From a78b5da75c693b48ff33c17a930029ca14fd1fea Mon Sep 17 00:00:00 2001
From: numzero <numzer0@yandex.ru>
Date: Tue, 20 Oct 2026 03:09:48 +0300
Subject: [PATCH] port to Qt5

---
 CMakeLists.txt         |  6 ++++--
 ui/CMakeLists.txt      |  4 ++--
 ui/src/main_window.cxx |  5 ++++-
 ui/src/viewport.cxx    | 17 ++++++++++-------
 4 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0042389..09a2b13 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,12 +5,14 @@ project(gear-cutter VERSION 1.0.0 LANGUAGES CXX)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-find_package(Qt6 REQUIRED COMPONENTS Gui Widgets)
+find_package(Qt5 REQUIRED COMPONENTS Core Gui Widgets X11Extras)
 find_program(CARGO cargo REQUIRED)
 set(CARGO_TARGET_DIR "${CMAKE_BINARY_DIR}/cargo")
 
 include(cbindgen.cmake)
 
-qt_standard_project_setup()
+set(CMAKE_AUTOMOC ON)
+set(CMAKE_AUTOUIC ON)
+include(GNUInstallDirs)
 
 add_subdirectory(ui)
diff --git a/ui/CMakeLists.txt b/ui/CMakeLists.txt
index 54a464d..b4c5980 100644
--- a/ui/CMakeLists.txt
+++ b/ui/CMakeLists.txt
@@ -1,6 +1,6 @@
 include(impl.cmake)
 
-qt_add_executable(gear-cutter
+add_executable(gear-cutter
 	src/api.cxx
 	src/main.cxx
 	src/main_window.cxx
@@ -8,6 +8,6 @@ qt_add_executable(gear-cutter
 	src/viewport.cxx
 )
 
-target_link_libraries(gear-cutter PRIVATE Qt6::Gui Qt6::Widgets)
+target_link_libraries(gear-cutter PRIVATE Qt5::Core Qt5::Gui Qt5::Widgets Qt5::X11Extras X11-xcb)
 target_link_libraries(gear-cutter PRIVATE gear_cutter_impl)
 target_include_directories(gear-cutter PRIVATE src)
diff --git a/ui/src/main_window.cxx b/ui/src/main_window.cxx
index 0e65394..4969779 100644
--- a/ui/src/main_window.cxx
+++ b/ui/src/main_window.cxx
@@ -1,7 +1,10 @@
 #include "main_window.hxx"
-
 #include "ui_main_window.h"
 
+#include <cmath>
+
+#include <QtMath>
+
 GearCutter::GearCutter(QWidget* parent)
 	: QMainWindow(parent),
 	  m_ui(new Ui::MainWindow) {
diff --git a/ui/src/viewport.cxx b/ui/src/viewport.cxx
index 14ca272..bdc0d2b 100644
--- a/ui/src/viewport.cxx
+++ b/ui/src/viewport.cxx
@@ -3,6 +3,10 @@
 #include <QApplication>
 #include <QEvent>
 #include <QGuiApplication>
+#include <QX11Info>
+
+// must be the last as it is macro-heavy
+#include <X11/Xlib-xcb.h>
 
 Viewport::Viewport(QWidget* parent, Qt::WindowFlags f)
 	: QWidget(parent, f) {
@@ -55,15 +59,14 @@ void Viewport::resizeEvent(QResizeEvent* event) {
 }
 
 void Viewport::recreate() try {
-	auto* app = qobject_cast<QGuiApplication*>(QApplication::instance());
-	if (!app)
-		throw std::runtime_error("not a GUI application (WTF?)");
+	auto* xlib_display = QX11Info::display();
+	if (!xlib_display)
+		throw std::runtime_error("got no X11 display");
 
-	auto* native = app->nativeInterface<QNativeInterface::QX11Application>();
-	if (!native)
-		throw std::runtime_error("X11 interface is not available");
+	auto* xcb_connection = XGetXCBConnection(xlib_display);
+	if (!xcb_connection)
+		throw std::runtime_error("failed to get the XCB connection from the X11 display");
 
-	auto* xcb_connection = native->connection();
 	std::uint32_t x11_window = winId();
 
 	fprintf(stderr, "connection %p, window %#08x\n", xcb_connection, x11_window);