resources/scripts/views/scrollable.lua - master - d.vision/division_engine_cpp

resources/scripts/views/scrollable.lua
101 строка3 KB
den163
Added scrollable widget. Improved error handling
30 ноя 2024, 23:46
30 ноя 2024, 23:465e455e6
---TODO: Add mask support

local division = require 'division'
local rect = require 'rect'
local single_child_view = require 'views.single_child_view'
local vec2 = require 'vec2'
local constrained_size = require 'constrained_size'

---@alias scrollable.scroll_direction 'horizontal'|'vertical'|'all'

---@class scrollable.options
---@field direction scrollable.scroll_direction
---@field child view

---@class scrollable: single_child_view, scrollable.options
---@overload fun(options: scrollable.options): scrollable
local scrollable = single_child_view:inherit 'scrollable'

---@class scrollable.state: single_child_view.state
---@field package _id entity_id
---@field package _prev_input_pos vec2
---@field package _offset vec2
---@field package _was_selected boolean
---@field package _on_update function
---@field package _render_rect rect
scrollable.state = single_child_view.state:inherit 'scrollable.state'

---@param options scrollable.options
function scrollable:__call(options)
    assert(options.child)
    assert(
        options.direction == 'horizontal' or
        options.direction == 'vertical' or
        options.direction == 'all'
    )

    return scrollable:new(options)
end

function scrollable:create_state()
    local state = scrollable.state:new()
    state._id = division:create_selectable()
    state._prev_input_pos = vec2()
    state._offset = vec2()
    state._was_selected = false
    state.child_state = self.child:create_state()

    state._on_update = function()
        if state._was_selected then
            if division:is_mouse_button_pressed(division.mouse_button.left) then
                local input_pos = division:mouse_position()
                local input_delta = input_pos - state._prev_input_pos

                if self.direction == 'horizontal' or self.direction == 'all' then
                    state._offset.x = state._offset.x + input_delta.x
                end

                if self.direction == 'vertical' or self.direction == 'all' then
                    state._offset.y = state._offset.y + input_delta.y
                end

                state._prev_input_pos = input_pos
                state:render(state._render_rect, self)
            else
                state._was_selected = false
            end
        elseif
            division:is_mouse_button_pressed(division.mouse_button.left) and
            division:has_selected_id() and
            division:get_selected_id() == state._id
        then
            state._was_selected = true
            state._prev_input_pos = division:mouse_position()
        end
    end

    division:add_update_listener(state._on_update)

    return state
end

function scrollable.state:layout(constraints, view)
    return constrained_size:unconstrained()
end

---@param view scrollable
function scrollable.state:render(render_rect, view)
    self._render_rect = render_rect

    division:set_collision_bounds(self._id, render_rect)
    local render_rect_with_offset = rect(render_rect.center + self._offset, render_rect.extents)
    self.child_state:render(render_rect_with_offset, view.child)
end

function scrollable.state:destroy()
    division:remove_update_listener(self._on_update)
    division:destroy_entity(self._id)
    single_child_view.state.destroy(self)
end

return scrollable