lite-xl/data/core/scrollbar.lua

309 lines
9.8 KiB
Lua

local core = require "core"
local common = require "core.common"
local config = require "core.config"
local style = require "core.style"
local Object = require "core.object"
---Scrollbar
---Use Scrollbar:set_size to set the bounding box of the view the scrollbar belongs to.
---Use Scrollbar:update to update the scrollbar animations.
---Use Scrollbar:draw to draw the scrollbar.
---Use Scrollbar:on_mouse_pressed, Scrollbar:on_mouse_released,
---Scrollbar:on_mouse_moved and Scrollbar:on_mouse_left to react to mouse movements;
---the scrollbar won't update automatically.
---Use Scrollbar:set_percent to set the scrollbar location externally.
---
---To manage all the orientations, the scrollbar changes the coordinates system
---accordingly. The "normal" coordinate system adapts the scrollbar coordinates
---as if it's always a vertical scrollbar, positioned at the end of the bounding box.
---@class core.scrollbar : core.object
local Scrollbar = Object:extend()
---@param direction "v" | "h" @Vertical or Horizontal
---@param alignment "s" | "e" @Start or End (left to right, top to bottom)
function Scrollbar:new(direction, alignment)
---Position information of the owner
self.rect = {
x = 0, y = 0, w = 0, h = 0,
---Scrollable size
scrollable = 0
}
self.normal_rect = {
across = 0,
along = 0,
across_size = 0,
along_size = 0,
scrollable = 0
}
---@type integer @Position in percent [0-1]
self.percent = 0
---@type boolean @Scrollbar dragging status
self.dragging = false
---@type integer @Private. Used to offset the start of the drag from the top of the thumb
self.drag_start_offset = 0
---What is currently being hovered. `thumb` implies` track`
self.hovering = { track = false, thumb = false }
---@type "v" | "h"@Vertical or Horizontal
self.direction = direction or "v"
---@type "s" | "e" @Start or End (left to right, top to bottom)
self.alignment = alignment or "e"
---@type number @Private. Used to keep track of animations
self.expand_percent = 0
end
function Scrollbar:real_to_normal(x, y, w, h)
x, y, w, h = x or 0, y or 0, w or 0, h or 0
if self.direction == "v" then
if self.alignment == "s" then
x = (self.rect.x + self.rect.w) - x - w
end
return x, y, w, h
else
if self.alignment == "s" then
y = (self.rect.y + self.rect.h) - y - h
end
return y, x, h, w
end
end
function Scrollbar:normal_to_real(x, y, w, h)
x, y, w, h = x or 0, y or 0, w or 0, h or 0
if self.direction == "v" then
if self.alignment == "s" then
x = (self.rect.x + self.rect.w) - x - w
end
return x, y, w, h
else
if self.alignment == "s" then
x = (self.rect.y + self.rect.h) - x - w
end
return y, x, h, w
end
end
function Scrollbar:_get_thumb_rect_normal()
local nr = self.normal_rect
local sz = nr.scrollable
if sz == math.huge or sz <= nr.along_size
then
return 0, 0, 0, 0
end
local along_size = math.max(20, nr.along_size * nr.along_size / sz)
local across_size = style.scrollbar_size
across_size = across_size + (style.expanded_scrollbar_size - style.scrollbar_size) * self.expand_percent
return
nr.across + nr.across_size - across_size,
nr.along + self.percent * nr.scrollable * (nr.along_size - along_size) / (sz - nr.along_size),
across_size,
along_size
end
---Get the thumb rect (the part of the scrollbar that can be dragged)
---@return integer,integer,integer,integer @x, y, w, h
function Scrollbar:get_thumb_rect()
return self:normal_to_real(self:_get_thumb_rect_normal())
end
function Scrollbar:_get_track_rect_normal()
local nr = self.normal_rect
local sz = nr.scrollable
if sz <= nr.along_size or sz == math.huge then
return 0, 0, 0, 0
end
local across_size = style.scrollbar_size
across_size = across_size + (style.expanded_scrollbar_size - style.scrollbar_size) * self.expand_percent
return
nr.across + nr.across_size - across_size,
nr.along,
across_size,
nr.along_size
end
---Get the track rect (the "background" of the scrollbar)
---@return number,number,number,number @x, y, w, h
function Scrollbar:get_track_rect()
return self:normal_to_real(self:_get_track_rect_normal())
end
function Scrollbar:_overlaps_normal(x, y)
local sx, sy, sw, sh = self:_get_thumb_rect_normal()
local result
if x >= sx - style.scrollbar_size * 3 and x <= sx + sw and y >= sy and y <= sy + sh then
result = "thumb"
else
sx, sy, sw, sh = self:_get_track_rect_normal()
if x >= sx - style.scrollbar_size * 3 and x <= sx + sw and y >= sy and y <= sy + sh then
result = "track"
end
end
return result
end
---Get what part of the scrollbar the coordinates overlap
---@return "thumb"|"track"|nil
function Scrollbar:overlaps(x, y)
x, y = self:real_to_normal(x, y)
return self:_overlaps_normal(x, y)
end
function Scrollbar:_on_mouse_pressed_normal(button, x, y, clicks)
local overlaps = self:_overlaps_normal(x, y)
if overlaps then
local _, along, _, along_size = self:_get_thumb_rect_normal()
self.dragging = true
if overlaps == "thumb" then
self.drag_start_offset = along - y
return true
elseif overlaps == "track" then
self.drag_start_offset = - along_size / 2
return (y - self.normal_rect.along - along_size / 2) / self.normal_rect.along_size
end
end
end
---Updates the scrollbar with mouse pressed info.
---Won't update the scrollbar position automatically.
---Use Scrollbar:set_percent to update it.
---
---This sets the dragging status if needed.
---
---Returns a falsy value if the event happened outside the scrollbar.
---Returns `true` if the thumb was pressed.
---If the track was pressed this returns a value between 0 and 1
---representing the percent of the position.
---@return boolean|number
function Scrollbar:on_mouse_pressed(button, x, y, clicks)
if button ~= "left" then return end
x, y = self:real_to_normal(x, y)
return self:_on_mouse_pressed_normal(button, x, y, clicks)
end
---Updates the scrollbar hover status.
---This gets called by other functions and shouldn't be called manually
function Scrollbar:_update_hover_status_normal(x, y)
local overlaps = self:_overlaps_normal(x, y)
self.hovering.thumb = overlaps == "thumb"
self.hovering.track = self.hovering.thumb or overlaps == "track"
return self.hovering.track or self.hovering.thumb
end
function Scrollbar:_on_mouse_released_normal(button, x, y)
self.dragging = false
return self:_update_hover_status_normal(x, y)
end
---Updates the scrollbar dragging status
function Scrollbar:on_mouse_released(button, x, y)
if button ~= "left" then return end
x, y = self:real_to_normal(x, y)
return self:_on_mouse_released_normal(button, x, y)
end
function Scrollbar:_on_mouse_moved_normal(x, y, dx, dy)
if self.dragging then
local nr = self.normal_rect
return common.clamp((y - nr.along + self.drag_start_offset) / nr.along_size, 0, 1)
end
return self:_update_hover_status_normal(x, y)
end
---Updates the scrollbar with mouse moved info.
---Won't update the scrollbar position automatically.
---Use Scrollbar:set_percent to update it.
---
---This updates the hovering status.
---
---Returns a falsy value if the event happened outside the scrollbar.
---Returns `true` if the scrollbar is hovered.
---If the scrollbar was being dragged, this returns a value between 0 and 1
---representing the percent of the position.
---@return boolean|number
function Scrollbar:on_mouse_moved(x, y, dx, dy)
x, y = self:real_to_normal(x, y)
dx, dy = self:real_to_normal(dx, dy) -- TODO: do we need this? (is this even correct?)
return self:_on_mouse_moved_normal(x, y, dx, dy)
end
---Updates the scrollbar hovering status
function Scrollbar:on_mouse_left()
self.hovering.track, self.hovering.thumb = false, false
end
---Updates the bounding box of the view the scrollbar belongs to.
---@param x number
---@param y number
---@param w number
---@param h number
---@param scrollable number @size of the scrollable area
function Scrollbar:set_size(x, y, w, h, scrollable)
self.rect.x, self.rect.y, self.rect.w, self.rect.h = x, y, w, h
self.rect.scrollable = scrollable
local nr = self.normal_rect
nr.across, nr.along, nr.across_size, nr.along_size = self:real_to_normal(x, y, w, h)
nr.scrollable = scrollable
end
---Updates the scrollbar location
---@param percent number @number between 0 and 1 representing the position of the middle part of the thumb
function Scrollbar:set_percent(percent)
self.percent = percent
end
---Updates the scrollbar animations
function Scrollbar:update()
-- TODO: move the animation code to its own class
local dest = (self.hovering.track or self.dragging) and 1 or 0
local diff = math.abs(self.expand_percent - dest)
if not config.transitions or diff < 0.05 or config.disabled_transitions["scroll"] then
self.expand_percent = dest
else
local rate = 0.3
if config.fps ~= 60 or config.animation_rate ~= 1 then
local dt = 60 / config.fps
rate = 1 - common.clamp(1 - rate, 1e-8, 1 - 1e-8)^(config.animation_rate * dt)
end
self.expand_percent = common.lerp(self.expand_percent, dest, rate)
end
if diff > 1e-8 then
core.redraw = true
end
end
---Draw the scrollbar track
function Scrollbar:draw_track()
if not (self.hovering.track or self.dragging)
and self.expand_percent == 0 then
return
end
local color = { table.unpack(style.scrollbar_track) }
color[4] = color[4] * self.expand_percent
local x, y, w, h = self:get_track_rect()
renderer.draw_rect(x, y, w, h, color)
end
---Draw the scrollbar thumb
function Scrollbar:draw_thumb()
local highlight = self.hovering.thumb or self.dragging
local color = highlight and style.scrollbar2 or style.scrollbar
local x, y, w, h = self:get_thumb_rect()
renderer.draw_rect(x, y, w, h, color)
end
---Draw both the scrollbar track and thumb
function Scrollbar:draw()
self:draw_track()
self:draw_thumb()
end
return Scrollbar