440 lines
12 KiB
Rust
440 lines
12 KiB
Rust
//! QR codes display information in a type of two-dimensional matrix barcode.
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//!
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//! # Example
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//! ```no_run
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//! # mod iced { pub mod widget { pub use iced_widget::*; } pub use iced_widget::Renderer; pub use iced_widget::core::*; }
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//! # pub type Element<'a, Message> = iced_widget::core::Element<'a, Message, iced_widget::Theme, iced_widget::Renderer>;
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//! #
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//! use iced::widget::qr_code;
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//!
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//! struct State {
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//! data: qr_code::Data,
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//! }
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//!
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//! #[derive(Debug, Clone)]
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//! enum Message {
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//! // ...
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//! }
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//!
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//! fn view(state: &State) -> Element<'_, Message> {
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//! qr_code(&state.data).into()
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//! }
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//! ```
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use crate::canvas;
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use crate::core::layout;
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use crate::core::mouse;
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use crate::core::renderer::{self, Renderer as _};
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use crate::core::widget::tree::{self, Tree};
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use crate::core::{
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Color, Element, Layout, Length, Pixels, Point, Rectangle, Size, Theme,
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Vector, Widget,
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};
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use crate::Renderer;
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use std::cell::RefCell;
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use thiserror::Error;
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const DEFAULT_CELL_SIZE: f32 = 4.0;
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const QUIET_ZONE: usize = 2;
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/// A type of matrix barcode consisting of squares arranged in a grid which
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/// can be read by an imaging device, such as a camera.
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///
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/// # Example
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/// ```no_run
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/// # mod iced { pub mod widget { pub use iced_widget::*; } pub use iced_widget::Renderer; pub use iced_widget::core::*; }
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/// # pub type Element<'a, Message> = iced_widget::core::Element<'a, Message, iced_widget::Theme, iced_widget::Renderer>;
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/// #
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/// use iced::widget::qr_code;
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///
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/// struct State {
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/// data: qr_code::Data,
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/// }
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///
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/// #[derive(Debug, Clone)]
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/// enum Message {
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/// // ...
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/// }
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///
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/// fn view(state: &State) -> Element<'_, Message> {
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/// qr_code(&state.data).into()
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/// }
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/// ```
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#[allow(missing_debug_implementations)]
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pub struct QRCode<'a, Theme = crate::Theme>
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where
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Theme: Catalog,
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{
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data: &'a Data,
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cell_size: f32,
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class: Theme::Class<'a>,
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}
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impl<'a, Theme> QRCode<'a, Theme>
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where
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Theme: Catalog,
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{
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/// Creates a new [`QRCode`] with the provided [`Data`].
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pub fn new(data: &'a Data) -> Self {
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Self {
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data,
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cell_size: DEFAULT_CELL_SIZE,
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class: Theme::default(),
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}
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}
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/// Sets the size of the squares of the grid cell of the [`QRCode`].
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pub fn cell_size(mut self, cell_size: impl Into<Pixels>) -> Self {
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self.cell_size = cell_size.into().0;
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self
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}
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/// Sets the size of the entire [`QRCode`].
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pub fn total_size(mut self, total_size: impl Into<Pixels>) -> Self {
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self.cell_size =
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total_size.into().0 / (self.data.width + 2 * QUIET_ZONE) as f32;
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self
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}
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/// Sets the style of the [`QRCode`].
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#[must_use]
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pub fn style(mut self, style: impl Fn(&Theme) -> Style + 'a) -> Self
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where
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Theme::Class<'a>: From<StyleFn<'a, Theme>>,
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{
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self.class = (Box::new(style) as StyleFn<'a, Theme>).into();
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self
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}
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/// Sets the style class of the [`QRCode`].
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#[cfg(feature = "advanced")]
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#[must_use]
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pub fn class(mut self, class: impl Into<Theme::Class<'a>>) -> Self {
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self.class = class.into();
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self
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}
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}
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impl<Message, Theme> Widget<Message, Theme, Renderer> for QRCode<'_, Theme>
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where
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Theme: Catalog,
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{
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fn tag(&self) -> tree::Tag {
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tree::Tag::of::<State>()
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}
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fn state(&self) -> tree::State {
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tree::State::new(State::default())
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}
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fn size(&self) -> Size<Length> {
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Size {
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width: Length::Shrink,
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height: Length::Shrink,
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}
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}
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fn layout(
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&self,
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_tree: &mut Tree,
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_renderer: &Renderer,
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_limits: &layout::Limits,
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) -> layout::Node {
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let side_length =
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(self.data.width + 2 * QUIET_ZONE) as f32 * self.cell_size;
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layout::Node::new(Size::new(side_length, side_length))
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}
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fn draw(
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&self,
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tree: &Tree,
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renderer: &mut Renderer,
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theme: &Theme,
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_style: &renderer::Style,
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layout: Layout<'_>,
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_cursor: mouse::Cursor,
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_viewport: &Rectangle,
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) {
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let state = tree.state.downcast_ref::<State>();
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let bounds = layout.bounds();
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let side_length = self.data.width + 2 * QUIET_ZONE;
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let style = theme.style(&self.class);
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let mut last_style = state.last_style.borrow_mut();
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if Some(style) != *last_style {
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self.data.cache.clear();
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*last_style = Some(style);
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}
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// Reuse cache if possible
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let geometry = self.data.cache.draw(renderer, bounds.size(), |frame| {
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// Scale units to cell size
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frame.scale(self.cell_size);
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// Draw background
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frame.fill_rectangle(
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Point::ORIGIN,
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Size::new(side_length as f32, side_length as f32),
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style.background,
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);
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// Avoid drawing on the quiet zone
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frame.translate(Vector::new(QUIET_ZONE as f32, QUIET_ZONE as f32));
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// Draw contents
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self.data
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.contents
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.iter()
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.enumerate()
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.filter(|(_, value)| **value == qrcode::Color::Dark)
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.for_each(|(index, _)| {
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let row = index / self.data.width;
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let column = index % self.data.width;
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frame.fill_rectangle(
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Point::new(column as f32, row as f32),
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Size::UNIT,
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style.cell,
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);
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});
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});
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renderer.with_translation(
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bounds.position() - Point::ORIGIN,
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|renderer| {
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use crate::graphics::geometry::Renderer as _;
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renderer.draw_geometry(geometry);
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},
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);
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}
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}
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impl<'a, Message, Theme> From<QRCode<'a, Theme>>
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for Element<'a, Message, Theme, Renderer>
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where
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Theme: Catalog + 'a,
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{
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fn from(qr_code: QRCode<'a, Theme>) -> Self {
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Self::new(qr_code)
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}
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}
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/// The data of a [`QRCode`].
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///
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/// It stores the contents that will be displayed.
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#[derive(Debug)]
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pub struct Data {
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contents: Vec<qrcode::Color>,
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width: usize,
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cache: canvas::Cache<Renderer>,
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}
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impl Data {
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/// Creates a new [`Data`] with the provided data.
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///
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/// This method uses an [`ErrorCorrection::Medium`] and chooses the smallest
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/// size to display the data.
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pub fn new(data: impl AsRef<[u8]>) -> Result<Self, Error> {
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let encoded = qrcode::QrCode::new(data)?;
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Ok(Self::build(encoded))
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}
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/// Creates a new [`Data`] with the provided [`ErrorCorrection`].
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pub fn with_error_correction(
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data: impl AsRef<[u8]>,
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error_correction: ErrorCorrection,
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) -> Result<Self, Error> {
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let encoded = qrcode::QrCode::with_error_correction_level(
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data,
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error_correction.into(),
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)?;
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Ok(Self::build(encoded))
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}
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/// Creates a new [`Data`] with the provided [`Version`] and
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/// [`ErrorCorrection`].
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pub fn with_version(
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data: impl AsRef<[u8]>,
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version: Version,
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error_correction: ErrorCorrection,
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) -> Result<Self, Error> {
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let encoded = qrcode::QrCode::with_version(
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data,
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version.into(),
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error_correction.into(),
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)?;
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Ok(Self::build(encoded))
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}
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fn build(encoded: qrcode::QrCode) -> Self {
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let width = encoded.width();
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let contents = encoded.into_colors();
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Self {
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contents,
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width,
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cache: canvas::Cache::new(),
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}
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}
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}
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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/// The size of a [`QRCode`].
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///
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/// The higher the version the larger the grid of cells, and therefore the more
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/// information the [`QRCode`] can carry.
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pub enum Version {
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/// A normal QR code version. It should be between 1 and 40.
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Normal(u8),
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/// A micro QR code version. It should be between 1 and 4.
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Micro(u8),
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}
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impl From<Version> for qrcode::Version {
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fn from(version: Version) -> Self {
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match version {
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Version::Normal(v) => qrcode::Version::Normal(i16::from(v)),
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Version::Micro(v) => qrcode::Version::Micro(i16::from(v)),
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}
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}
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}
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/// The error correction level.
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///
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/// It controls the amount of data that can be damaged while still being able
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/// to recover the original information.
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///
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/// A higher error correction level allows for more corrupted data.
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub enum ErrorCorrection {
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/// Low error correction. 7% of the data can be restored.
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Low,
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/// Medium error correction. 15% of the data can be restored.
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Medium,
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/// Quartile error correction. 25% of the data can be restored.
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Quartile,
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/// High error correction. 30% of the data can be restored.
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High,
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}
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impl From<ErrorCorrection> for qrcode::EcLevel {
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fn from(ec_level: ErrorCorrection) -> Self {
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match ec_level {
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ErrorCorrection::Low => qrcode::EcLevel::L,
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ErrorCorrection::Medium => qrcode::EcLevel::M,
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ErrorCorrection::Quartile => qrcode::EcLevel::Q,
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ErrorCorrection::High => qrcode::EcLevel::H,
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}
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}
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}
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/// An error that occurred when building a [`Data`] for a [`QRCode`].
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
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pub enum Error {
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/// The data is too long to encode in a QR code for the chosen [`Version`].
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#[error(
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"The data is too long to encode in a QR code for the chosen version"
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)]
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DataTooLong,
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/// The chosen [`Version`] and [`ErrorCorrection`] combination is invalid.
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#[error(
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"The chosen version and error correction level combination is invalid."
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)]
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InvalidVersion,
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/// One or more characters in the provided data are not supported by the
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/// chosen [`Version`].
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#[error(
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"One or more characters in the provided data are not supported by the \
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chosen version"
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)]
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UnsupportedCharacterSet,
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/// The chosen ECI designator is invalid. A valid designator should be
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/// between 0 and 999999.
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#[error(
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"The chosen ECI designator is invalid. A valid designator should be \
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between 0 and 999999."
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)]
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InvalidEciDesignator,
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/// A character that does not belong to the character set was found.
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#[error("A character that does not belong to the character set was found")]
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InvalidCharacter,
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}
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impl From<qrcode::types::QrError> for Error {
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fn from(error: qrcode::types::QrError) -> Self {
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use qrcode::types::QrError;
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match error {
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QrError::DataTooLong => Error::DataTooLong,
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QrError::InvalidVersion => Error::InvalidVersion,
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QrError::UnsupportedCharacterSet => Error::UnsupportedCharacterSet,
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QrError::InvalidEciDesignator => Error::InvalidEciDesignator,
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QrError::InvalidCharacter => Error::InvalidCharacter,
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}
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}
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}
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#[derive(Default)]
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struct State {
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last_style: RefCell<Option<Style>>,
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}
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/// The appearance of a QR code.
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#[derive(Debug, Clone, Copy, PartialEq)]
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pub struct Style {
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/// The color of the QR code data cells
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pub cell: Color,
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/// The color of the QR code background
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pub background: Color,
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}
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/// The theme catalog of a [`QRCode`].
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pub trait Catalog {
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/// The item class of the [`Catalog`].
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type Class<'a>;
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/// The default class produced by the [`Catalog`].
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fn default<'a>() -> Self::Class<'a>;
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/// The [`Style`] of a class with the given status.
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fn style(&self, class: &Self::Class<'_>) -> Style;
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}
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/// A styling function for a [`QRCode`].
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pub type StyleFn<'a, Theme> = Box<dyn Fn(&Theme) -> Style + 'a>;
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impl Catalog for Theme {
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type Class<'a> = StyleFn<'a, Self>;
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fn default<'a>() -> Self::Class<'a> {
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Box::new(default)
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}
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fn style(&self, class: &Self::Class<'_>) -> Style {
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class(self)
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}
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}
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/// The default style of a [`QRCode`].
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pub fn default(theme: &Theme) -> Style {
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let palette = theme.palette();
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Style {
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cell: palette.text,
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background: palette.background,
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}
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}
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