134 lines
3.9 KiB
Lua
134 lines
3.9 KiB
Lua
---------------------------------------------------------------------------
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-- @author Lukáš Hrázký
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-- @copyright 2012 Lukáš Hrázký
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-- @release @AWESOME_VERSION@
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-- @classmod wibox.layout.constraint
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---------------------------------------------------------------------------
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local pairs = pairs
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local type = type
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local setmetatable = setmetatable
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local base = require("wibox.widget.base")
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local math = math
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local constraint = { mt = {} }
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--- Layout a constraint layout
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function constraint:layout(context, width, height)
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if self.widget then
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return { base.place_widget_at(self.widget, 0, 0, width, height) }
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end
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end
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--- Fit a constraint layout into the given space
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function constraint:fit(context, width, height)
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local w, h
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if self.widget then
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w = self._strategy(width, self._width)
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h = self._strategy(height, self._height)
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w, h = base.fit_widget(self, context, self.widget, w, h)
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else
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w, h = 0, 0
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end
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w = self._strategy(w, self._width)
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h = self._strategy(h, self._height)
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return w, h
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end
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--- Set the widget that this layout adds a constraint on.
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function constraint:set_widget(widget)
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self.widget = widget
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self:emit_signal("widget::layout_changed")
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end
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--- Get the number of children element
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-- @treturn table The children
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function constraint:get_children()
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return {self.widget}
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end
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--- Set the strategy to use for the constraining. Valid values are 'max',
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-- 'min' or 'exact'. Throws an error on invalid values.
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function constraint:set_strategy(val)
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local func = {
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min = function(real_size, constraint)
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return constraint and math.max(constraint, real_size) or real_size
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end,
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max = function(real_size, constraint)
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return constraint and math.min(constraint, real_size) or real_size
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end,
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exact = function(real_size, constraint)
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return constraint or real_size
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end
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}
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if not func[val] then
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error("Invalid strategy for constraint layout: " .. tostring(val))
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end
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self._strategy = func[val]
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self:emit_signal("widget::layout_changed")
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end
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--- Set the maximum width to val. nil for no width limit.
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function constraint:set_width(val)
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self._width = val
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self:emit_signal("widget::layout_changed")
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end
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--- Set the maximum height to val. nil for no height limit.
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function constraint:set_height(val)
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self._height = val
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self:emit_signal("widget::layout_changed")
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end
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--- Reset this layout. The widget will be unreferenced, strategy set to "max"
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-- and the constraints set to nil.
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function constraint:reset()
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self._width = nil
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self._height = nil
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self:set_strategy("max")
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self:set_widget(nil)
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end
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--- Returns a new constraint layout. This layout will constraint the size of a
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-- widget according to the strategy. Note that this will only work for layouts
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-- that respect the widget's size, eg. fixed layout. In layouts that don't
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-- (fully) respect widget's requested size, the inner widget still might get
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-- drawn with a size that does not fit the constraint, eg. in flex layout.
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-- @param[opt] widget A widget to use.
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-- @param[opt] strategy How to constraint the size. 'max' (default), 'min' or
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-- 'exact'.
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-- @param[opt] width The maximum width of the widget. nil for no limit.
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-- @param[opt] height The maximum height of the widget. nil for no limit.
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local function new(widget, strategy, width, height)
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local ret = base.make_widget()
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for k, v in pairs(constraint) do
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if type(v) == "function" then
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ret[k] = v
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end
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end
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ret:set_strategy(strategy or "max")
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ret:set_width(width)
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ret:set_height(height)
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if widget then
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ret:set_widget(widget)
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end
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return ret
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end
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function constraint.mt:__call(...)
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return new(...)
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end
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return setmetatable(constraint, constraint.mt)
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-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80
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