Initial revision
diff --git a/Lib/stdwin/Sliders.py b/Lib/stdwin/Sliders.py
new file mode 100755
index 0000000..8953efd
--- /dev/null
+++ b/Lib/stdwin/Sliders.py
@@ -0,0 +1,74 @@
+# Module 'Sliders'
+#
+# Sliders are somewhat like buttons but have an extra hook that is
+# called whenever their value is changed.
+
+import stdwin
+from stdwinevents import *
+import rect
+from minmax import min, max
+from Buttons import ClassicButton
+
+
+# Field indices in event detail
+#
+_HV = 0
+_CLICKS = 1
+_BUTTON = 2
+_MASK = 3
+
+
+# A dragslider is the simplest possible slider.
+# It looks like a button but dragging the mouse left or right
+# changes the controlled value.
+#
+class DragSlider() = ClassicButton():
+ #
+ # INVARIANTS maintained by the define and setval methods:
+ #
+ # self.min <= self.val <= self.max
+ # self.text = `self.val`
+ #
+ # (Notice that unlike in Python ranges, the end point belongs
+ # to the range.)
+ #
+ def define(self, (win, bounds)):
+ self.min = 0
+ self.val = 50
+ self.max = 100
+ self.setval_hook = 0
+ self.pretext = self.postext = ''
+ self.text = self.pretext + `self.val` + self.postext
+ self = ClassicButton.define(self, (win, bounds, self.text))
+ return self
+ #
+ def setval(self, val):
+ val = min(self.max, max(self.min, val))
+ if val <> self.val:
+ self.val = val
+ self.text = self.pretext + `self.val` + self.postext
+ if self.setval_hook:
+ self.setval_hook(self)
+ self.redraw()
+ #
+ def settext(self, text):
+ pass # shouldn't be called at all
+ #
+ def mouse_down(self, detail):
+ h, v = hv = detail[_HV]
+ if self.enabled and self.mousetest(hv):
+ self.anchor = h
+ self.oldval = self.val
+ self.active = 1
+ #
+ def mouse_move(self, detail):
+ if self.active:
+ h, v = detail[_HV]
+ self.setval(self.oldval + (h - self.anchor))
+ #
+ def mouse_up(self, detail):
+ if self.active:
+ h, v = detail[_HV]
+ self.setval(self.oldval + (h - self.anchor))
+ self.active = 0
+ #