From 327dcc078de33bd1601a78e86b71e93a21cb1d20 Mon Sep 17 00:00:00 2001
From: Noah Davis <noahadvs@gmail.com>
Date: Sat, 27 Jan 2024 10:10:10 -0500
Subject: [PATCH] QPainterPath: Fix boundingRect and controlPointRect ignoring
 start point

The boundingRect and controlPointRect did not use the start point from
the `QPainterPath(const QPointF &startPoint)` constructor until the
`dirtyBounds` or `dirtyControlBounds` member variables were set to true.
Those two are false on construction. This bug was fixed by adding a new
constructor for QPainterPathPrivate that initializes the `elements`,
`bounds` and `controlBounds` member variables with the start point from
the constructor.

There is also an autotest to verify that the top left of the
boundingRect and controlPointRect are at the same position as
elementAt(0) when the start point constructor is used.

[ChangeLog][QtGui][QPainterPath] boundingRect() and controlPointRect()
now use the start point from QPainterPath(const QPointF &startPoint).

Pick-to: 6.6 6.5
Change-Id: I7bf30364406c14ed60f75d24b78a9a5535f75d93
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
(cherry picked from commit a4f44e06988e91c21c85e0e9f29d656d61f9c68e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/gui/painting/qpainterpath.cpp             |  4 +--
 src/gui/painting/qpainterpath_p.h             | 15 ++++++++++
 .../qpainterpath/tst_qpainterpath.cpp         | 28 +++++++++++++++++++
 3 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/src/gui/painting/qpainterpath.cpp b/src/gui/painting/qpainterpath.cpp
index b57bb0b13bb..536318b3a8b 100644
--- a/src/gui/painting/qpainterpath.cpp
+++ b/src/gui/painting/qpainterpath.cpp
@@ -517,10 +517,8 @@ QPainterPath::QPainterPath(const QPainterPath &other) = default;
 */
 
 QPainterPath::QPainterPath(const QPointF &startPoint)
-    : d_ptr(new QPainterPathPrivate)
+    : d_ptr(new QPainterPathPrivate(startPoint))
 {
-    Element e = { startPoint.x(), startPoint.y(), MoveToElement };
-    d_func()->elements << e;
 }
 
 void QPainterPath::detach()
diff --git a/src/gui/painting/qpainterpath_p.h b/src/gui/painting/qpainterpath_p.h
index 55164bc3477..a07b6cca37d 100644
--- a/src/gui/painting/qpainterpath_p.h
+++ b/src/gui/painting/qpainterpath_p.h
@@ -119,6 +119,21 @@ public:
     {
     }
 
+    QPainterPathPrivate(QPointF startPoint)
+        : QSharedData(),
+          elements{ { startPoint.x(), startPoint.y(), QPainterPath::MoveToElement } },
+          cStart(0),
+          fillRule(Qt::OddEvenFill),
+          bounds(startPoint, QSizeF(0, 0)),
+          controlBounds(startPoint, QSizeF(0, 0)),
+          require_moveTo(false),
+          dirtyBounds(false),
+          dirtyControlBounds(false),
+          convex(false),
+          pathConverter(nullptr)
+    {
+    }
+
     QPainterPathPrivate(const QPainterPathPrivate &other) noexcept
         : QSharedData(other),
           elements(other.elements),
diff --git a/tests/auto/gui/painting/qpainterpath/tst_qpainterpath.cpp b/tests/auto/gui/painting/qpainterpath/tst_qpainterpath.cpp
index 20ee6e07c78..cb03d6cf469 100644
--- a/tests/auto/gui/painting/qpainterpath/tst_qpainterpath.cpp
+++ b/tests/auto/gui/painting/qpainterpath/tst_qpainterpath.cpp
@@ -81,6 +81,8 @@ private slots:
 
     void intersectionEquality();
     void intersectionPointOnEdge();
+
+    void boundsAtStartPoint();
 };
 
 void tst_QPainterPath::cleanupTestCase()
@@ -1442,6 +1444,32 @@ void tst_QPainterPath::intersectionPointOnEdge()
     QVERIFY(p.intersects(r));
 }
 
+void tst_QPainterPath::boundsAtStartPoint()
+{
+    const QPointF startPoint(10, 10);
+    const QPainterPath constructedPath(startPoint);
+    {
+        const auto boundingRect = constructedPath.boundingRect();
+        const auto topLeft = boundingRect.topLeft();
+        QCOMPARE(topLeft, startPoint);
+        QCOMPARE(topLeft, constructedPath.elementAt(0));
+        QCOMPARE(boundingRect, constructedPath.controlPointRect());
+    }
+
+    QPainterPath defaultPath;
+    defaultPath.moveTo(startPoint);
+    {
+        const auto boundingRect = defaultPath.boundingRect();
+        const auto topLeft = boundingRect.topLeft();
+        QCOMPARE(topLeft, startPoint);
+        QCOMPARE(topLeft, defaultPath.elementAt(0));
+        QCOMPARE(boundingRect, defaultPath.controlPointRect());
+    }
+
+    QCOMPARE(constructedPath.boundingRect(), defaultPath.boundingRect());
+    QCOMPARE(constructedPath.controlPointRect(), defaultPath.controlPointRect());
+}
+
 QTEST_APPLESS_MAIN(tst_QPainterPath)
 
 #include "tst_qpainterpath.moc"