Long live QColor::fromString()!

It is customary for Qt types that can be constructed from string-ish
to provide a fromString() named constructor. QColor didn't, relying
instead on a set of overloaded implicit and explicit constructors.

Add the named constructor, with the intent to deprecate the string-ish
QColor constructors after a grace period.

To prevent new users from using known-to-become-deprecated API, mark
the old functions as \obsolete.

Also rename isValidColor() to isValidColorName(). The only reason why
these are lumped together in single commit is so that their docs can
refer to each other instead of having to temporarily refer to obsolete
API.

[ChangeLog][QtGui][QColor] Added fromString() and isValidColorName(),
both taking QAnyStringView.

Task-number: QTBUG-101389
Change-Id: I2857c728257ad2f14c7c968b45547bdf07c44b63
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

1 files changed, 31 insertions, 21 deletions

diff --git a/tests/auto/gui/painting/qcolor/tst_qcolor.cpp b/tests/auto/gui/painting/qcolor/tst_qcolor.cpp
index 5c93a41b71..47e684b55c 100644
--- a/tests/auto/gui/painting/qcolor/tst_qcolor.cpp
+++ b/tests/auto/gui/painting/qcolor/tst_qcolor.cpp
@@ -54,8 +54,8 @@ private slots:
     void name();
     void namehex_data();
     void namehex();
-    void setNamedColor_data();
-    void setNamedColor();
+    void fromString_data();
+    void fromString();
 
     void constructNamedColorWithSpace();
 
@@ -243,13 +243,13 @@ void tst_QColor::isValid_data()
     QTest::newRow("defaultConstructor") << QColor() << false;
     QTest::newRow("rgbConstructor-valid") << QColor(2,5,7) << true;
     QTest::newRow("rgbConstructor-invalid") << QColor(2,5,999) << false;
-    QTest::newRow("nameQStringConstructor-valid") << QColor(QString("#ffffff")) << true;
-    QTest::newRow("nameQStringConstructor-invalid") << QColor(QString("#ffffgg")) << false;
-    QTest::newRow("nameQStringConstructor-empty") << QColor(QString("")) << false;
-    QTest::newRow("nameQStringConstructor-named") << QColor(QString("red")) << true;
-    QTest::newRow("nameCharConstructor-valid") << QColor("#ffffff") << true;
-    QTest::newRow("nameCharConstructor-invalid") << QColor("#ffffgg") << false;
-    QTest::newRow("nameCharConstructor-invalid-2") << QColor("#fffffg") << false;
+    QTest::newRow("nameQStringConstructor-valid") << QColor::fromString("#ffffff") << true;
+    QTest::newRow("nameQStringConstructor-invalid") << QColor::fromString("#ffffgg") << false;
+    QTest::newRow("nameQStringConstructor-empty") << QColor::fromString("") << false;
+    QTest::newRow("nameQStringConstructor-named") << QColor::fromString("red") << true;
+    QTest::newRow("nameCharConstructor-valid") << QColor::fromString("#ffffff") << true;
+    QTest::newRow("nameCharConstructor-invalid") << QColor::fromString("#ffffgg") << false;
+    QTest::newRow("nameCharConstructor-invalid-2") << QColor::fromString("#fffffg") << false;
 }
 
 void tst_QColor::isValid()
@@ -336,6 +336,7 @@ void tst_QColor::namehex()
     QFETCH(QString, hexcolor);
     QFETCH(QColor, color);
     QCOMPARE(QColor(hexcolor), color);
+    QCOMPARE(QColor::fromString(hexcolor), color);
 }
 
 void tst_QColor::globalColors_data()
@@ -721,25 +722,27 @@ static const int rgbTblSize = sizeof(rgbTbl) / sizeof(RGBData);
 
 #undef rgb
 
-void tst_QColor::setNamedColor_data()
+void tst_QColor::fromString_data()
 {
     QTest::addColumn<QColor>("byCtor");
     QTest::addColumn<QColor>("bySetNamedColor");
+    QTest::addColumn<QColor>("byFromString");
     QTest::addColumn<QColor>("expected");
 
     for (const auto e : rgbTbl) {
         QColor expected;
         expected.setRgba(e.value);
 
-#define ROW(expr)                                \
-        do {                                     \
-            QColor bySetNamedColor;              \
-            bySetNamedColor.setNamedColor(expr); \
-            auto byCtor = QColor(expr);          \
-            QTest::addRow("%s: %s", e.name, #expr) \
-                << byCtor << bySetNamedColor << expected;    \
-        } while (0)                              \
-        /*end*/
+#define ROW(expr) row(expr, #expr)
+        auto row = [&] (auto expr, const char *exprS) {
+            QColor bySetNamedColor;
+            bySetNamedColor.setNamedColor(expr);
+            auto byCtor = QColor(expr);
+            QTest::addRow("%s: %s", e.name, exprS)
+                << byCtor << bySetNamedColor
+                << QColor::fromString(expr)
+                << expected;
+        };
 
         const auto l1 = QLatin1String(e.name);
         const auto l1UpperBA = QByteArray(e.name).toUpper();
@@ -766,14 +769,16 @@ void tst_QColor::setNamedColor_data()
     }
 }
 
-void tst_QColor::setNamedColor()
+void tst_QColor::fromString()
 {
     QFETCH(QColor, byCtor);
     QFETCH(QColor, bySetNamedColor);
+    QFETCH(QColor, byFromString);
     QFETCH(QColor, expected);
 
     QCOMPARE(byCtor, expected);
     QCOMPARE(bySetNamedColor, expected);
+    QCOMPARE(byFromString, expected);
 }
 
 
@@ -781,14 +786,19 @@ void tst_QColor::constructNamedColorWithSpace()
 {
     QColor whiteSmoke("white smoke");
     QCOMPARE(whiteSmoke, QColor(245, 245, 245));
+    QCOMPARE(QColor::fromString("white smoke"), QColorConstants::Svg::whitesmoke);
 }
 
 void tst_QColor::colorNames()
 {
-    QStringList all = QColor::colorNames();
+    const QStringList all = QColor::colorNames();
     QCOMPARE(all.size(), rgbTblSize);
     for (int i = 0; i < all.size(); ++i)
         QCOMPARE(all.at(i), QLatin1String(rgbTbl[i].name));
+    for (const QString &name : all)
+        QVERIFY(QColor::isValidColorName(name));
+    for (const auto &e : rgbTbl)
+        QVERIFY(QColor::isValidColorName(e.name));
 }
 
 void tst_QColor::spec()