Qt: Fix crash in sprite viewer magnification (fixes #1362)

CHANGES

@@ -11,6 +11,7 @@ Other fixes:
  - Qt: Fix overrides getting discarded (fixes mgba.io/i/1354)
  - Qt: Fix saved scale not getting set on resize (fixes mgba.io/i/1074)
  - CMake: Fix .deb imagemagick dependencies
+ - Qt: Fix crash in sprite viewer magnification (fixes mgba.io/i/1362)
 Misc:
  - Qt: Add missing HEVC NVENC option (fixes mgba.io/i/1323)
  - Qt: Improve camera initialization

src/platform/qt/TilePainter.cpp

@@ -62,8 +62,11 @@ void TilePainter::setTileCount(int tiles) {
 		setMinimumSize(m_size, h - (h % m_size));
 	} else {		
 		int w = minimumSize().width() / m_size;
+		if (!w) {
+			w = 1;
+		}
 		int h = (tiles + w - 1) * m_size / w;
-		setMinimumSize(minimumSize().width(), h - (h % m_size));
+		setMinimumSize(w * m_size, h - (h % m_size));
 	}
 	resizeEvent(nullptr);
 }