72 lines
2.5 KiB
Lua
72 lines
2.5 KiB
Lua
local Constraints = require "lib.simple_ui.constraints"
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--- @class Flex : MultiChildElement
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--- @field direction "horizontal" | "vertical"
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--- @field mainAxisSize "max" | "min"
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--- @field mainAxisAlignment "start" | "center" | "end"
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local flex = setmetatable({}, require "lib.simple_ui.multi_child_element")
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flex.__index = flex
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flex.type = "Flex"
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flex.direction = "horizontal"
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flex.mainAxisSize = "max"
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flex.mainAxisAlignment = "start"
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function flex:layout()
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local mainAxisSize = 0
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local crossAxisSize = 0
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if self.direction == "horizontal" then
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for _, child in ipairs(self.children) do
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child.constraints = Constraints { maxHeight = self.constraints.maxHeight }
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child:layout()
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if child.size.y > crossAxisSize then crossAxisSize = child.size.y end
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mainAxisSize = mainAxisSize + child.size.x
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end
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local start = 0
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if self.mainAxisAlignment == "center" then
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start = self.constraints.maxWidth / 2 - mainAxisSize / 2
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elseif self.mainAxisAlignment == "end" then
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start = self.constraints.maxWidth - mainAxisSize
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end
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local shift = 0
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for _, child in ipairs(self.children) do
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child.offset = Vec3 { self.offset.x + start + shift, self.offset.y }
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shift = shift + child.size.x
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end
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if self.mainAxisSize == "max" then
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self.size = Vec3 { self.constraints.maxWidth, crossAxisSize }
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else
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self.size = Vec3 { mainAxisSize, crossAxisSize }
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end
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else
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for _, child in ipairs(self.children) do
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child.constraints = Constraints { maxWidth = self.constraints.maxWidth }
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child:layout()
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if child.size.x > crossAxisSize then crossAxisSize = child.size.x end
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mainAxisSize = mainAxisSize + child.size.y
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end
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local start = 0
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if self.mainAxisAlignment == "center" then
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start = self.constraints.maxHeight / 2 - mainAxisSize / 2
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elseif self.mainAxisAlignment == "end" then
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start = self.constraints.maxHeight - mainAxisSize
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end
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local shift = 0
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for _, child in ipairs(self.children) do
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child.offset = Vec3 { self.offset.x, self.offset.y + start + shift }
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shift = shift + child.size.y
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end
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if self.mainAxisSize == "max" then
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self.size = Vec3 { crossAxisSize, self.constraints.maxHeight }
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else
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self.size = Vec3 { crossAxisSize, mainAxisSize }
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end
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end
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end
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return flex
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