diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml index 9e73d3d3..bc531abf 100644 --- a/.github/workflows/test.yml +++ b/.github/workflows/test.yml @@ -29,5 +29,5 @@ jobs: run: cargo check --package iced --target wasm32-unknown-unknown - name: Check compilation of `tour` example run: cargo build --package tour --target wasm32-unknown-unknown - - name: Check compilation of `pokedex` example - run: cargo build --package pokedex --target wasm32-unknown-unknown + - name: Check compilation of `todos` example + run: cargo build --package todos --target wasm32-unknown-unknown diff --git a/examples/pokedex/src/main.rs b/examples/pokedex/src/main.rs index 187e5dee..f432f0fc 100644 --- a/examples/pokedex/src/main.rs +++ b/examples/pokedex/src/main.rs @@ -1,6 +1,6 @@ use iced::{ button, futures, image, Align, Application, Button, Column, Command, - Container, Element, Image, Length, Row, Settings, Text, + Container, Element, Length, Row, Settings, Text, }; pub fn main() -> iced::Result { @@ -112,16 +112,20 @@ struct Pokemon { name: String, description: String, image: image::Handle, + image_viewer: image::viewer::State, } impl Pokemon { const TOTAL: u16 = 807; - fn view(&self) -> Element { + fn view(&mut self) -> Element { Row::new() .spacing(20) .align_items(Align::Center) - .push(Image::new(self.image.clone())) + .push(image::Viewer::new( + &mut self.image_viewer, + self.image.clone(), + )) .push( Column::new() .spacing(20) @@ -200,6 +204,7 @@ impl Pokemon { .map(|c| if c.is_control() { ' ' } else { c }) .collect(), image, + image_viewer: image::viewer::State::new(), }) } diff --git a/graphics/src/widget/image.rs b/graphics/src/widget/image.rs index 30f446e8..bdf03de3 100644 --- a/graphics/src/widget/image.rs +++ b/graphics/src/widget/image.rs @@ -1,11 +1,14 @@ //! Display images in your user interface. +pub mod viewer; + use crate::backend::{self, Backend}; + use crate::{Primitive, Renderer}; use iced_native::image; use iced_native::mouse; use iced_native::Layout; -pub use iced_native::image::{Handle, Image}; +pub use iced_native::image::{Handle, Image, Viewer}; impl image::Renderer for Renderer where diff --git a/graphics/src/widget/image/viewer.rs b/graphics/src/widget/image/viewer.rs new file mode 100644 index 00000000..28dffc4f --- /dev/null +++ b/graphics/src/widget/image/viewer.rs @@ -0,0 +1,55 @@ +//! Zoom and pan on an image. +use crate::backend::{self, Backend}; +use crate::{Primitive, Renderer}; + +use iced_native::image; +use iced_native::image::viewer; +use iced_native::mouse; +use iced_native::{Rectangle, Size, Vector}; + +impl viewer::Renderer for Renderer +where + B: Backend + backend::Image, +{ + fn draw( + &mut self, + state: &viewer::State, + bounds: Rectangle, + image_size: Size, + translation: Vector, + handle: image::Handle, + is_mouse_over: bool, + ) -> Self::Output { + ( + { + Primitive::Clip { + bounds, + content: Box::new(Primitive::Translate { + translation, + content: Box::new(Primitive::Image { + handle, + bounds: Rectangle { + x: bounds.x, + y: bounds.y, + ..Rectangle::with_size(image_size) + }, + }), + }), + offset: Vector::new(0, 0), + } + }, + { + if state.is_cursor_grabbed() { + mouse::Interaction::Grabbing + } else if is_mouse_over + && (image_size.width > bounds.width + || image_size.height > bounds.height) + { + mouse::Interaction::Grab + } else { + mouse::Interaction::Idle + } + }, + ) + } +} diff --git a/native/src/widget/image.rs b/native/src/widget/image.rs index 51d7ba26..4d8e0a3f 100644 --- a/native/src/widget/image.rs +++ b/native/src/widget/image.rs @@ -1,4 +1,7 @@ //! Display images in your user interface. +pub mod viewer; +pub use viewer::Viewer; + use crate::layout; use crate::{Element, Hasher, Layout, Length, Point, Rectangle, Size, Widget}; diff --git a/native/src/widget/image/viewer.rs b/native/src/widget/image/viewer.rs new file mode 100644 index 00000000..4ec3faf6 --- /dev/null +++ b/native/src/widget/image/viewer.rs @@ -0,0 +1,392 @@ +//! Zoom and pan on an image. +use crate::event::{self, Event}; +use crate::image; +use crate::layout; +use crate::mouse; +use crate::{ + Clipboard, Element, Hasher, Layout, Length, Point, Rectangle, Size, Vector, + Widget, +}; + +use std::hash::Hash; + +/// A frame that displays an image with the ability to zoom in/out and pan. +#[allow(missing_debug_implementations)] +pub struct Viewer<'a> { + state: &'a mut State, + padding: u16, + width: Length, + height: Length, + min_scale: f32, + max_scale: f32, + scale_step: f32, + handle: image::Handle, +} + +impl<'a> Viewer<'a> { + /// Creates a new [`Viewer`] with the given [`State`] and [`Handle`]. + /// + /// [`Handle`]: image::Handle + pub fn new(state: &'a mut State, handle: image::Handle) -> Self { + Viewer { + state, + padding: 0, + width: Length::Shrink, + height: Length::Shrink, + min_scale: 0.25, + max_scale: 10.0, + scale_step: 0.10, + handle, + } + } + + /// Sets the padding of the [`Viewer`]. + pub fn padding(mut self, units: u16) -> Self { + self.padding = units; + self + } + + /// Sets the width of the [`Viewer`]. + pub fn width(mut self, width: Length) -> Self { + self.width = width; + self + } + + /// Sets the height of the [`Viewer`]. + pub fn height(mut self, height: Length) -> Self { + self.height = height; + self + } + + /// Sets the max scale applied to the image of the [`Viewer`]. + /// + /// Default is `10.0` + pub fn max_scale(mut self, max_scale: f32) -> Self { + self.max_scale = max_scale; + self + } + + /// Sets the min scale applied to the image of the [`Viewer`]. + /// + /// Default is `0.25` + pub fn min_scale(mut self, min_scale: f32) -> Self { + self.min_scale = min_scale; + self + } + + /// Sets the percentage the image of the [`Viewer`] will be scaled by + /// when zoomed in / out. + /// + /// Default is `0.10` + pub fn scale_step(mut self, scale_step: f32) -> Self { + self.scale_step = scale_step; + self + } + + /// Returns the bounds of the underlying image, given the bounds of + /// the [`Viewer`]. Scaling will be applied and original aspect ratio + /// will be respected. + fn image_size(&self, renderer: &Renderer, bounds: Size) -> Size + where + Renderer: self::Renderer + image::Renderer, + { + let (width, height) = renderer.dimensions(&self.handle); + + let (width, height) = { + let dimensions = (width as f32, height as f32); + + let width_ratio = bounds.width / dimensions.0; + let height_ratio = bounds.height / dimensions.1; + + let ratio = width_ratio.min(height_ratio); + + let scale = self.state.scale; + + if ratio < 1.0 { + (dimensions.0 * ratio * scale, dimensions.1 * ratio * scale) + } else { + (dimensions.0 * scale, dimensions.1 * scale) + } + }; + + Size::new(width, height) + } +} + +impl<'a, Message, Renderer> Widget for Viewer<'a> +where + Renderer: self::Renderer + image::Renderer, +{ + fn width(&self) -> Length { + self.width + } + + fn height(&self) -> Length { + self.height + } + + fn layout( + &self, + renderer: &Renderer, + limits: &layout::Limits, + ) -> layout::Node { + let (width, height) = renderer.dimensions(&self.handle); + + let aspect_ratio = width as f32 / height as f32; + + let mut size = limits + .width(self.width) + .height(self.height) + .resolve(Size::new(width as f32, height as f32)); + + let viewport_aspect_ratio = size.width / size.height; + + if viewport_aspect_ratio > aspect_ratio { + size.width = width as f32 * size.height / height as f32; + } else { + size.height = height as f32 * size.width / width as f32; + } + + layout::Node::new(size) + } + + fn on_event( + &mut self, + event: Event, + layout: Layout<'_>, + cursor_position: Point, + _messages: &mut Vec, + renderer: &Renderer, + _clipboard: Option<&dyn Clipboard>, + ) -> event::Status { + let bounds = layout.bounds(); + let is_mouse_over = bounds.contains(cursor_position); + + match event { + Event::Mouse(mouse::Event::WheelScrolled { delta }) + if is_mouse_over => + { + match delta { + mouse::ScrollDelta::Lines { y, .. } + | mouse::ScrollDelta::Pixels { y, .. } => { + let previous_scale = self.state.scale; + + if y < 0.0 && previous_scale > self.min_scale + || y > 0.0 && previous_scale < self.max_scale + { + self.state.scale = (if y > 0.0 { + self.state.scale * (1.0 + self.scale_step) + } else { + self.state.scale / (1.0 + self.scale_step) + }) + .max(self.min_scale) + .min(self.max_scale); + + let image_size = + self.image_size(renderer, bounds.size()); + + let factor = + self.state.scale / previous_scale - 1.0; + + let cursor_to_center = + cursor_position - bounds.center(); + + let adjustment = cursor_to_center * factor + + self.state.current_offset * factor; + + self.state.current_offset = Vector::new( + if image_size.width > bounds.width { + self.state.current_offset.x + adjustment.x + } else { + 0.0 + }, + if image_size.height > bounds.height { + self.state.current_offset.y + adjustment.y + } else { + 0.0 + }, + ); + } + } + } + } + Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left)) + if is_mouse_over => + { + self.state.cursor_grabbed_at = Some(cursor_position); + self.state.starting_offset = self.state.current_offset; + } + Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left)) => { + self.state.cursor_grabbed_at = None + } + Event::Mouse(mouse::Event::CursorMoved { position }) => { + if let Some(origin) = self.state.cursor_grabbed_at { + let image_size = self.image_size(renderer, bounds.size()); + + let hidden_width = (image_size.width - bounds.width / 2.0) + .max(0.0) + .round(); + + let hidden_height = (image_size.height + - bounds.height / 2.0) + .max(0.0) + .round(); + + let delta = position - origin; + + let x = if bounds.width < image_size.width { + (self.state.starting_offset.x - delta.x) + .min(hidden_width) + .max(-hidden_width) + } else { + 0.0 + }; + + let y = if bounds.height < image_size.height { + (self.state.starting_offset.y - delta.y) + .min(hidden_height) + .max(-hidden_height) + } else { + 0.0 + }; + + self.state.current_offset = Vector::new(x, y); + } + } + _ => {} + } + + event::Status::Ignored + } + + fn draw( + &self, + renderer: &mut Renderer, + _defaults: &Renderer::Defaults, + layout: Layout<'_>, + cursor_position: Point, + _viewport: &Rectangle, + ) -> Renderer::Output { + let bounds = layout.bounds(); + + let image_size = self.image_size(renderer, bounds.size()); + + let translation = { + let image_top_left = Vector::new( + bounds.width / 2.0 - image_size.width / 2.0, + bounds.height / 2.0 - image_size.height / 2.0, + ); + + image_top_left - self.state.offset(bounds, image_size) + }; + + let is_mouse_over = bounds.contains(cursor_position); + + self::Renderer::draw( + renderer, + &self.state, + bounds, + image_size, + translation, + self.handle.clone(), + is_mouse_over, + ) + } + + fn hash_layout(&self, state: &mut Hasher) { + struct Marker; + std::any::TypeId::of::().hash(state); + + self.width.hash(state); + self.height.hash(state); + self.padding.hash(state); + + self.handle.hash(state); + } +} + +/// The local state of a [`Viewer`]. +#[derive(Debug, Clone, Copy)] +pub struct State { + scale: f32, + starting_offset: Vector, + current_offset: Vector, + cursor_grabbed_at: Option, +} + +impl Default for State { + fn default() -> Self { + Self { + scale: 1.0, + starting_offset: Vector::default(), + current_offset: Vector::default(), + cursor_grabbed_at: None, + } + } +} + +impl State { + /// Creates a new [`State`]. + pub fn new() -> Self { + State::default() + } + + /// Returns the current offset of the [`State`], given the bounds + /// of the [`Viewer`] and its image. + fn offset(&self, bounds: Rectangle, image_size: Size) -> Vector { + let hidden_width = + (image_size.width - bounds.width / 2.0).max(0.0).round(); + + let hidden_height = + (image_size.height - bounds.height / 2.0).max(0.0).round(); + + Vector::new( + self.current_offset.x.min(hidden_width).max(-hidden_width), + self.current_offset.y.min(hidden_height).max(-hidden_height), + ) + } + + /// Returns if the cursor is currently grabbed by the [`Viewer`]. + pub fn is_cursor_grabbed(&self) -> bool { + self.cursor_grabbed_at.is_some() + } +} + +/// The renderer of an [`Viewer`]. +/// +/// Your [renderer] will need to implement this trait before being +/// able to use a [`Viewer`] in your user interface. +/// +/// [renderer]: crate::renderer +pub trait Renderer: crate::Renderer + Sized { + /// Draws the [`Viewer`]. + /// + /// It receives: + /// - the [`State`] of the [`Viewer`] + /// - the bounds of the [`Viewer`] widget + /// - the [`Size`] of the scaled [`Viewer`] image + /// - the translation of the clipped image + /// - the [`Handle`] to the underlying image + /// - whether the mouse is over the [`Viewer`] or not + /// + /// [`Handle`]: image::Handle + fn draw( + &mut self, + state: &State, + bounds: Rectangle, + image_size: Size, + translation: Vector, + handle: image::Handle, + is_mouse_over: bool, + ) -> Self::Output; +} + +impl<'a, Message, Renderer> From> for Element<'a, Message, Renderer> +where + Renderer: 'a + self::Renderer + image::Renderer, + Message: 'a, +{ + fn from(viewer: Viewer<'a>) -> Element<'a, Message, Renderer> { + Element::new(viewer) + } +} diff --git a/src/widget.rs b/src/widget.rs index b9b65499..edd35d2d 100644 --- a/src/widget.rs +++ b/src/widget.rs @@ -37,7 +37,8 @@ mod platform { #[cfg_attr(docsrs, doc(cfg(feature = "image")))] pub mod image { //! Display images in your user interface. - pub use crate::runtime::image::{Handle, Image}; + pub use crate::runtime::image::viewer; + pub use crate::runtime::image::{Handle, Image, Viewer}; } #[cfg_attr(docsrs, doc(cfg(feature = "svg")))]