Initial revision

4 files changed, 942 insertions, 0 deletions

diff --git a/Lib/lib-stdwin/Buttons.py b/Lib/lib-stdwin/Buttons.py
new file mode 100644
index 0000000000..d6ad6e3111
--- /dev/null
+++ b/Lib/lib-stdwin/Buttons.py
@@ -0,0 +1,397 @@
+# Module 'Buttons' -- see README
+#
+# Module functionality is now split in two parts:
+# - 'appearance' defines what it looks like
+# - 'reactivity' defines how it acts to mouse events
+
+
+# Import module 'rect' renamed as '_rect'
+#
+import rect
+_rect = rect
+del rect
+
+
+# Field indices in mouse event detail
+#
+_HV = 0
+_CLICKS = 1
+_BUTTON = 2
+_MASK = 3
+
+
+# BaseAppearance provides defaults for all appearance methods.
+# In fact it looks like a label.
+#
+class BaseAppearance():
+	#
+	# Initialization
+	#
+	def init_appearance(self, (win, bounds)):
+		win.change(bounds)
+		self.win = win
+		self.bounds = bounds
+		self.enabled = 1
+		self.hilited = 0
+		self.selected = 0
+		self.text = ''
+	#
+	# Changing the parameters
+	#
+	def settext(self, text):
+		self.text = text
+		self.redraw()
+	#
+	def setbounds(self, bounds):
+		# This elays drawing until after all buttons are moved
+		self.win.change(self.bounds)
+		self.bounds = bounds
+		self.win.change(bounds)
+	#
+	# Changing the state bits
+	#
+	def enable(self, flag):
+		if flag <> self.enabled:
+			self.enabled = flag
+			self.flipenable(self.win.begindrawing())
+	#
+	def hilite(self, flag):
+		if flag <> self.hilited:
+			self.hilited = flag
+			self.fliphilite(self.win.begindrawing())
+	#
+	def select(self, flag):
+		if flag <> self.selected:
+			self.selected = flag
+			self.redraw()
+	#
+	# Generic drawing mechanism.
+	# There should be no reason to override redraw() or draw() methods.
+	#
+	def redraw(self):
+		self.draw(self.win.begindrawing(), self.bounds)
+	#
+	def draw(self, (d, area)):
+		area = _rect.intersect(area, self.bounds)
+		if area = _rect.empty:
+			return
+		d.cliprect(area)
+		d.erase(self.bounds)
+		self.drawit(d)
+		d.noclip()
+	#
+	# The drawit() method is fairly generic but may be overridden.
+	#
+	def drawit(self, d):
+		self.drawpict(d)	# Box, circle etc.; also 'selected'
+		if self.text:
+			hv = self.textpos(d)
+			d.text(hv, self.text)
+		if not self.enabled:
+			self.flipenable(d)
+		if self.hilited:
+			self.fliphilite(d)
+	#
+	# Default drawing detail functions.
+	# Overriding these is normally sufficient to get different
+	# appearances.
+	# No picture; centered text; enable crosses out; hilite inverts.
+	#
+	def drawpict(self, d):
+		pass
+	#
+	def textpos(self, d):
+		# XXX shouldn't this be done once by init/settext()?
+		(left, top), (right, bottom) = self.bounds
+		h = (left + right - d.textwidth(self.text)) / 2
+		v = (top + bottom - d.lineheight()) / 2
+		return h, v
+	#
+	def flipenable(self, d):
+		_xorcross(d, self.bounds)
+	#
+	def fliphilite(self, d):
+		d.invert(_rect.inset(self.bounds, (3, 3)))
+
+
+# Subroutine to cross out a rectangle.
+#
+def _xorcross(d, bounds):
+	((left, top), (right, bottom)) = bounds
+	left = left + 2
+	right = right - 2
+	top = top + 2
+	bottom = bottom - 3
+	d.xorline(((left, top), (right, bottom)))
+	d.xorline((left, bottom), (right, top))
+
+
+# LabelAppearance displays a centered string.
+# selected --> underlined
+# disabled --> crossed out
+# hilited  --> inverted
+#
+class LabelAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		if self.selected:
+			# Underline it
+			d.line((left+1, bottom-1), (right-1, bottom-1))
+		#
+		if not self.enabled: self._crossout(d)
+		if self.hilited: self._invert(d)
+	#
+
+
+# ButtonAppearance displays a centered string in a box.
+# selected --> bold border
+# disabled --> crossed out
+# hilited  --> inverted
+#
+class ButtonAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		d.box(_rect.inset(self.bounds, (1, 1)))
+		if self.selected:
+			# Make a thicker box
+			d.box(self.bounds)
+			d.box(_rect.inset(self.bounds, (2, 2)))
+			d.box(_rect.inset(self.bounds, (3, 3)))
+	#
+
+
+# CheckAppearance displays a small square box and a left-justified string.
+# selected --> a cross appears in the box
+# disabled --> whole button crossed out
+# hilited  --> box is inverted
+#
+class CheckAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		boxbounds = (left, top), (left+size, bottom)
+		d.box(boxbounds)
+		if self.selected: _xorcross(d, boxbounds)
+	#
+	def textpos(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		h = left + size + d.textwidth(' ')
+		v = top + (size - d.lineheight()) / 2
+		return h, v
+	#
+	def fliphilite(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		boxbounds = (left, top), (left+size, bottom)
+		d.invert(boxbounds)
+	#
+
+
+# RadioAppearance displays a round indicator and a left-justified string.
+# selected --> a dot appears in the indicator
+# disabled --> whole button crossed out
+# hilited  --> indicator is inverted
+#
+class RadioAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		radius = size / 2
+		h, v = left + radius, top + radius
+		d.circle((h, v), radius - 1)
+		if self.selected:
+			some = radius/3
+			d.paint((h-some, v-some), (h+some, v+some))
+	#
+	def textpos(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		h = left + size + d.textwidth(' ')
+		v = top + (size - d.lineheight()) / 2
+		return h, v
+	#
+	def fliphilite(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		d.invert((left, top), (left + size, bottom))
+	#
+
+
+# NoReactivity ignores mouse and timer events.
+# The trigger methods call the corresponding hooks set by the user.
+# Hooks (and triggers) mean the following:
+# down_hook	called on some mouse-down events
+# active_hook	called on some mouse-move events
+# up_hook	called on mouse-up events
+# on_hook	called for buttons with on/off state, when it goes on
+# timer_hook	called on timer events
+# hook		called when a button 'fires' or a radiobutton goes on
+# There are usually extra conditions, e.g., hooks are only called
+# when the button is enabled, or active, or selected (on).
+#
+class NoReactivity():
+	#
+	def init_reactivity(self):
+		self.down_hook = self.active_hook = self.up_hook = \
+		  self.on_hook = self.off_hook = self.timer_hook = \
+		  self.hook = self.active = 0
+	#
+	def mousetest(self, hv):
+		return _rect.pointinrect(hv, self.bounds)
+	#
+	def mouse_down(self, detail):
+		pass
+	#
+	def mouse_move(self, detail):
+		pass
+	#
+	def mouse_up(self, detail):
+		pass
+	#
+	def timer(self):
+		pass
+	#
+	def down_trigger(self):
+		if self.down_hook: self.down_hook(self)
+	#
+	def active_trigger(self):
+		if self.active_hook: self.active_hook(self)
+	#
+	def up_trigger(self):
+		if self.up_hook: self.up_hook(self)
+	#
+	def on_trigger(self):
+		if self.on_hook: self.on_hook(self)
+	#
+	def off_trigger(self):
+		if self.off_hook: self.off_hook(self)
+	#
+	def timer_trigger(self):
+		if self.timer_hook: self.timer_hook(self)
+	#
+	def trigger(self):
+		if self.hook: self.hook(self)
+
+
+# ToggleReactivity acts like a simple pushbutton.
+# It toggles its hilite state on mouse down events.
+# Its timer_trigger method is called for all timer events while hilited.
+#
+class ToggleReactivity() = NoReactivity():
+	#
+	def mouse_down(self, detail):
+		if self.enabled and self.mousetest(detail[_HV]):
+			self.active = 1
+			self.hilite(not self.hilited)
+			self.down_trigger()
+	#
+	def mouse_move(self, detail):
+		if self.active:
+			self.active_trigger()
+	#
+	def mouse_up(self, detail):
+		if self.active:
+			self.up_trigger()
+			self.active = 0
+	#
+	def timer(self):
+		if self.hilited:
+			self.timer_trigger()
+	#
+	def down_trigger(self):
+		if self.hilited:
+			self.on_trigger()
+		else:
+			self.off_trigger()
+		self.trigger()
+	#
+
+
+# TriggerReactivity acts like a fancy pushbutton.
+# It hilites itself while the mouse is down within its bounds.
+#
+class TriggerReactivity() = NoReactivity():
+	#
+	def mouse_down(self, detail):
+		if self.enabled and self.mousetest(detail[_HV]):
+			self.active = 1
+			self.hilite(1)
+			self.down_trigger()
+	#
+	def mouse_move(self, detail):
+		if self.active:
+			self.hilite(self.mousetest(detail[_HV]))
+			if self.hilited:
+				self.active_trigger()
+	#
+	def mouse_up(self, detail):
+		if self.active:
+			self.hilite(self.mousetest(detail[_HV]))
+			if self.hilited:
+				self.up_trigger()
+				self.trigger()
+			self.active = 0
+			self.hilite(0)
+	#
+	def timer(self):
+		if self.active and self.hilited:
+			self.active_trigger()
+	#
+
+
+# CheckReactivity handles mouse events like TriggerReactivity,
+# It overrides the up_trigger method to flip its selected state.
+#
+class CheckReactivity() = TriggerReactivity():
+	#
+	def up_trigger(self):
+		self.select(not self.selected)
+		if self.selected:
+			self.on_trigger()
+		else:
+			self.off_trigger()
+		self.trigger()
+
+
+# RadioReactivity turns itself on and the other buttons in its group
+# off when its up_trigger method is called.
+#
+class RadioReactivity() = TriggerReactivity():
+	#
+	def init_reactivity(self):
+		TriggerReactivity.init_reactivity(self)
+		self.group = []
+	#
+	def up_trigger(self):
+		for b in self.group:
+			if b <> self:
+				if b.selected:
+					b.select(0)
+					b.off_trigger()
+		self.select(1)
+		self.on_trigger()
+		self.trigger()
+
+
+# Auxiliary class for 'define' method.
+#
+class Define():
+	#
+	def define(self, (win, bounds, text)):
+		self.init_appearance(win, bounds)
+		self.text = text
+		self.init_reactivity()
+		return self
+
+
+# Ready-made button classes
+#
+class BaseButton() = NoReactivity(), BaseAppearance(), Define(): pass
+class Label() = NoReactivity(), LabelAppearance(), Define(): pass
+class ClassicButton() = TriggerReactivity(), ButtonAppearance(), Define(): pass
+class CheckButton() = CheckReactivity(), CheckAppearance(), Define(): pass
+class RadioButton() = RadioReactivity(), RadioAppearance(), Define(): pass
+class Toggle() = ToggleReactivity(), ButtonAppearance(), Define(): pass
diff --git a/Lib/lib-stdwin/Sliders.py b/Lib/lib-stdwin/Sliders.py
new file mode 100644
index 0000000000..8953efd166
--- /dev/null
+++ b/Lib/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
+	#
diff --git a/Lib/stdwin/Buttons.py b/Lib/stdwin/Buttons.py
new file mode 100755
index 0000000000..d6ad6e3111
--- /dev/null
+++ b/Lib/stdwin/Buttons.py
@@ -0,0 +1,397 @@
+# Module 'Buttons' -- see README
+#
+# Module functionality is now split in two parts:
+# - 'appearance' defines what it looks like
+# - 'reactivity' defines how it acts to mouse events
+
+
+# Import module 'rect' renamed as '_rect'
+#
+import rect
+_rect = rect
+del rect
+
+
+# Field indices in mouse event detail
+#
+_HV = 0
+_CLICKS = 1
+_BUTTON = 2
+_MASK = 3
+
+
+# BaseAppearance provides defaults for all appearance methods.
+# In fact it looks like a label.
+#
+class BaseAppearance():
+	#
+	# Initialization
+	#
+	def init_appearance(self, (win, bounds)):
+		win.change(bounds)
+		self.win = win
+		self.bounds = bounds
+		self.enabled = 1
+		self.hilited = 0
+		self.selected = 0
+		self.text = ''
+	#
+	# Changing the parameters
+	#
+	def settext(self, text):
+		self.text = text
+		self.redraw()
+	#
+	def setbounds(self, bounds):
+		# This elays drawing until after all buttons are moved
+		self.win.change(self.bounds)
+		self.bounds = bounds
+		self.win.change(bounds)
+	#
+	# Changing the state bits
+	#
+	def enable(self, flag):
+		if flag <> self.enabled:
+			self.enabled = flag
+			self.flipenable(self.win.begindrawing())
+	#
+	def hilite(self, flag):
+		if flag <> self.hilited:
+			self.hilited = flag
+			self.fliphilite(self.win.begindrawing())
+	#
+	def select(self, flag):
+		if flag <> self.selected:
+			self.selected = flag
+			self.redraw()
+	#
+	# Generic drawing mechanism.
+	# There should be no reason to override redraw() or draw() methods.
+	#
+	def redraw(self):
+		self.draw(self.win.begindrawing(), self.bounds)
+	#
+	def draw(self, (d, area)):
+		area = _rect.intersect(area, self.bounds)
+		if area = _rect.empty:
+			return
+		d.cliprect(area)
+		d.erase(self.bounds)
+		self.drawit(d)
+		d.noclip()
+	#
+	# The drawit() method is fairly generic but may be overridden.
+	#
+	def drawit(self, d):
+		self.drawpict(d)	# Box, circle etc.; also 'selected'
+		if self.text:
+			hv = self.textpos(d)
+			d.text(hv, self.text)
+		if not self.enabled:
+			self.flipenable(d)
+		if self.hilited:
+			self.fliphilite(d)
+	#
+	# Default drawing detail functions.
+	# Overriding these is normally sufficient to get different
+	# appearances.
+	# No picture; centered text; enable crosses out; hilite inverts.
+	#
+	def drawpict(self, d):
+		pass
+	#
+	def textpos(self, d):
+		# XXX shouldn't this be done once by init/settext()?
+		(left, top), (right, bottom) = self.bounds
+		h = (left + right - d.textwidth(self.text)) / 2
+		v = (top + bottom - d.lineheight()) / 2
+		return h, v
+	#
+	def flipenable(self, d):
+		_xorcross(d, self.bounds)
+	#
+	def fliphilite(self, d):
+		d.invert(_rect.inset(self.bounds, (3, 3)))
+
+
+# Subroutine to cross out a rectangle.
+#
+def _xorcross(d, bounds):
+	((left, top), (right, bottom)) = bounds
+	left = left + 2
+	right = right - 2
+	top = top + 2
+	bottom = bottom - 3
+	d.xorline(((left, top), (right, bottom)))
+	d.xorline((left, bottom), (right, top))
+
+
+# LabelAppearance displays a centered string.
+# selected --> underlined
+# disabled --> crossed out
+# hilited  --> inverted
+#
+class LabelAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		if self.selected:
+			# Underline it
+			d.line((left+1, bottom-1), (right-1, bottom-1))
+		#
+		if not self.enabled: self._crossout(d)
+		if self.hilited: self._invert(d)
+	#
+
+
+# ButtonAppearance displays a centered string in a box.
+# selected --> bold border
+# disabled --> crossed out
+# hilited  --> inverted
+#
+class ButtonAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		d.box(_rect.inset(self.bounds, (1, 1)))
+		if self.selected:
+			# Make a thicker box
+			d.box(self.bounds)
+			d.box(_rect.inset(self.bounds, (2, 2)))
+			d.box(_rect.inset(self.bounds, (3, 3)))
+	#
+
+
+# CheckAppearance displays a small square box and a left-justified string.
+# selected --> a cross appears in the box
+# disabled --> whole button crossed out
+# hilited  --> box is inverted
+#
+class CheckAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		boxbounds = (left, top), (left+size, bottom)
+		d.box(boxbounds)
+		if self.selected: _xorcross(d, boxbounds)
+	#
+	def textpos(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		h = left + size + d.textwidth(' ')
+		v = top + (size - d.lineheight()) / 2
+		return h, v
+	#
+	def fliphilite(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		boxbounds = (left, top), (left+size, bottom)
+		d.invert(boxbounds)
+	#
+
+
+# RadioAppearance displays a round indicator and a left-justified string.
+# selected --> a dot appears in the indicator
+# disabled --> whole button crossed out
+# hilited  --> indicator is inverted
+#
+class RadioAppearance() = BaseAppearance():
+	#
+	def drawpict(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		radius = size / 2
+		h, v = left + radius, top + radius
+		d.circle((h, v), radius - 1)
+		if self.selected:
+			some = radius/3
+			d.paint((h-some, v-some), (h+some, v+some))
+	#
+	def textpos(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		h = left + size + d.textwidth(' ')
+		v = top + (size - d.lineheight()) / 2
+		return h, v
+	#
+	def fliphilite(self, d):
+		(left, top), (right, bottom) = self.bounds
+		size = bottom - top
+		d.invert((left, top), (left + size, bottom))
+	#
+
+
+# NoReactivity ignores mouse and timer events.
+# The trigger methods call the corresponding hooks set by the user.
+# Hooks (and triggers) mean the following:
+# down_hook	called on some mouse-down events
+# active_hook	called on some mouse-move events
+# up_hook	called on mouse-up events
+# on_hook	called for buttons with on/off state, when it goes on
+# timer_hook	called on timer events
+# hook		called when a button 'fires' or a radiobutton goes on
+# There are usually extra conditions, e.g., hooks are only called
+# when the button is enabled, or active, or selected (on).
+#
+class NoReactivity():
+	#
+	def init_reactivity(self):
+		self.down_hook = self.active_hook = self.up_hook = \
+		  self.on_hook = self.off_hook = self.timer_hook = \
+		  self.hook = self.active = 0
+	#
+	def mousetest(self, hv):
+		return _rect.pointinrect(hv, self.bounds)
+	#
+	def mouse_down(self, detail):
+		pass
+	#
+	def mouse_move(self, detail):
+		pass
+	#
+	def mouse_up(self, detail):
+		pass
+	#
+	def timer(self):
+		pass
+	#
+	def down_trigger(self):
+		if self.down_hook: self.down_hook(self)
+	#
+	def active_trigger(self):
+		if self.active_hook: self.active_hook(self)
+	#
+	def up_trigger(self):
+		if self.up_hook: self.up_hook(self)
+	#
+	def on_trigger(self):
+		if self.on_hook: self.on_hook(self)
+	#
+	def off_trigger(self):
+		if self.off_hook: self.off_hook(self)
+	#
+	def timer_trigger(self):
+		if self.timer_hook: self.timer_hook(self)
+	#
+	def trigger(self):
+		if self.hook: self.hook(self)
+
+
+# ToggleReactivity acts like a simple pushbutton.
+# It toggles its hilite state on mouse down events.
+# Its timer_trigger method is called for all timer events while hilited.
+#
+class ToggleReactivity() = NoReactivity():
+	#
+	def mouse_down(self, detail):
+		if self.enabled and self.mousetest(detail[_HV]):
+			self.active = 1
+			self.hilite(not self.hilited)
+			self.down_trigger()
+	#
+	def mouse_move(self, detail):
+		if self.active:
+			self.active_trigger()
+	#
+	def mouse_up(self, detail):
+		if self.active:
+			self.up_trigger()
+			self.active = 0
+	#
+	def timer(self):
+		if self.hilited:
+			self.timer_trigger()
+	#
+	def down_trigger(self):
+		if self.hilited:
+			self.on_trigger()
+		else:
+			self.off_trigger()
+		self.trigger()
+	#
+
+
+# TriggerReactivity acts like a fancy pushbutton.
+# It hilites itself while the mouse is down within its bounds.
+#
+class TriggerReactivity() = NoReactivity():
+	#
+	def mouse_down(self, detail):
+		if self.enabled and self.mousetest(detail[_HV]):
+			self.active = 1
+			self.hilite(1)
+			self.down_trigger()
+	#
+	def mouse_move(self, detail):
+		if self.active:
+			self.hilite(self.mousetest(detail[_HV]))
+			if self.hilited:
+				self.active_trigger()
+	#
+	def mouse_up(self, detail):
+		if self.active:
+			self.hilite(self.mousetest(detail[_HV]))
+			if self.hilited:
+				self.up_trigger()
+				self.trigger()
+			self.active = 0
+			self.hilite(0)
+	#
+	def timer(self):
+		if self.active and self.hilited:
+			self.active_trigger()
+	#
+
+
+# CheckReactivity handles mouse events like TriggerReactivity,
+# It overrides the up_trigger method to flip its selected state.
+#
+class CheckReactivity() = TriggerReactivity():
+	#
+	def up_trigger(self):
+		self.select(not self.selected)
+		if self.selected:
+			self.on_trigger()
+		else:
+			self.off_trigger()
+		self.trigger()
+
+
+# RadioReactivity turns itself on and the other buttons in its group
+# off when its up_trigger method is called.
+#
+class RadioReactivity() = TriggerReactivity():
+	#
+	def init_reactivity(self):
+		TriggerReactivity.init_reactivity(self)
+		self.group = []
+	#
+	def up_trigger(self):
+		for b in self.group:
+			if b <> self:
+				if b.selected:
+					b.select(0)
+					b.off_trigger()
+		self.select(1)
+		self.on_trigger()
+		self.trigger()
+
+
+# Auxiliary class for 'define' method.
+#
+class Define():
+	#
+	def define(self, (win, bounds, text)):
+		self.init_appearance(win, bounds)
+		self.text = text
+		self.init_reactivity()
+		return self
+
+
+# Ready-made button classes
+#
+class BaseButton() = NoReactivity(), BaseAppearance(), Define(): pass
+class Label() = NoReactivity(), LabelAppearance(), Define(): pass
+class ClassicButton() = TriggerReactivity(), ButtonAppearance(), Define(): pass
+class CheckButton() = CheckReactivity(), CheckAppearance(), Define(): pass
+class RadioButton() = RadioReactivity(), RadioAppearance(), Define(): pass
+class Toggle() = ToggleReactivity(), ButtonAppearance(), Define(): pass
diff --git a/Lib/stdwin/Sliders.py b/Lib/stdwin/Sliders.py
new file mode 100755
index 0000000000..8953efd166
--- /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
+	#