Fixes : #662

The default intercell spacing value that is obtained from Cocoa for
width is 17. So providing a HCELL_GAP value of 17 for width and
retaining the same value of 1 for height. VCELL_GAP is 1.

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Table.java

@@ -91,7 +91,9 @@ public class Table extends Composite {
 	static final int FIRST_COLUMN_MINIMUM_WIDTH = 5;
 	static final int IMAGE_GAP = 3;
 	static final int TEXT_GAP = 2;
-	static final int CELL_GAP = 1;
+	/*Default Horizontal inter-cell spacing value obtained from Cocoa is 17*/
+	static final int HCELL_GAP = 17;
+	static final int VCELL_GAP =1;
 
 /**
  * Constructs a new instance of this class given its parent
@@ -473,7 +475,7 @@ public Point computeSize (int wHint, int hHint, boolean changed) {
 			}
 		} else {
 			GC gc = new GC (this);
-			width += calculateWidth (items, 0, gc) + CELL_GAP;
+			width += calculateWidth (items, 0, gc) + HCELL_GAP;
 			gc.dispose ();
 		}
 		if ((style & SWT.CHECK) != 0) width += getCheckColumnWidth ();
@@ -549,7 +551,8 @@ void createHandle () {
 	widget.setDelegate(widget);
 	widget.setColumnAutoresizingStyle (OS.NSTableViewNoColumnAutoresizing);
 	NSSize spacing = new NSSize();
-	spacing.width = spacing.height = CELL_GAP;
+	spacing.width= HCELL_GAP;
+	spacing.height = VCELL_GAP;
 	widget.setIntercellSpacing(spacing);
 	widget.setDoubleAction(OS.sel_sendDoubleSelection);
 
@@ -1661,7 +1664,7 @@ public int getItemCount () {
  */
 public int getItemHeight () {
 	checkWidget ();
-	return (int)((NSTableView)view).rowHeight() + CELL_GAP;
+	return (int)((NSTableView)view).rowHeight() + VCELL_GAP;
 }
 
 /**
@@ -1911,8 +1914,8 @@ NSRect headerRectOfColumn (long id, long sel, long column) {
 	if (column == 1) {
 		NSRect returnValue = callSuperRect(id, sel, column);
 		// Save a call to [NSTableView intercellSpacing] by using our constant.
-		returnValue.width += (checkColumn.width() + CELL_GAP);
-		returnValue.x -= (checkColumn.width() + CELL_GAP);
+		returnValue.width += (checkColumn.width() + HCELL_GAP);
+		returnValue.x -= (checkColumn.width() + HCELL_GAP);
 		return returnValue;
 	}
 	return callSuperRect(id, sel, column);

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/TableColumn.java

@@ -508,7 +508,7 @@ public int getWidth () {
 	checkWidget ();
 	int width = (int)nsColumn.width();
 	// TODO how to differentiate 0 and 1 cases?
-	if (width > 0) width += Table.CELL_GAP;
+	if (width > 0) width += Table.HCELL_GAP;
 	return width;
 }
 
@@ -774,7 +774,7 @@ public void setWidth (int width) {
 	checkWidget ();
 	if (width < 0) return;
 	// TODO how to differentiate 0 and 1 cases?
-	width = Math.max (0, width - Table.CELL_GAP);
+	width = Math.max (0, width - Table.HCELL_GAP);
 	nsColumn.setWidth (width);
 }
 

bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/TableItem.java

@@ -186,7 +186,7 @@ int calculateWidth (int index, GC gc, boolean rowSelected) {
 		width = event.width;
 	}
 	if (index == 0) this.width = width;
-	return width;
+	return width+Table.HCELL_GAP;
 }
 
 @Override