MacSurf 0.7 — Cleanup

Released: 2026-05-26
Codename: Cleanup
Engine HEAD: fixes271b
Verified on: Power Macintosh G3 iMac, Mac OS 9.1

The headline

Twelve issues closed in a single day. v0.7 is the "resolve all known issues" sprint — a focused correctness + cleanup round on top of v0.6.2's speed work. Nine commits (fixes264 → fixes271b) cleared the entire open-issues backlog on mplsllc/macsurf. Author CSS now reaches more paint paths, image-heavy navigation stays memory-clean, CSS Grid honors author alignment intent, and a long-standing struct-naming workaround got resolved at the root.

Two things stand out from the round:

1. Element-scoped var() resolution. Author CSS like .header { background-image: var(--tile) } now resolves correctly when --tile is defined inline on a different element's style="..." attribute. Mactrove's --header-tile random-header pattern just works.
2. CSS Grid V2 alignment with zero libcss surgery. The previous attempt (fixes159) had failed in nine rounds trying to add a new vendor property; turned out libcss already had public accessors for justify-content, align-content, align-items, align-self — just had to consume them.

What landed (by area)

CSS correctness

• fixes264 — var() resolves element's own inline --custom-prop. Threads the cascading element's inline_style sheet through lookup_var() as highest-priority source. Works for the same-element case (element defines and uses the var).
• fixes267 — Doc-global inline-extras custom-property table. Aggregates custom_properties from every style="..." attribute parsed by nscss_create_inline_style into a doc-global table consulted by lookup_var(). Covers the cross-element case (parent defines, child uses). Cleared per html_create so per-page state doesn't bleed. Pragmatic V1 — last-writer-wins for name collisions, which covers mactrove's single---header-tile-element pattern.
• fixes266 — background-image: linear-gradient(...) rewrite. New cssh_css preprocessor pass renames background-image: to -macsurf-gradient: when the value's first non-whitespace token is linear-gradient( or radial-gradient(. Author CSS using standard CSS3 syntax now reaches the existing vendor gradient paint path. Stacked layered backgrounds still drop on the trailing comma (no regression). Wired into both external sheets and inline-style attributes.
• fixes270 — CSS Grid V2 alignment. layout_grid consumes css_computed_justify_content (inline-axis track distribution: flex-end, center, space-between, space-around, space-evenly) and css_computed_align_content (block-axis distribution when there's a definite container height). Discovery that closed the prior 9-round fixes159 stall: libcss already exposed these accessors — no new vendor property needed. fixes270a preserves the CSS-declared container height through the redistribution so the box paints at full declared size instead of shrinking back to natural content height. align-items / align-self had already shipped at fixes178d; justify-items / justify-self deferred (libcss does not expose those accessors).

Image / memory hygiene

• fixes265 — Direct image URL navigation scale-fit-to-cap. Typing a large image URL (e.g. https://example.com/photo.jpg) in the address bar pre-fix rendered blank because browser_window passed natural dimensions (4000×3000 → 48 MB RGBA, exceeds the 16 MB per-image ceiling). Pre-clamps dst_w/dst_h proportionally in macos9_qt_image_redraw before the cap-check, preserving aspect ratio. Integer-only math (CW8 PPC long long is unsafe per the well-documented gotcha).
• fixes268 #10 — Decoded-image purge on top-level nav. New macos9_purge_decoded_images() evicts the QT-deferred LRU and zeroes macsurf__decoded_img_bytes_current. Called from browser_window_content_ready after hlcache_handle_release of the old current_content; llcache_clean(true) purges the low-level cache alongside. Heavy-page → heavy-page navigation now starts with fresh budget headroom. Verified on hardware as img purge: evicted=1769472 remaining=0 on a real nav.
• fixes269 #8 — Above-fold lazy decode. macos9_qt_image_redraw now early-returns when the image's destination rect lies entirely outside the redraw clip. NetSurf core's box-tree walker prunes most below-fold boxes but occasionally invokes redraw on parents whose bbox intersects the clip while specific children don't. Below-fold images stay undecoded until the user scrolls into them; scroll fires a new redraw with a different clip that triggers the decode.

Diagnostic visibility

• fixes268 #9 — Total CSS budget by importance. New 384 KB cumulative cap on CSS bytes per page in nscss_process_data. Sheets arriving after the cap is hit short-circuit immediately (document order wins — site's main stylesheet processes fully, vendor tail sheets get truncated). macsurf__site_css_total_bytes reset per page in html_create.
• fixes268 #11 — Heavy mode + blocker= field. SITE diagnostic line now emits heavy=N blocker=NAME (none / img_budget / css_budget / fetch_slots / fonts) and css_total=N/cap. heavy=1 latches when any skip counter is non-zero; blocker name picked by priority order. Visible at every html_reformat completion.
• fixes268a — SITE line unsilencer. fixes253 had silenced SITE url=... lines by default as a log-noise reduction. v0.7 requires the SITE line for css_total= and blocker= verification per the issue acceptance criteria, so SITE is back to firing per reformat. Low volume — survivable.

Multicol

• fixes268 #17 — Multicol balancing via bisection. layout_multicol_inner's per-segment target_height now goes through a new multicol_compute_target_height() helper:
  • column-fill: auto uses the viewport height as target (was identical to balance pre-fix; auto was unimplemented).
  • column-fill: balance starts with max(tallest, ceil(total/count)) heuristic, then bisects downward (6 iterations, 8px convergence) to the smallest target that still fits in count columns. Tighter, more visually balanced output for non-uniform item heights.

Build cleanup

• fixes271b — box_multicol_data rename + Linux/Mac box.h alignment. The _ns suffix on struct box_multicol_seg_ns and struct box_multicol_dat_ns was a fixes199h workaround for a CW8 redefinition error. Root cause turned out to be that the Mac's box.h had been carrying these struct definitions plus a multicol_data field on struct box since fixes199h, while the Linux box.h had neither. Aligned: added the structs + field to Linux's box.h, removed the duplicates from layout_internal.h, restored standard names (box_multicol_segment, box_multicol_data) in layout.c. Source trees now match across platforms; single source of truth in box.h.

Issues closed (12)

All on mplsllc/macsurf:

| # | Title | Resolution |
| --- | --- | --- |
| #2 | Image memory pressure on modern image-heavy pages | fixes268 #10 (purge on nav) + existing fixes161b/162/259/265 deferred-decode |
| #3 | %u specifier in macsurf_debug_log_writef calls | Audit found no remaining hits; already resolved |
| #4 | CSS Grid V2 alignment | fixes270 / fixes270a |
| #5 | Wheel-mouse scroll can crash | Not reproducible on user's hardware; fixes140/141 defensive disable remains effective |
| #8 | Lazy image decode + above-the-fold bias | fixes269 |
| #9 | Total CSS budget by importance | fixes268 |
| #10 | Purge memory cache + decoded-image budget on top-level navigation | fixes268 |
| #11 | Heavy-site mode + blocker= field in SITE diagnostic line | fixes268 |
| #12 | fixes161 memory sweep umbrella | All constituent issues shipped |
| #17 | Multicol V2 — Balancing | fixes268 |
| #18 | Header Audit & Build Cleanup (Struct Renaming) | fixes271b |
| #22 | var() referencing parent's inline --custom-prop drops | fixes267 |

Plus #23 (background-image gradient drops) and #24 (direct image URL blank) filed and closed for the early-session work (fixes266, fixes265).

Verified on hardware

• test.html — fixes264/266/267 probes: purple cross-element var() block + four gradient blocks (vertical 2-stop, horizontal 2-stop, vertical 3-stop, radial). All paint correctly post-fixes267.
• test2.html — fixes268 probes: M1 multicol balance with mixed heights + M2 column-fill: auto in 200px container. Plus fixes267/266 regression checks.
• test3.html — fixes270 probes GA1–GA7: justify-content (center, flex-end, space-between, space-around, space-evenly), align-content: center (200px container, fixes270a confirmation), align-items: flex-end regression check. All seven probes render correctly.
• MacSurf Debug.log confirms fixes268 SITE line: heavy=0 blocker=none ... css_total=N/393216 ... per reformat, img purge: evicted=N remaining=0 on real navigation events.

Known limitations carried forward

• justify-items / justify-self (cell horizontal alignment on grids) — libcss in this vintage does not expose css_computed_justify_items / css_computed_justify_self. Either libcss surgery (the trap zone — see project memory) or a text-align workaround would close the gap. Lower priority since container-level distribution (V1 shipped) covers most layouts.
• Stacked background-image: linear-gradient(...), linear-gradient(...) — single-gradient case works; multi-layer parser fails on the trailing comma. Same as pre-fix behaviour, no regression.
• TLS fingerprint blocks (Google / Facebook) — carried from v0.6.x; needs ALPN extension support in macTLS or a TLS 1.3 swap. The persistent dead-host list makes them fast-fail.
• gap: A B two-value form — single value works (97% of cases), two-value collapses to column-gap=B. Full-fidelity row-gap storage requires a new bit slot in css_computed_style_i.bits[].
• JPEG photo plot still slow when scrolling — pre-scale at decode time is partially shipped (fixes162 + fixes259), but real-content scroll jank persists. Per-tick re-decode vs cached display-size bitmap is the next look.

Build

MacSurf.mcp did not need to add any new .c files for v0.7 — every fix touched existing source files. Three header-level cleanups in fixes271b across box.h, layout_internal.h, layout.c. CW8 partition unchanged (16 MB preferred / 8 MB minimum).

SheepShaver smoke

OS 9.0.4 in SheepShaver still good for Carbon init / UI / rendering smoke. Networking remains the SheepShaver limitation; not a substitute for hardware fetcher testing.

Download

• MacSurf.sit — ready-to-run StuffIt archive. Expand on Mac OS 9.1+ with CarbonLib 1.5+ and launch.
• Source: this repository at tag v0.7.