Add QFontMetrics support

CHANGELOG.md

@@ -19,7 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Support for further types: `QLine`, `QLineF`, `QImage`, `QPainter`, `QFont`, `QPen`, `QPolygon`, `QPolygonF`
+- Support for further types: `QLine`, `QLineF`, `QImage`, `QPainter`, `QFont`, `QPen`, `QPolygon`, `QPolygonF`, `QFontMetrics`
 - `internal_pointer_mut()` function on `QModelIndex`
 - `c_void` in CXX-Qt-lib for easy access to `void *`
 - `CxxQtThread` is now marked as `Sync` so that it can be used by reference

crates/cxx-qt-lib-headers/include/gui/qfontmetrics.h

@@ -0,0 +1,22 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2024 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+// clang-format on
+// SPDX-FileContributor: Laurent Montel <[email protected]>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+#pragma once
+
+#include <QtGui/QFontMetrics>
+
+#include "rust/cxx.h"
+
+// Define namespace otherwise we hit a GCC bug
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480
+namespace rust {
+
+template<>
+struct IsRelocatable<QFontMetrics> : ::std::true_type
+{
+};
+
+} // namespace rust

crates/cxx-qt-lib-headers/src/lib.rs

@@ -70,6 +70,11 @@ pub fn build_opts() -> cxx_qt_build::CxxQtBuildersOpts {
         #[cfg(feature = "qt_gui")]
         (include_str!("../include/gui/qfont.h"), "qfont.h"),
         #[cfg(feature = "qt_gui")]
+        (
+            include_str!("../include/gui/qfontmetrics.h"),
+            "qfontmetrics.h",
+        ),
+        #[cfg(feature = "qt_gui")]
         (
             include_str!("../include/gui/qguiapplication.h"),
             "qguiapplication.h",

crates/cxx-qt-lib/build.rs

@@ -141,6 +141,7 @@ fn main() {
             "core/qvector/qvector_qcolor",
             "gui/qcolor",
             "gui/qfont",
+            "gui/qfontmetrics",
             "gui/qguiapplication",
             "gui/qimage",
             "gui/qpainterpath",
@@ -201,6 +202,7 @@ fn main() {
         cpp_files.extend([
             "gui/qcolor",
             "gui/qfont",
+            "gui/qfontmetrics",
             "gui/qguiapplication",
             "gui/qimage",
             "gui/qpainterpath",

crates/cxx-qt-lib/src/gui/mod.rs

@@ -36,6 +36,9 @@ pub use qfont::{
     QFontStyleHint, QFontStyleStrategy,
 };
 
+mod qfontmetrics;
+pub use qfontmetrics::QFontMetrics;
+
 mod qpainterpath;
 pub use qpainterpath::QPainterPath;
 

crates/cxx-qt-lib/src/gui/qfontmetrics.cpp

@@ -0,0 +1,22 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2024 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+// clang-format on
+// SPDX-FileContributor: Laurent Montel <[email protected]>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+#include "cxx-qt-lib/qfontmetrics.h"
+
+#include "../assertion_utils.h"
+
+// https://code.qt.io/cgit/qt/qtbase.git/tree/src/gui/text/qfontmetrics.h?h=v5.15.6-lts-lgpl#n147
+// https://code.qt.io/cgit/qt/qtbase.git/tree/src/gui/text/qfontmetrics.h?h=v6.2.4#n117
+assert_alignment_and_size(QFontMetrics,
+                          alignof(::std::size_t),
+                          sizeof(::std::size_t));
+
+static_assert(!::std::is_trivially_copy_assignable<QFontMetrics>::value);
+static_assert(!::std::is_trivially_copy_constructible<QFontMetrics>::value);
+
+static_assert(!::std::is_trivially_destructible<QFontMetrics>::value);
+static_assert(QTypeInfo<QFontMetrics>::isRelocatable);

crates/cxx-qt-lib/src/gui/qfontmetrics.rs

@@ -0,0 +1,146 @@
+// SPDX-FileCopyrightText: 2024 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+// SPDX-FileContributor: Laurent Montel <[email protected]>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+use cxx::{type_id, ExternType};
+use std::mem::MaybeUninit;
+
+#[cxx::bridge]
+mod ffi {
+    unsafe extern "C++" {
+        include!("cxx-qt-lib/qfontmetrics.h");
+        type QFontMetrics = super::QFontMetrics;
+        include!("cxx-qt-lib/qrect.h");
+        type QRect = crate::QRect;
+        include!("cxx-qt-lib/qstring.h");
+        type QString = crate::QString;
+        include!("cxx-qt-lib/qfont.h");
+        type QFont = crate::QFont;
+
+        /// Returns the ascent of the font.
+        fn ascent(self: &QFontMetrics) -> i32;
+
+        /// Returns the average width of glyphs in the font.
+        #[rust_name = "average_char_width"]
+        fn averageCharWidth(self: &QFontMetrics) -> i32;
+
+        /// Returns the bounding rectangle of the characters in the string specified by text.
+        /// The bounding rectangle always covers at least the set of pixels the text would cover if drawn at (0, 0).
+        #[rust_name = "bounding_rect"]
+        fn boundingRect(self: &QFontMetrics, text: &QString) -> QRect;
+
+        /// Returns the cap height of the font.
+        /// The cap height of a font is the height of a capital letter above the baseline. It specifically is
+        /// the height of capital letters that are flat - such as H or I - as opposed to round letters such
+        /// as O, or pointed letters like A, both of which may display overshoot.
+        #[rust_name = "cap_height"]
+        fn capHeight(self: &QFontMetrics) -> i32;
+
+        /// Returns the descent of the font.
+        /// The descent is the distance from the base line to the lowest point characters extend to. In practice,
+        /// some font designers break this rule, e.g. to accommodate a certain character,
+        /// so it is possible (though rare) that this value will be too small.
+        fn descent(self: &QFontMetrics) -> i32;
+
+        /// Returns the height of the font.
+        fn height(self: &QFontMetrics) -> i32;
+
+        /// Returns the horizontal advance in pixels of the first len characters of text. If len is negative (the default),
+        /// the entire string is used. The entire length of text is analysed even if len is substantially shorter.
+        #[rust_name = "horizontal_advance"]
+        fn horizontalAdvance(self: &QFontMetrics, text: &QString, len: i32) -> i32;
+
+        /// Returns the leading of the font.
+        fn leading(self: &QFontMetrics) -> i32;
+
+        /// Returns the distance from one base line to the next.
+        /// This value is always equal to leading()+height().
+        #[rust_name = "line_spacing"]
+        fn lineSpacing(self: &QFontMetrics) -> i32;
+
+        /// Returns the width of the underline and strikeout lines, adjusted for the point size of the font.
+        #[rust_name = "line_width"]
+        fn lineWidth(self: &QFontMetrics) -> i32;
+
+        /// Returns the width of the widest character in the font.
+        #[rust_name = "max_width"]
+        fn maxWidth(self: &QFontMetrics) -> i32;
+
+        /// Returns the minimum left bearing of the font.
+        #[rust_name = "min_left_bearing"]
+        fn minLeftBearing(self: &QFontMetrics) -> i32;
+
+        /// Returns the minimum right bearing of the font.
+        #[rust_name = "min_right_bearing"]
+        fn minRightBearing(self: &QFontMetrics) -> i32;
+
+        /// Returns the distance from the base line to where an overline should be drawn.
+        #[rust_name = "overline_position"]
+        fn overlinePos(self: &QFontMetrics) -> i32;
+
+        /// Returns the distance from the base line to where the strikeout line should be drawn.
+        #[rust_name = "strike_out_position"]
+        fn strikeOutPos(self: &QFontMetrics) -> i32;
+
+        /// Returns a tight bounding rectangle around the characters in the string specified by text.
+        /// The bounding rectangle always covers at least the set of pixels the text would cover if drawn at (0, 0).
+        #[rust_name = "tight_bounding_rect"]
+        fn tightBoundingRect(self: &QFontMetrics, text: &QString) -> QRect;
+
+        /// Returns the distance from the base line to where an underscore should be drawn.
+        #[rust_name = "underline_position"]
+        fn underlinePos(self: &QFontMetrics) -> i32;
+
+        /// Returns the 'x' height of the font. This is often but not always the same as the height of the character 'x'.
+        #[rust_name = "x_height"]
+        fn xHeight(self: &QFontMetrics) -> i32;
+    }
+
+    #[namespace = "rust::cxxqtlib1"]
+    unsafe extern "C++" {
+        include!("cxx-qt-lib/common.h");
+
+        #[doc(hidden)]
+        #[rust_name = "qfontmetrics_drop"]
+        fn drop(fontmetics: &mut QFontMetrics);
+
+        #[doc(hidden)]
+        #[rust_name = "qfontmetrics_clone"]
+        fn construct(font: &QFontMetrics) -> QFontMetrics;
+
+        #[doc(hidden)]
+        #[rust_name = "qfontmetrics_init_from_qfont"]
+        fn construct(font: &QFont) -> QFontMetrics;
+    }
+}
+
+#[repr(C)]
+pub struct QFontMetrics {
+    _cspec: MaybeUninit<usize>,
+}
+
+impl Drop for QFontMetrics {
+    fn drop(&mut self) {
+        ffi::qfontmetrics_drop(self);
+    }
+}
+
+impl Clone for QFontMetrics {
+    fn clone(&self) -> Self {
+        ffi::qfontmetrics_clone(self)
+    }
+}
+
+impl From<&ffi::QFont> for QFontMetrics {
+    fn from(font: &ffi::QFont) -> Self {
+        ffi::qfontmetrics_init_from_qfont(font)
+    }
+}
+
+// Safety:
+//
+// Static checks on the C++ side to ensure the size is the same.
+unsafe impl ExternType for QFontMetrics {
+    type Id = type_id!("QFontMetrics");
+    type Kind = cxx::kind::Trivial;
+}

crates/cxx-qt-lib/src/gui/qpainter.rs

@@ -173,6 +173,8 @@ mod ffi {
         type QPen = crate::QPen;
         include!("cxx-qt-lib/qpolygon.h");
         type QPolygon = crate::QPolygon;
+        include!("cxx-qt-lib/qfontmetrics.h");
+        type QFontMetrics = crate::QFontMetrics;
 
         /// Returns the current background mode.
         #[rust_name = "background_mode"]
@@ -286,6 +288,10 @@ mod ffi {
         /// Returns the currently set font used for drawing text.
         fn font(self: &QPainter) -> &QFont;
 
+        /// Returns the font metrics for the painter if the painter is active.
+        #[rust_name = "font_metrics_or_undefined"]
+        fn fontMetrics(self: &QPainter) -> QFontMetrics;
+
         /// Returns true if clipping has been set; otherwise returns false.
         #[rust_name = "has_clipping"]
         fn hasClipping(self: &QPainter) -> bool;
@@ -415,4 +421,14 @@ impl QPainter {
             None
         }
     }
+
+    /// Returns the bounding rectangle of the current clip if there is a clip;
+    /// otherwise returns `None`. Note that the clip region is given in logical coordinates.
+    pub fn font_metrics(&self) -> Option<ffi::QFontMetrics> {
+        if self.is_active() {
+            Some(self.font_metrics_or_undefined())
+        } else {
+            None
+        }
+    }
 }

tests/qt_types_standalone/CMakeLists.txt

@@ -53,6 +53,7 @@ add_executable(${APP_NAME}
     cpp/qcoreapplication.h
     cpp/qdate.h
     cpp/qdatetime.h
+    cpp/qfontmetrics.h
     cpp/qguiapplication.h
     cpp/qhash.h
     cpp/qline.h

tests/qt_types_standalone/cpp/main.cpp

@@ -12,6 +12,7 @@
 #include "qcoreapplication.h"
 #include "qdate.h"
 #include "qdatetime.h"
+#include "qfontmetrics.h"
 #include "qguiapplication.h"
 #include "qhash.h"
 #include "qline.h"
@@ -92,6 +93,7 @@ main(int argc, char* argv[])
   runTest(QScopedPointer<QObject>(new QVector3DTest));
   runTest(QScopedPointer<QObject>(new QVector4DTest));
   runTest(QScopedPointer<QObject>(new QPolygonTest));
+  runTest(QScopedPointer<QObject>(new QFontMetricsTest));
 
   return status;
 }

tests/qt_types_standalone/cpp/qfontmetrics.h

@@ -0,0 +1,59 @@
+// clang-format off
+// SPDX-FileCopyrightText: 2024 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+// clang-format on
+// SPDX-FileContributor: Laurent Montel <[email protected]>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+#pragma once
+
+#include <QtGui/QFont>
+#include <QtGui/QFontMetrics>
+#include <QtGui/QGuiApplication>
+#include <QtTest/QTest>
+
+#include "cxx-qt-gen/qfontmetrics.cxx.h"
+
+class QFontMetricsTest : public QObject
+{
+  Q_OBJECT
+
+private Q_SLOTS:
+  void construct()
+  {
+    std::vector<char*> args;
+    std::string path = "/path";
+    args.push_back(path.data());
+    auto argc = static_cast<int>(args.size());
+
+    // QFontDatabase needs a QGuiApplication first
+    QGuiApplication app(argc, args.data());
+    app.setApplicationName(QStringLiteral("kdab"));
+
+    QFont f;
+    const int pointSize = 40;
+    f.setPointSize(pointSize);
+    const auto m = constructor_qfontmetrics(f);
+    QCOMPARE(m.ascent(), 57);
+    QCOMPARE(m.height(), 73);
+  }
+  void clone()
+  {
+    std::vector<char*> args;
+    std::string path = "/path";
+    args.push_back(path.data());
+    auto argc = static_cast<int>(args.size());
+
+    // QFontDatabase needs a QGuiApplication first
+    QGuiApplication app(argc, args.data());
+    app.setApplicationName(QStringLiteral("kdab"));
+
+    QFont f;
+    f.setBold(true);
+    f.setPointSize(30);
+    const auto m = QFontMetrics(f);
+
+    const auto c = clone_qfontmetrics(m);
+    QCOMPARE(m.ascent(), c.ascent());
+    QCOMPARE(m.height(), c.height());
+  }
+};

tests/qt_types_standalone/rust/build.rs

@@ -12,6 +12,7 @@ fn main() {
         .file("src/qcoreapplication.rs")
         .file("src/qdate.rs")
         .file("src/qdatetime.rs")
+        .file("src/qfontmetrics.rs")
         .file("src/qguiapplication.rs")
         .file("src/qhash.rs")
         .file("src/qline.rs")

tests/qt_types_standalone/rust/src/lib.rs

@@ -9,6 +9,7 @@ mod qcolor;
 mod qcoreapplication;
 mod qdate;
 mod qdatetime;
+mod qfontmetrics;
 mod qguiapplication;
 mod qhash;
 mod qline;