Crate skia_rs_ffi 

C FFI bindings for skia-rs.

This crate provides C-compatible bindings for use from other languages. It exposes a C API that mirrors the Skia C API for drop-in compatibility.

Safety

All FFI functions are inherently unsafe. Callers must ensure:

• Pointers are valid and non-null (unless explicitly documented otherwise)
• Proper lifetime management (using the appropriate _unref functions)
• Thread safety requirements are followed (see below)

Every exported sk_* function wraps its body in catch_panic / catch_panic_void so that a Rust panic can never unwind into C. If a panic is caught the function returns a default value (null pointer, zero, false, identity matrix, etc.) and sets a thread-visible flag readable via sk_last_call_panicked.

Reference Counting

Objects follow Skia’s reference counting model:

• Objects are created with a reference count of 1
• sk_*_ref() increments the reference count
• sk_*_unref() decrements the reference count and frees when it reaches 0
• Use sk_refcnt_get_count() to query the current count

Reference counting operations (ref/unref) are thread-safe and use atomic operations internally. The generic sk_refcnt_get_count / sk_refcnt_is_unique entry points perform a magic-tag check before reading the refcount field, so passing a non-refcounted pointer returns 0 instead of reading arbitrary memory.

ABI Initialization

Callers must invoke sk_init once at startup, passing the major / minor version the client was compiled against. sk_init returns false if the versions are incompatible; the caller should then abort rather than calling any other sk_* function.

Modules

abi

Binary ABI Compatibility Layer

Structs

RefCounted

Reference counted wrapper for FFI objects.

sk_canvas_t

Opaque canvas handle.

sk_color4f_t

C-compatible 4-component color (float RGBA).

sk_imageinfo_t

C-compatible image info structure.

sk_ipoint_t

C-compatible integer point structure.

sk_irect_t

C-compatible integer rectangle structure.

sk_isize_t

C-compatible integer size structure.

sk_matrix44_t

C-compatible 4x4 matrix structure (column-major).

sk_matrix_t

C-compatible matrix structure.

sk_path_iter_t

Stateful iterator over a path’s verbs.

sk_picture_recorder_t

Opaque picture recorder. Not reference counted — single ownership.

sk_point_t

C-compatible point structure.

sk_recording_canvas_t

Recording canvas handle. Returned by sk_picture_recorder_begin_recording and accepted by [sk_recording_canvas_*] — it is not interchangeable with sk_canvas_t (which is raster-backed).

sk_rect_t

C-compatible rectangle structure.

sk_size_t

C-compatible size structure.

Enums

sk_clip_op_t

Clip operation for canvas clipping functions.

sk_region_op_t

Region operation for region manipulation functions.

sk_trim_mode_t

Trim path effect mode.

Constants

SK_PATH_VERB_CLOSE

ABI-stable verb code for a contour close.

SK_PATH_VERB_CONIC

ABI-stable verb code for a conic section.

SK_PATH_VERB_CUBIC

ABI-stable verb code for a cubic bezier.

SK_PATH_VERB_DONE

Sentinel verb code returned once the iterator is exhausted.

SK_PATH_VERB_LINE

ABI-stable verb code for a line segment.

SK_PATH_VERB_MOVE

ABI-stable verb codes emitted by sk_path_iter_next.

SK_PATH_VERB_QUAD

ABI-stable verb code for a quadratic bezier.

Functions

sk_canvas_clear^⚠

Clear the canvas with a color.

sk_canvas_clip_path^⚠

Intersect or subtract a path from the clip.

sk_canvas_clip_rect^⚠

Intersect or subtract a rectangle from the clip.

sk_canvas_concat^⚠

Concatenate a matrix onto the canvas’s current transform.

sk_canvas_draw_path^⚠

Draw a path on the canvas, honoring the canvas’s current transform and clip stack.

sk_canvas_draw_rect^⚠

Draw a rect on the canvas, honoring the canvas’s current transform and clip stack.

sk_canvas_draw_text_blob^⚠

Draw a text blob on a canvas at (x, y).

sk_canvas_get_clip_ibounds^⚠

Fill out with the device-space integer clip bounds of this canvas.

sk_canvas_get_height^⚠

Get the height of the canvas.

sk_canvas_get_width^⚠

Get the width of the canvas.

sk_canvas_release^⚠

Release a canvas acquired via sk_surface_lock_canvas.

sk_canvas_restore^⚠

Restore the most recently saved matrix and clip.

sk_canvas_rotate^⚠

Rotate the canvas coordinate system (degrees).

sk_canvas_save^⚠

Save the current transformation matrix and clip stack.

sk_canvas_save_layer^⚠

Save a layer — pushes a save frame that records the layer bounds and paint for composition on restore.

sk_canvas_scale^⚠

Scale the canvas coordinate system.

sk_canvas_translate^⚠

Translate the canvas coordinate system.

sk_colorfilter_new_identity^⚠

Create an identity color-matrix filter.

sk_colorfilter_new_matrix^⚠

Create a color-matrix filter from 20 floats (row-major 4x5).

sk_colorfilter_new_saturation^⚠

Create a saturation color filter (1.0 = identity, 0.0 = grayscale).

sk_colorfilter_ref^⚠

Increment color filter refcount.

sk_colorfilter_unref^⚠

Decrement color filter refcount.

sk_colorspace_from_icc^⚠

Parse a color space from a raw ICC profile byte buffer. Returns null on failure (malformed profile, missing acsp magic, etc.).

sk_colorspace_is_linear^⚠

Return true if this color space has a linear transfer function.

sk_colorspace_is_srgb^⚠

Return true if this color space is sRGB.

sk_colorspace_new_display_p3^⚠

Create a new Display P3 color space.

sk_colorspace_new_srgb^⚠

Create a new sRGB color space.

sk_colorspace_new_srgb_linear^⚠

Create a new linear sRGB color space.

sk_colorspace_ref^⚠

Increment color space refcount.

sk_colorspace_unref^⚠

Decrement color space refcount.

sk_font_get_size^⚠

Get font size.

sk_font_measure_text^⚠

Measure a UTF-8 text string at the font’s current size. Returns the advance width in pixels; negative return indicates an invalid font or invalid UTF-8.

sk_font_new^⚠

Create a font from a typeface and size.

sk_font_ref^⚠

Increment font refcount.

sk_font_unref^⚠

Decrement font refcount.

sk_image_encode_png^⚠

Encode an image as PNG into a caller-allocated buffer.

sk_image_from_color^⚠

Create an image filled with a single color.

sk_image_from_encoded^⚠

Decode an encoded image (PNG/JPEG/…) from a byte buffer.

sk_image_get_height^⚠

Get the image height.

sk_image_get_refcnt^⚠

Get the reference count of an image.

sk_image_get_width^⚠

Get the image width.

sk_image_ref^⚠

Increment the reference count of an image.

sk_image_unref^⚠

Decrement the reference count of an image.

sk_imagefilter_new_blur^⚠

Create a Gaussian blur image filter.

sk_imagefilter_ref^⚠

Increment image filter refcount.

sk_imagefilter_unref^⚠

Decrement image filter refcount.

sk_init

Initialize the library and verify ABI compatibility.

sk_is_available^⚠

Check if the library is available.

sk_is_initialized

Check whether sk_init has been called successfully.

sk_last_call_panicked

Check if the last FFI call panicked.

sk_maskfilter_new_blur^⚠

Create a blur mask filter with the given sigma (pixels).

sk_maskfilter_ref^⚠

Increment mask filter refcount.

sk_maskfilter_unref^⚠

Decrement mask filter refcount.

sk_matrix44_concat^⚠

Concatenate two 4x4 matrices: result = a * b.

sk_matrix44_determinant^⚠

Return the determinant of the matrix.

sk_matrix44_from_array^⚠

Construct a sk_matrix44_t from 16 column-major floats.

sk_matrix44_invert^⚠

Invert a 4x4 matrix. Returns true on success; result is unchanged if the matrix is singular.

sk_matrix44_is_identity^⚠

Return true if the matrix is the identity matrix.

sk_matrix44_map_point^⚠

Map a 2D point through a 4x4 matrix (projects through W).

sk_matrix44_new^⚠

Create an identity sk_matrix44_t.

sk_matrix_concat^⚠

Concatenate two matrices.

sk_matrix_determinant^⚠

Return the determinant of the matrix.

sk_matrix_invert^⚠

Invert a matrix into result. Returns true on success, false if the matrix is singular (non-invertible); on failure result is unchanged.

sk_matrix_is_identity^⚠

Return true if the matrix is the identity.

sk_matrix_map_point^⚠

Map a point through a matrix.

sk_matrix_set_identity^⚠

Set matrix to identity.

sk_matrix_set_rotate^⚠

Set matrix to rotate (degrees).

sk_matrix_set_scale^⚠

Set matrix to scale.

sk_matrix_set_translate^⚠

Set matrix to translate.

sk_paint_clone^⚠

Clone a paint.

sk_paint_delete^⚠

Decrement the reference count of a paint (alias for unref).

sk_paint_get_color^⚠

Get the paint color.

sk_paint_get_color4f^⚠

Get the paint color as float RGBA.

sk_paint_get_refcnt^⚠

Get the reference count of a paint.

sk_paint_get_stroke_width^⚠

Get the stroke width.

sk_paint_is_antialias^⚠

Check if anti-alias is enabled.

sk_paint_new^⚠

Create a new paint.

sk_paint_ref^⚠

Increment the reference count of a paint.

sk_paint_set_antialias^⚠

Set anti-alias.

sk_paint_set_blend_mode^⚠

Set the paint’s blend mode (matches abi::SkBlendModeABI).

sk_paint_set_color^⚠

Set the paint color.

sk_paint_set_color4f^⚠

Set the paint color as float RGBA.

sk_paint_set_color_filter^⚠

Attach a color filter to the paint. Passing null clears it.

sk_paint_set_image_filter^⚠

Attach an image filter to the paint. Passing null clears it.

sk_paint_set_mask_filter^⚠

Attach a mask filter to the paint. Passing null clears it.

sk_paint_set_path_effect^⚠

Attach a path effect to a paint, or clear it if effect is null. The paint takes its own Arc reference; the caller retains their own.

sk_paint_set_shader^⚠

Attach a shader to the paint. Passing null clears it.

sk_paint_set_stroke_width^⚠

Set the stroke width.

sk_paint_set_style^⚠

Set the paint style.

sk_paint_unref^⚠

Decrement the reference count of a paint.

sk_path_clone^⚠

Clone a path.

sk_path_contains^⚠

Check if path contains a point.

sk_path_delete^⚠

Decrement the reference count of a path (alias for unref).

sk_path_get_bounds^⚠

Get the path bounds.

sk_path_get_filltype^⚠

Get the fill type.

sk_path_get_refcnt^⚠

Get the reference count of a path.

sk_path_is_empty^⚠

Check if path is empty.

sk_path_iter_delete^⚠

Destroy a path iterator.

sk_path_iter_new^⚠

Create an iterator over a path’s verbs.

sk_path_iter_next^⚠

Advance the iterator. Fills up to four points in out_points (caller provides at least 4 slots) and the conic weight (if applicable) in out_weight. Returns the verb code; SK_PATH_VERB_DONE indicates exhaustion.

sk_path_new^⚠

Create a new path.

sk_path_ref^⚠

Increment the reference count of a path.

sk_path_set_filltype^⚠

Set the fill type.

sk_path_unref^⚠

Decrement the reference count of a path.

sk_pathbuilder_add_circle^⚠

Add a circle.

sk_pathbuilder_add_oval^⚠

Add an oval.

sk_pathbuilder_add_rect^⚠

Add a rectangle.

sk_pathbuilder_close^⚠

Close the path.

sk_pathbuilder_cubic_to^⚠

Cubic bezier to a point.

sk_pathbuilder_delete^⚠

Decrement the reference count of a path builder (alias for unref).

sk_pathbuilder_detach^⚠

Build the path and reset the builder.

sk_pathbuilder_line_to^⚠

Line to a point.

sk_pathbuilder_move_to^⚠

Move to a point.

sk_pathbuilder_new^⚠

Create a new path builder.

sk_pathbuilder_quad_to^⚠

Quadratic bezier to a point.

sk_pathbuilder_ref^⚠

Increment the reference count of a path builder.

sk_pathbuilder_snapshot^⚠

Build the path without resetting the builder.

sk_pathbuilder_unref^⚠

Decrement the reference count of a path builder.

sk_patheffect_new_dash^⚠

Create a dash path effect. intervals must be non-null with count positive entries; the pattern is duplicated internally if count is odd, matching Skia’s semantics. phase shifts where the pattern starts. Returns null if the intervals are invalid (empty, negative, or sum to 0).

sk_patheffect_new_trim^⚠

Create a trim path effect. start and end are normalized lengths in [0, 1].

sk_patheffect_ref^⚠

Increment path effect refcount.

sk_patheffect_unref^⚠

Decrement path effect refcount.

sk_picture_approximate_op_count^⚠

Get the approximate operation count of a picture.

sk_picture_get_cull_rect^⚠

Get the picture’s cull rect.

sk_picture_playback^⚠

Play a recorded picture back onto a raster canvas.

sk_picture_recorder_begin_recording^⚠

Begin recording into a fresh picture. Returns a recording canvas handle that draw ops append to. The caller drops the handle via sk_recording_canvas_release but must call sk_picture_recorder_finish_recording to get the recorded picture.

sk_picture_recorder_delete^⚠

Destroy a picture recorder.

sk_picture_recorder_finish_recording^⚠

Finish recording and return the captured picture. Returns null if the recorder was not recording. After this call the recorder can be reused with another sk_picture_recorder_begin_recording.

sk_picture_recorder_new^⚠

Create a new picture recorder.

sk_picture_ref^⚠

Increment picture refcount.

sk_picture_unref^⚠

Decrement picture refcount.

sk_recording_canvas_draw_path^⚠

Draw a path into the recording canvas.

sk_recording_canvas_draw_rect^⚠

Draw a rect into the recording canvas. The rect is captured in the caller-space coordinates (post-transform) so playback can place it on any target canvas.

sk_recording_canvas_release^⚠

Release a recording canvas handle acquired via sk_picture_recorder_begin_recording. Does not finalize the recording — call sk_picture_recorder_finish_recording for that.

sk_recording_canvas_restore^⚠

Pop a save on the recording canvas’s state.

sk_recording_canvas_save^⚠

Push a save onto the recording canvas’s state.

sk_recording_canvas_translate^⚠

Translate the recording canvas’s current transform.

sk_refcnt_get_count^⚠

Get the reference count of an object.

sk_refcnt_is_unique^⚠

Check if an object has only one reference (is unique).

sk_region_contains^⚠

Return true if the region contains a point.

sk_region_get_bounds^⚠

Get the region’s integer bounds.

sk_region_is_empty^⚠

Return true if the region is empty.

sk_region_new^⚠

Create a new, empty region.

sk_region_op_rect^⚠

Apply a rect op on the region.

sk_region_ref^⚠

Increment region refcount.

sk_region_set_rect^⚠

Set the region to a single integer rectangle. Returns true if the rect was non-empty (the region now holds it), false if empty (the region is cleared).

sk_region_unref^⚠

Decrement region refcount.

sk_shader_get_refcnt^⚠

Get shader refcount.

sk_shader_new_linear_gradient^⚠

Create a linear gradient shader.

sk_shader_new_radial_gradient^⚠

Create a radial gradient shader.

sk_shader_new_sweep_gradient^⚠

Create a sweep gradient shader.

sk_shader_ref^⚠

Increment shader refcount.

sk_shader_unref^⚠

Decrement shader refcount.

sk_surface_clear^⚠

Clear a surface with a color.

sk_surface_draw_circle^⚠

Draw a circle on a surface.

sk_surface_draw_line^⚠

Draw a line on a surface.

sk_surface_draw_path^⚠

Draw a path on a surface.

sk_surface_draw_rect^⚠

Draw a rect on a surface.

sk_surface_get_height^⚠

Get the height of a surface.

sk_surface_get_refcnt^⚠

Get the reference count of a surface.

sk_surface_get_width^⚠

Get the width of a surface.

sk_surface_is_unique^⚠

Check if the surface has only one reference.

sk_surface_lock_canvas^⚠

Acquire a canvas borrowed from the given surface.

sk_surface_new_raster^⚠

Create a new raster surface.

sk_surface_new_raster_with_info^⚠

Create a raster surface with specific image info.

sk_surface_peek_pixels^⚠

Get the pixel data from a surface (unsynchronized borrow).

sk_surface_read_pixels^⚠

Copy the pixel data from a surface into a caller-owned buffer.

sk_surface_ref^⚠

Increment the reference count of a surface.

sk_surface_unref^⚠

Decrement the reference count of a surface.

sk_textblob_get_bounds^⚠

Get text blob bounds.

sk_textblob_make_from_text^⚠

Build a text blob from a NUL-terminated UTF-8 string. text and font must be valid, non-null pointers; returns null otherwise.

sk_textblob_ref^⚠

Increment text blob refcount.

sk_textblob_unref^⚠

Decrement text blob refcount.

sk_typeface_default^⚠

Create the default typeface.

sk_typeface_from_data^⚠

Load a typeface from raw font file data (TTF/OTF).

sk_typeface_get_refcnt^⚠

Get typeface refcount.

sk_typeface_glyph_count^⚠

Get the typeface’s glyph count.

sk_typeface_ref^⚠

Increment typeface refcount.

sk_typeface_units_per_em^⚠

Get the typeface’s units-per-em.

sk_typeface_unref^⚠

Decrement typeface refcount.

sk_version^⚠

Get the library version as a NUL-terminated static string.

Type Aliases

sk_color_t

C-compatible color (ARGB packed).

sk_colorfilter_t

Reference counted color filter.

sk_colorspace_t

Reference counted ColorSpace.

sk_font_t

Reference counted font type (typeface + size + options).

sk_image_t

Reference counted image type.

sk_imagefilter_t

Reference counted image filter.

sk_maskfilter_t

Reference counted mask filter.

sk_paint_t

Reference counted paint type.

sk_path_t

Reference counted path type.

sk_pathbuilder_t

Reference counted path builder type.

sk_patheffect_t

Reference counted PathEffectRef.

sk_picture_t

Reference counted [Picture].

sk_refcnt_t

Opaque reference counted object type.

sk_region_t

Reference counted Region.

sk_shader_t

Reference counted shader type.

sk_surface_t

Reference counted surface type.

sk_textblob_t

Reference counted TextBlob.

sk_typeface_t

Reference counted typeface type.