GskCanavas: draw default content when custom View calls super.onDraw()

src/api-impl-jni/generated_headers/android_graphics_drawable_Drawable.h

@@ -31,6 +31,14 @@ JNIEXPORT jlong JNICALL Java_android_graphics_drawable_Drawable_native_1construc
 JNIEXPORT void JNICALL Java_android_graphics_drawable_Drawable_native_1invalidate
   (JNIEnv *, jobject, jlong);
 
+/*
+ * Class:     android_graphics_drawable_Drawable
+ * Method:    native_draw
+ * Signature: (JJII)V
+ */
+JNIEXPORT void JNICALL Java_android_graphics_drawable_Drawable_native_1draw
+  (JNIEnv *, jobject, jlong, jlong, jint, jint);
+
 #ifdef __cplusplus
 }
 #endif

src/api-impl-jni/generated_headers/android_view_View.h

@@ -199,6 +199,14 @@ extern "C" {
 #define android_view_View_TEXT_DIRECTION_LTR 3L
 #undef android_view_View_TEXT_DIRECTION_RTL
 #define android_view_View_TEXT_DIRECTION_RTL 4L
+/*
+ * Class:     android_view_View
+ * Method:    native_onDraw
+ * Signature: (JJ)V
+ */
+JNIEXPORT void JNICALL Java_android_view_View_native_1onDraw
+  (JNIEnv *, jobject, jlong, jlong);
+
 /*
  * Class:     android_view_View
  * Method:    setOnTouchListener

src/api-impl-jni/graphics/android_graphics_drawable_Drawable.c

@@ -89,3 +89,9 @@ JNIEXPORT jlong JNICALL Java_android_graphics_drawable_Drawable_native_1construc
 JNIEXPORT void JNICALL Java_android_graphics_drawable_Drawable_native_1invalidate(JNIEnv *env, jobject this, jlong paintable_ptr) {
 	gdk_paintable_invalidate_contents(GDK_PAINTABLE(_PTR(paintable_ptr)));
 }
+
+JNIEXPORT void JNICALL Java_android_graphics_drawable_Drawable_native_1draw(JNIEnv *env, jobject this, jlong paintable_ptr, jlong snapshot_ptr, jint width, jint height) {
+	GdkSnapshot *snapshot = (GdkSnapshot *)_PTR(snapshot_ptr);
+	GdkPaintable *paintable = GDK_PAINTABLE(_PTR(paintable_ptr));
+	gdk_paintable_snapshot(paintable, snapshot, width, height);
+}

src/api-impl-jni/views/android_view_View.c

@@ -583,3 +583,9 @@ JNIEXPORT void JNICALL Java_android_view_View_native_1queueAllocate(JNIEnv *env,
 {
 	gtk_widget_queue_allocate(GTK_WIDGET(_PTR(widget_ptr)));
 }
+
+JNIEXPORT void JNICALL Java_android_view_View_native_1onDraw(JNIEnv *env, jobject this, jlong widget_ptr, jlong snapshot_ptr)
+{
+	WrapperWidget *wrapper = WRAPPER_WIDGET(gtk_widget_get_parent(GTK_WIDGET(_PTR(widget_ptr))));
+	wrapper_widget_draw_children(wrapper, GDK_SNAPSHOT(_PTR(snapshot_ptr)));
+}

src/api-impl-jni/widgets/WrapperWidget.c

@@ -94,23 +94,30 @@ void wrapper_widget_allocate(GtkWidget *widget, int width, int height, int basel
 		gtk_widget_size_allocate(wrapper->background, &allocation, baseline);
 }
 
+void wrapper_widget_draw_children(WrapperWidget *wrapper, GdkSnapshot *snapshot)
+{
+	GtkWidget *widget = &wrapper->parent_instance;
+	GtkWidget *child = gtk_widget_get_first_child(widget);
+	while (child) {
+		gtk_widget_snapshot_child(widget, child, snapshot);
+		child = gtk_widget_get_next_sibling(child);
+	}
+}
+
 static void wrapper_widget_snapshot(GtkWidget *widget, GdkSnapshot *snapshot)
 {
 	WrapperWidget *wrapper = WRAPPER_WIDGET(widget);
 	if (wrapper->real_height > 0 && wrapper->real_width > 0) {
 		gtk_snapshot_push_clip(snapshot, &GRAPHENE_RECT_INIT(0, 0, wrapper->real_width, wrapper->real_height));
 	}
-	GtkWidget *child = gtk_widget_get_first_child(widget);
-	while (child) {
-		gtk_widget_snapshot_child(widget, child, snapshot);
-		child = gtk_widget_get_next_sibling(child);
-	}
 	if (wrapper->draw_method) {
 		JNIEnv *env = get_jni_env();
 		_SET_LONG_FIELD(wrapper->canvas, "snapshot", _INTPTR(snapshot));
 		(*env)->CallVoidMethod(env, wrapper->jobj, wrapper->draw_method, wrapper->canvas);
 		if ((*env)->ExceptionCheck(env))
 			(*env)->ExceptionDescribe(env);
+	} else {
+		wrapper_widget_draw_children(wrapper, snapshot);
 	}
 	if (wrapper->real_height > 0 && wrapper->real_width > 0) {
 		gtk_snapshot_pop(snapshot);

src/api-impl-jni/widgets/WrapperWidget.h

@@ -35,6 +35,7 @@ void wrapper_widget_set_jobject(WrapperWidget *wrapper, JNIEnv *env, jobject job
 void wrapper_widget_queue_draw(WrapperWidget *wrapper);
 void wrapper_widget_set_layout_params(WrapperWidget *wrapper, int width, int height);
 void wrapper_widget_set_background(WrapperWidget *wrapper, GdkPaintable *paintable);
+void wrapper_widget_draw_children(WrapperWidget *wrapper, GdkSnapshot *snapshot);
 
 void _setOnTouchListener(JNIEnv *env, jobject this, GtkWidget *widget, jobject on_touch_listener);
 

src/api-impl/android/graphics/GskCanvas.java

@@ -5,7 +5,7 @@ package android.graphics;
  *   - implements Canvas for onscreen rendering inside GTKs snapshot function
  */
 public class GskCanvas extends Canvas {
-	private long snapshot;
+	public long snapshot;
 	private int save_count = 0;
 
 	public GskCanvas(long snapshot) {

src/api-impl/android/graphics/drawable/Drawable.java

@@ -17,6 +17,7 @@ import android.content.res.Resources.Theme;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.ColorFilter;
+import android.graphics.GskCanvas;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffColorFilter;
 import android.graphics.Rect;
@@ -74,7 +75,10 @@ public class Drawable {
 		return mBounds;
 	}
 
-	public void draw(Canvas canvas) {}
+	public void draw(Canvas canvas) {
+		if (canvas instanceof GskCanvas)
+			native_draw(paintable, ((GskCanvas)canvas).snapshot, mBounds.width(), mBounds.height());
+	}
 
 	public boolean setState(int[] stateSet) {
 		if (!Arrays.equals(this.mStateSet, stateSet)) {
@@ -261,4 +265,5 @@ public class Drawable {
 	protected static native long native_paintable_from_path(String path);
 	protected native long native_constructor();
 	protected native void native_invalidate(long paintable);
+	protected native void native_draw(long paintable, long snapshot, int width, int height);
 }

src/api-impl/android/view/View.java

@@ -7,6 +7,7 @@ import android.content.res.ColorStateList;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
+import android.graphics.GskCanvas;
 import android.graphics.Matrix;
 import android.graphics.Paint;
 import android.graphics.Rect;
@@ -899,7 +900,11 @@ public class View implements Drawable.Callback {
 			return null;
 	}
 
-	public void onDraw(Canvas canvas) {}
+	protected native void native_onDraw(long widget, long snapshot);
+	public void onDraw(Canvas canvas) {
+		if (canvas instanceof GskCanvas)
+			native_onDraw(widget, ((GskCanvas)canvas).snapshot);
+	}
 	public void draw(Canvas canvas) {
 		onDraw(canvas);
 	}