Struct CGContext 

pub struct CGContext { /* private fields */ }

Available on crate feature cg only.

Reference-counted CGContextRef backed by a bitmap.

Clones retain the same mutable native context; they are not independent drawing surfaces.

Implementations

impl CGContext

pub const unsafe fn from_raw(ptr: *mut c_void) -> Self

Wrap a raw CGContextRef pointer — takes ownership without retaining.

Safety

ptr must be a non-null CGContextRef whose ownership the caller is transferring to the returned CGContext.

pub fn new_rgba8(width: usize, height: usize) -> Result<Self, CFError>

Create a premultiplied-last RGBA8 bitmap context.

Errors

Returns CFError if Core Graphics fails to create the bitmap context.

pub fn new_grayscale(width: usize, height: usize) -> Result<Self, CFError>

Create an 8-bit grayscale bitmap context.

Errors

Returns CFError if Core Graphics fails to create the bitmap context.

pub fn width(&self) -> usize

Width in pixels.

pub fn height(&self) -> usize

Height in pixels.

pub fn bytes_per_row(&self) -> usize

Bytes per row.

pub fn bits_per_component(&self) -> usize

Bits per component.

pub fn bits_per_pixel(&self) -> usize

Bits per pixel.

pub fn data(&self) -> *mut u8

Raw bitmap data pointer.

Dereferencing the pointer is unsafe because retained aliases and native drawing operations can mutate the same storage.

pub fn color_space(&self) -> Option<CGColorSpace>

The context color space, if one is set.

pub fn alpha_info(&self) -> u32

The raw CGImageAlphaInfo value for the bitmap context.

pub unsafe fn as_bytes(&self) -> &[u8]

The bitmap storage as immutable bytes.

Safety

Every byte in the range must already be initialized. For the returned reference’s lifetime, the bitmap allocation must remain live and immovable, and no retained alias or native call may draw into, clear, replace, or otherwise mutate the context storage.

pub unsafe fn as_bytes_mut(&mut self) -> &mut [u8]

The bitmap storage as mutable bytes.

Safety

Every byte in the range must already be initialized. For the returned reference’s lifetime, the caller must have unique access to the bitmap storage across every retained wrapper and native alias, and no drawing or snapshot operation may access the context.

pub fn set_rgb_fill_color(&self, r: f64, g: f64, b: f64, a: f64)

Set the current fill color in DeviceRGB.

pub fn set_rgb_stroke_color(&self, r: f64, g: f64, b: f64, a: f64)

Set the current stroke color in DeviceRGB.

pub fn set_line_width(&self, w: f64)

Set the stroke line width.

pub fn clear_rect(&self, x: f64, y: f64, w: f64, h: f64)

Clear a rectangle to transparent black.

pub fn fill_rect(&self, x: f64, y: f64, w: f64, h: f64)

Fill a rectangle.

pub fn stroke_rect(&self, x: f64, y: f64, w: f64, h: f64)

Stroke a rectangle.

pub fn begin_path(&self)

Begin a new path.

pub fn close_path(&self)

Close the current path.

pub fn move_to(&self, x: f64, y: f64)

Move the current point.

pub fn add_line_to(&self, x: f64, y: f64)

Add a line segment to the current path.

pub fn add_rect(&self, x: f64, y: f64, w: f64, h: f64)

Add a rectangle to the current path.

pub fn add_ellipse_in_rect(&self, x: f64, y: f64, w: f64, h: f64)

Add an ellipse inscribed in the rectangle.

pub fn fill_path(&self)

Fill the current path.

pub fn stroke_path(&self)

Stroke the current path.

pub fn draw_image(&self, x: f64, y: f64, w: f64, h: f64, image: &CGImage)

Draw an image into the target rectangle.

pub fn translate(&self, tx: f64, ty: f64)

Translate the current transformation matrix.

pub fn scale(&self, sx: f64, sy: f64)

Scale the current transformation matrix.

pub fn rotate(&self, radians: f64)

Rotate the current transformation matrix.

pub fn save_g_state(&self)

Save the current graphics state.

pub fn restore_g_state(&self)

Restore the most recently saved graphics state.

pub fn snapshot_to_image(&self) -> Option<CGImage>

Snapshot the current bitmap contents to a CGImage.

pub const fn as_ptr(&self) -> *mut c_void

Raw CGContextRef pointer.

Trait Implementations

impl Clone for CGContext

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CGContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for CGContext

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.