Support getting of system theme. (#118)

samples/SkijaInjectSample/src/main/kotlin/SkijaInjectSample/App.kt

@@ -7,10 +7,7 @@ import org.jetbrains.skija.paragraph.FontCollection
 import org.jetbrains.skija.paragraph.ParagraphBuilder
 import org.jetbrains.skija.paragraph.ParagraphStyle
 import org.jetbrains.skija.paragraph.TextStyle
-import org.jetbrains.skiko.SkiaLayer
-import org.jetbrains.skiko.SkiaRenderer
-import org.jetbrains.skiko.SkiaWindow
-import org.jetbrains.skiko.toBufferedImage
+import org.jetbrains.skiko.*
 import java.awt.Dimension
 import java.awt.Toolkit
 import java.awt.event.*
@@ -198,7 +195,7 @@ fun displayScene(renderer: Renderer, width: Int, height: Int, nanoTime: Long, xp
     val style = ParagraphStyle()
     val paragraph = ParagraphBuilder(style, fontCollection)
             .pushStyle(TextStyle().setColor(0xFF000000.toInt()))
-            .addText("Graphics API: ${renderer.layer.renderApi} ✿ﾟ")
+            .addText("Graphics API: ${renderer.layer.renderApi} ✿ﾟ ${currentSystemTheme}")
             .popStyle()
             .build()
     paragraph.layout(Float.POSITIVE_INFINITY)

skiko/build.gradle.kts

@@ -461,6 +461,7 @@ tasks.withType(LinkSharedLibrary::class.java).configureEach {
         OS.Windows -> {
             linkerArgs.addAll(
                 listOf(
+                    "Advapi32.lib",
                     "gdi32.lib",
                     "Dwmapi.lib",
                     "opengl32.lib",

skiko/src/jvmMain/cpp/linux/drawlayer.cc

@@ -60,4 +60,11 @@ extern "C"
         JAWT_X11DrawingSurfaceInfo *dsi_x11 = fromJavaPointer<JAWT_X11DrawingSurfaceInfo *>(platformInfoPtr);
         return (float) getDpiScaleByDisplay(dsi_x11->display);
     }
+
+     JNIEXPORT jint JNICALL Java_org_jetbrains_skiko_SystemThemeKt_getCurrentSystemTheme(JNIEnv *env, jobject topLevel)
+     {
+        // Unknown.
+        return 2;
+     }
+
 } // extern "C"
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skiko/src/jvmMain/cpp/windows/drawlayer.cc

@@ -27,4 +27,34 @@ extern "C"
         JAWT_Win32DrawingSurfaceInfo* dsi_win = fromJavaPointer<JAWT_Win32DrawingSurfaceInfo *>(platformInfoPtr);
         return (jlong) dsi_win->hwnd;
     }
+
+    JNIEXPORT jint JNICALL Java_org_jetbrains_skiko_SystemThemeKt_getCurrentSystemTheme(JNIEnv *env, jobject topLevel)
+    {
+        auto subkey = L"Software\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize";
+        auto name = L"AppsUseLightTheme";
+        DWORD result;
+        DWORD result_length = sizeof(result);
+        auto status = RegGetValueW(
+                HKEY_CURRENT_USER,
+                subkey,
+                name,
+                RRF_RT_DWORD,
+                NULL,
+                &result,
+                &result_length
+        );
+        switch (status) {
+            case ERROR_SUCCESS:
+                if (result) {
+                    // Light.
+                    return 0;
+                } else {
+                    // Dark.
+                    return 1;
+                }
+             default:
+                // Unknown.
+                return 2;
+         }
+    }
 } // extern "C"
\ No newline at end of file

skiko/src/jvmMain/kotlin/org/jetbrains/skiko/SystemTheme.kt

+package org.jetbrains.skiko
+
+enum class SystemTheme {
+    DARK,
+    LIGHT,
+    UNKNOWN
+}
+
+val currentSystemTheme: SystemTheme
+    get() = when (getCurrentSystemTheme()) {
+        0 -> SystemTheme.LIGHT
+        1 -> SystemTheme.DARK
+        else -> SystemTheme.UNKNOWN
+    }
+
+// Common
+external private fun getCurrentSystemTheme(): Int

skiko/src/jvmMain/objectiveC/macos/Drawlayer.mm

@@ -191,6 +191,18 @@ JNIEXPORT void JNICALL Java_org_jetbrains_skiko_PlatformOperationsKt_osxDisableT
     });
 }
 
+JNIEXPORT jint JNICALL Java_org_jetbrains_skiko_SystemThemeKt_getCurrentSystemTheme(JNIEnv *env, jobject topLevel)
+{
+    NSString *osxMode = [[NSUserDefaults standardUserDefaults] stringForKey:@"AppleInterfaceStyle"];
+    if ([@"Dark" isEqualToString:osxMode]) {
+        // Dark.
+        return 1;
+    } else {
+        // Light.
+        return 0;
+    }
+}
+
 void getMetalDeviceAndQueue(void** device, void** queue)
 {
     id<MTLDevice> fDevice = MTLCreateSystemDefaultDevice();
@@ -199,4 +211,6 @@ void getMetalDeviceAndQueue(void** device, void** queue)
     *queue = (__bridge void*)fQueue;
 }
 
+
+
 } // extern C
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