Struct zng::image::Img

pub struct Img { /* private fields */ }

State of an ImageVar.

Each instance of this struct represent a single state,

Implementations

impl Img

pub fn new(view: ViewImage) -> Img

New from existing ViewImage.

pub fn dummy(error: Option<Txt>) -> Img

Create a dummy image in the loaded or error state.

pub fn is_loading(&self) -> bool

Returns true if the is still acquiring or decoding the image bytes.

pub fn is_loaded(&self) -> bool

If the image is successfully loaded in the view-process.

pub fn is_error(&self) -> bool

If the image failed to load.

pub fn error(&self) -> Option<Txt>

Returns an error message if the image failed to load.

pub fn wait_done(&self) -> impl Future<Output = ()> + Send + Sync + 'static

Returns a future that awaits until this image is loaded or encountered an error.

pub fn size(&self) -> Size2D<Px, Px>

Returns the image size in pixels, or zero if it is not loaded.

pub fn ppi(&self) -> Option<ImagePpi>

Returns the image pixel-per-inch metadata if the image is loaded and the metadata was retrieved.

pub fn is_opaque(&self) -> bool

Returns true if the image is fully opaque or it is not loaded.

pub fn is_mask(&self) -> bool

Returns true if the image pixels are a single channel (A8).

pub fn view(&self) -> Option<&ViewImage>

Connection to the image resource, if it is loaded.

pub fn layout_size(&self, ctx: &LayoutMetrics) -> Size2D<Px, Px>

Calculate an ideal layout size for the image.

The image is scaled considering the ppi and screen scale factor. If the image has no ppi falls back to the screen_ppi in both dimensions.

pub fn calc_size( &self, ctx: &LayoutMetrics, fallback_ppi: ImagePpi, ignore_image_ppi: bool, ) -> Size2D<Px, Px>

Calculate a layout size for the image.

Parameters

• ctx: Used to get the screen resolution.
• fallback_ppi: Resolution used if ppi is None.
• ignore_image_ppi: If true always uses the fallback_ppi as the resolution.

pub fn pixels(&self) -> Option<IpcBytes>

Reference the decoded pre-multiplied BGRA8 pixel buffer or A8 if is_mask.

pub fn copy_pixels(&self, rect: Rect<Px, Px>) -> Option<(Rect<Px, Px>, Vec<u8>)>

Copy the rect selection from pixels.

The rect is in pixels, with the origin (0, 0) at the top-left of the image.

Returns the copied selection and the pixel buffer.

Note that the selection can change if rect is not fully contained by the image area.

pub async fn encode(&self, format: Txt) -> Result<IpcBytes, EncodeError>

Encode the image to the format.

pub async fn save(&self, path: impl Into<PathBuf>) -> Result<(), Error>

Encode and write the image to path.

The image format is guessed from the file extension.

pub async fn save_with_format( &self, format: Txt, path: impl Into<PathBuf>, ) -> Result<(), Error>

Encode and write the image to path.

The image is encoded to the format, the file extension can be anything.

Trait Implementations

impl Clone for Img

fn clone(&self) -> Img

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Img

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

Formats the value using the given formatter.

impl Img for Img

fn renderer_id(&self, renderer: &ViewRenderer) -> ImageTextureId

Gets the image ID in the renderer namespace.

fn alpha_type(&self) -> AlphaType

Returns a value that indicates if the image is already pre-multiplied.

impl PartialEq for Img

fn eq(&self, other: &Img) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.