apprt/embedded: add API for reporting color scheme

include/ghostty.h

@@ -144,6 +144,11 @@ typedef enum {
     GHOSTTY_TAB_NEXT = -2,
 } ghostty_tab_e;
 
+typedef enum {
+    GHOSTTY_COLOR_SCHEME_LIGHT = 0,
+    GHOSTTY_COLOR_SCHEME_DARK = 1,
+} ghostty_color_scheme_e;
+
 // This is a packed struct (see src/input/mouse.zig) but the C standard
 // afaik doesn't let us reliably define packed structs so we build it up
 // from scratch.
@@ -475,6 +480,7 @@ void ghostty_surface_refresh(ghostty_surface_t);
 void ghostty_surface_set_content_scale(ghostty_surface_t, double, double);
 void ghostty_surface_set_focus(ghostty_surface_t, bool);
 void ghostty_surface_set_size(ghostty_surface_t, uint32_t, uint32_t);
+void ghostty_surface_set_color_scheme(ghostty_surface_t, ghostty_color_scheme_e);
 ghostty_input_mods_e ghostty_surface_key_translation_mods(ghostty_surface_t, ghostty_input_mods_e);
 void ghostty_surface_key(ghostty_surface_t, ghostty_input_key_s);
 void ghostty_surface_text(ghostty_surface_t, const char *, uintptr_t);

src/Surface.zig

@@ -2803,7 +2803,7 @@ fn dragLeftClickBefore(
 
 /// Call to notify Ghostty that the color scheme for the terminal has
 /// changed.
-pub fn colorSchemeCallback(self: *Surface, scheme: apprt.ColorScheme) void {
+pub fn colorSchemeCallback(self: *Surface, scheme: apprt.ColorScheme) !void {
     self.color_scheme = scheme;
 }
 

src/apprt/embedded.zig

@@ -689,6 +689,13 @@ pub const Surface = struct {
         };
     }
 
+    pub fn colorSchemeCallback(self: *Surface, scheme: apprt.ColorScheme) void {
+        self.core_surface.colorSchemeCallback(scheme) catch |err| {
+            log.err("error setting color scheme err={}", .{err});
+            return;
+        };
+    }
+
     pub fn mouseButtonCallback(
         self: *Surface,
         action: input.MouseButtonState,
@@ -1516,6 +1523,19 @@ pub const CAPI = struct {
         surface.updateSize(w, h);
     }
 
+    /// Update the color scheme of the surface.
+    export fn ghostty_surface_set_color_scheme(surface: *Surface, scheme_raw: c_int) void {
+        const scheme = std.meta.intToEnum(apprt.ColorScheme, scheme_raw) catch {
+            log.warn(
+                "invalid color scheme to ghostty_surface_set_color_scheme value={}",
+                .{scheme_raw},
+            );
+            return;
+        };
+
+        surface.colorSchemeCallback(scheme);
+    }
+
     /// Update the content scale of the surface.
     export fn ghostty_surface_set_content_scale(surface: *Surface, x: f64, y: f64) void {
         surface.updateContentScale(x, y);