML(elt, bitDepthId, &ok);
+    return fromXML(elt, channelDepthId, &ok);
 }
 
-KoColor KoColor::fromXML(const QDomElement& elt, const QString& bitDepthId, bool* ok)
+KoColor KoColor::fromXML(const QDomElement& elt, const QString& channelDepthId, bool* ok)
 {
     *ok = true;
     QString modelId;
@@ -336,7 +336,7 @@ KoColor KoColor::fromXML(const QDomElement& elt, const QString& bitDepthId, bool
             profileName.clear();
         }
     }
-    const KoColorSpace* cs = KoColorSpaceRegistry::instance()->colorSpace(modelId, bitDepthId, profileName);
+    const KoColorSpace* cs = KoColorSpaceRegistry::instance()->colorSpace(modelId, channelDepthId, profileName);
     if (cs == 0) {
         QList<KoID> list =  KoColorSpaceRegistry::instance()->colorDepthList(modelId, KoColorSpaceRegistry::AllColorSpaces);
         if (!list.empty()) {
@@ -354,6 +354,29 @@ KoColor KoColor::fromXML(const QDomElement& elt, const QString& bitDepthId, bool
     }
 }
 
+QString KoColor::toXML() const
+{
+    QDomDocument cdataDoc = QDomDocument("color");
+    QDomElement cdataRoot = cdataDoc.createElement("color");
+    cdataDoc.appendChild(cdataRoot);
+    cdataRoot.setAttribute("channeldepth", colorSpace()->colorDepthId().id());
+    toXML(cdataDoc, cdataRoot);
+    return cdataDoc.toString();
+}
+
+KoColor KoColor::fromXML(const QString &xml)
+{
+    KoColor c;
+    QDomDocument doc;
+    if (doc.setContent(xml)) {
+        QDomElement e = doc.documentElement().firstChild().toElement();
+        QString channelDepthID = e.attribute("channeldepth", Integer16BitsColorDepthID.id());
+        bool ok;
+        c = KoColor::fromXML(e, channelDepthID, &ok);
+    }
+    return c;
+}
+
 QString KoColor::toQString(const KoColor &color)
 {
     QStringList ls;

libs/pigment/KoColor.h

@@ -218,21 +218,21 @@ public:
      * at http://create.freedesktop.org/wiki/index.php/Swatches_-_colour_file_format
      *
      * @param elt the element to unserialize (\<CMYK /\>, \<sRGB /\>, \<RGB /\>)
-     * @param bitDepthId the bit depth is unspecified by the spec, this allow to select
+     * @param channelDepthId the bit depth is unspecified by the spec, this allow to select
      *                   a preferred bit depth for creating the KoColor object (if that
      *                   bit depth isn't available, this function will randomly select
      *                   an other bit depth)
      * @return the unserialize color, or an empty color object if the function failed
      *         to unserialize the color
      */
-    static KoColor fromXML(const QDomElement& elt, const QString & bitDepthId);
+    static KoColor fromXML(const QDomElement& elt, const QString & channelDepthId);
 
     /**
      * Unserialize a color following Create's swatch color specification available
      * at http://create.freedesktop.org/wiki/index.php/Swatches_-_colour_file_format
      *
      * @param elt the element to unserialize (\<CMYK /\>, \<sRGB /\>, \<RGB /\>)
-     * @param bitDepthId the bit depth is unspecified by the spec, this allow to select
+     * @param channelDepthId the bit depth is unspecified by the spec, this allow to select
      *                   a preferred bit depth for creating the KoColor object (if that
      *                   bit depth isn't available, this function will randomly select
      *                   an other bit depth)
@@ -240,7 +240,24 @@ public:
      * @return the unserialize color, or an empty color object if the function failed
      *         to unserialize the color
      */
-    static KoColor fromXML(const QDomElement& elt, const QString & bitDepthId, bool* ok);
+    static KoColor fromXML(const QDomElement& elt, const QString & channelDepthId, bool* ok);
+
+
+    /**
+     * @brief toXML creates a string with XML that represents the current color. The XML
+     * is extended with a "channeldepth" attribute so we can restore the color to the same
+     * channel depth.
+     * @return a valid XML document in a string
+     */
+    QString toXML() const;
+
+    /**
+     * @brief fromXML restores a KoColor from a string saved with toXML(). If the
+     * string does not contain the "channeldepth" attribute, 16 bit integer is assumed.
+     * @param xml a valid XML document
+     * @return a new KoColor object
+     */
+    static KoColor fromXML(const QString &xml);
 
     /**
      * @brief toQString create a user-visible string of the channel names and the channel values

libs/pigment/tests/TestKoColor.cpp

@@ -87,4 +87,14 @@ void TestKoColor::testConversion()
     kc.convertTo(csDst);
 }
 
+void TestKoColor::testSimpleSerialization()
+{
+    QColor c = Qt::green;
+    KoColor k;
+    k.fromQColor(c);
+    QString xml = k.toXML();
+    KoColor k2 = KoColor::fromXML(xml);
+    QVERIFY(k2.colorSpace() == k.colorSpace());
+}
+
 KISTEST_MAIN(TestKoColor)

libs/pigment/tests/TestKoColor.h

@@ -31,6 +31,7 @@ private:
 private Q_SLOTS:
     void testSerialization();
     void testConversion();
+    void testSimpleSerialization();
 };
 
 #endif