Bug 573387 - [GTK4] ControlExample fix errors due to GTK3 only functions

- Moved gtk_widget_add_events & their corresponding mask into GTK3 only
guard
- In Text, moved gtk_entry_set_width_chars into previous style check for
SWT.SINGLE and into GTK3 guard
- Replaced gtk_entry_get_layout with GTK4 equivalent
- Proper GTK4 font description retrieval in getFontDescription
- Place gtk_widget_set_redraw_on_allocate &
gtk_widget_set_double_buffered behind GTK3 only guard

Change-Id: I589dc8cf24add948d79b7e527b0868fd9021b41c
Signed-off-by: Paul D'Pong <sdamrong@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.swt/+/180552
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Alexander Kurtakov <akurtako@redhat.com>

5 files changed, 56 insertions, 34 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java
index 8809d0b82a..806e8d6a4b 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Composite.java
@@ -397,20 +397,23 @@ void createHandle (int index, boolean fixed, boolean scrolled) {
 			GTK3.gtk_container_add (handle, socketHandle);
 		}
 	}
-	if ((style & SWT.NO_REDRAW_RESIZE) != 0 && (style & SWT.RIGHT_TO_LEFT) == 0) {
-		GTK3.gtk_widget_set_redraw_on_allocate (handle, false);
-	}
-	/*
-	* Bug in GTK.  When a widget is double buffered and the back
-	* pixmap is null, the double buffer pixmap is filled with the
-	* background of the widget rather than the current contents of
-	* the screen.  If nothing is drawn during an expose event,
-	* the pixels are altered.  The fix is to clear double buffering
-	* when NO_BACKGROUND is set and DOUBLE_BUFFERED
-	* is not explicitly set.
-	*/
-	if ((style & SWT.DOUBLE_BUFFERED) == 0 && (style & SWT.NO_BACKGROUND) != 0) {
-		GTK3.gtk_widget_set_double_buffered (handle, false);
+
+	if (!GTK.GTK4) {
+		if ((style & SWT.NO_REDRAW_RESIZE) != 0 && (style & SWT.RIGHT_TO_LEFT) == 0) {
+			GTK3.gtk_widget_set_redraw_on_allocate (handle, false);
+		}
+		/*
+		* Bug in GTK.  When a widget is double buffered and the back
+		* pixmap is null, the double buffer pixmap is filled with the
+		* background of the widget rather than the current contents of
+		* the screen.  If nothing is drawn during an expose event,
+		* the pixels are altered.  The fix is to clear double buffering
+		* when NO_BACKGROUND is set and DOUBLE_BUFFERED
+		* is not explicitly set.
+		*/
+		if ((style & SWT.DOUBLE_BUFFERED) == 0 && (style & SWT.NO_BACKGROUND) != 0) {
+			GTK3.gtk_widget_set_double_buffered (handle, false);
+		}
 	}
 }
 
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
index 5c3a376c02..8b3be27724 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Control.java
@@ -3139,15 +3139,29 @@ long getFontDescription () {
 		// returns pointer owned by GTK. The workaround is to make a copy of the data.
 		long gtkOwnedPointer = GTK.gtk_style_context_get_font(context, GTK.GTK_STATE_FLAG_NORMAL);
 		return OS.pango_font_description_copy(gtkOwnedPointer);
-	} else if (GTK.GTK4) {
-		GTK.gtk_style_context_get(context, GTK.gtk_style_property_font, fontDesc, 0);
-		return fontDesc [0];
 	} else {
-		GTK.gtk_style_context_save(context);
-		GTK.gtk_style_context_set_state(context, GTK.GTK_STATE_FLAG_NORMAL);
-		GTK.gtk_style_context_get(context, GTK.GTK_STATE_FLAG_NORMAL, GTK.gtk_style_property_font, fontDesc, 0);
-		GTK.gtk_style_context_restore(context);
-		return fontDesc [0];
+		if (GTK.GTK4) {
+			long[] fontPtr = new long[1];
+			long settings = GTK.gtk_settings_get_default();
+			OS.g_object_get(settings, GTK.gtk_style_property_font, fontPtr, 0);
+			if (fontPtr[0] != 0) {
+				int length = C.strlen(fontPtr[0]);
+				if (length != 0) {
+					byte[] fontString = new byte[length + 1];
+					C.memmove(fontString, fontPtr[0], length);
+					OS.g_free(fontPtr[0]);
+					return OS.pango_font_description_from_string(fontString);
+				}
+			}
+
+			return 0;
+		} else {
+			GTK.gtk_style_context_save(context);
+			GTK.gtk_style_context_set_state(context, GTK.GTK_STATE_FLAG_NORMAL);
+			GTK.gtk_style_context_get(context, GTK.GTK_STATE_FLAG_NORMAL, GTK.gtk_style_property_font, fontDesc, 0);
+			GTK.gtk_style_context_restore(context);
+			return fontDesc [0];
+		}
 	}
 }
 
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/DateTime.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/DateTime.java
index fd89010ab5..326070eb24 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/DateTime.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/DateTime.java
@@ -955,15 +955,14 @@ void hookEvents () {
 	if (isCalendar ()) {
 		hookEventsForCalendar ();
 	} else {
-		int eventMask =	GDK.GDK_POINTER_MOTION_MASK | GDK.GDK_BUTTON_PRESS_MASK | GDK.GDK_BUTTON_RELEASE_MASK;
-		GTK3.gtk_widget_add_events (textEntryHandle, eventMask);
-
-
 		if ((style & SWT.DROP_DOWN) == 0 ) {
 			hookEventsForDateTimeSpinner ();
 		}
 
 		if (!GTK.GTK4) {
+			int eventMask =	GDK.GDK_POINTER_MOTION_MASK | GDK.GDK_BUTTON_PRESS_MASK | GDK.GDK_BUTTON_RELEASE_MASK;
+			GTK3.gtk_widget_add_events(textEntryHandle, eventMask);
+
 			if (OS.G_OBJECT_TYPE (textEntryHandle) == GTK3.GTK_TYPE_MENU ()) {
 				hookEventsForMenu ();
 			}
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Sash.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Sash.java
index 576cda7b12..f9b5a23e4f 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Sash.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Sash.java
@@ -484,7 +484,7 @@ long gtk_realize (long widget) {
 @Override
 void hookEvents () {
 	super.hookEvents ();
-	GTK3.gtk_widget_add_events (handle, GDK.GDK_POINTER_MOTION_HINT_MASK);
+	if (!GTK.GTK4) GTK3.gtk_widget_add_events(handle, GDK.GDK_POINTER_MOTION_HINT_MASK);
 }
 
 @Override
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Text.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Text.java
index 851bfa5606..45942fc512 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Text.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Text.java
@@ -234,6 +234,8 @@ void createHandle (int index) {
 		} else {
 			GTK3.gtk_widget_set_has_window(fixedHandle, true);
 			GTK3.gtk_container_add(fixedHandle, handle);
+
+			GTK3.gtk_entry_set_width_chars(handle, 1);
 		}
 
 		GTK.gtk_editable_set_editable(handle, (style & SWT.READ_ONLY) == 0);
@@ -298,9 +300,7 @@ void createHandle (int index) {
 		GTK.gtk_text_view_set_justification (handle, just);
 	}
 	imContext = OS.imContextLast();
-	if ((style & SWT.SINGLE) != 0) {
-		GTK3.gtk_entry_set_width_chars(handle, 1);
-	}
+	
 	// In GTK 3 font description is inherited from parent widget which is not how SWT has always worked,
 	// reset to default font to get the usual behavior
 	setFontDescription(defaultFont().handle);
@@ -613,11 +613,17 @@ Point computeSizeInPixels (int wHint, int hHint, boolean changed) {
 	checkWidget ();
 	if (wHint != SWT.DEFAULT && wHint < 0) wHint = 0;
 	if (hHint != SWT.DEFAULT && hHint < 0) hHint = 0;
-	int[] w = new int [1], h = new int [1];
+	int[] w = new int[1], h = new int[1];
 	if ((style & SWT.SINGLE) != 0) {
-		GTK.gtk_widget_realize (handle);
-		long layout = GTK3.gtk_entry_get_layout (handle);
-		OS.pango_layout_get_pixel_size (layout, w, h);
+		long layout;
+		if (GTK.GTK4) {
+			long context = GTK.gtk_widget_get_pango_context(handle);
+			layout = OS.pango_layout_new(context);
+		} else {
+			GTK.gtk_widget_realize(handle);
+			layout = GTK3.gtk_entry_get_layout(handle);
+		}
+		OS.pango_layout_get_pixel_size(layout, w, h);
 	} else {
 		byte [] start =  new byte [ITER_SIZEOF], end  =  new byte [ITER_SIZEOF];
 		GTK.gtk_text_buffer_get_bounds (bufferHandle, start, end);