Struct artano::Canvas

pub struct Canvas { /* fields omitted */ }

Methods

impl Canvas

pub fn read_from_buffer(buf: &[u8]) -> Result<Canvas>

Creates a new canvas based on a buffer of bytes.

A canvas consists of both a base layer and an upscaled annotation layer (at 3x the original resolution? Depends on how we count that, I guess...). Text is rendered first at this upscaled size and then downsampled onto the background.

pub fn add_annotation<'a>(
    &mut self,
    annotation: &Annotation,
    font: &Font<'a>,
    scale_multiplier: f32
)

Adds an annotation to the canvas.

This renders the annotation to the upscaled layer of the canvas that will eventually be overlaid onto the canvas proper. Text is laid out and drawn at this stage, meaning each annotation is individually rendered.

pub fn render(&mut self)

Produces the final rendering of the canvas.

This rendering step applies the upscaled overlay to the base canvas, thereby adding the desired text to the image proper. This is done via resizing and then overlaying. It's not rocket surgery; the whole process is three lines of code.

I've added this documentation just as a reminder of what's actually going on here.

pub fn save_jpg<W: Write>(&self, stream: &mut W) -> Result<()>

pub fn save_png<W: Write>(&self, stream: &mut W) -> Result<()>