Introduce PathText path element

For text rendering in Qt Quick, we currently have the limitation
that when rendering text at such a large size that the distance
fields start showing artifacts, the only option is to use
NativeRendering, which will look nice, but which will use a lot
of texture memory for the glyph cache, since it will actually
cache the glyphs at the requested size.

A suggested approach would be to fall back to using triangulated
paths when the font gets large enough, but the work on this was
never completed.

It turns out that we can get this now, basically for free, since
we already support rendering arbitrary QPainterPaths using
Qt Quick Shapes. The only thing missing is the ability to add
the path of a given text to the shape. This patch fills in that
gap.

Note that this is currently not supported by nvidia renderer.

[ChangeLog][QtQuick] Added PathText path element which can be
used together with Qt Quick Shapes to get text rendering that
does not cache glyphs in a texture, but triangulates the
outlines of the glyphs instead.

Change-Id: I436e1476b129b324cf7a54f89a1b18e0579e8185
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

4 files changed, 78 insertions, 1 deletions

diff --git a/examples/quick/shapes/content/item18.qml b/examples/quick/shapes/content/item18.qml
new file mode 100644
index 0000000000..3774d19bc5
--- /dev/null
+++ b/examples/quick/shapes/content/item18.qml
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.15
+import QtQuick.Shapes 1.0
+
+Rectangle {
+    color: "lightGray"
+
+    Shape {
+        anchors.centerIn: parent
+        width: 200
+        height: 100
+
+        ShapePath {
+            id: capTest
+            strokeColor: "black"
+            strokeWidth: 1
+            fillColor: "black"
+
+            PathText { x: 0; y: 100; font.family: "Arial"; font.pixelSize: 150; text: "Qt!" }
+        }
+    }
+}
diff --git a/examples/quick/shapes/content/shapegallery.qml b/examples/quick/shapes/content/shapegallery.qml
index 86445e25c2..e5a7c51483 100644
--- a/examples/quick/shapes/content/shapegallery.qml
+++ b/examples/quick/shapes/content/shapegallery.qml
@@ -130,6 +130,10 @@ Rectangle {
             name: "Tiger"
             shapeUrl: "item17.qml"
         }
+        ListElement {
+            name: "Text"
+            shapeUrl: "item18.qml"
+        }
     }
 
     property int gridSpacing: 10
diff --git a/examples/quick/shapes/shapes.pro b/examples/quick/shapes/shapes.pro
index ff6fa422fb..f99d941804 100644
--- a/examples/quick/shapes/shapes.pro
+++ b/examples/quick/shapes/shapes.pro
@@ -24,7 +24,8 @@ OTHER_FILES += content/main.qml \
                content/item13.qml \
                content/item14.qml \
                content/item15.qml \
-               content/item17.qml
+               content/item17.qml \
+               content/item18.qml
 
 target.path = $$[QT_INSTALL_EXAMPLES]/quick/shapes
 INSTALLS += target
diff --git a/examples/quick/shapes/shapes.qrc b/examples/quick/shapes/shapes.qrc
index e03c0e8a0a..6de463dd33 100644
--- a/examples/quick/shapes/shapes.qrc
+++ b/examples/quick/shapes/shapes.qrc
@@ -28,5 +28,6 @@
         <file alias="item14.qml">content/item14.qml</file>
         <file alias="item15.qml">content/item15.qml</file>
         <file alias="item17.qml">content/item17.qml</file>
+        <file alias="item18.qml">content/item18.qml</file>
     </qresource>
 </RCC>