Merge pull request #2229 from clarkmoody/custom-qr-style

QR Code Styling

6 files changed, 191 insertions, 77 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8660cc5a..8f0f96a3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `hovered` styling for `Svg` widget. [#2163](https://github.com/iced-rs/iced/pull/2163)
 - `height` method for `TextEditor`. [#2221](https://github.com/iced-rs/iced/pull/2221)
 - Customizable style for `TextEditor`. [#2159](https://github.com/iced-rs/iced/pull/2159)
+- Customizable style for `QRCode`. [#2229](https://github.com/iced-rs/iced/pull/2229)
 - Border width styling for `Toggler`. [#2219](https://github.com/iced-rs/iced/pull/2219)
 - `RawText` variant for `Primitive` in `iced_graphics`. [#2158](https://github.com/iced-rs/iced/pull/2158)
 - `Stream` support for `Command`. [#2150](https://github.com/iced-rs/iced/pull/2150)
@@ -116,6 +117,7 @@ Many thanks to...
 - @Calastrophe
 - @casperstorm
 - @cfrenette
+- @clarkmoody
 - @Davidster
 - @Decodetalkers
 - @derezzedex
diff --git a/examples/qr_code/src/main.rs b/examples/qr_code/src/main.rs
index 867ebfa4..8b2e9500 100644
--- a/examples/qr_code/src/main.rs
+++ b/examples/qr_code/src/main.rs
@@ -1,6 +1,6 @@
 use iced::widget::qr_code::{self, QRCode};
-use iced::widget::{column, container, text, text_input};
-use iced::{Alignment, Color, Element, Length, Sandbox, Settings};
+use iced::widget::{column, container, pick_list, row, text, text_input};
+use iced::{Alignment, Element, Length, Sandbox, Settings, Theme};
 
 pub fn main() -> iced::Result {
     QRGenerator::run(Settings::default())
@@ -9,12 +9,14 @@ pub fn main() -> iced::Result {
 #[derive(Default)]
 struct QRGenerator {
     data: String,
-    qr_code: Option<qr_code::State>,
+    qr_code: Option<qr_code::Data>,
+    theme: Theme,
 }
 
 #[derive(Debug, Clone)]
 enum Message {
     DataChanged(String),
+    ThemeChanged(Theme),
 }
 
 impl Sandbox for QRGenerator {
@@ -36,18 +38,19 @@ impl Sandbox for QRGenerator {
                 self.qr_code = if data.is_empty() {
                     None
                 } else {
-                    qr_code::State::new(&data).ok()
+                    qr_code::Data::new(&data).ok()
                 };
 
                 self.data = data;
             }
+            Message::ThemeChanged(theme) => {
+                self.theme = theme;
+            }
         }
     }
 
     fn view(&self) -> Element<Message> {
-        let title = text("QR Code Generator")
-            .size(70)
-            .style(Color::from([0.5, 0.5, 0.5]));
+        let title = text("QR Code Generator").size(70);
 
         let input =
             text_input("Type the data of your QR code here...", &self.data)
@@ -55,7 +58,18 @@ impl Sandbox for QRGenerator {
                 .size(30)
                 .padding(15);
 
-        let mut content = column![title, input]
+        let choose_theme = row![
+            text("Theme:"),
+            pick_list(
+                Theme::ALL,
+                Some(self.theme.clone()),
+                Message::ThemeChanged,
+            )
+        ]
+        .spacing(10)
+        .align_items(Alignment::Center);
+
+        let mut content = column![title, input, choose_theme]
             .width(700)
             .spacing(20)
             .align_items(Alignment::Center);
@@ -72,4 +86,8 @@ impl Sandbox for QRGenerator {
             .center_y()
             .into()
     }
+
+    fn theme(&self) -> Theme {
+        self.theme.clone()
+    }
 }
diff --git a/style/src/lib.rs b/style/src/lib.rs
index e4097434..3c2865eb 100644
--- a/style/src/lib.rs
+++ b/style/src/lib.rs
@@ -24,6 +24,7 @@ pub mod menu;
 pub mod pane_grid;
 pub mod pick_list;
 pub mod progress_bar;
+pub mod qr_code;
 pub mod radio;
 pub mod rule;
 pub mod scrollable;
diff --git a/style/src/qr_code.rs b/style/src/qr_code.rs
new file mode 100644
index 00000000..02c4709a
--- /dev/null
+++ b/style/src/qr_code.rs
@@ -0,0 +1,20 @@
+//! Change the appearance of a QR code.
+use crate::core::Color;
+
+/// The appearance of a QR code.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct Appearance {
+    /// The color of the QR code data cells
+    pub cell: Color,
+    /// The color of the QR code background
+    pub background: Color,
+}
+
+/// A set of rules that dictate the style of a QR code.
+pub trait StyleSheet {
+    /// The supported style of the [`StyleSheet`].
+    type Style: Default;
+
+    /// Produces the style of a QR code.
+    fn appearance(&self, style: &Self::Style) -> Appearance;
+}
diff --git a/style/src/theme.rs b/style/src/theme.rs
index e579a1c2..afb4d027 100644
--- a/style/src/theme.rs
+++ b/style/src/theme.rs
@@ -12,6 +12,7 @@ use crate::menu;
 use crate::pane_grid;
 use crate::pick_list;
 use crate::progress_bar;
+use crate::qr_code;
 use crate::radio;
 use crate::rule;
 use crate::scrollable;
@@ -956,6 +957,46 @@ impl<T: Fn(&Theme) -> progress_bar::Appearance> progress_bar::StyleSheet for T {
     }
 }
 
+/// The style of a QR Code.
+#[derive(Default)]
+pub enum QRCode {
+    /// The default style.
+    #[default]
+    Default,
+    /// A custom style.
+    Custom(Box<dyn qr_code::StyleSheet<Style = Theme>>),
+}
+
+impl<T: Fn(&Theme) -> qr_code::Appearance + 'static> From<T> for QRCode {
+    fn from(f: T) -> Self {
+        Self::Custom(Box::new(f))
+    }
+}
+
+impl qr_code::StyleSheet for Theme {
+    type Style = QRCode;
+
+    fn appearance(&self, style: &Self::Style) -> qr_code::Appearance {
+        let palette = self.palette();
+
+        match style {
+            QRCode::Default => qr_code::Appearance {
+                cell: palette.text,
+                background: palette.background,
+            },
+            QRCode::Custom(custom) => custom.appearance(self),
+        }
+    }
+}
+
+impl<T: Fn(&Theme) -> qr_code::Appearance> qr_code::StyleSheet for T {
+    type Style = Theme;
+
+    fn appearance(&self, style: &Self::Style) -> qr_code::Appearance {
+        (self)(style)
+    }
+}
+
 /// The style of a rule.
 #[derive(Default)]
 pub enum Rule {
diff --git a/widget/src/qr_code.rs b/widget/src/qr_code.rs
index 6a748e63..eeb1526f 100644
--- a/widget/src/qr_code.rs
+++ b/widget/src/qr_code.rs
@@ -3,53 +3,71 @@ use crate::canvas;
 use crate::core::layout;
 use crate::core::mouse;
 use crate::core::renderer::{self, Renderer as _};
-use crate::core::widget::Tree;
+use crate::core::widget::tree::{self, Tree};
 use crate::core::{
-    Color, Element, Layout, Length, Point, Rectangle, Size, Vector, Widget,
+    Element, Layout, Length, Point, Rectangle, Size, Vector, Widget,
 };
 use crate::graphics::geometry::Renderer as _;
 use crate::Renderer;
+
+use std::cell::RefCell;
 use thiserror::Error;
 
+pub use crate::style::qr_code::{Appearance, StyleSheet};
+
 const DEFAULT_CELL_SIZE: u16 = 4;
 const QUIET_ZONE: usize = 2;
 
 /// A type of matrix barcode consisting of squares arranged in a grid which
 /// can be read by an imaging device, such as a camera.
 #[derive(Debug)]
-pub struct QRCode<'a> {
-    state: &'a State,
-    dark: Color,
-    light: Color,
+pub struct QRCode<'a, Theme = crate::Theme>
+where
+    Theme: StyleSheet,
+{
+    data: &'a Data,
     cell_size: u16,
+    style: Theme::Style,
 }
 
-impl<'a> QRCode<'a> {
-    /// Creates a new [`QRCode`] with the provided [`State`].
-    pub fn new(state: &'a State) -> Self {
+impl<'a, Theme> QRCode<'a, Theme>
+where
+    Theme: StyleSheet,
+{
+    /// Creates a new [`QRCode`] with the provided [`Data`].
+    pub fn new(data: &'a Data) -> Self {
         Self {
+            data,
             cell_size: DEFAULT_CELL_SIZE,
-            dark: Color::BLACK,
-            light: Color::WHITE,
-            state,
+            style: Default::default(),
         }
     }
 
-    /// Sets both the dark and light [`Color`]s of the [`QRCode`].
-    pub fn color(mut self, dark: Color, light: Color) -> Self {
-        self.dark = dark;
-        self.light = light;
-        self
-    }
-
     /// Sets the size of the squares of the grid cell of the [`QRCode`].
     pub fn cell_size(mut self, cell_size: u16) -> Self {
         self.cell_size = cell_size;
         self
     }
+
+    /// Sets the style of the [`QRCode`].
+    pub fn style(mut self, style: impl Into<Theme::Style>) -> Self {
+        self.style = style.into();
+        self
+    }
 }
 
-impl<'a, Message, Theme> Widget<Message, Theme, Renderer> for QRCode<'a> {
+impl<'a, Message, Theme> Widget<Message, Theme, Renderer> for QRCode<'a, Theme>
+where
+    Theme: StyleSheet,
+{
+    fn tag(&self) -> tree::Tag {
+        tree::Tag::of::<State>()
+    }
+
+    fn state(&self) -> tree::State {
+        tree::State::new(State::default())
+    }
+
     fn size(&self) -> Size<Length> {
         Size {
             width: Length::Shrink,
@@ -63,7 +81,7 @@ impl<'a, Message, Theme> Widget<Message, Theme, Renderer> for QRCode<'a> {
         _renderer: &Renderer,
         _limits: &layout::Limits,
     ) -> layout::Node {
-        let side_length = (self.state.width + 2 * QUIET_ZONE) as f32
+        let side_length = (self.data.width + 2 * QUIET_ZONE) as f32
             * f32::from(self.cell_size);
 
         layout::Node::new(Size::new(side_length, side_length))
@@ -71,53 +89,60 @@ impl<'a, Message, Theme> Widget<Message, Theme, Renderer> for QRCode<'a> {
 
     fn draw(
         &self,
-        _state: &Tree,
+        tree: &Tree,
         renderer: &mut Renderer,
-        _theme: &Theme,
+        theme: &Theme,
         _style: &renderer::Style,
         layout: Layout<'_>,
         _cursor: mouse::Cursor,
         _viewport: &Rectangle,
     ) {
+        let state = tree.state.downcast_ref::<State>();
+
         let bounds = layout.bounds();
-        let side_length = self.state.width + 2 * QUIET_ZONE;
+        let side_length = self.data.width + 2 * QUIET_ZONE;
+
+        let appearance = theme.appearance(&self.style);
+        let mut last_appearance = state.last_appearance.borrow_mut();
+
+        if Some(appearance) != *last_appearance {
+            self.data.cache.clear();
+
+            *last_appearance = Some(appearance);
+        }
 
         // Reuse cache if possible
-        let geometry =
-            self.state.cache.draw(renderer, bounds.size(), |frame| {
-                // Scale units to cell size
-                frame.scale(self.cell_size);
-
-                // Draw background
-                frame.fill_rectangle(
-                    Point::ORIGIN,
-                    Size::new(side_length as f32, side_length as f32),
-                    self.light,
-                );
-
-                // Avoid drawing on the quiet zone
-                frame.translate(Vector::new(
-                    QUIET_ZONE as f32,
-                    QUIET_ZONE as f32,
-                ));
-
-                // Draw contents
-                self.state
-                    .contents
-                    .iter()
-                    .enumerate()
-                    .filter(|(_, value)| **value == qrcode::Color::Dark)
-                    .for_each(|(index, _)| {
-                        let row = index / self.state.width;
-                        let column = index % self.state.width;
-
-                        frame.fill_rectangle(
-                            Point::new(column as f32, row as f32),
-                            Size::UNIT,
-                            self.dark,
-                        );
-                    });
-            });
+        let geometry = self.data.cache.draw(renderer, bounds.size(), |frame| {
+            // Scale units to cell size
+            frame.scale(self.cell_size);
+
+            // Draw background
+            frame.fill_rectangle(
+                Point::ORIGIN,
+                Size::new(side_length as f32, side_length as f32),
+                appearance.background,
+            );
+
+            // Avoid drawing on the quiet zone
+            frame.translate(Vector::new(QUIET_ZONE as f32, QUIET_ZONE as f32));
+
+            // Draw contents
+            self.data
+                .contents
+                .iter()
+                .enumerate()
+                .filter(|(_, value)| **value == qrcode::Color::Dark)
+                .for_each(|(index, _)| {
+                    let row = index / self.data.width;
+                    let column = index % self.data.width;
+
+                    frame.fill_rectangle(
+                        Point::new(column as f32, row as f32),
+                        Size::UNIT,
+                        appearance.cell,
+                    );
+                });
+        });
 
         renderer.with_translation(
             bounds.position() - Point::ORIGIN,
@@ -128,26 +153,28 @@ impl<'a, Message, Theme> Widget<Message, Theme, Renderer> for QRCode<'a> {
     }
 }
 
-impl<'a, Message, Theme> From<QRCode<'a>>
+impl<'a, Message, Theme> From<QRCode<'a, Theme>>
     for Element<'a, Message, Theme, Renderer>
+where
+    Theme: StyleSheet + 'a,
 {
-    fn from(qr_code: QRCode<'a>) -> Self {
+    fn from(qr_code: QRCode<'a, Theme>) -> Self {
         Self::new(qr_code)
     }
 }
 
-/// The state of a [`QRCode`].
+/// The data of a [`QRCode`].
 ///
-/// It stores the data that will be displayed.
+/// It stores the contents that will be displayed.
 #[derive(Debug)]
-pub struct State {
+pub struct Data {
     contents: Vec<qrcode::Color>,
     width: usize,
     cache: canvas::Cache,
 }
 
-impl State {
-    /// Creates a new [`State`] with the provided data.
+impl Data {
+    /// Creates a new [`Data`] with the provided data.
     ///
     /// This method uses an [`ErrorCorrection::Medium`] and chooses the smallest
     /// size to display the data.
@@ -157,7 +184,7 @@ impl State {
         Ok(Self::build(encoded))
     }
 
-    /// Creates a new [`State`] with the provided [`ErrorCorrection`].
+    /// Creates a new [`Data`] with the provided [`ErrorCorrection`].
     pub fn with_error_correction(
         data: impl AsRef<[u8]>,
         error_correction: ErrorCorrection,
@@ -170,7 +197,7 @@ impl State {
         Ok(Self::build(encoded))
     }
 
-    /// Creates a new [`State`] with the provided [`Version`] and
+    /// Creates a new [`Data`] with the provided [`Version`] and
     /// [`ErrorCorrection`].
     pub fn with_version(
         data: impl AsRef<[u8]>,
@@ -249,7 +276,7 @@ impl From<ErrorCorrection> for qrcode::EcLevel {
     }
 }
 
-/// An error that occurred when building a [`State`] for a [`QRCode`].
+/// An error that occurred when building a [`Data`] for a [`QRCode`].
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Error)]
 pub enum Error {
     /// The data is too long to encode in a QR code for the chosen [`Version`].
@@ -298,3 +325,8 @@ impl From<qrcode::types::QrError> for Error {
         }
     }
 }
+
+#[derive(Default)]
+struct State {
+    last_appearance: RefCell<Option<Appearance>>,
+}