Make QQuickAttachedPropertyPropagator public

This type has been used internally as QQuickAttachedObject by the
Imagine, Material and Universal styles to enable propagation of colors,
dark mode flags, etc. for a while now. Users would benefit from having
access to it to create their own styles (although it's not just limited
to that use case).

This patch:

- Makes the type public in quickcontrols2.
- Adds documentation and an example.
- Fixes the test_window test to ensure that propagation through child
  windows actually works.

[ChangeLog][Controls] Added QQuickAttachedPropertyPropagator, which
provides a way to propagate attached properties from parent objects
to children. This is especially useful when creating your own style.

Fixes: QTBUG-63267
Change-Id: I2f1794dc4a9f2be56fad2f5e5f39e2ab845157fa
Reviewed-by: Fabian Kosmale <[email protected]>
Reviewed-by: Richard Moe Gustavsen <[email protected]>

1 files changed, 8 insertions, 8 deletions

diff --git a/src/quickcontrols2/material/qquickmaterialstyle.cpp b/src/quickcontrols2/material/qquickmaterialstyle.cpp
index b4c782f023..9114462828 100644
--- a/src/quickcontrols2/material/qquickmaterialstyle.cpp
+++ b/src/quickcontrols2/material/qquickmaterialstyle.cpp
@@ -399,7 +399,7 @@ static QQuickMaterialStyle::Theme effectiveTheme(QQuickMaterialStyle::Theme them
     return theme;
 }
 
-QQuickMaterialStyle::QQuickMaterialStyle(QObject *parent) : QQuickAttachedObject(parent),
+QQuickMaterialStyle::QQuickMaterialStyle(QObject *parent) : QQuickAttachedPropertyPropagator(parent),
     m_customPrimary(globalPrimaryCustom),
     m_customAccent(globalAccentCustom),
     m_customForeground(globalForegroundCustom),
@@ -412,7 +412,7 @@ QQuickMaterialStyle::QQuickMaterialStyle(QObject *parent) : QQuickAttachedObject
     m_foreground(globalForeground),
     m_background(globalBackground)
 {
-    QQuickAttachedObject::init();
+    QQuickAttachedPropertyPropagator::initialize();
 }
 
 QQuickMaterialStyle *QQuickMaterialStyle::qmlAttachedProperties(QObject *object)
@@ -464,7 +464,7 @@ void QQuickMaterialStyle::inheritTheme(Theme theme)
 void QQuickMaterialStyle::propagateTheme()
 {
     const auto styles = attachedChildren();
-    for (QQuickAttachedObject *child : styles) {
+    for (QQuickAttachedPropertyPropagator *child : styles) {
         QQuickMaterialStyle *material = qobject_cast<QQuickMaterialStyle *>(child);
         if (material)
             material->inheritTheme(m_theme);
@@ -530,7 +530,7 @@ void QQuickMaterialStyle::inheritPrimary(uint primary, bool custom)
 void QQuickMaterialStyle::propagatePrimary()
 {
     const auto styles = attachedChildren();
-    for (QQuickAttachedObject *child : styles) {
+    for (QQuickAttachedPropertyPropagator *child : styles) {
         QQuickMaterialStyle *material = qobject_cast<QQuickMaterialStyle *>(child);
         if (material)
             material->inheritPrimary(m_primary, m_customPrimary);
@@ -594,7 +594,7 @@ void QQuickMaterialStyle::inheritAccent(uint accent, bool custom)
 void QQuickMaterialStyle::propagateAccent()
 {
     const auto styles = attachedChildren();
-    for (QQuickAttachedObject *child : styles) {
+    for (QQuickAttachedPropertyPropagator *child : styles) {
         QQuickMaterialStyle *material = qobject_cast<QQuickMaterialStyle *>(child);
         if (material)
             material->inheritAccent(m_accent, m_customAccent);
@@ -666,7 +666,7 @@ void QQuickMaterialStyle::inheritForeground(uint foreground, bool custom, bool h
 void QQuickMaterialStyle::propagateForeground()
 {
     const auto styles = attachedChildren();
-    for (QQuickAttachedObject *child : styles) {
+    for (QQuickAttachedPropertyPropagator *child : styles) {
         QQuickMaterialStyle *material = qobject_cast<QQuickMaterialStyle *>(child);
         if (material)
             material->inheritForeground(m_foreground, m_customForeground, m_hasForeground);
@@ -731,7 +731,7 @@ void QQuickMaterialStyle::inheritBackground(uint background, bool custom, bool h
 void QQuickMaterialStyle::propagateBackground()
 {
     const auto styles = attachedChildren();
-    for (QQuickAttachedObject *child : styles) {
+    for (QQuickAttachedPropertyPropagator *child : styles) {
         QQuickMaterialStyle *material = qobject_cast<QQuickMaterialStyle *>(child);
         if (material)
             material->inheritBackground(m_background, m_customBackground, m_hasBackground);
@@ -1319,7 +1319,7 @@ void QQuickMaterialStyle::initGlobals()
     }
 }
 
-void QQuickMaterialStyle::attachedParentChange(QQuickAttachedObject *newParent, QQuickAttachedObject *oldParent)
+void QQuickMaterialStyle::attachedParentChange(QQuickAttachedPropertyPropagator *newParent, QQuickAttachedPropertyPropagator *oldParent)
 {
     Q_UNUSED(oldParent);
     QQuickMaterialStyle *material = qobject_cast<QQuickMaterialStyle *>(newParent);