Qt: Fix sprite export pausing game indefinitely (fixes #841)

CHANGES

@@ -16,6 +16,7 @@ Bugfixes:
  - GB Serialize: Fix deserializing video STAT
  - GB, GBA Savedata: Fix savestate-related save overwriting (fixes mgba.io/i/834)
  - Qt: Fix timezone issues with time overrides
+ - Qt: Fix sprite export pausing game indefinitely (fixes mgba.io/i/841)
 Misc:
  - Qt: Don't rebuild library view if style hasn't changed
  - SDL: Fix 2.0.5 build on macOS under some circumstances

src/platform/qt/ObjView.cpp

@@ -247,7 +247,6 @@ void ObjView::updateTilesGB(bool force) {
 
 #ifdef USE_PNG
 void ObjView::exportObj() {
-	GameController::Interrupter interrupter(m_controller);
 	QString filename = GBAApp::app()->getSaveFileName(this, tr("Export sprite"),
 	                                                  tr("Portable Network Graphics (*.png)"));
 	VFile* vf = VFileDevice::open(filename, O_WRONLY | O_CREAT | O_TRUNC);
@@ -256,6 +255,7 @@ void ObjView::exportObj() {
 		return;
 	}
 
+	GameController::Interrupter interrupter(m_controller);
 	mTileCacheSetPalette(m_tileCache.get(), m_objInfo.paletteSet);
 	png_structp png = PNGWriteOpen(vf);
 	png_infop info = PNGWriteHeader8(png, m_objInfo.width * 8, m_objInfo.height * 8);