Convert the Transmission.Format, Transmission.Medium, and
Transmission.Compression types from plain Zig enums to lib.Enum so
they get a C-compatible backing type when building with c_abi. This
lets the C API layer reuse the types directly instead of maintaining
separate mirror enums.
Move Format.bpp() to a standalone Transmission.formatBpp() function
since lib.Enum types cannot have decls.
In the C API layer, rename kitty_gfx to kitty_storage and command to
kitty_cmd for clarity, and simplify the format/compression getters
to direct assignment now that the types are shared.
Add a GhosttyKittyGraphicsImage opaque type and API for looking up
images by ID and querying their properties. This complements the
existing placement iterator by allowing direct image introspection.
The new ghostty_kitty_graphics_image() function looks up an image by
its ID from the storage, returning a borrowed opaque handle. Properties
are queried via ghostty_kitty_image_get() using the new
GhosttyKittyGraphicsImageData enum, which exposes id, number, width,
height, format, compression, and a borrowed data pointer with length.
Format and compression are exposed as their own C enum types
(GhosttyKittyImageFormat and GhosttyKittyImageCompression) rather
than raw integers.
Add a C API for iterating over Kitty graphics placements via the
new GhosttyKittyGraphics opaque handle. The API follows the same
pattern as the render state row iterator: allocate an iterator with
ghostty_kitty_graphics_placement_iterator_new, populate it from a
graphics handle via ghostty_kitty_graphics_get with the
PLACEMENT_ITERATOR data kind, advance with
ghostty_kitty_graphics_placement_next, and query per-placement
fields with ghostty_kitty_graphics_placement_get.
The terminal sys module provides runtime-swappable function pointers
for operations that depend on external implementations (e.g. PNG
decoding). This exposes that functionality through the C API via a
ghostty_sys_set() function, modeled after the ghostty_terminal_set()
enum-based option pattern.
Embedders can install a PNG decode callback to enable Kitty Graphics
Protocol PNG support. The callback receives a userdata pointer
(set via GHOSTTY_SYS_OPT_USERDATA) and a GhosttyAllocator that must
be used to allocate the returned pixel data, since the library takes
ownership of the buffer. Passing NULL clears the callback and
disables the feature.
Add four new terminal options for configuring Kitty graphics at runtime
through the C API: storage limit, and the three loading medium flags
(file, temporary file, shared memory).
The storage limit setter propagates to all initialized screens and
uses setLimit which handles eviction when lowering the limit. The
medium setters similarly propagate to all screens. Getters read from
the active screen. All options compile to no-ops or return no_value
when kitty graphics are disabled at build time.
The default kitty image storage limit was 320 MB for all build
artifacts. For libghostty, this is overly generous since it is an
embedded library where conservative memory usage is preferred.
Lower the default to 10 MB when building as the lib artifact while
keeping the 320 MB default for the full Ghostty application.
Move kitty_image_storage_limit and kitty_image_loading_limits into
Terminal.Options so callers can set them at construction time
rather than calling setter functions after init. The values flow
through to Screen.Options during ScreenSet initialization. Termio
now passes both at construction, keeping the setter functions for
the updateConfig path.
Add a Limits type to LoadingImage that controls which transmission
mediums (file, temporary_file, shared_memory) are allowed when
loading images. This defaults to "direct" (most restrictive) on
ImageStorage and is set to "all" by Termio, allowing apprt
embedders like libghostty to restrict medium types for resource or
security reasons.
The limits are stored on ImageStorage, plumbed through
Screen.Options for screen initialization and inheritance, and
enforced in graphics_exec during both query and transmit. Two new
Terminal methods (setKittyGraphicsSizeLimit, setKittyGraphicsLoadingLimits)
centralize updating all screens, replacing the manual iteration
previously done in Termio.
Introduce terminal/sys.zig which provides runtime-swappable function
pointers for operations that depend on external implementations. This
allows embedders of the terminal package to swap out implementations
at startup without hard dependencies on specific libraries.
The first function exposed is decode_png, which defaults to a wuffs
implementation. The kitty graphics image loader now calls through
sys.decode_png instead of importing wuffs directly.
This allows us to enable Kitty graphics support in libghostty-vt
for all targets except wasm32-freestanding.
Wire up the APC handler to `terminal.TerminalStream` to process
APC sequences, enabling support for kitty graphics commands in
libghostty, in theory.
The "in theory" is because we still don't export a way to actually
enable Kitty graphics in libghostty because we have some other things in
the way: PNG decoding and OS filesystem access that need to be more
conditionally compiled before we can enable the feature. However, this
is a step in the right direction, and we can at least verify that the
APC handler works via a test in Ghostty GUI.
Add a new GhosttySelection C API type (selection.h / c/selection.zig)
that pairs two GhosttyGridRef endpoints with a rectangle flag. This maps
directly to the internal Selection type using untracked pins.
The formatter terminal options gain an optional selection pointer. When
non-null the formatter restricts output to the specified range instead
of emitting the entire screen. When null the existing behavior of
formatting the full screen is preserved.
Add a new GhosttySelection C API type (selection.h / c/selection.zig)
that pairs two GhosttyGridRef endpoints with a rectangle flag. This
maps directly to the internal Selection type using untracked pins.
The formatter terminal options gain an optional selection pointer.
When non-null the formatter restricts output to the specified range
instead of emitting the entire screen. When null the existing
behavior of formatting the full screen is preserved.
Add ghostty_grid_ref_hyperlink_uri to extract the OSC 8 hyperlink
URI from a cell at a grid reference position. Follows the same
buffer pattern as ghostty_grid_ref_graphemes: callers pass a buffer
and get back the byte length, or GHOSTTY_OUT_OF_SPACE with the
required size if the buffer is too small. Cells without a hyperlink
return success with length 0.
The function previously took a size_t* out-parameter for the string
length. Since the JSON blob is now null-terminated, the len parameter
is unnecessary. Remove it from the Zig implementation, C header, and
the WASM example consumer which no longer needs to allocate and free
a usize just to read the length.
Add a new C API function that returns a comptime-generated JSON string
describing the size, alignment, and field layout of every C API extern
struct. This lets FFI consumers (particularly WASM) construct structs
by byte offset without hardcoding platform-specific layout.
The JSON is built at comptime using std.json.Stringify via a
StructInfo type that holds per-struct metadata and implements
jsonStringify. A StaticStringMap keyed by C struct name provides
lookup by name as well as iteration for the JSON serialization.
The function is declared in types.h alongside the other common types
and exported as ghostty_type_json.
Fixes#11957
erasePage now updates page_serial_min when the first page is erased,
and asserts that only front or back pages are erased since
page_serial_min cannot represent serial gaps from middle erasure.
To enforce this invariant at the API level, PageList.eraseRows is
now private. Two public wrappers replace it: eraseHistory always
starts from the beginning of history, and eraseActive takes a y
coordinate (with bounds assertion) and always starts from the top
of the active area. This makes middle-page erasure impossible by
construction.
Add version (std.SemanticVersion) to the terminal build options so that
the terminal module has access to the application version at comptime.
The add() function breaks it out into version_string, version_major,
version_minor, version_patch, and version_build terminal options.
On the C API side, five new GhosttyBuildInfo variants expose these
through ghostty_build_info(). String values use GhosttyString; numeric
values use size_t. When no build metadata is present, version_build
returns a zero-length string.
The c-vt-build-info example is updated to query and print all version
fields.
Trailing state capture now is encapsulated in a struct `Capture` and all
parsers access the data via `p.capture.trailing()` rather than directly
from the writer.
This is primarily to prep for the OSC parser to be able to capture the
entire sequence (not just the trailing part) so we can setup libghostty
for fallback handlers so libghostty implementers can have custom OSC
behaviors.
But, it has the benefit of making our OSC parser much cleaner too.
Add ghostty_paste_encode() which encodes paste data for writing to
the terminal pty. It strips unsafe control bytes, wraps in bracketed
paste sequences when requested, and replaces newlines with carriage
returns for unbracketed mode. The input buffer is modified in place
and the encoded result is written to a caller-provided output buffer,
following the same buffer/out_written pattern as the other encode
functions like ghostty_size_report_encode.
Update the c-vt-paste example with an encode_example() demonstrating
the new function and add corresponding @snippet references in the
header documentation.
Add set/get support for foreground, background, cursor, and palette
default colors through ghostty_terminal_set and ghostty_terminal_get.
Four new set options (COLOR_FOREGROUND, COLOR_BACKGROUND, COLOR_CURSOR,
COLOR_PALETTE) write directly to the terminal color defaults. Passing
NULL clears the value for RGB colors or resets the palette to the
built-in default. All set operations mark the palette dirty flag for
the renderer.
Eight new get data types retrieve either the effective color (override
or default, via DynamicRGB.get) or the default color only (ignoring
any OSC overrides). Effective getters for RGB colors return the new
NO_VALUE result code when no color is configured. The palette getters
return the current or original palette respectively.
Adds the GHOSTTY_NO_VALUE result code for cases where a queried value
is simply not configured, distinct from GHOSTTY_INVALID_VALUE which
indicates a caller error.
Each C API file independently imported ../../lib/allocator.zig as
lib_alloc. Now that terminal/lib.zig re-exports the allocator module
as lib.alloc, use that instead. This removes the redundant import
and keeps all lib dependencies flowing through the single lib.zig
entry point.
Previously every file in the terminal package independently imported
build_options and ../lib/main.zig, then computed the same
lib_target constant. This was repetitive and meant each file needed
both imports just to get the target.
Introduce src/terminal/lib.zig which computes the target once and
re-exports the commonly used lib types (Enum, TaggedUnion, Struct,
String, checkGhosttyHEnum, structSizedFieldFits). All terminal
package files now import lib.zig and use lib.target instead of the
local lib_target constant, removing the per-file boilerplate.
The resize function now requires cell_width_px and cell_height_px
parameters and handles the full resize sequence: computing and
setting width_px/height_px on the terminal, clearing synchronized output mode
so changes display immediately, and encoding a mode 2048 in-band size report
via the write_pty callback when that mode is enabled.
A valid width/height px is critical for some applications and protocols
and some applications rely directly on in-band size reports, so this
change is necessary to support those use cases.
Add total_rows and scrollback_rows as new TerminalData variants
queryable through the existing ghostty_terminal_get interface, using the
cached O(1) total_rows field from PageList rather than introducing
standalone functions.
Add total_rows and scrollback_rows as new TerminalData variants
queryable through the existing ghostty_terminal_get interface,
using the cached O(1) total_rows field from PageList rather than
introducing standalone functions.
Previously ghostty_terminal_set required all values to be passed as
pointers to the value, even when the value itself was already a
pointer (userdata, function pointer callbacks). This forced callers
into awkward patterns like compound literals or intermediate
variables just to take the address of a pointer.
Now pointer-typed options (userdata and all callbacks) are passed
directly as the value parameter. Only non-pointer types like
GhosttyString still require a pointer to the value. This
simplifies InType to return the actual stored type for each option
and lets setTyped work with those types directly.
Add title and pwd as both gettable data keys
(GHOSTTY_TERMINAL_DATA_TITLE/PWD) and settable options
(GHOSTTY_TERMINAL_OPT_TITLE/PWD) in the C terminal API. Getting
returns a borrowed GhosttyString; setting copies the data into the
terminal via setTitle/setPwd.
The underlying Terminal.setTitle/setPwd now append a null sentinel so
that getTitle/getPwd can return sentinel-terminated slices ([:0]const
u8), which is useful for downstream consumers that need C strings.
Change ghostty_terminal_set to return GhosttyResult instead of void
so that the new title/pwd options can report allocation failures.
Existing option-setting calls cannot fail so the return value is
backwards-compatible for callers that discard it.
The DA1 trampoline was converting C feature codes into a local
stack buffer and returning a slice pointing into it. This is
unsound because the slice outlives the stack frame once the
trampoline returns, leaving reportDeviceAttributes reading
invalid memory.
Move the scratch buffer into the wrapper effects struct so that
its lifetime extends beyond the trampoline call, keeping the
returned slice valid for the caller.
Assign handler.effects as a struct literal instead of setting fields
individually. This lets the compiler catch missing fields if new
effects are added to the Effects struct.
Also sort the callback function typedefs in vt/terminal.h
alphabetically (Bell, ColorScheme, DeviceAttributes, Enquiry, Size,
TitleChanged, WritePty, Xtversion).
Rename device_status.h to device.h and add C-compatible structs for
device attributes (DA1/DA2/DA3) responses. The new header includes
defines for all known conformance levels, DA1 feature codes, and DA2
device type identifiers.
Add a GhosttyTerminalDeviceAttributesFn callback that C consumers can
set via GHOSTTY_TERMINAL_OPT_DEVICE_ATTRIBUTES. The callback follows
the existing bool + out-pointer pattern used by color_scheme and size
callbacks. When the callback is unset or returns false, the trampoline
returns a default VT220 response (conformance level 62, ANSI color).
The DA1 primary features use a fixed [64]uint16_t inline array with a
num_features count rather than a pointer, so the entire struct is
value-typed and can be safely copied without lifetime concerns.
Change device_status.ColorScheme from a plain Zig enum to
lib.Enum so it uses c_int backing when targeting the C ABI.
Add a color_scheme callback to the C terminal effects, following
the bool + out-pointer pattern used by the size callback. The
trampoline converts between the C calling convention and the
internal stream handler color_scheme effect, returning null when
no callback is set.
Add device_status.h header with GhosttyColorScheme enum and wire
it through terminal.h as GHOSTTY_TERMINAL_OPT_COLOR_SCHEME (= 7)
with GhosttyTerminalColorSchemeFn.
Add GHOSTTY_TERMINAL_OPT_SIZE so C consumers can respond to
XTWINOPS size queries (CSI 14/16/18 t). The callback receives a
GhosttySizeReportSize out-pointer and returns true if the size is
available, or false to silently ignore the query. The trampoline
converts the bool + out-pointer pattern to the optional that the
Zig handler expects.
Add GHOSTTY_TERMINAL_OPT_TITLE_CHANGED so C consumers are notified
when the terminal title changes via OSC 0 or OSC 2 sequences. The
callback has the same fire-and-forget shape as bell.
Add GHOSTTY_TERMINAL_OPT_ENQUIRY and GHOSTTY_TERMINAL_OPT_XTVERSION
so C consumers can respond to ENQ (0x05) and XTVERSION (CSI > q)
queries. Both callbacks return a GhosttyString rather than using
out-pointers.
Introduce GhosttyString in types.h as a borrowed byte string
(ptr + len) backed by lib.String on the Zig side. This will be
reusable for future callbacks that need to return string data.
Without an xtversion callback the trampoline returns an empty
string, which causes the handler to report the default
"libghostty" version. Without an enquiry callback no response
is sent.
Test that the write_pty callback receives correct DECRQM response
data and userdata, that queries are silently ignored without a
callback, and that setting null clears the callback. Test that
the bell callback fires on single and multiple BEL characters
with correct userdata, and that BEL without a callback is safe.
Add GHOSTTY_TERMINAL_OPT_BELL so C consumers can receive bell
notifications during VT processing. The bell trampoline follows
the same pattern as write_pty.
Move the C function pointer typedefs (WritePtyFn, BellFn) into
the Effects struct namespace to keep callback types co-located
with their storage and trampolines.
Add a typed option setter ghostty_terminal_set() following the
existing setopt pattern used by the key encoder and render state
APIs. This is the first step toward exposing stream_terminal
Handler.Effects through the C API.
The initial implementation includes a write_pty callback and a
shared userdata pointer. The write_pty callback is invoked
synchronously during ghostty_terminal_vt_write() when the terminal
needs to send a response back to the pty, such as DECRQM mode
reports or device status responses.
Trampolines are always installed at terminal creation time and
no-op when no C callback is set, so callers can configure
callbacks at any point without reinitializing the stream. The C
callback state is grouped into an internal Effects struct on the
TerminalWrapper to simplify adding more callbacks in the future.
## What
On Windows, calling `free()` on memory allocated by libghostty crashes
because Zig and MSVC use separate heaps.
This adds `ghostty_free()` so consumers can free library-allocated
memory safely on all platforms.
## Why
When Zig builds a DLL on Windows with `link_libc = true`, it does not
link the Windows C runtime (`ucrtbase.dll`). Instead it uses its own
libc built on top of `KERNEL32.dll`. So `builtin.link_libc` is true and
`c_allocator` is selected, but Zig's `malloc` and MSVC's `malloc` are
different implementations with different heaps. 💥
On Linux/macOS this is not a problem because Zig links the system libc
and everyone shares the same heap. On Windows, `free(buf)` from MSVC
tries to free memory from Zig's heap and you get a debug assertion
failure or undefined behavior.
The `format_alloc` docs said "the buffer can be freed with `free()`" but
that is only true when the library and consumer share the same C
runtime, which is not the case on Windows.
## How
- Add `ghostty_free(allocator, ptr, len)` that frees through the same
allocator that did the allocation
- Update `format_alloc` docs to point to `ghostty_free()` instead of
`free()`
- Update all 3 examples to use `ghostty_free(NULL, buf, len)`
The signature takes an allocator because raw buffers (unlike objects
like terminals or formatters) do not store their allocator internally.
The caller already has all three values: the allocator they passed, the
pointer, and the length they got back.
I went back and forth on the naming. Other options I considered:
`ghostty_alloc_free(allocator, ptr, len)` or returning a `GhosttyBuffer`
wrapper with its own `_free`. Happy to change the naming if there is a
preference.
No impact on Linux/macOS. `ghostty_free()` works correctly there too, it
just happens to call the same `free()` the consumer would have called
anyway.
## Verified
- `zig build test-lib-vt` passes on Windows, macOS arm64, Linux x86_64
(exit 0)
- `zig build test` passes on Windows (2575/2619 passed, 1 pre-existing
font sprite failure) and macOS (exit 0)
- cmake shared example builds, links, and runs correctly on Windows with
`ghostty_free()` (no more heap crash)
## What I Learnt
- What I wrote in Why
- Zig allocators require the length to free (no hidden metadata headers
like C's malloc). This is a deliberate design choice for explicit
control.
- The standard pattern for C libraries on Windows is "whoever allocates,
frees" (like `curl_free()`, `SDL_free()`). This avoids cross-runtime
heap issues entirely.
Add a ghostty_alloc function that pairs with the existing
ghostty_free, giving embedders a symmetric malloc/free-style
API for buffer allocation through the libghostty allocator
interface. Returns NULL on allocation failure.
Extract the inline free_alloc function from main.zig into a new
allocator.zig module in the C API layer. The function is renamed
to alloc_free in main.zig (and free in allocator.zig) for
consistency with the other C API naming conventions. Add tests
for null pointer, allocated memory, and null allocator fallback.
