Bug 466112 - Use the correct GDK calls to

compute the client area for the monitors

Change-Id: I4d94860d40d2726e98c2416a50c8bc72fa9d9286
Signed-off-by: Stefan Xenos <sxenos@google.com>

6 files changed, 75 insertions, 10 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c
index f16748c0c7..14c8a5d58f 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os.c
@@ -7443,6 +7443,28 @@ JNIEXPORT jint JNICALL OS_NATIVE(_1gdk_1screen_1get_1monitor_1width_1mm)
 }
 #endif
 
+#ifndef NO__1gdk_1screen_1get_1monitor_1workarea
+JNIEXPORT void JNICALL OS_NATIVE(_1gdk_1screen_1get_1monitor_1workarea)
+	(JNIEnv *env, jclass that, jintLong arg0, jint arg1, jobject arg2)
+{
+	GdkRectangle _arg2, *lparg2=NULL;
+	OS_NATIVE_ENTER(env, that, _1gdk_1screen_1get_1monitor_1workarea_FUNC);
+	if (arg2) if ((lparg2 = &_arg2) == NULL) goto fail;
+/*
+	gdk_screen_get_monitor_workarea((GdkScreen *)arg0, arg1, lparg2);
+*/
+	{
+		OS_LOAD_FUNCTION(fp, gdk_screen_get_monitor_workarea)
+		if (fp) {
+			((void (CALLING_CONVENTION*)(GdkScreen *, jint, GdkRectangle *))fp)((GdkScreen *)arg0, arg1, lparg2);
+		}
+	}
+fail:
+	if (arg2 && lparg2) setGdkRectangleFields(env, arg2, lparg2);
+	OS_NATIVE_EXIT(env, that, _1gdk_1screen_1get_1monitor_1workarea_FUNC);
+}
+#endif
+
 #ifndef NO__1gdk_1screen_1get_1n_1monitors
 JNIEXPORT jint JNICALL OS_NATIVE(_1gdk_1screen_1get_1n_1monitors)
 	(JNIEnv *env, jclass that, jintLong arg0)
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_custom.h b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_custom.h
index 0d3a411445..88015a8a01 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_custom.h
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_custom.h
@@ -508,6 +508,7 @@
 #define gtk_style_context_invalidate_LIB LIB_GTK
 #define gtk_hsv_to_rgb_LIB LIB_GTK
 #define gtk_rgb_to_hsv_LIB LIB_GTK
+#define gdk_screen_get_monitor_workarea_LIB LIB_GDK
 #define gdk_window_set_background_pattern_LIB LIB_GTK
 #define gtk_widget_input_shape_combine_region_LIB LIB_GTK
 #define gtk_entry_set_placeholder_text_LIB LIB_GTK
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c
index 5b8b2ceb58..157145a6c0 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.c
@@ -559,6 +559,7 @@ char * OS_nativeFunctionNames[] = {
 	"_1gdk_1screen_1get_1monitor_1at_1window",
 	"_1gdk_1screen_1get_1monitor_1geometry",
 	"_1gdk_1screen_1get_1monitor_1width_1mm",
+	"_1gdk_1screen_1get_1monitor_1workarea",
 	"_1gdk_1screen_1get_1n_1monitors",
 	"_1gdk_1screen_1get_1primary_1monitor",
 	"_1gdk_1screen_1height",
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h
index cba5bbc91f..05432e91b2 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/os_stats.h
@@ -569,6 +569,7 @@ typedef enum {
 	_1gdk_1screen_1get_1monitor_1at_1window_FUNC,
 	_1gdk_1screen_1get_1monitor_1geometry_FUNC,
 	_1gdk_1screen_1get_1monitor_1width_1mm_FUNC,
+	_1gdk_1screen_1get_1monitor_1workarea_FUNC,
 	_1gdk_1screen_1get_1n_1monitors_FUNC,
 	_1gdk_1screen_1get_1primary_1monitor_FUNC,
 	_1gdk_1screen_1height_FUNC,
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/OS.java b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/OS.java
index 97b8d52d23..4114367e95 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/OS.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/org/eclipse/swt/internal/gtk/OS.java
@@ -5497,6 +5497,22 @@ public static final void gdk_screen_get_monitor_geometry (long /*int*/ screen, i
 		lock.unlock();
 	}
 }
+
+/**
+ * @method flags=dynamic
+ * @param screen cast=(GdkScreen *)
+ * @param dest flags=no_in
+ */
+public static final native void _gdk_screen_get_monitor_workarea (long /*int*/ screen, int monitor_num, GdkRectangle dest);
+public static final void gdk_screen_get_monitor_workarea (long /*int*/ screen, int monitor_num, GdkRectangle dest) {
+	lock.lock();
+	try {
+		_gdk_screen_get_monitor_workarea(screen, monitor_num, dest);
+	} finally {
+		lock.unlock();
+	}
+}
+
 /**
  * @method flags=dynamic
  * @param screen cast=(GdkScreen *)
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
index 6afbc710d1..0967eb5d96 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
@@ -1931,7 +1931,7 @@ Rectangle getWorkArea() {
 public Monitor [] getMonitors () {
 	checkDevice ();
 	Monitor [] monitors = null;
-	Rectangle workArea = getWorkArea();
+	Rectangle workArea = getWorkArea ();
 	long /*int*/ screen = OS.gdk_screen_get_default ();
 	if (screen != 0) {
 		int monitorCount = OS.gdk_screen_get_n_monitors (screen);
@@ -1946,16 +1946,40 @@ public Monitor [] getMonitors () {
 				monitor.y = dest.y;
 				monitor.width = dest.width;
 				monitor.height = dest.height;
-				if (i == 0 && workArea != null) {
-					monitor.clientX = workArea.x;
-					monitor.clientY = workArea.y;
-					monitor.clientWidth = workArea.width;
-					monitor.clientHeight = workArea.height;
+
+				if (OS.GTK_VERSION >= OS.VERSION (3, 4, 0)) {
+					// workarea was defined in GTK 3.4. If present, it will return the best results
+					// since it takes into account per-monitor trim
+					OS.gdk_screen_get_monitor_workarea (screen, i, dest);
+					monitor.clientX = dest.x;
+					monitor.clientY = dest.y;
+					monitor.clientWidth = dest.width;
+					monitor.clientHeight = dest.height;
 				} else {
-					monitor.clientX = monitor.x;
-					monitor.clientY = monitor.y;
-					monitor.clientWidth = monitor.width;
-					monitor.clientHeight = monitor.height;
+					// If we're on an older version of gtk without the workarea function, see if we can use
+					// the getWorkArea function. In the case of multi-monitors, this will return something that
+					// is approximately a bounding rectangle for the work areas of all the monitors, so intersecting
+					// that rectangle with the monitor boundaries will provide an approximation of the per-monitor
+					// work area.
+					if (workArea != null) {
+						monitor.clientX = Math.max (monitor.x, workArea.x);
+						monitor.clientY = Math.max (monitor.y, workArea.y);
+						monitor.clientHeight = Math
+								.max(Math.min (monitor.y + monitor.height, workArea.y + workArea.height)
+										- monitor.clientY, 0);
+						monitor.clientWidth = Math.max (
+								Math.min (monitor.x + monitor.width, workArea.x + workArea.width) - monitor.clientX,
+								0);
+					}
+
+					// If getWorkArea is not available or it did not return a rectangle that intersects the monitor
+					// bounds, then use the monitor bounds itself as the work area.
+					if (workArea == null || monitor.clientWidth == 0 || monitor.clientHeight == 0) {
+						monitor.clientX = monitor.x;
+						monitor.clientY = monitor.y;
+						monitor.clientHeight = monitor.height;
+						monitor.clientWidth = monitor.width;
+					}
 				}
 				monitors [i] = monitor;
 			}