gui_toolkit 0.13.0

Changed

• Interaction states show at once: hover, press, focus, selection and disabled no longer fade in or out (hot_t, active_t, focus_t, disabled_t go from 0 to 1 in the frame that sees the change), and box colours jump to their targets (a selected row, the hovered menu item). A hover change asks for no further frame. A change of palette still cross-fades every colour for ui.PALETTE_FADE_MS (160 ms).
• Hover and press fills are visible: the theme's new state entries hover_fill / press_fill are fractions of the way to the palette's tint (white on dark palettes, black on light ones) in sRGB values, drawn over the surface actually under the box (ui.box_under) with the alpha that gives that step in either blend space (draw.alpha_like_srgb). Per role: buttons 7 % / 13 %, ghost and icon buttons 8 % / 14 %, accent and danger buttons 10 % / 18 %, list rows 5 % / 9 %, tabs 6 % / 10 %, segments 7 % / 12 %, anything else with .Draw_Hot_Effects 7 % / 12 %; menu items show their selection under the pointer (8 % more while pressed). The old tiny overlay (1.4 % / 2 % in linear light) is gone. The tint entry hover itself is unchanged.
• Fields: the border of a line_edit under the pointer moves 22 % toward the tint (input hover_border).
• No press "squish" by default; Theme.press_squish (e.g. 0.04) brings it back, at once and without animation.

Added

• Theme.transition_ms: > 0 brings back short cross-fades of the interaction states (default 0); Theme.serial, bumped by theme_add, theme_set and apply_palette when a colour changes.
• Selectable list_rows have .Draw_Hot_Effects (tag list_row, built under it only); segmented items light up under the pointer (tag segment); tabs items have the tag tab.
• "<tags> hot text": the text colour of a clickable box under the pointer (falls back to the normal one). remove_button hot text is the palette's red, remove_button hover_fill / press_fill a light red step: push the tag remove_button around an icon_button for a delete cross.
• Box_Flag.Hot_Within: a box stays hot (and lit) while the pointer is on a clickable box inside it; selectable list_rows have it (a row and its delete button). ui.hot_within(key): the same question while building (last frame's tree), e.g. to show a row's buttons only while the pointer is on it.
• list_row keeps a cursor given with next({cursor = .Hand}) (rows that open something).
• ui.state_fill(box, name, under), ui.box_under(box), ui.srgb_step(a, b, t): the theme's state steps for custom draw procs.
• draw.alpha_like_srgb: the inverse of alpha_like_linear (the alpha that looks in a blend space as a given alpha blended in sRGB values).
• tests/states: instant states, transitions on demand, palette cross-fade, the size of the steps in both blend spaces.