Struct BlendKernel 

pub struct BlendKernel;

GPU-style image blending kernel (CPU simulation via Rayon).

Operates on packed RGBA (4 bytes / pixel) buffers. dst is modified in place (it acts as both the base and the output).

Implementations

impl BlendKernel

pub fn blend( src: &[u8], dst: &mut [u8], width: u32, height: u32, mode: BlendMode, opacity: u8, ) -> Result<BlendStats, BlendError>

Blend src over dst using the specified blend mode and global opacity.

opacity controls how much of src is mixed in (0 = invisible, 255 = fully opaque). The per-pixel alpha in src is also respected by all modes.

Errors

Returns BlendError if buffers or dimensions are invalid.

pub fn blend_masked( src: &[u8], dst: &mut [u8], mask: &[u8], width: u32, height: u32, mode: BlendMode, global_opacity: u8, ) -> Result<BlendStats, BlendError>

Blend with a per-pixel opacity mask (single channel, one byte per pixel).

Each pixel’s effective opacity is global_opacity * mask[i] / 255.

Errors

Returns BlendError if any buffer or mask length is invalid.

pub fn composite_layers( layers: &[(&[u8], u8)], width: u32, height: u32, ) -> Result<Vec<u8>, BlendError>

Composite multiple layers using Porter-Duff “over” operator.

Layers are composited from bottom to top (index 0 is the base). Each (buffer, opacity) entry is blended onto the accumulator.

Errors

Returns BlendError if any layer has incorrect dimensions.

pub fn apply_tint( src: &[u8], dst: &mut [u8], width: u32, height: u32, tint: [u8; 4], ) -> Result<(), BlendError>

Apply a constant color tint (multiply by a solid RGBA color).

Each pixel is multiplied component-wise by tint / 255.

Errors

Returns BlendError if buffer or dimensions are invalid.

pub fn premultiply_alpha( buf: &mut [u8], width: u32, height: u32, ) -> Result<(), BlendError>

Premultiply RGB channels by the alpha channel in place.

Input: [R, G, B, A] straight alpha. Output: [R*A/255, G*A/255, B*A/255, A] premultiplied.

Errors

Returns BlendError on dimension or buffer mismatch.

pub fn unpremultiply_alpha( buf: &mut [u8], width: u32, height: u32, ) -> Result<(), BlendError>

Un-premultiply alpha (divide RGB by alpha).

Pixels with A = 0 are left as [0, 0, 0, 0].

Errors

Returns BlendError on dimension or buffer mismatch.

Trait Implementations

impl Clone for BlendKernel

fn clone(&self) -> BlendKernel

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BlendKernel

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

Formats the value using the given formatter.

impl Default for BlendKernel

fn default() -> BlendKernel

Returns the “default value” for a type.