gui_toolkit 0.52.0

Added

• tools/slugsmall: DirectWrite's bitmaps against Slug with each combination of its small-text settings, stacked in one PNG per scene and scale with a 3x enlargement (odin run tools/slugsmall -define:FONT_BACKEND=native).
• Slug: four coverage samples per pixel (font.Settings.slug_supersample_ppem) for glyphs at that size or less, on a rotated grid, each over its own half-pixel box. Off by default.
• Slug: stem darkening (font.Settings.slug_darken): every edge of small glyphs moves outwards by that many pixels at 12 px per em and less, fading out by 36, on the side the glyph's winding says (Slug_Glyph.orient). Off by default.
• Slug: hinted outlines for small text (font.Settings.slug_hint_ppem): screen-aligned glyphs at that size or less use an outline hinted for their size by the native backend's light auto-hinter (skrifa: vertical only, the baseline and x-height on whole pixels), cached per quarter pixel; gt_glyph_outline_hinted, Text_Backend.outline_hinted. Off by default.

Fixed

• Segmented controls: the labels are no longer engraved (button segment sheen 0): lit below on the pill and shadowed above on the track, the selected and the other labels looked a pixel apart.