Add declarative QQuickTextMetrics API from QQuickFontMetrics invokables

This allows use of a declarative API for the functions in QFontMetricsF
which take parameters. This solves the problem of QML expressions that
use QML methods not being re-evaluated when the internal data changes,
by allowing the user to set the arguments as properties of a
TextMetrics object, that would otherwise have to be passed to QML
methods.

For example:

    FontMetrics {
        id: fontMetrics
    }

    property rect r: fontMetrics.boundingRect("Blah")

At some point, the font of the FontMetrics object is changed, but r
will still represent the original bounding rect. Instead, the user will
now write:

    TextMetrics {
        id: textMetrics
        text: "Blah"
    }

    property rect r: textMetrics.boundingRect

The QML methods remain in QQuickFontMetrics for those who need an
imperative API.

[ChangeLog][QtQuick] Added QQuickTextMetrics, which provides a
declarative API for the functions in QFontMetricsF which take
arguments.

Change-Id: I019dc4639531906fc751ba61281cc1c695742287
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/quick/util/util.pri b/src/quick/util/util.pri
index 35553070dc..76cf1996bc 100644
--- a/src/quick/util/util.pri
+++ b/src/quick/util/util.pri
@@ -27,7 +27,8 @@ SOURCES += \
     $$PWD/qquickanimatorjob.cpp \
     $$PWD/qquickanimatorcontroller.cpp \
     $$PWD/qquickprofiler.cpp \
-    $$PWD/qquickfontmetrics.cpp
+    $$PWD/qquickfontmetrics.cpp \
+    $$PWD/qquicktextmetrics.cpp
 
 HEADERS += \
     $$PWD/qquickapplication_p.h\
@@ -62,4 +63,5 @@ HEADERS += \
     $$PWD/qquickanimatorjob_p.h \
     $$PWD/qquickanimatorcontroller_p.h \
     $$PWD/qquickprofiler_p.h \
-    $$PWD/qquickfontmetrics_p.h
+    $$PWD/qquickfontmetrics_p.h \
+    $$PWD/qquicktextmetrics_p.h