QQuickTextNodeEngine: don't create background when its alpha is 0

If the alpha value for the background color of a text element is 0,
we don't need to create a rectangle node to represent it, as the
rectangle will be invisible anyway.

[ChangeLog][QtQuick][QQuickTextNodeEngine] don't create a new
rectangle node as the background of text, when the alpha of it is
0

Fixes: QTBUG-76137
Change-Id: I40c624ee8f61740fd07e7d3751a78b6224882913
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

1 files changed, 16 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicktext/data/transparentBackground.qml b/tests/auto/quick/qquicktext/data/transparentBackground.qml
new file mode 100644
index 0000000000..a10a1779bb
--- /dev/null
+++ b/tests/auto/quick/qquicktext/data/transparentBackground.qml
@@ -0,0 +1,16 @@
+import QtQuick 2.0
+
+Rectangle {
+    width: 200
+    height: 200
+    color: "white"
+    Text {
+        objectName: "text"
+        textFormat: Text.RichText
+        anchors.fill: parent
+        color: "black"
+        text: "<h1 style=\"background-color:rgba(255,255,255,0.00)\">foo</h1>"
+        verticalAlignment: Text.AlignTop
+        horizontalAlignment: Text.AlignLeft
+    }
+}