dgui: fix regression in DirectScrolledFrame (see #699)

Made initialization ignore the setScrollBarWidth function
Respect the length/height of the scrollbar and only change the actual
width in the setScrollBarWidth function
Added a very basic unittest class for the scrolledFrame

Closes #864

direct/src/gui/DirectScrolledFrame.py

@@ -77,9 +77,11 @@ class DirectScrolledFrame(DirectFrame):
         self.initialiseoptions(DirectScrolledFrame)
 
     def setScrollBarWidth(self):
+        if self.fInit: return
+
         w = self['scrollBarWidth']
-        self.verticalScroll["frameSize"] = (-w / 2.0, w / 2.0, -1, 1)
-        self.horizontalScroll["frameSize"] = (-1, 1, -w / 2.0, w / 2.0)
+        self.verticalScroll["frameSize"] = (-w / 2.0, w / 2.0, self.verticalScroll["frameSize"][2], self.verticalScroll["frameSize"][3])
+        self.horizontalScroll["frameSize"] = (self.horizontalScroll["frameSize"][0], self.horizontalScroll["frameSize"][1], -w / 2.0, w / 2.0)
 
     def setCanvasSize(self):
         f = self['canvasSize']

tests/gui/test_DirectScrolledFrame.py

@@ -0,0 +1,36 @@
+from direct.gui.DirectScrolledFrame import DirectScrolledFrame
+import pytest
+
+
+def test_set_scrollbar_width():
+    w = 1
+
+    frm = DirectScrolledFrame(scrollBarWidth=w)
+
+    assert frm['scrollBarWidth'] == 1
+
+    assert frm.verticalScroll['frameSize'] == (-w / 2.0, w / 2.0, -1, 1)
+    assert frm.horizontalScroll['frameSize'] == (-1, 1, -w / 2.0, w / 2.0)
+
+    # manual changes to the framesize
+    frm.verticalScroll['frameSize'] = (-2, 2, -4, 4)
+    frm.horizontalScroll['frameSize'] = (-4, 4, -2, 2)
+    assert frm.verticalScroll['frameSize'] == (-2, 2, -4, 4)
+    assert frm.horizontalScroll['frameSize'] == (-4, 4, -2, 2)
+
+    # change scrollbar width to a new value
+    w = 2
+    frm['scrollBarWidth'] = w
+
+    # check, new value is set correct
+    assert frm['scrollBarWidth'] == 2
+
+    # check if new size is set correct
+    assert frm.verticalScroll['frameSize'] == (-w / 2.0, w / 2.0, -4, 4)
+    assert frm.horizontalScroll['frameSize'] == (-4, 4, -w / 2.0, w / 2.0)
+
+
+def test_set_scrollbar_width_on_init():
+    frm = DirectScrolledFrame(verticalScroll_frameSize=(-2, 2, -4, 4), horizontalScroll_frameSize=(-4, 4, -2, 2))
+    assert frm.verticalScroll['frameSize'] == (-2, 2, -4, 4)
+    assert frm.horizontalScroll['frameSize'] == (-4, 4, -2, 2)