fix sprites for pixel ratios that are not 1 and 2

- OpenGL ES 2 doesn't allow NPOT textures with wrap-around
- The Sprite object reported the map's pixelRatio, even though it loaded @2x assets
- Copying icons from the sprite into the atlas now uses bilinear scaling to scale up to the actual size

1 files changed, 15 insertions, 0 deletions

diff --git a/src/mbgl/util/compression.hpp b/src/mbgl/util/compression.hpp
new file mode 100644
index 0000000000..a33b2476a7
--- /dev/null
+++ b/src/mbgl/util/compression.hpp
@@ -0,0 +1,15 @@
+#ifndef MBGL_UTIL_COMPRESSION
+#define MBGL_UTIL_COMPRESSION
+
+#include <string>
+
+namespace mbgl {
+namespace util {
+
+std::string compress(const std::string &raw);
+std::string decompress(const std::string &raw);
+
+}
+}
+
+#endif