As mentioned here and here and here, the GTK version of SWT wastes much space in tables and trees. Even with the GTK theming, rows in trees have still too much space between them:
I spent some time with GDB to find out where the additional padding above and below the text of each item comes from. In the end I found out, that text cell renderers in GTK (gtk/gtkcellrenderertext.c) have a default y-padding of 2 pixels set:
GTK_CELL_RENDERER (celltext)->ypad = 2
While you can’t do much to fix it in Eclipse right now, here’s the hack to make it work for your own SWT programs:
val t: swt.widgets.Tree = //
import swt.internal.gtk.OS
val rendererMethod = t.getClass.getDeclaredMethod("getTextRenderer", java.lang.Long.TYPE)
rendererMethod.setAccessible(true)
val h = OS.gtk_tree_view_get_column (t.handle, 0)
val r = rendererMethod.invoke(t,java.lang.Long.valueOf(h)).asInstanceOf[java.lang.Long].longValue
OS.g_object_set (r, OS.ypad, 0, 0)
With this set, the tree from above looks much more compact:
