cosmic/widget/
header_bar.rs

1// Copyright 2022 System76 <info@system76.com>
2// SPDX-License-Identifier: MPL-2.0
3
4use crate::cosmic_theme::{Density, Spacing};
5use crate::{Element, theme, widget};
6use apply::Apply;
7use derive_setters::Setters;
8use iced_core::{Length, Size, Vector, Widget, layout, text, widget::tree};
9use std::borrow::Cow;
10
11#[must_use]
12pub fn header_bar<'a, Message>() -> HeaderBar<'a, Message> {
13    HeaderBar {
14        title: Cow::Borrowed(""),
15        on_close: None,
16        on_drag: None,
17        on_maximize: None,
18        on_minimize: None,
19        on_right_click: None,
20        start: Vec::new(),
21        center: Vec::new(),
22        end: Vec::new(),
23        density: None,
24        focused: false,
25        maximized: false,
26        sharp_corners: false,
27        is_ssd: false,
28        on_double_click: None,
29        transparent: false,
30    }
31}
32
33#[derive(Setters)]
34pub struct HeaderBar<'a, Message> {
35    /// Defines the title of the window
36    #[setters(skip)]
37    title: Cow<'a, str>,
38
39    /// A message emitted when the close button is pressed.
40    #[setters(strip_option)]
41    on_close: Option<Message>,
42
43    /// A message emitted when dragged.
44    #[setters(strip_option)]
45    on_drag: Option<Message>,
46
47    /// A message emitted when the maximize button is pressed.
48    #[setters(strip_option)]
49    on_maximize: Option<Message>,
50
51    /// A message emitted when the minimize button is pressed.
52    #[setters(strip_option)]
53    on_minimize: Option<Message>,
54
55    /// A message emitted when the header is double clicked,
56    /// usually used to maximize the window.
57    #[setters(strip_option)]
58    on_double_click: Option<Message>,
59
60    /// A message emitted when the header is right clicked.
61    #[setters(strip_option)]
62    on_right_click: Option<Message>,
63
64    /// Elements packed at the start of the headerbar.
65    #[setters(skip)]
66    start: Vec<Element<'a, Message>>,
67
68    /// Elements packed in the center of the headerbar.
69    #[setters(skip)]
70    center: Vec<Element<'a, Message>>,
71
72    /// Elements packed at the end of the headerbar.
73    #[setters(skip)]
74    end: Vec<Element<'a, Message>>,
75
76    /// Controls the density of the headerbar.
77    #[setters(strip_option)]
78    density: Option<Density>,
79
80    /// Focused state of the window
81    focused: bool,
82
83    /// Maximized state of the window
84    maximized: bool,
85
86    /// Whether the corners of the window should be sharp
87    sharp_corners: bool,
88
89    /// HeaderBar used for server-side decorations
90    is_ssd: bool,
91
92    /// Whether the headerbar should be transparent
93    transparent: bool,
94}
95
96impl<'a, Message: Clone + 'static> HeaderBar<'a, Message> {
97    /// Defines the title of the window
98    #[must_use]
99    pub fn title(mut self, title: impl Into<Cow<'a, str>> + 'a) -> Self {
100        self.title = title.into();
101        self
102    }
103
104    /// Pushes an element to the start region.
105    #[must_use]
106    pub fn start(mut self, widget: impl Into<Element<'a, Message>> + 'a) -> Self {
107        self.start.push(widget.into());
108        self
109    }
110
111    /// Pushes an element to the center region.
112    #[must_use]
113    pub fn center(mut self, widget: impl Into<Element<'a, Message>> + 'a) -> Self {
114        self.center.push(widget.into());
115        self
116    }
117
118    /// Pushes an element to the end region.
119    #[must_use]
120    pub fn end(mut self, widget: impl Into<Element<'a, Message>> + 'a) -> Self {
121        self.end.push(widget.into());
122        self
123    }
124}
125
126pub struct HeaderBarWidget<'a, Message> {
127    start: Element<'a, Message>,
128    center: Option<Element<'a, Message>>,
129    end: Element<'a, Message>,
130}
131
132impl<'a, Message> HeaderBarWidget<'a, Message> {
133    pub fn new(
134        start: Element<'a, Message>,
135        center: Option<Element<'a, Message>>,
136        end: Element<'a, Message>,
137    ) -> Self {
138        Self { start, center, end }
139    }
140
141    fn elems(&self) -> impl Iterator<Item = &Element<'a, Message>> {
142        std::iter::once(&self.start)
143            .chain(std::iter::once(&self.end))
144            .chain(self.center.as_ref())
145    }
146
147    fn elems_mut(&mut self) -> impl Iterator<Item = &mut Element<'a, Message>> {
148        std::iter::once(&mut self.start)
149            .chain(std::iter::once(&mut self.end))
150            .chain(self.center.as_mut())
151    }
152}
153
154impl<'a, Message: Clone + 'static> Widget<Message, crate::Theme, crate::Renderer>
155    for HeaderBarWidget<'a, Message>
156{
157    fn diff(&mut self, tree: &mut tree::Tree) {
158        if let Some(center) = &mut self.center {
159            tree.diff_children(&mut [&mut self.start, &mut self.end, center]);
160        } else {
161            tree.diff_children(&mut [&mut self.start, &mut self.end]);
162        }
163    }
164
165    fn children(&self) -> Vec<tree::Tree> {
166        self.elems().map(tree::Tree::new).collect()
167    }
168
169    fn size(&self) -> Size<Length> {
170        Size {
171            width: Length::Fill,
172            height: Length::Shrink,
173        }
174    }
175
176    fn layout(
177        &mut self,
178        tree: &mut tree::Tree,
179        renderer: &crate::Renderer,
180        limits: &layout::Limits,
181    ) -> layout::Node {
182        let width = limits.max().width;
183        let height = limits.max().height;
184        let gap = 8.0;
185
186        let end_node =
187            self.end
188                .as_widget_mut()
189                .layout(&mut tree.children[1], renderer, &limits.loose());
190        let end_width = end_node.size().width;
191
192        let start_available = (width - end_width - gap).max(0.0);
193        let start_node = self.start.as_widget_mut().layout(
194            &mut tree.children[0],
195            renderer,
196            &layout::Limits::new(Size::ZERO, Size::new(start_available, height)),
197        );
198        let start_width = start_node.size().width;
199
200        let vcenter = |node: layout::Node, x: f32| -> layout::Node {
201            let dy = ((height - node.size().height) / 2.0).max(0.0);
202            node.translate(Vector::new(x, dy))
203        };
204
205        let mut child_nodes = Vec::with_capacity(3);
206        child_nodes.push(vcenter(start_node, 0.0));
207        child_nodes.push(vcenter(end_node, width - end_width));
208
209        if let Some(center) = &mut self.center {
210            let slot_start = start_width + gap;
211            let slot_end = (width - end_width - gap).max(slot_start);
212            let slot_width = slot_end - slot_start;
213            // this instead of `node.size().width` prevents center jitter as text ellipsizes
214            let natural_width = center
215                .as_widget_mut()
216                .layout(&mut tree.children[2], renderer, &limits.loose())
217                .size()
218                .width;
219
220            let node = center.as_widget_mut().layout(
221                &mut tree.children[2],
222                renderer,
223                &layout::Limits::new(Size::ZERO, Size::new(slot_width, height)),
224            );
225
226            let ideal_x = (width - natural_width) / 2.0;
227            let max_x = (width - end_width - gap - natural_width).max(slot_start);
228            let center_x = ideal_x.clamp(slot_start, max_x);
229
230            child_nodes.push(vcenter(node, center_x))
231        }
232
233        layout::Node::with_children(Size::new(width, height), child_nodes)
234    }
235
236    fn draw(
237        &self,
238        tree: &tree::Tree,
239        renderer: &mut crate::Renderer,
240        theme: &crate::Theme,
241        style: &iced_core::renderer::Style,
242        layout: iced_core::Layout<'_>,
243        cursor: iced_core::mouse::Cursor,
244        viewport: &iced_core::Rectangle,
245    ) {
246        self.elems()
247            .zip(&tree.children)
248            .zip(layout.children())
249            .for_each(|((e, s), l)| {
250                e.as_widget()
251                    .draw(s, renderer, theme, style, l, cursor, viewport);
252            });
253    }
254
255    fn update(
256        &mut self,
257        state: &mut tree::Tree,
258        event: &iced_core::Event,
259        layout: iced_core::Layout<'_>,
260        cursor: iced_core::mouse::Cursor,
261        renderer: &crate::Renderer,
262        clipboard: &mut dyn iced_core::Clipboard,
263        shell: &mut iced_core::Shell<'_, Message>,
264        viewport: &iced_core::Rectangle,
265    ) {
266        self.elems_mut()
267            .zip(&mut state.children)
268            .zip(layout.children())
269            .for_each(|((e, s), l)| {
270                e.as_widget_mut()
271                    .update(s, event, l, cursor, renderer, clipboard, shell, viewport);
272            });
273    }
274
275    fn mouse_interaction(
276        &self,
277        state: &tree::Tree,
278        layout: iced_core::Layout<'_>,
279        cursor: iced_core::mouse::Cursor,
280        viewport: &iced_core::Rectangle,
281        renderer: &crate::Renderer,
282    ) -> iced_core::mouse::Interaction {
283        self.elems()
284            .zip(&state.children)
285            .zip(layout.children())
286            .map(|((e, s), l)| {
287                e.as_widget()
288                    .mouse_interaction(s, l, cursor, viewport, renderer)
289            })
290            .max()
291            .unwrap_or(iced_core::mouse::Interaction::None)
292    }
293
294    fn operate(
295        &mut self,
296        state: &mut tree::Tree,
297        layout: iced_core::Layout<'_>,
298        renderer: &crate::Renderer,
299        operation: &mut dyn iced_core::widget::Operation<()>,
300    ) {
301        self.elems_mut()
302            .zip(&mut state.children)
303            .zip(layout.children())
304            .for_each(|((e, s), l)| {
305                e.as_widget_mut().operate(s, l, renderer, operation);
306            });
307    }
308
309    fn overlay<'b>(
310        &'b mut self,
311        state: &'b mut tree::Tree,
312        layout: iced_core::Layout<'b>,
313        renderer: &crate::Renderer,
314        viewport: &iced_core::Rectangle,
315        translation: Vector,
316    ) -> Option<iced_core::overlay::Element<'b, Message, crate::Theme, crate::Renderer>> {
317        self.elems_mut()
318            .zip(&mut state.children)
319            .zip(layout.children())
320            .find_map(|((e, s), l)| {
321                e.as_widget_mut()
322                    .overlay(s, l, renderer, viewport, translation)
323            })
324    }
325
326    fn drag_destinations(
327        &self,
328        state: &tree::Tree,
329        layout: iced_core::Layout<'_>,
330        renderer: &crate::Renderer,
331        dnd_rectangles: &mut iced_core::clipboard::DndDestinationRectangles,
332    ) {
333        self.elems()
334            .zip(&state.children)
335            .zip(layout.children())
336            .for_each(|((e, s), l)| {
337                e.as_widget()
338                    .drag_destinations(s, l, renderer, dnd_rectangles);
339            });
340    }
341
342    #[cfg(feature = "a11y")]
343    /// get the a11y nodes for the widget
344    fn a11y_nodes(
345        &self,
346        layout: iced_core::Layout<'_>,
347        state: &tree::Tree,
348        p: iced::mouse::Cursor,
349    ) -> iced_accessibility::A11yTree {
350        iced_accessibility::A11yTree::join(
351            self.elems()
352                .zip(&state.children)
353                .zip(layout.children())
354                .map(|((e, s), l)| e.as_widget().a11y_nodes(l, s, p)),
355        )
356    }
357}
358
359impl<'a, Message: Clone + 'static> From<HeaderBarWidget<'a, Message>> for Element<'a, Message> {
360    fn from(w: HeaderBarWidget<'a, Message>) -> Self {
361        Element::new(w)
362    }
363}
364
365impl<'a, Message: Clone + 'static> HeaderBar<'a, Message> {
366    /// Converts the headerbar builder into an Iced element.
367    pub fn view(mut self) -> Element<'a, Message> {
368        let Spacing {
369            space_xxxs,
370            space_xxs,
371            ..
372        } = theme::spacing();
373
374        // Take ownership of the regions to be packed.
375        let start = std::mem::take(&mut self.start);
376        let center = std::mem::take(&mut self.center);
377        let mut end = std::mem::take(&mut self.end);
378
379        // Also packs the window controls at the very end.
380        end.push(self.window_controls(space_xxs));
381
382        let padding = if self.is_ssd {
383            [2, 8, 2, 8]
384        } else {
385            match (
386                self.density.unwrap_or_else(crate::config::header_size),
387                self.maximized, // window border handling
388            ) {
389                (Density::Compact, true) => [4, 8, 4, 8],
390                (Density::Compact, false) => [3, 7, 4, 7],
391                (_, true) => [8, 8, 8, 8],
392                (_, false) => [7, 7, 8, 7],
393            }
394        };
395
396        let start = widget::row::with_children(start)
397            .spacing(space_xxxs)
398            .align_y(iced::Alignment::Center)
399            .into();
400        let center = if !center.is_empty() {
401            Some(
402                widget::row::with_children(center)
403                    .spacing(space_xxxs)
404                    .align_y(iced::Alignment::Center)
405                    .into(),
406            )
407        } else if !self.title.is_empty() {
408            Some(
409                widget::text::heading(self.title)
410                    .wrapping(text::Wrapping::None)
411                    .ellipsize(text::Ellipsize::End(text::EllipsizeHeightLimit::Lines(1)))
412                    .into(),
413            )
414        } else {
415            None
416        };
417        let end = widget::row::with_children(end)
418            .spacing(space_xxs)
419            .align_y(iced::Alignment::Center)
420            .into();
421
422        let mut widget = HeaderBarWidget::new(start, center, end)
423            .apply(widget::container)
424            .class(theme::Container::HeaderBar {
425                focused: self.focused,
426                sharp_corners: self.sharp_corners,
427                transparent: self.transparent,
428            })
429            .height(Length::Fixed(32.0 + padding[0] as f32 + padding[2] as f32))
430            .padding(padding)
431            .apply(widget::mouse_area);
432
433        if let Some(message) = self.on_drag {
434            widget = widget.on_drag(message);
435        }
436        if let Some(message) = self.on_maximize {
437            widget = widget.on_release(message);
438        }
439        if let Some(message) = self.on_double_click {
440            widget = widget.on_double_press(message);
441        }
442        if let Some(message) = self.on_right_click {
443            widget = widget.on_right_press(message);
444        }
445
446        widget.into()
447    }
448
449    /// Creates the widget for window controls.
450    fn window_controls(&mut self, spacing: u16) -> Element<'a, Message> {
451        macro_rules! icon {
452            ($name:expr, $size:expr, $on_press:expr) => {{
453                widget::icon::from_name($name)
454                    .apply(widget::button::icon)
455                    .padding(8)
456                    .class(theme::Button::HeaderBar)
457                    .selected(self.focused)
458                    .icon_size($size)
459                    .on_press($on_press)
460            }};
461        }
462
463        widget::row::with_capacity(3)
464            .push_maybe(
465                self.on_minimize
466                    .take()
467                    .map(|m| icon!("window-minimize-symbolic", 16, m)),
468            )
469            .push_maybe(self.on_maximize.take().map(|m| {
470                if self.maximized {
471                    icon!("window-restore-symbolic", 16, m)
472                } else {
473                    icon!("window-maximize-symbolic", 16, m)
474                }
475            }))
476            .push_maybe(
477                self.on_close
478                    .take()
479                    .map(|m| icon!("window-close-symbolic", 16, m)),
480            )
481            .spacing(spacing)
482            .align_y(iced::Alignment::Center)
483            .into()
484    }
485}
486
487impl<'a, Message: Clone + 'static> From<HeaderBar<'a, Message>> for Element<'a, Message> {
488    fn from(headerbar: HeaderBar<'a, Message>) -> Self {
489        headerbar.view()
490    }
491}
cosmic/widget/header_bar.rs

cosmic/widget/
header_bar.rs
