4 files changed, 27 insertions, 2 deletions
diff --git a/include/llmr/style/style_bucket.hpp b/include/llmr/style/style_bucket.hpp
index 1e3cb2db0a..b963caba80 100644
--- a/include/llmr/style/style_bucket.hpp
+++ b/include/llmr/style/style_bucket.hpp
@@ -40,6 +40,7 @@ class StyleBucketText {
 public:
     std::string field;
     TextPathType path = TextPathType::Default;
+    TextTransformType transform = TextTransformType::Default;
     std::string font;
     float max_size = 16.0f;
     float max_width = 15.0f * 24;
diff --git a/include/llmr/style/types.hpp b/include/llmr/style/types.hpp
index 95365947f4..fd862c00d4 100644
--- a/include/llmr/style/types.hpp
+++ b/include/llmr/style/types.hpp
@@ -52,6 +52,13 @@ enum class TextPathType : uint8_t {
     Default = Horizontal
 };
 
+enum class TextTransformType : uint8_t {
+    None,
+    Uppercase,
+    Lowercase,
+    Default = None
+};
+
 enum class TranslateAnchorType : uint8_t {
     Map,
     Viewport,
@@ -98,6 +105,12 @@ inline TextPathType parseTextPathType(const std::string &path) {
     return TextPathType::Default;
 }
 
+inline TextTransformType parseTextTransformType(const std::string& transform) {
+    if (transform == "uppercase") return TextTransformType::Uppercase;
+    if (transform == "lowercase") return TextTransformType::Lowercase;
+    return TextTransformType::Default;
+};
+
 inline TranslateAnchorType parseTranslateAnchorType(const std::string &anchor) {
     if (anchor == "map") return TranslateAnchorType::Map;
     if (anchor == "viewport") return TranslateAnchorType::Viewport;
diff --git a/src/map/tile_parser.cpp b/src/map/tile_parser.cpp
index 02f1a50f5d..c420f81111 100644
--- a/src/map/tile_parser.cpp
+++ b/src/map/tile_parser.cpp
@@ -19,6 +19,8 @@
 #include <llmr/util/std.hpp>
 #include <llmr/util/utf.hpp>
 
+#include <locale>
+
 #ifdef __linux__
 #include <boost/regex.hpp>
 namespace regex_impl = boost;
@@ -208,8 +210,16 @@ std::unique_ptr<Bucket> TileParser::createTextBucket(const VectorTileLayer& laye
                 return nullptr;
             VectorTileFeature feature{feature_pbf, layer};
 
-            const std::u32string string = ucs4conv.convert(
-                util::replaceTokens(properties.field, feature.properties));
+            std::string u8string = util::replaceTokens(properties.field, feature.properties);
+
+            auto& convert = std::use_facet<std::ctype<char>>(std::locale());
+            if (properties.transform == TextTransformType::Uppercase) {
+                convert.toupper(&u8string[0], &u8string[0] + u8string.size());
+            } else if (properties.transform == TextTransformType::Lowercase) {
+                convert.tolower(&u8string[0], &u8string[0] + u8string.size());
+            }
+
+            std::u32string string = ucs4conv.convert(u8string);
 
             // Loop through all characters of this text and collect unique codepoints.
             for (char32_t chr : string) {
diff --git a/src/style/style_parser.cpp b/src/style/style_parser.cpp
index 645f3aa0f3..e33db355e8 100644
--- a/src/style/style_parser.cpp
+++ b/src/style/style_parser.cpp
@@ -890,6 +890,7 @@ void StyleParser::parseRender(JSVal value, std::shared_ptr<StyleLayer> &layer) {
 
         parseRenderProperty(value, render.field, "text-field");
         parseRenderProperty(value, render.path, "text-path", parseTextPathType);
+        parseRenderProperty(value, render.transform, "text-transform", parseTextTransformType);
         parseRenderProperty(value, render.font, "text-font");
         parseRenderProperty(value, render.max_size, "text-max-size");
         if (parseRenderProperty(value, render.max_width, "text-max-width")) {