# yasl gaps for wsap_term

Date: 2026-10-12
yasl head checked: `97e5cc6` (same commit on `https://git.wsap.dev/yasl.git/`)
wsap_term state: the project builds and all 89 non-fuzz tests pass.

## Summary

The project already uses the new yasl API. Drag start, carry, and the
source-side end work on X11 and Cocoa. Some drag and input features are
still missing on some backends. Most of the gaps are in yasl. A few are in
this project.

## Drag and drop

### 1. X11 and Cocoa never send drop-target events (yasl)

yasl has these target events:

- `YASL_DRAG_OVER`, `YASL_DRAG_LEAVE`, `YASL_DRAG_DROP` (surface `drag` callback)
- `YASL_DROP_OVER`, `YASL_DROP_LEAVE` (surface `drop` callback)

Only the Wayland backend sends them:

- `src/wayland/clipboard.c`
- `src/wayland/drag.c`

X11 and Cocoa send only the source-side end (`YASL_DRAG_DROPPED` or
`YASL_DRAG_CANCELLED`).

Effect in wsap_term: a tab dragged onto another window's tab bar gets no
hover and no drop on X11 or macOS. The tab falls back to a new window
(`flight_end` in `src/window/terminal/transfer.c`).

Needed in yasl: send the target events from the X11 and Cocoa drag code.

### 2. Drag images are ignored on X11 and Cocoa (yasl)

- X11: `drag_start` in `src/x11/window.c` has `(void)image;`.
- Cocoa: `cocoa_display_drag_start` in `src/cocoa/window.m` has `(void)image;`.

Effect: the drag image is not shown. The project does not use the image on
these backends today, because they report `YASL_CAP_DRAG_CARRY`. The
project uses the image only when carry is missing. That path runs on
Wayland without toplevel-drag.

Needed in yasl: draw the image, or document that it is unsupported.

## Input and file drops

### 3. X11 does not send file drops (yasl)

`YASL_INPUT_DROP_FILES` is sent only by:

- `src/common/input.c` (helper)
- `src/cocoa/window.m`
- `src/wayland/pointer.c`

Effect: dropping files onto a terminal window does nothing on X11.

Needed in yasl: XDND file-drop handling for X11.

### 4. IME preedit is missing on X11 (yasl)

The X11 input context uses `XIMPreeditNothing`. The yasl README already
says X11 does not support IME preedit text.

Effect: composed text (for example CJK input) does not show inline on X11.

## Popups, selection, and caps

### 5. Cocoa has no popups (yasl)

`cocoa_surface_create_popup` and `cocoa_surface_popup_reposition` are
stubs that return NULL or false. `cocoa_display_caps` does not set
`YASL_CAP_POPUPS`.

Effect: the project's native menu popup is off on macOS. `open_popup` in
`src/window/ui/ui_menu.c` returns false, so the menu stays in the window.

### 6. X11 has no popups (yasl)

`caps()` in `src/x11/window.c` does not set `YASL_CAP_POPUPS`.

Effect: same as item 5. Menus stay in the window on X11.

### 7. Cocoa has no primary selection (yasl)

`cocoa_display_caps` does not set `YASL_CAP_PRIMARY_SELECTION`. yasl says an
unsupported primary selection is a no-op.

Effect: select-to-copy and middle-click paste do nothing on macOS. The
terminal calls these in `src/window/terminal/view.c` (`window_copy` and
`window_paste` with `YASL_PRIMARY`).

### 8. X11 and Cocoa have no CSD or frame pacing flags (yasl)

These caps are set on Wayland only. Cocoa sets `YASL_CAP_FRAME_PACING`.
X11 sets neither. The project does not read these flags for drawing
decisions in the current code. Check this before you rely on pacing on
X11.

## Project-side gaps (wsap_term)

### 9. Reset does not clear pointer buttons

yasl's `YASL_INPUT_RESET` says the app must clear held keys and buttons,
and composition state.

`window_native_input` in `src/window/native_input.c` clears only keyboard
state. Pointer presses are tracked by the UI widgets, so a press that a
reset interrupts can stay stuck until the next press or release.

Suggested fix: send a pointer-release-like event to the UI, or add a
UI-level reset.

## What is already fine

- Cursor: now uses `YASL_CURSOR_HIDDEN` (`src/window/ui/ui_route.c`).
- Accessibility on macOS: uses the typed view handle
  (`src/window/ui/accessibility/accessibility.m`). This file compiles only
  on macOS. It was not compiled here.
- Pen input: pressure and tilt fields match yasl's contract.
- Mouse buttons: 0 is primary, 1 is middle, 2 is secondary. This matches
  the project.
- Drag and carry: wired to the caps. Used on X11 and Cocoa with no code
  change.

## Suggested order

1. Drop-target events on X11 and Cocoa (item 1). This unblocks tab merge.
2. X11 file drops (item 3).
3. Cocoa primary selection (item 7). Affects everyday terminal use on macOS.
4. Popups on X11 and Cocoa (items 5 and 6), if menus need them.
5. Project reset fix (item 9).
6. Drag images (item 2), IME preedit (item 4), and frame-pacing caps (item 8)
   as lower priority.