NEW: Official filament color selection approved

- Add a filament picker dialog for official color selection
- Enable displaying multiple filament colors in the picker dialog and preview sidebar
- Introduce two new config options:
  - `filament_multi_colors`
  - `filament_color_types`
  to both the application config and the 3MF config

jira: STUDIO-12346

Change-Id: I66f8c1ec9147df4f5948c8a329c1737551280e63
(cherry picked from commit 522dc0bbca49033a1ba9725ca7f6c3ea729691a6)

src/slic3r/GUI/FilamentBitmapUtils.hpp

@@ -0,0 +1,26 @@
+#ifndef slic3r_GUI_FilamentBitmapUtils_hpp_
+#define slic3r_GUI_FilamentBitmapUtils_hpp_
+
+#include <wx/bitmap.h>
+#include <wx/colour.h>
+#include <vector>
+
+namespace Slic3r { namespace GUI {
+
+enum class FilamentRenderMode {
+    Single,
+    Dual,
+    Triple,
+    Quadruple,
+    Gradient
+};
+
+// Create a colour swatch bitmap. The render mode is chosen automatically from the
+// number of colours unless force_gradient is true.
+wxBitmap create_filament_bitmap(const std::vector<wxColour>& colors,
+                              const wxSize& size,
+                              bool force_gradient = false);
+
+}} // namespace Slic3r::GUI
+
+#endif // slic3r_GUI_FilamentBitmapUtils_hpp_