[GTK3] Issue 371 - Fix crash when taking a snapshot on Wayland

In short, our implementation doesn't seem to support taking snapshots of
partially unmapped widgets when running Wayland instead of X11.

Instead of trying to implement a workaround in native code, I think it's
more efficient (for both the sake of complexity and maintainability) to
elevate our snapshot mechanism from C to Java code. Where necessary, we
call the native GTK methods either by the GTK/GDK class or via wrapper
methods implemented by WindowBuilder.

The snapshot is taken by creating a new image using the bounds of the
widget and by painting the area it's occupying on the screen via GC.
Note that this approach assumes that the widget isn't obstructed. But a
similar restriction already exists on the native implementation.

Shells represent a special edge-case. Instead of only taking a snapshot
of the client area, the whole shell is considered. This way the title
bar is included as well, rendering the explicit painting of its
decorations obsolete.

Author: ptziegler

org.eclipse.wb.os.linux/build.properties

@@ -4,6 +4,5 @@ bin.includes = META-INF/,\
                .,\
                plugin.xml,\
                os/,\
-               icons/,\
                plugin.properties,\
                about.html

org.eclipse.wb.os.linux/icons/decorations/button-close-icon.png

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2011 Google, Inc.
+ * Copyright (c) 2011, 2023 Google, Inc.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -196,6 +196,42 @@ static cairo_surface_t* fetchMenuVisualData(GtkMenu *menu, JNIEnv *envir, jintAr
 // JNI
 //
 ////////////////////////////////////////////////////////////////////////////
+JNIEXPORT jboolean JNICALL 
+	OS_NATIVE(_1gdk_1window_1is_1visible)
+		(JNIEnv *envir, jobject that, JHANDLE windowHandle) {
+	return gdk_window_is_visible((GdkWindow*)unwrap_pointer(envir, windowHandle));
+}
+JNIEXPORT void JNICALL 
+	OS_NATIVE(_1gdk_1window_1get_1geometry)
+		(JNIEnv *envir, jobject that, JHANDLE windowHandle, jintArray x, jintArray y, jintArray width, jintArray height) {
+	jint x1;
+	jint y1;
+	jint width1;
+	jint height1;
+	gdk_window_get_geometry((GdkWindow*)unwrap_pointer(envir, windowHandle), &x1, &y1, &width1, &height1);
+	if (x != NULL) {
+		(*envir) -> SetIntArrayRegion(envir, x, 0, 1, &x1);
+	}
+	if (y != NULL) {
+		(*envir) -> SetIntArrayRegion(envir, y, 0, 1, &y1);
+	}
+	if (width != NULL) {
+		(*envir) -> SetIntArrayRegion(envir, width, 0, 1, &width1);
+	}
+	if (height != NULL) {
+		(*envir) -> SetIntArrayRegion(envir, height, 0, 1, &height1);
+	}
+}
+JNIEXPORT JHANDLE JNICALL 
+	OS_NATIVE(_1gtk_1widget_1get_1window)
+		(JNIEnv *envir, jobject that, JHANDLE widgetHandle) {
+	return (JHANDLE)wrap_pointer(envir, gtk_widget_get_window((GtkWidget*)unwrap_pointer(envir, widgetHandle)));
+}
+JNIEXPORT JHANDLE JNICALL 
+	OS_NATIVE(_1gdk_1window_1process_1updates)
+		(JNIEnv *envir, jobject that, JHANDLE widgetHandle, jboolean update_children) {
+	gdk_window_process_updates((GdkWindow*)unwrap_pointer(envir, widgetHandle), update_children);
+}
 JNIEXPORT jboolean JNICALL 
 	OS_NATIVE(_1toggle_1above)
 		(JNIEnv *envir, jobject that, JHANDLE widgetHandle, jboolean forceToggle) {
@@ -216,26 +252,6 @@ JNIEXPORT jboolean JNICALL
 	gtk_widget_hide((GtkWidget*)unwrap_pointer(envir, widgetHandle));
 	return JNI_TRUE;
 }
-// shot
-JNIEXPORT JHANDLE JNICALL OS_NATIVE(_1makeShot)(
-			JNIEnv *envir, jobject that, JHANDLE widgetHandle, jobject callback) {
-	m_envir = envir;
-	if (callback != NULL) {
-		m_callback = (*envir)->NewGlobalRef(envir, callback);
-		jclass clazz = (*envir)->GetObjectClass(envir, m_callback);
-		m_IScreenshotCallback_storeImage = (*envir)->GetMethodID(envir, clazz, "storeImage", CALLBACK_SIG);
-		/* uncomment this for debug purposes
-		m_IScreenshotCallback_log = (*envir)->GetMethodID(envir, clazz, "log", "(Ljava/lang/String;)V"); */
-	}
-	// make shot
-	cairo_surface_t* surface = makeShot((GtkWidget*)unwrap_pointer(envir, widgetHandle));
-	// clean up
-	if (callback != NULL) {
-		(*envir)->DeleteGlobalRef(envir, m_callback);
-	}
-	m_callback = NULL;
-	return (JHANDLE)wrap_pointer(envir, surface);
-}
 // menu
 JNIEXPORT JHANDLE JNICALL OS_NATIVE(_1fetchMenuVisualData)(
 			JNIEnv *envir, jobject that, JHANDLE jmenuHandle, jintArray jsizes) {
@@ -248,11 +264,6 @@ JNIEXPORT void JNICALL OS_NATIVE(_1getWidgetBounds)(
 			JNIEnv *envir, jobject that, JHANDLE jhandle, jintArray jsizes) {
 	getWidgetBounds((GtkWidget*)unwrap_pointer(envir, jhandle), envir, jsizes);
 }
-// unref
-JNIEXPORT void JNICALL OS_NATIVE(_1disposeImageHandle)(
-			JNIEnv *envir, jobject that, JHANDLE jhandle) {
-	cairo_surface_destroy((cairo_surface_t*)unwrap_pointer(envir, jhandle));
-}
 // other
 static int isValidVersion() {
 	return gtk_major_version == 3 && gtk_minor_version >= 0;