1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
use std::collections::HashSet;

use stretch::geometry::Size;
use stretch::node::Stretch;
use stretch::number::Number;
use stretch::style::{Dimension, Style};

use geom::{Percent, Polygon};

use crate::widgets::Container;
use crate::{
    Autocomplete, Checkbox, Color, Dropdown, EventCtx, GfxCtx, HorizontalAlignment, Menu, Outcome,
    PersistentSplit, ScreenDims, ScreenPt, ScreenRectangle, Slider, Spinner, TextBox,
    VerticalAlignment, Widget, WidgetImpl, WidgetOutput,
};

pub struct Panel {
    top_level: Widget,
    horiz: HorizontalAlignment,
    vert: VerticalAlignment,
    dims: Dims,

    scrollable_x: bool,
    scrollable_y: bool,
    contents_dims: ScreenDims,
    container_dims: ScreenDims,
    clip_rect: Option<ScreenRectangle>,
}

impl Panel {
    pub fn new(top_level: Widget) -> PanelBuilder {
        PanelBuilder {
            top_level,
            horiz: HorizontalAlignment::Center,
            vert: VerticalAlignment::Center,
            dims: Dims::MaxPercent(Percent::int(100), Percent::int(100)),
        }
    }

    /// Returns an empty panel. `event` and `draw` will have no effect.
    pub fn empty(ctx: &mut EventCtx) -> Panel {
        Panel::new(Widget::col(vec![])).build_custom(ctx)
    }

    fn update_container_dims_for_canvas_dims(&mut self, canvas_dims: ScreenDims) {
        let new_container_dims = match self.dims {
            Dims::MaxPercent(w, h) => ScreenDims::new(
                self.contents_dims.width.min(w.inner() * canvas_dims.width),
                self.contents_dims
                    .height
                    .min(h.inner() * canvas_dims.height),
            ),
            Dims::ExactPercent(w, h) => {
                ScreenDims::new(w * canvas_dims.width, h * canvas_dims.height)
            }
        };
        self.container_dims = new_container_dims;
    }

    fn recompute_scrollbar_layout(&mut self, ctx: &EventCtx) {
        let old_scrollable_x = self.scrollable_x;
        let old_scrollable_y = self.scrollable_y;
        let old_scroll_offset = self.scroll_offset();

        self.scrollable_x = self.contents_dims.width > self.container_dims.width;
        self.scrollable_y = self.contents_dims.height > self.container_dims.height;

        // Unwrap the main widget from any scrollable containers if necessary.
        if old_scrollable_y {
            let container = self.top_level.widget.downcast_mut::<Container>().unwrap();
            self.top_level = container.members.remove(0);
        }

        if old_scrollable_x {
            let container = self.top_level.widget.downcast_mut::<Container>().unwrap();
            self.top_level = container.members.remove(0);
        }

        let top_left = ctx
            .canvas
            .align_window(self.container_dims, self.horiz, self.vert);

        // Wrap the main widget in scrollable containers if necessary.
        if self.scrollable_x {
            let old_top_level = std::mem::replace(&mut self.top_level, Widget::nothing());
            self.top_level = Widget::custom_col(vec![
                old_top_level,
                Slider::horizontal(
                    ctx,
                    self.container_dims.width,
                    self.container_dims.width
                        * (self.container_dims.width / self.contents_dims.width),
                    0.0,
                )
                .named("horiz scrollbar")
                .abs(top_left.x, top_left.y + self.container_dims.height),
            ]);
        }

        if self.scrollable_y {
            let old_top_level = std::mem::replace(&mut self.top_level, Widget::nothing());
            self.top_level = Widget::custom_row(vec![
                old_top_level,
                Slider::vertical(
                    ctx,
                    self.container_dims.height,
                    self.container_dims.height
                        * (self.container_dims.height / self.contents_dims.height),
                    0.0,
                )
                .named("vert scrollbar")
                .abs(top_left.x + self.container_dims.width, top_left.y),
            ]);
        }

        self.update_scroll_sliders(ctx, old_scroll_offset);

        self.clip_rect = if self.scrollable_x || self.scrollable_y {
            Some(ScreenRectangle::top_left(top_left, self.container_dims))
        } else {
            None
        };
    }

    // TODO: this method potentially gets called multiple times in a render pass as an
    // optimization, we could replace all the current call sites with a "dirty" flag, e.g.
    // `set_needs_layout()` and then call `layout_if_needed()` once at the last possible moment
    fn recompute_layout(&mut self, ctx: &EventCtx, recompute_bg: bool) {
        self.recompute_scrollbar_layout(ctx);
        let mut stretch = Stretch::new();
        let root = stretch
            .new_node(
                Style {
                    ..Default::default()
                },
                Vec::new(),
            )
            .unwrap();

        let mut nodes = vec![];
        self.top_level.get_flexbox(root, &mut stretch, &mut nodes);
        nodes.reverse();

        // TODO Express more simply. Constraining this seems useless.
        let container_size = Size {
            width: Number::Undefined,
            height: Number::Undefined,
        };
        stretch.compute_layout(root, container_size).unwrap();

        // TODO I'm so confused why these 2 are acting differently. :(
        let effective_dims = if self.scrollable_x || self.scrollable_y {
            self.container_dims
        } else {
            let result = stretch.layout(root).unwrap();
            ScreenDims::new(result.size.width.into(), result.size.height.into())
        };
        let top_left = ctx
            .canvas
            .align_window(effective_dims, self.horiz, self.vert);
        let offset = self.scroll_offset();
        self.top_level.apply_flexbox(
            &stretch,
            &mut nodes,
            top_left.x,
            top_left.y,
            offset,
            ctx,
            recompute_bg,
            false,
        );
        assert!(nodes.is_empty());
    }

    fn scroll_offset(&self) -> (f64, f64) {
        let x = if self.scrollable_x {
            self.slider("horiz scrollbar").get_percent()
                * (self.contents_dims.width - self.container_dims.width).max(0.0)
        } else {
            0.0
        };
        let y = if self.scrollable_y {
            self.slider("vert scrollbar").get_percent()
                * (self.contents_dims.height - self.container_dims.height).max(0.0)
        } else {
            0.0
        };
        (x, y)
    }

    fn update_scroll_sliders(&mut self, ctx: &EventCtx, offset: (f64, f64)) -> bool {
        let mut changed = false;
        if self.scrollable_x {
            changed = true;
            let max = (self.contents_dims.width - self.container_dims.width).max(0.0);
            if max == 0.0 {
                self.slider_mut("horiz scrollbar").set_percent(ctx, 0.0);
            } else {
                self.slider_mut("horiz scrollbar")
                    .set_percent(ctx, abstutil::clamp(offset.0, 0.0, max) / max);
            }
        }
        if self.scrollable_y {
            changed = true;
            let max = (self.contents_dims.height - self.container_dims.height).max(0.0);
            if max == 0.0 {
                self.slider_mut("vert scrollbar").set_percent(ctx, 0.0);
            } else {
                self.slider_mut("vert scrollbar")
                    .set_percent(ctx, abstutil::clamp(offset.1, 0.0, max) / max);
            }
        }
        changed
    }

    fn set_scroll_offset(&mut self, ctx: &EventCtx, offset: (f64, f64)) {
        if self.update_scroll_sliders(ctx, offset) {
            self.recompute_layout(ctx, false);
        }
    }

    pub fn event(&mut self, ctx: &mut EventCtx) -> Outcome {
        if (self.scrollable_x || self.scrollable_y)
            && ctx
                .canvas
                .get_cursor_in_screen_space()
                .map(|pt| self.top_level.rect.contains(pt))
                .unwrap_or(false)
        {
            if let Some((dx, dy)) = ctx.input.get_mouse_scroll() {
                let x_offset = if self.scrollable_x {
                    self.scroll_offset().0 + dx * (ctx.canvas.gui_scroll_speed as f64)
                } else {
                    0.0
                };
                let y_offset = if self.scrollable_y {
                    self.scroll_offset().1 - dy * (ctx.canvas.gui_scroll_speed as f64)
                } else {
                    0.0
                };
                self.set_scroll_offset(ctx, (x_offset, y_offset));
            }
        }

        if ctx.input.is_window_resized() {
            self.update_container_dims_for_canvas_dims(ctx.canvas.get_window_dims());
            self.recompute_layout(ctx, false);
        }

        let before = self.scroll_offset();
        let mut output = WidgetOutput::new();
        self.top_level.widget.event(ctx, &mut output);
        if self.scroll_offset() != before || output.redo_layout {
            self.recompute_layout(ctx, true);
        }

        output.outcome
    }

    pub fn draw(&self, g: &mut GfxCtx) {
        if let Some(ref rect) = self.clip_rect {
            g.enable_clipping(rect.clone());
            g.canvas.mark_covered_area(rect.clone());
        } else {
            g.canvas.mark_covered_area(self.top_level.rect.clone());
        }

        // Debugging
        if false {
            g.fork_screenspace();
            g.draw_polygon(Color::RED.alpha(0.5), self.top_level.rect.to_polygon());

            let top_left = g
                .canvas
                .align_window(self.container_dims, self.horiz, self.vert);
            g.draw_polygon(
                Color::BLUE.alpha(0.5),
                Polygon::rectangle(self.container_dims.width, self.container_dims.height)
                    .translate(top_left.x, top_left.y),
            );
            g.unfork();
        }

        self.top_level.draw(g);
        if self.scrollable_x || self.scrollable_y {
            g.disable_clipping();

            // Draw the scrollbars after clipping is disabled, because they actually live just
            // outside the rectangle.
            if self.scrollable_x {
                self.slider("horiz scrollbar").draw(g);
            }
            if self.scrollable_y {
                self.slider("vert scrollbar").draw(g);
            }
        }
    }

    pub fn get_all_click_actions(&self) -> HashSet<String> {
        let mut actions = HashSet::new();
        self.top_level.get_all_click_actions(&mut actions);
        actions
    }

    pub fn restore(&mut self, ctx: &mut EventCtx, prev: &Panel) {
        self.set_scroll_offset(ctx, prev.scroll_offset());

        self.top_level.restore(ctx, &prev);

        // Since we just moved things around, let all widgets respond to the mouse being somewhere
        ctx.no_op_event(true, |ctx| assert_eq!(self.event(ctx), Outcome::Nothing));
    }

    pub fn scroll_to_member(&mut self, ctx: &EventCtx, name: String) {
        if let Some(w) = self.top_level.find(&name) {
            let y1 = w.rect.y1;
            self.set_scroll_offset(ctx, (0.0, y1));
        } else {
            panic!("Can't scroll_to_member of unknown {}", name);
        }
    }

    pub fn has_widget(&self, name: &str) -> bool {
        self.top_level.find(name).is_some()
    }

    pub fn slider(&self, name: &str) -> &Slider {
        self.find(name)
    }
    pub fn slider_mut(&mut self, name: &str) -> &mut Slider {
        self.find_mut(name)
    }

    pub fn take_menu_choice<T: 'static>(&mut self, name: &str) -> T {
        self.find_mut::<Menu<T>>(name).take_current_choice()
    }

    pub fn is_checked(&self, name: &str) -> bool {
        self.find::<Checkbox>(name).enabled
    }
    pub fn maybe_is_checked(&self, name: &str) -> Option<bool> {
        if self.has_widget(name) {
            Some(self.find::<Checkbox>(name).enabled)
        } else {
            None
        }
    }

    pub fn text_box(&self, name: &str) -> String {
        self.find::<TextBox>(name).get_line()
    }

    pub fn spinner(&self, name: &str) -> isize {
        self.find::<Spinner>(name).current
    }
    pub fn modify_spinner(&mut self, name: &str, delta: isize) {
        self.find_mut::<Spinner>(name).modify(delta)
    }

    pub fn dropdown_value<T: 'static + PartialEq + Clone, I: Into<String>>(&self, name: I) -> T {
        self.find::<Dropdown<T>>(&name.into()).current_value()
    }
    pub fn maybe_dropdown_value<T: 'static + PartialEq + Clone, I: Into<String>>(
        &self,
        name: I,
    ) -> Option<T> {
        let name = name.into();
        if self.has_widget(&name) {
            Some(self.find::<Dropdown<T>>(&name).current_value())
        } else {
            None
        }
    }
    pub fn persistent_split_value<T: 'static + PartialEq + Clone>(&self, name: &str) -> T {
        self.find::<PersistentSplit<T>>(name).current_value()
    }

    pub fn autocomplete_done<T: 'static + Clone>(&self, name: &str) -> Option<Vec<T>> {
        self.find::<Autocomplete<T>>(name).final_value()
    }

    pub fn maybe_find(&self, name: &str) -> Option<&Widget> {
        self.top_level.find(name)
    }

    pub fn find<T: WidgetImpl>(&self, name: &str) -> &T {
        if let Some(w) = self.top_level.find(name) {
            if let Some(x) = w.widget.downcast_ref::<T>() {
                x
            } else {
                panic!("Found widget {}, but wrong type", name);
            }
        } else {
            panic!("Can't find widget {}", name);
        }
    }
    pub fn find_mut<T: WidgetImpl>(&mut self, name: &str) -> &mut T {
        if let Some(w) = self.top_level.find_mut(name) {
            if let Some(x) = w.widget.downcast_mut::<T>() {
                x
            } else {
                panic!("Found widget {}, but wrong type", name);
            }
        } else {
            panic!("Can't find widget {}", name);
        }
    }

    pub fn rect_of(&self, name: &str) -> &ScreenRectangle {
        &self.top_level.find(name).unwrap().rect
    }
    // TODO Deprecate
    pub fn center_of(&self, name: &str) -> ScreenPt {
        self.rect_of(name).center()
    }
    pub fn center_of_panel(&self) -> ScreenPt {
        self.top_level.rect.center()
    }

    pub fn align(&mut self, horiz: HorizontalAlignment, vert: VerticalAlignment) {
        self.horiz = horiz;
        self.vert = vert;
    }
    pub fn align_above(&mut self, ctx: &mut EventCtx, other: &Panel) {
        // Small padding
        self.vert = VerticalAlignment::Above(other.top_level.rect.y1 - 5.0);
        self.recompute_layout(ctx, false);

        // Since we just moved things around, let all widgets respond to the mouse being somewhere
        ctx.no_op_event(true, |ctx| assert_eq!(self.event(ctx), Outcome::Nothing));
    }
    pub fn align_below(&mut self, ctx: &mut EventCtx, other: &Panel, pad: f64) {
        self.vert = VerticalAlignment::Below(other.top_level.rect.y2 + pad);
        self.recompute_layout(ctx, false);

        // Since we just moved things around, let all widgets respond to the mouse being somewhere
        ctx.no_op_event(true, |ctx| assert_eq!(self.event(ctx), Outcome::Nothing));
    }

    /// All margins/padding/etc from the previous widget are retained.
    pub fn replace(&mut self, ctx: &mut EventCtx, id: &str, mut new: Widget) {
        let old = self.top_level.find_mut(id).unwrap();
        new.layout.style = old.layout.style;
        *old = new;
        self.recompute_layout(ctx, true);
        // TODO Same no_op_event as align_above? Should we always do this in recompute_layout?
    }

    /// Removes a widget from the panel. Does not recalculate layout!
    pub fn take(&mut self, id: &str) -> Widget {
        self.top_level.take(id).unwrap()
    }

    pub fn clicked_outside(&self, ctx: &mut EventCtx) -> bool {
        // TODO No great way to populate OSD from here with "click to cancel"
        !self.top_level.rect.contains(ctx.canvas.get_cursor()) && ctx.normal_left_click()
    }

    pub fn currently_hovering(&self) -> Option<&String> {
        self.top_level.currently_hovering()
    }
}

pub struct PanelBuilder {
    top_level: Widget,
    horiz: HorizontalAlignment,
    vert: VerticalAlignment,
    dims: Dims,
}

enum Dims {
    MaxPercent(Percent, Percent),
    ExactPercent(f64, f64),
}

impl PanelBuilder {
    pub fn build(mut self, ctx: &mut EventCtx) -> Panel {
        self.top_level = self.top_level.padding(16).bg(ctx.style.panel_bg);
        self.build_custom(ctx)
    }

    pub fn build_custom(self, ctx: &mut EventCtx) -> Panel {
        let mut panel = Panel {
            top_level: self.top_level,

            horiz: self.horiz,
            vert: self.vert,
            dims: self.dims,

            scrollable_x: false,
            scrollable_y: false,
            contents_dims: ScreenDims::new(0.0, 0.0),
            container_dims: ScreenDims::new(0.0, 0.0),
            clip_rect: None,
        };
        if let Dims::ExactPercent(w, h) = panel.dims {
            // Don't set size, because then scrolling breaks -- the actual size has to be based on
            // the contents.
            panel.top_level.layout.style.min_size = Size {
                width: Dimension::Points((w * ctx.canvas.window_width) as f32),
                height: Dimension::Points((h * ctx.canvas.window_height) as f32),
            };
        }

        // There is a dependency cycle in our layout logic. As a consequence:
        //   1. we have to call `recompute_layout` twice here
        //   2. panels don't responsively change `contents_dims`
        //
        // - `panel.top_level.rect`, used here to set content_dims, is set by `recompute_layout`.
        // - the output of `recompute_layout` depends on `container_dims`
        // - `container_dims`, in the case of `MaxPercent`, depend on `content_dims`
        //
        // TODO: to support Panel's that can resize their `contents_dims`, we'll need to detangle
        // this dependency. This might entail decomposing the flexbox calculation to layout first
        // the inner content, and then potentially a second pass to layout any x/y scrollbars.
        panel.recompute_layout(ctx, false);
        panel.contents_dims =
            ScreenDims::new(panel.top_level.rect.width(), panel.top_level.rect.height());
        panel.update_container_dims_for_canvas_dims(ctx.canvas.get_window_dims());
        panel.recompute_layout(ctx, false);

        // Just trigger error if a button is double-defined
        panel.get_all_click_actions();
        // Let all widgets initially respond to the mouse being somewhere
        ctx.no_op_event(true, |ctx| assert_eq!(panel.event(ctx), Outcome::Nothing));
        panel
    }

    pub fn aligned(mut self, horiz: HorizontalAlignment, vert: VerticalAlignment) -> PanelBuilder {
        self.horiz = horiz;
        self.vert = vert;
        self
    }

    pub fn max_size(mut self, width: Percent, height: Percent) -> PanelBuilder {
        if width == Percent::int(100) && height == Percent::int(100) {
            panic!("By default, Panels are capped at 100% of the screen. This is redundant.");
        }
        self.dims = Dims::MaxPercent(width, height);
        self
    }

    pub fn exact_size_percent(mut self, pct_width: usize, pct_height: usize) -> PanelBuilder {
        self.dims = Dims::ExactPercent((pct_width as f64) / 100.0, (pct_height as f64) / 100.0);
        self
    }
}