Disable screensaver while projecting (untested on Windows)

xs/src/libslic3r/GUI/GUI.cpp

@@ -0,0 +1,37 @@
+#include "GUI.hpp"
+
+#if __APPLE__
+#import <IOKit/pwr_mgt/IOPMLib.h>
+#elif _WIN32
+#include <Windows.h>
+#pragma comment(lib, "user32.lib")
+#endif
+
+namespace Slic3r { namespace GUI {
+
+IOPMAssertionID assertionID;
+
+void
+disable_screensaver()
+{
+    #if __APPLE__
+    CFStringRef reasonForActivity = CFSTR("Slic3r");
+    IOReturn success = IOPMAssertionCreateWithName(kIOPMAssertionTypeNoDisplaySleep, 
+        kIOPMAssertionLevelOn, reasonForActivity, &assertionID); 
+    // ignore result: success == kIOReturnSuccess
+    #elif _WIN32
+    SetThreadExecutionState(EXECUTION_STATE.ES_DISPLAY_REQUIRED | EXECUTION_STATE.ES_CONTINUOUS);
+    #endif
+}
+
+void
+enable_screensaver()
+{
+    #if __APPLE__
+    IOReturn success = IOPMAssertionRelease(assertionID);
+    #elif _WIN32
+    SetThreadExecutionState(EXECUTION_STATE.ES_CONTINUOUS);
+    #endif
+}
+
+} }

xs/src/libslic3r/GUI/GUI.hpp

@@ -0,0 +1,11 @@
+#ifndef slic3r_GUI_hpp_
+#define slic3r_GUI_hpp_
+
+namespace Slic3r { namespace GUI {
+
+void disable_screensaver();
+void enable_screensaver();
+
+} }
+
+#endif