57 lines
2.8 KiB
Text
57 lines
2.8 KiB
Text
# scroll_bar.ludic - a scroll box's bar: .ui-scrollbar, the track down its right edge, and its
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# .ui-thumb, styled by the default sheet or a theme as the box's own parts. A press on the thumb holds
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# it where it was taken; a press on the track jumps the thumb's middle to the pointer and holds it there.
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# the bar's parts, styled as descendants of the box, and where they are at this offset
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function sb_geo(ui_st: mut UiState, n: UiNode, off: float, room: float, most: float) -> void {
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let bar = ct_part(ui_st, n, "ui-scrollbar", "")
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bar.tag = "div"
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bar.parent = n
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push(bar.children, ct_part(ui_st, n, "ui-thumb", ""))
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cs_tree(ui_st, bar)
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ui_st.sb_bar = bar
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ui_st.sb_w = ui_px(ui_st, 6.0)
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if bar.w >= 0.0 { ui_st.sb_w = bar.w }
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ui_st.sb_x = n.x + n.cw - ui_st.sb_w - bar.mr
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var least = ui_px(ui_st, 24.0)
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if len(bar.children) > 0 and bar.children[0].min_h > 0.0 { least = bar.children[0].min_h }
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ui_st.sb_th = Math.min(Math.max(n.ch * room / (room + most), least), n.ch)
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ui_st.sb_ty = n.y
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if most > 0.0 { ui_st.sb_ty = n.y + (n.ch - ui_st.sb_th) * Math.clamp(off, 0.0, most) / most }
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}
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# the pointer on the bar: taken on a press over it, moved while held, let go on release
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function sb_input(ui_st: mut UiState, n: UiNode, off: float, room: float, most: float) -> float {
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let i = ui_st.in_now
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if most <= 0.0 or room <= 0.0 { return off }
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if i.down and not ui_st.in_was_down and ui_st.sc_drag == "" {
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sb_geo(ui_st, n, off, room, most)
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let reach = Math.min(ui_st.sb_x, n.x + n.cw - ui_px(ui_st, 14.0))
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let over = i.x >= reach and i.y >= n.y and i.x < n.x + n.cw and i.y < n.y + n.ch
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if over and not ui_st.sb_bar.hidden {
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ui_st.sc_drag = n.key
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ui_st.sc_grab = ui_st.sb_th / 2.0
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if i.y >= ui_st.sb_ty and i.y < ui_st.sb_ty + ui_st.sb_th { ui_st.sc_grab = i.y - ui_st.sb_ty }
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}
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}
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if ui_st.sc_drag != n.key { return off }
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sb_geo(ui_st, n, off, room, most)
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let span = n.ch - ui_st.sb_th
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if span <= 0.0 { return off }
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return (i.y - ui_st.sc_grab - n.y) / span * most
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}
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# the track, then the thumb over it; scrollbar-color on the box wins over the parts' backgrounds
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function sc_bar(ui_st: mut UiState, n: UiNode) -> void {
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let room = n.ch - ly_vin(n)
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let most = n.content_h - ly_vin(n) - room
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if most <= 0.0 or ui_st.ui_be.rect == null { return }
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sb_geo(ui_st, n, n.scroll_y, room, most)
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let bar = ui_st.sb_bar
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if bar.hidden { return }
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var track = bar.bg
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if n.bar_track != -2 { track = n.bar_track }
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if track >= 0 { fr_box(ui_st, ui_st.sb_x, n.y, ui_st.sb_w, n.ch, bar.radius, track, bar.bg_a * ui_st.fr_ga) }
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if len(bar.children) == 0 { return }
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let t = bar.children[0]
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var thumb = t.bg
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if n.bar_c >= 0 { thumb = n.bar_c }
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if thumb >= 0 { fr_box(ui_st, ui_st.sb_x, ui_st.sb_ty, ui_st.sb_w, ui_st.sb_th, t.radius, thumb, t.bg_a * ui_st.fr_ga) }
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}
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