Add binding for SkCanvas::getSurface()

skiko/src/commonMain/kotlin/org/jetbrains/skia/Canvas.kt

@@ -55,6 +55,21 @@ open class Canvas internal constructor(ptr: NativePointer, managed: Boolean, int
         reachabilityBarrier(bitmap)
     }
 
+    /**
+     * Sometimes a canvas is owned by a surface.
+     * If it is, [surface] will return that surface, else this will null.
+     *
+     * @return the surface this canvas is owned by, or null if it is not owned by any surface.
+     */
+    val surface: Surface?
+        get() = try {
+            Stats.onNativeCall()
+            val ptr = _nGetSurface(_ptr)
+            if (ptr == NullPointer) null else Surface(ptr)
+        } finally {
+            reachabilityBarrier(this)
+        }
+
     fun drawPoint(x: Float, y: Float, paint: Paint): Canvas {
         Stats.onNativeCall()
         _nDrawPoint(_ptr, x, y, getPtr(paint))
@@ -1241,6 +1256,9 @@ private external fun Canvas_nGetFinalizer(): NativePointer
 @ExternalSymbolName("org_jetbrains_skia_Canvas__1nMakeFromBitmap")
 private external fun _nMakeFromBitmap(bitmapPtr: NativePointer, flags: Int, pixelGeometry: Int): NativePointer
 
+@ExternalSymbolName("org_jetbrains_skia_Canvas__1nGetSurface")
+private external fun _nGetSurface(ptr: NativePointer): NativePointer
+
 @ExternalSymbolName("org_jetbrains_skia_Canvas__1nDrawPoint")
 private external fun _nDrawPoint(ptr: NativePointer, x: Float, y: Float, paintPtr: NativePointer)
 

skiko/src/jvmMain/cpp/common/Canvas.cc

@@ -23,6 +23,13 @@ extern "C" JNIEXPORT jlong JNICALL Java_org_jetbrains_skia_CanvasKt__1nMakeFromB
     return reinterpret_cast<jlong>(canvas);
 }
 
+extern "C" JNIEXPORT jlong JNICALL Java_org_jetbrains_skia_CanvasKt__1nGetSurface
+  (JNIEnv* env, jclass jclass, jlong ptr) {
+    SkCanvas* instance = reinterpret_cast<SkCanvas*>(static_cast<uintptr_t>(ptr));
+    SkSurface* surface = instance->getSurface();
+    return reinterpret_cast<jlong>(surface);
+}
+
 extern "C" JNIEXPORT void JNICALL Java_org_jetbrains_skia_CanvasKt__1nDrawPoint
   (JNIEnv* env, jclass jclass, jlong canvasPtr, jfloat x, jfloat y, jlong paintPtr) {
     SkCanvas* canvas = reinterpret_cast<SkCanvas*>(static_cast<uintptr_t>(canvasPtr));

skiko/src/nativeJsMain/cpp/Canvas.cc

@@ -22,6 +22,13 @@ SKIKO_EXPORT KNativePointer org_jetbrains_skia_Canvas__1nMakeFromBitmap
     return reinterpret_cast<KNativePointer>(canvas);
 }
 
+SKIKO_EXPORT KNativePointer org_jetbrains_skia_CanvasKt__1nGetSurface
+  (KNativePointer ptr) {
+    SkCanvas* instance = reinterpret_cast<SkCanvas*>((ptr));
+    SkSurface* surface = instance->getSurface();
+    return reinterpret_cast<KNativePointer>(surface);
+}
+
 SKIKO_EXPORT void org_jetbrains_skia_Canvas__1nDrawPoint
   (KNativePointer canvasPtr, KFloat x, KFloat y, KNativePointer paintPtr) {
     SkCanvas* canvas = reinterpret_cast<SkCanvas*>((canvasPtr));