64 lines
2.7 KiB
Lua
64 lines
2.7 KiB
Lua
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-- A dead-simple layout helper for the editor sidebar. Everything works in the
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-- sidebar's local coordinate space (0,0 = top-left of sideBarCanvas) — the same
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-- space editorDraw / editorMouseHandler already use — so section rects double as
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-- love.graphics.setScissor rects and as hit boxes. No dependencies, no state of
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-- its own beyond the scroll table the caller hands in.
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Layout = {}
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-- point-in-rect
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function Layout.hit(r, x, y)
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return x >= r.x and x < r.x + r.w and y >= r.y and y < r.y + r.h
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end
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-- Clip drawing to a section. setScissor ignores the active graphics transform,
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-- so multiply the virtual-space rect by editorRenderScale to hit real canvas
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-- pixels. Clamp to non-negative: a too-narrow/short sidebar (e.g. a square
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-- window with no room for it) would otherwise hand setScissor a negative size.
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function Layout.clip(r)
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local s = editorRenderScale or 1
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love.graphics.setScissor(r.x * s, r.y * s, math.max(0, r.w * s), math.max(0, r.h * s))
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end
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function Layout.unclip() love.graphics.setScissor() end
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-- A vertical scrolling list confined to rect `r`. `state` is any table the
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-- caller keeps between frames to hold `state.scroll`; it is clamped here.
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-- Returns helpers to place / cull / hit-test `count` items of height `itemH`.
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function Layout.list(state, r, itemH, count, gap)
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gap = gap or 6
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local step = itemH + gap
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local content = count * step
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local maxScroll = math.max(0, content - r.h)
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state.scroll = math.max(0, math.min(state.scroll or 0, maxScroll))
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local scroll = state.scroll
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return {
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rect = r, itemH = itemH, step = step, count = count, maxScroll = maxScroll, scroll = scroll,
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-- top-left corner of item i (1-based), in sidebar space
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pos = function(i) return r.x, r.y + (i - 1) * step - scroll end,
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-- is item i at all inside the visible window? (cheap cull)
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visible = function(i)
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local y = r.y + (i - 1) * step - scroll
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return y + itemH > r.y and y < r.y + r.h
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end,
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-- index at a sidebar-space point, or nil if outside the list / no item
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at = function(x, y)
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if not Layout.hit(r, x, y) then return nil end
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local i = math.floor((y - r.y + scroll) / step) + 1
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if i >= 1 and i <= count then return i end
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return nil
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end,
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}
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end
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-- Thin scrollbar thumb on the right edge of a list, drawn only when it scrolls.
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function Layout.scrollbar(list)
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if list.maxScroll <= 0 then return end
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local r = list.rect
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local thumb = math.max(16, r.h * (r.h / (r.h + list.maxScroll)))
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local ty = r.y + (r.h - thumb) * (list.scroll / list.maxScroll)
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local pr, pg, pb, pa = love.graphics.getColor()
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love.graphics.setColor(255, 255, 255, 90)
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love.graphics.rectangle("fill", r.x + r.w - 4, ty, 3, thumb)
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love.graphics.setColor(pr, pg, pb, pa)
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end
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