pcbjam/docs/features/fork-cleanup/05-wx-layer-fixes.md

05 — Fix in the wxWidgets wasm port, not in KiCad

Several KiCad-side #ifdef __EMSCRIPTEN__ patches work around quirks of the wxUniversal / wasm port. The project rule is to fix wasm-only bugs in the wasm layer. Moving these into the wxwidgets fork's wasm port removes the KiCad divergence — and in the tooltip case, re-enables a whole class of UI. The wx wasm port is the sanctioned place for this work, so these don't count against the "minimize upstream edits" goal the way KiCad edits do.

1. HiDPI scale factor — currently changes native behavior

common/gal/hidpi_gl_canvas.cpp (+2/−2) changes GetScaleFactor() from GetContentScaleFactor() to GetDPIScaleFactor() unconditionally — and those two differ on MSW, so this silently alters native Windows builds (see 07). Likewise pcbnew/widgets/appearance_controls.cpp (+4/−1) swaps GetScaleFactor()→GetContentScaleFactor() in GetBestSize().

Do: implement GetContentScaleFactor() correctly (devicePixelRatio) in the wx wasm port and revert both KiCad edits.

2. GetCurrentSelection() on wxUniversal choices

common/eda_draw_frame.cpp (+8), pcbnew/dialogs/panel_setup_layers.cpp (+2/−2), eeschema/dialogs/dialog_sim_command.cpp (+1/−1) work around wxUniversal's wxChoice/wxComboBox where GetCurrentSelection() / IsEmpty() misbehave, by substituting GetSelection() / GetCount().

Do: make GetCurrentSelection() delegate to GetSelection() in the wxUniv/wasm layer — removes all of these at once. (Some of these are also upstream-friendly as plain wx fixes; see 06.)

3. Header self-sufficiency

include/gal/hidpi_gl_canvas.h (+1) adds #include <wx/window.h> before wx/glcanvas.h because the wx wasm port's glcanvas.h isn't self-sufficient.

Do: fix the include self-sufficiency in the wx wasm port's glcanvas.h; revert the KiCad include. (Trivially upstreamable as header hygiene either way.)

4. Tooltips — implement wxToolTip in the wasm port (this re-enables a feature)

wxUSE_TOOLTIPS is 0 in the generated wasm setup.h because upstream wxWidgets configure hard-disables tooltips for wxUniversal ("wxTooltip not supported yet in wxUniversal", wxwidgets/configure.in:7316) — there is no src/univ/tooltip.cpp. KiCad carries ~12 files of wxUSE_TOOLTIPS guards / #ifndef __EMSCRIPTEN__ wxToolTip::Enable to cope.

Do (porting task, 2–4 days, in the wx fork): add src/wasm/tooltip.cpp + include/wx/wasm/tooltip.h — a generic tooltip (hover timer + a wxTipWindow/wxPopupWindow near the pointer; popups are already proven working per tests/WHATWORKS.md), patch the configure gate for the wasm port, regen configure, wire into the makefiles.

Then, KiCad-side, this becomes pure deletion:

• Remove #ifndef __EMSCRIPTEN__ around wxToolTip::Enable(...) in common/pgm_base.cpp, common/dialogs/dialog_design_block_properties.cpp, eeschema/dialogs/dialog_sheet_properties.cpp, eeschema/dialogs/dialog_symbol_properties.cpp.
• The #if wxUSE_TOOLTIPS guards (include/widgets/wx_dataviewctrl.h, common/dialogs/dialog_paste_special.cpp, common/widgets/wx_infobar.cpp, pcbnew/dialogs/dialog_board_reannotate.cpp, include/pcb_base_frame.h) auto-activate — and can be dropped as fork diff, ~8 files reclaimed.

Big UX win: every SetToolTip(...) in KiCad lights up. (The interim upstream-friendly move is to re-spell the bare #ifndef __EMSCRIPTEN__ guards as #if wxUSE_TOOLTIPS — see 06 — so they're correct regardless of when the wx work lands.)

5. Other wx-port-shaped items

• common/pgm_base.cpp wxToolTip::Enable/SetAutoPop under #ifndef __EMSCRIPTEN__ — folds into §4, or provide a no-op wxToolTip in the port.
• common/tool/actions.cpp Backspace hotkey — handled by config in 03.
• wxUSE_FSWATCHER (off): leave off — MEMFS has no change notification and nothing edits files externally in a single-user browser. KiCad's #if wxUSE_FSWATCHER guards are upstream-friendly as-is (see 06).

Net

KiCad edit	wx-port fix	Removes
hidpi_gl_canvas.cpp, appearance_controls.cpp	GetContentScaleFactor()	2 files + a native bug
eda_draw_frame.cpp, panel_setup_layers.cpp, dialog_sim_command.cpp	GetCurrentSelection() delegate	3 files
hidpi_gl_canvas.h	self-sufficient glcanvas.h	1 header
~12 tooltip-guard files	src/wasm/tooltip.cpp	~12 files + enables tooltips