[core][iOS] Source iOS styles from default_styles

Moved mbgl::util::default_styles to a more appropriate location, where iOS platform code can also find it. Moved -[MGLMapView bundledStyleURLs] (which is now deprecated) and the style switcher in iosapp to default_styles.

Added a collection of convenience methods for getting style URLs. It makes little sense to layer an enum atop this, as MapKit does, because MGLMapView styles aren’t limited to this set. A good analogy is UIColor. This also makes for a good entry point for future runtime styling APIs.

Introduced independent constants for each default style, because it’s more common to need access to a particular style than to iterate over them. This fact is apparent in the MGLStyle class, which now uses macros and assertions to ensure that it’s kept up-to-date with changes in default_styles.

/ref #1462

1 files changed, 32 insertions, 0 deletions

diff --git a/include/mbgl/util/default_styles.hpp b/include/mbgl/util/default_styles.hpp
new file mode 100644
index 0000000000..3f5b6bd312
--- /dev/null
+++ b/include/mbgl/util/default_styles.hpp
@@ -0,0 +1,32 @@
+#ifndef MBGL_PLATFORM_DEFAULT_STYLES
+#define MBGL_PLATFORM_DEFAULT_STYLES
+
+#include <vector>
+#include <string>
+
+namespace mbgl {
+namespace util {
+namespace default_styles {
+
+struct DefaultStyle {
+    const char* url;
+    const char* name;
+};
+
+extern const DefaultStyle streets;
+extern const DefaultStyle emerald;
+extern const DefaultStyle light;
+extern const DefaultStyle dark;
+extern const DefaultStyle satellite;
+extern const DefaultStyle hybrid;
+
+const DefaultStyle orderedStyles[] = {
+    streets, emerald, light, dark, satellite, hybrid,
+};
+const size_t numOrderedStyles = sizeof(orderedStyles) / sizeof(DefaultStyle);
+
+} // end namespace default_styles
+} // end namespace util
+} // end namespace mbgl
+
+#endif