added slint example

Author: StephanKa

src/CMakeLists.txt

@@ -48,6 +48,11 @@ IF(CPP_STARTER_USE_OPEN62541)
     ADD_SUBDIRECTORY(open62541)
 ENDIF()
 
+# slint example
+IF(CPP_STARTER_USE_SLINT)
+    MESSAGE("Using slint")
+    ADD_SUBDIRECTORY(slint)
+ENDIF()
 
 FIND_PACKAGE(docopt REQUIRED)
 FIND_PACKAGE(spdlog REQUIRED)

src/slint/CMakeLists.txt

@@ -0,0 +1,22 @@
+INCLUDE(FetchContent)
+
+FIND_PACKAGE(Slint QUIET)
+IF(NOT Slint_FOUND)
+    MESSAGE(STATUS "Slint could not be located in the CMake module search path. Downloading it from Git and building it locally")
+    FETCHCONTENT_DECLARE(
+            Slint
+            GIT_REPOSITORY https://github.com/slint-ui/slint.git
+            GIT_TAG v1.9.2  # pin to a specific release for reproducible builds
+            SOURCE_SUBDIR api/cpp
+            GIT_SHALLOW TRUE  # faster clone, no full history needed
+    )
+    FETCHCONTENT_MAKEAVAILABLE(Slint)
+ENDIF()
+
+ADD_EXECUTABLE(slintExample src/main.cpp)
+TARGET_LINK_LIBRARIES(slintExample PRIVATE Slint::Slint)
+SLINT_TARGET_SOURCES(slintExample ui/app-window.slint)
+# On Windows, copy the Slint DLL next to the application binary so that it's found.
+IF(WIN32)
+    ADD_CUSTOM_COMMAND(TARGET slintExample POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_RUNTIME_DLLS:slintExample> $<TARGET_FILE_DIR:slintExample> COMMAND_EXPAND_LISTS)
+ENDIF()

src/slint/src/main.cpp

@@ -0,0 +1,13 @@
+#include <app-window.h>
+
+int main()
+{
+    auto ui = AppWindow::create();
+
+    ui->on_request_increase_value([ui]{
+        ui->set_counter(ui->get_counter() + 1);
+    });
+
+    ui->run();
+    return 0;
+}

src/slint/ui/app-window.slint

@@ -0,0 +1,17 @@
+import { Button, VerticalBox } from "std-widgets.slint";
+
+export component AppWindow inherits Window {
+    in-out property<int> counter: 42;
+    callback request-increase-value();
+    VerticalBox {
+        Text {
+            text: "Counter: \{root.counter}";
+        }
+        Button {
+            text: "Increase value";
+            clicked => {
+                root.request-increase-value();
+            }
+        }
+     }
+}