StratoSDK is a framework with a declarative approach similar to Flutter/React, written and designed entirely for Rust.
| 1 | use std::{ |
| 2 | mem, |
| 3 | sync::{Arc, Mutex, MutexGuard}, |
| 4 | }; |
| 5 | |
| 6 | use pathfinder_color::ColorU; |
| 7 | use pathfinder_geometry::{ |
| 8 | rect::RectF, |
| 9 | vector::{vec2f, Vector2F}, |
| 10 | }; |
| 11 | |
| 12 | use crate::{ |
| 13 | event::DispatchedEvent, platform::Cursor, AfterLayoutContext, AppContext, Element, |
| 14 | EventContext, PaintContext, SizeConstraint, |
| 15 | }; |
| 16 | |
| 17 | use super::{Fill, Point, ZIndex}; |
| 18 | |
| 19 | const DRAGBAR_WIDTH: f32 = 5.0; |
| 20 | |
| 21 | /// A UI element with internal resizing ability. |
| 22 | /// |
| 23 | /// This element takes a ResizableStateHandle to receive a starting size and |
| 24 | /// manage dimensions as the element is resized. |
| 25 | /// |
| 26 | /// Supports both horizontal and vertical resizing via the ResizeDirection. |
| 27 | /// |
| 28 | /// TODO: |
| 29 | /// - Take a configurable dragbar size instead of always using 5.0 |
| 30 | pub struct Resizable { |
| 31 | child: Box<dyn Element>, |
| 32 | origin: Option<Vector2F>, |
| 33 | dragbar: Dragbar, |
| 34 | state_handle: ResizableStateHandle, |
| 35 | size: Option<Vector2F>, |
| 36 | bounds_callback: Option<BoundsCallback>, |
| 37 | resize_handler: Option<Handler>, |
| 38 | start_resize_handler: Option<Handler>, |
| 39 | end_resize_handler: Option<Handler>, |
| 40 | hovering_dragbar: bool, |
| 41 | direction: ResizeDirection, |
| 42 | origin_delta: Vector2F, |
| 43 | dragbar_offset: f32, |
| 44 | } |
| 45 | |
| 46 | type Handler = Box<dyn FnMut(&mut EventContext, &AppContext)>; |
| 47 | pub type BoundsCallback = Box<dyn FnMut(Vector2F) -> (f32, f32)>; |
| 48 | |
| 49 | /// Similar to MouseStateHandle, the view that incorporates the owner can instantiate, |
| 50 | /// read, and set the state. |
| 51 | pub type ResizableStateHandle = Arc<Mutex<ResizableState>>; |
| 52 | pub fn resizable_state_handle(size: f32) -> ResizableStateHandle { |
| 53 | Arc::new(Mutex::new(ResizableState::new(size))) |
| 54 | } |
| 55 | |
| 56 | pub struct ResizableState { |
| 57 | size: f32, |
| 58 | bounds: Option<(f32, f32)>, |
| 59 | mode: ResizableMode, |
| 60 | } |
| 61 | |
| 62 | #[derive(Default)] |
| 63 | pub enum ResizableMode { |
| 64 | Dragging { |
| 65 | last_position: Vector2F, |
| 66 | }, |
| 67 | #[default] |
| 68 | Stationary, |
| 69 | } |
| 70 | |
| 71 | impl ResizableState { |
| 72 | pub fn new(size: f32) -> Self { |
| 73 | Self { |
| 74 | size, |
| 75 | bounds: None, |
| 76 | mode: Default::default(), |
| 77 | } |
| 78 | } |
| 79 | pub fn size(&self) -> f32 { |
| 80 | self.size |
| 81 | } |
| 82 | |
| 83 | pub fn clamp_size(&mut self) { |
| 84 | if let Some((min, max)) = self.bounds { |
| 85 | self.size = self.size.clamp(min, max); |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | fn check_for_resize( |
| 90 | &mut self, |
| 91 | position: Vector2F, |
| 92 | origin: Option<Vector2F>, |
| 93 | dragbar_side: DragBarSide, |
| 94 | ) -> Option<Vector2F> { |
| 95 | if let ResizableMode::Dragging { last_position } = self.mode { |
| 96 | self.resize(last_position, position, origin, dragbar_side) |
| 97 | } else { |
| 98 | None |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | fn is_resizing(&self) -> bool { |
| 103 | matches!(self.mode, ResizableMode::Dragging { .. }) |
| 104 | } |
| 105 | |
| 106 | fn resize( |
| 107 | &mut self, |
| 108 | old_position: Vector2F, |
| 109 | new_position: Vector2F, |
| 110 | origin: Option<Vector2F>, |
| 111 | dragbar_side: DragBarSide, |
| 112 | ) -> Option<Vector2F> { |
| 113 | let mut resized = false; |
| 114 | |
| 115 | if let Some(origin) = origin { |
| 116 | let delta = match dragbar_side { |
| 117 | DragBarSide::Right => new_position.x() - old_position.x(), |
| 118 | DragBarSide::Left => old_position.x() - new_position.x(), |
| 119 | DragBarSide::Bottom => new_position.y() - old_position.y(), |
| 120 | DragBarSide::Top => old_position.y() - new_position.y(), |
| 121 | }; |
| 122 | |
| 123 | let old_size = self.size; |
| 124 | if delta.abs() >= f32::EPSILON { |
| 125 | resized = true; |
| 126 | self.size += delta; |
| 127 | self.clamp_size(); |
| 128 | } |
| 129 | let size = self.size; |
| 130 | |
| 131 | // The last position should reflect the latest position of the dragbar. |
| 132 | let last_position = match dragbar_side { |
| 133 | // With a right-side dragbar, the latest position of the dragbar will |
| 134 | // be the old origin of the element plus the new width/height. |
| 135 | DragBarSide::Right => origin + vec2f(size, 0.), |
| 136 | // With a left-side dragbar, the latest position of the dragbar will |
| 137 | // be the old origin of the element minus the bounded delta of the drag. |
| 138 | DragBarSide::Left => origin - vec2f(size - old_size, 0.), |
| 139 | // With a bottom-side dragbar, the latest position of the dragbar will |
| 140 | // be the old origin of the element plus the new height. |
| 141 | DragBarSide::Bottom => origin + vec2f(0., size), |
| 142 | // With a top-side dragbar, the latest position of the dragbar will |
| 143 | // be the old origin of the element minus the bounded delta of the drag. |
| 144 | DragBarSide::Top => origin - vec2f(0., size - old_size), |
| 145 | }; |
| 146 | |
| 147 | let origin_delta = match dragbar_side { |
| 148 | DragBarSide::Right => Vector2F::zero(), |
| 149 | DragBarSide::Left => vec2f(old_size - size, 0.), |
| 150 | DragBarSide::Bottom => Vector2F::zero(), |
| 151 | DragBarSide::Top => vec2f(0., old_size - size), |
| 152 | }; |
| 153 | |
| 154 | self.mode = ResizableMode::Dragging { last_position }; |
| 155 | |
| 156 | if resized { |
| 157 | Some(origin_delta) |
| 158 | } else { |
| 159 | None |
| 160 | } |
| 161 | } else { |
| 162 | None |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | pub fn begin_resizing(&mut self, position: Vector2F) { |
| 167 | self.mode = ResizableMode::Dragging { |
| 168 | last_position: position, |
| 169 | }; |
| 170 | } |
| 171 | |
| 172 | pub fn end_resizing(&mut self) { |
| 173 | self.mode = ResizableMode::Stationary; |
| 174 | } |
| 175 | |
| 176 | pub fn set_size(&mut self, new_size: f32) { |
| 177 | self.size = new_size; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | struct Dragbar { |
| 182 | bounds: Option<RectF>, |
| 183 | origin: Option<Point>, |
| 184 | size: Option<Vector2F>, |
| 185 | z_index: Option<ZIndex>, |
| 186 | color: Fill, |
| 187 | side: DragBarSide, |
| 188 | } |
| 189 | |
| 190 | #[derive(Copy, Clone, Default)] |
| 191 | pub enum DragBarSide { |
| 192 | Left, |
| 193 | #[default] |
| 194 | Right, |
| 195 | Top, |
| 196 | Bottom, |
| 197 | } |
| 198 | |
| 199 | #[derive(Copy, Clone, Default)] |
| 200 | pub enum ResizeDirection { |
| 201 | #[default] |
| 202 | Horizontal, |
| 203 | Vertical, |
| 204 | } |
| 205 | |
| 206 | impl Dragbar { |
| 207 | pub fn new() -> Self { |
| 208 | let color = Fill::Solid(ColorU::transparent_black()); |
| 209 | Self { |
| 210 | bounds: None, |
| 211 | origin: None, |
| 212 | size: None, |
| 213 | z_index: None, |
| 214 | color, |
| 215 | side: Default::default(), |
| 216 | } |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | impl Resizable { |
| 221 | pub fn new(state_handle: ResizableStateHandle, child: Box<dyn Element>) -> Self { |
| 222 | Self { |
| 223 | child, |
| 224 | origin: None, |
| 225 | state_handle, |
| 226 | size: None, |
| 227 | bounds_callback: None, |
| 228 | resize_handler: None, |
| 229 | start_resize_handler: None, |
| 230 | end_resize_handler: None, |
| 231 | dragbar: Dragbar::new(), |
| 232 | hovering_dragbar: false, |
| 233 | direction: ResizeDirection::Horizontal, |
| 234 | origin_delta: Vector2F::zero(), |
| 235 | dragbar_offset: 0.0, |
| 236 | } |
| 237 | } |
| 238 | |
| 239 | /// Adds a callback which will be called on a resize. |
| 240 | /// Generally, this should trigger a re-render in the parent. |
| 241 | pub fn on_resize<F>(mut self, callback: F) -> Self |
| 242 | where |
| 243 | F: FnMut(&mut EventContext, &AppContext) + 'static, |
| 244 | { |
| 245 | self.resize_handler = Some(Box::new(callback)); |
| 246 | self |
| 247 | } |
| 248 | |
| 249 | pub fn on_start_resizing<F>(mut self, callback: F) -> Self |
| 250 | where |
| 251 | F: FnMut(&mut EventContext, &AppContext) + 'static, |
| 252 | { |
| 253 | self.start_resize_handler = Some(Box::new(callback)); |
| 254 | self |
| 255 | } |
| 256 | |
| 257 | pub fn on_end_resizing<F>(mut self, callback: F) -> Self |
| 258 | where |
| 259 | F: FnMut(&mut EventContext, &AppContext) + 'static, |
| 260 | { |
| 261 | self.end_resize_handler = Some(Box::new(callback)); |
| 262 | self |
| 263 | } |
| 264 | |
| 265 | /// Sets a function that computes the (min, max) bounds on the width/height |
| 266 | /// of the resizable. The bounds are updated at paint time. |
| 267 | pub fn with_bounds_callback(mut self, callback: BoundsCallback) -> Self { |
| 268 | self.bounds_callback = Some(callback); |
| 269 | self |
| 270 | } |
| 271 | |
| 272 | pub fn with_dragbar_color(mut self, color: Fill) -> Self { |
| 273 | self.dragbar.color = color; |
| 274 | self |
| 275 | } |
| 276 | |
| 277 | pub fn with_dragbar_side(mut self, side: DragBarSide) -> Self { |
| 278 | self.dragbar.side = side; |
| 279 | // Automatically set direction based on side |
| 280 | self.direction = match side { |
| 281 | DragBarSide::Left | DragBarSide::Right => ResizeDirection::Horizontal, |
| 282 | DragBarSide::Top | DragBarSide::Bottom => ResizeDirection::Vertical, |
| 283 | }; |
| 284 | self |
| 285 | } |
| 286 | |
| 287 | /// Sets an offset for the dragbar position. |
| 288 | /// Positive values move the dragbar outwards (away from the center of the element). |
| 289 | /// Negative values move the dragbar inwards (towards the center of the element). |
| 290 | pub fn with_dragbar_offset(mut self, offset: f32) -> Self { |
| 291 | self.dragbar_offset = offset; |
| 292 | self |
| 293 | } |
| 294 | |
| 295 | fn state(&mut self) -> MutexGuard<'_, ResizableState> { |
| 296 | self.state_handle |
| 297 | .lock() |
| 298 | .expect("Resizable state should be accessible") |
| 299 | } |
| 300 | |
| 301 | /// Determine if the mouse is hovering over the dragbar |
| 302 | /// |
| 303 | /// If there is another element above this one at the cursor position, then we treat that as |
| 304 | /// outside the element for purposes of MouseState |
| 305 | fn is_mouse_hovering_dragbar(&self, ctx: &EventContext, position: Vector2F) -> bool { |
| 306 | let Some(dragbar_origin) = self.dragbar.origin else { |
| 307 | log::warn!("self.origin was None in `Hoverable::is_mouse_in`"); |
| 308 | return false; |
| 309 | }; |
| 310 | let Some(dragbar_size) = self.dragbar.size else { |
| 311 | log::warn!("self.size() was None in `Hoverable::is_mouse_in`"); |
| 312 | return false; |
| 313 | }; |
| 314 | let Some(z_index) = self.dragbar.z_index else { |
| 315 | log::warn!("self.child_max_z_index was None in `Hoverable::is_mouse_in`"); |
| 316 | return false; |
| 317 | }; |
| 318 | |
| 319 | let is_hovering = ctx |
| 320 | .visible_rect(dragbar_origin, dragbar_size) |
| 321 | .is_some_and(|bound| bound.contains_point(position)); |
| 322 | |
| 323 | let point = Point::from_vec2f(position, z_index); |
| 324 | let is_covered = ctx.is_covered(point); |
| 325 | |
| 326 | is_hovering && !is_covered |
| 327 | } |
| 328 | } |
| 329 | |
| 330 | impl Element for Resizable { |
| 331 | fn layout( |
| 332 | &mut self, |
| 333 | constraint: crate::SizeConstraint, |
| 334 | ctx: &mut crate::LayoutContext, |
| 335 | app: &AppContext, |
| 336 | ) -> Vector2F { |
| 337 | // Use the window size to set bounds on the width/height |
| 338 | if let Some(bounds_callback) = self.bounds_callback.as_mut() { |
| 339 | let mut new_bounds = bounds_callback(ctx.window_size); |
| 340 | if new_bounds.0 > new_bounds.1 { |
| 341 | log::error!("Resizable: min bound is greater than max bound"); |
| 342 | new_bounds = (new_bounds.0, new_bounds.0); |
| 343 | } |
| 344 | self.state().bounds = Some(new_bounds); |
| 345 | |
| 346 | // With new bounds, we should also clamp the current width/height. |
| 347 | self.state().clamp_size(); |
| 348 | } |
| 349 | |
| 350 | let size = self.state().size; |
| 351 | |
| 352 | // We set the child constraints to never be greater than the current width/height constraint. |
| 353 | let child_constraint = match self.direction { |
| 354 | ResizeDirection::Horizontal => SizeConstraint { |
| 355 | min: (constraint.min) |
| 356 | .max(Vector2F::zero()) |
| 357 | .min(Vector2F::new(size, f32::MAX)), |
| 358 | max: (constraint.max) |
| 359 | .max(Vector2F::zero()) |
| 360 | .min(Vector2F::new(size, f32::MAX)), |
| 361 | }, |
| 362 | ResizeDirection::Vertical => SizeConstraint { |
| 363 | min: (constraint.min) |
| 364 | .max(Vector2F::zero()) |
| 365 | .min(Vector2F::new(f32::MAX, size)), |
| 366 | max: (constraint.max) |
| 367 | .max(Vector2F::zero()) |
| 368 | .min(Vector2F::new(f32::MAX, size)), |
| 369 | }, |
| 370 | }; |
| 371 | let child_size = self.child.layout(child_constraint, ctx, app); |
| 372 | |
| 373 | let size = child_size; |
| 374 | self.size = Some(size); |
| 375 | size |
| 376 | } |
| 377 | |
| 378 | fn after_layout(&mut self, ctx: &mut AfterLayoutContext, app: &AppContext) { |
| 379 | self.child.after_layout(ctx, app) |
| 380 | } |
| 381 | |
| 382 | fn paint(&mut self, origin: Vector2F, ctx: &mut PaintContext, app: &AppContext) { |
| 383 | self.child.paint(origin, ctx, app); |
| 384 | |
| 385 | // Draw the dragbar and record its size and position |
| 386 | let child_size = self.child.size().unwrap(); |
| 387 | let (dragbar_origin, dragbar_size) = match self.dragbar.side { |
| 388 | DragBarSide::Left => ( |
| 389 | origin - vec2f(self.dragbar_offset, 0.), |
| 390 | vec2f(DRAGBAR_WIDTH, child_size.y()), |
| 391 | ), |
| 392 | DragBarSide::Right => ( |
| 393 | origin + vec2f(child_size.x() - DRAGBAR_WIDTH + self.dragbar_offset, 0.), |
| 394 | vec2f(DRAGBAR_WIDTH, child_size.y()), |
| 395 | ), |
| 396 | DragBarSide::Top => ( |
| 397 | origin - vec2f(0., self.dragbar_offset), |
| 398 | vec2f(child_size.x(), DRAGBAR_WIDTH), |
| 399 | ), |
| 400 | DragBarSide::Bottom => ( |
| 401 | origin + vec2f(0., child_size.y() - DRAGBAR_WIDTH + self.dragbar_offset), |
| 402 | vec2f(child_size.x(), DRAGBAR_WIDTH), |
| 403 | ), |
| 404 | }; |
| 405 | |
| 406 | ctx.scene |
| 407 | .draw_rect_with_hit_recording(RectF::new(dragbar_origin, dragbar_size)) |
| 408 | .with_background(self.dragbar.color); |
| 409 | |
| 410 | self.dragbar.bounds = Some(RectF::new(dragbar_origin, dragbar_size)); |
| 411 | self.dragbar.origin = Some(Point::from_vec2f(dragbar_origin, ctx.scene.z_index())); |
| 412 | self.dragbar.size = Some(dragbar_size); |
| 413 | self.dragbar.z_index = Some(ctx.scene.max_active_z_index()); |
| 414 | |
| 415 | self.origin = Some(origin); |
| 416 | self.origin_delta = Vector2F::zero(); |
| 417 | } |
| 418 | |
| 419 | fn dispatch_event( |
| 420 | &mut self, |
| 421 | event: &DispatchedEvent, |
| 422 | ctx: &mut EventContext, |
| 423 | app: &AppContext, |
| 424 | ) -> bool { |
| 425 | let child_handled = self.child.dispatch_event(event, ctx, app); |
| 426 | |
| 427 | match event.raw_event() { |
| 428 | crate::Event::LeftMouseDown { position, .. } => { |
| 429 | // If a mouse-down on the dragbar element occurred, put the view into resizing mode |
| 430 | if self |
| 431 | .dragbar |
| 432 | .bounds |
| 433 | .is_some_and(|bounds| bounds.contains_point(*position)) |
| 434 | { |
| 435 | self.state().begin_resizing(*position); |
| 436 | dispatch_callback(self.resize_handler.as_mut(), ctx, app); |
| 437 | return true; |
| 438 | } |
| 439 | } |
| 440 | |
| 441 | crate::Event::LeftMouseUp { .. } => { |
| 442 | // If a mouse-up occurs, take the view out of resizing mode |
| 443 | if self.state().is_resizing() { |
| 444 | ctx.reset_cursor(); |
| 445 | self.state().end_resizing(); |
| 446 | dispatch_callback(self.end_resize_handler.as_mut(), ctx, app); |
| 447 | return true; |
| 448 | } |
| 449 | } |
| 450 | |
| 451 | crate::Event::LeftMouseDragged { position, .. } => { |
| 452 | if self.state().is_resizing() { |
| 453 | let dragbar_side = self.dragbar.side; |
| 454 | let origin = self.origin.map(|origin| origin + self.origin_delta); |
| 455 | let resized = self |
| 456 | .state() |
| 457 | .check_for_resize(*position, origin, dragbar_side); |
| 458 | self.origin_delta += resized.unwrap_or_default(); |
| 459 | if resized.is_some() { |
| 460 | dispatch_callback(self.resize_handler.as_mut(), ctx, app) |
| 461 | } |
| 462 | return true; |
| 463 | } |
| 464 | } |
| 465 | crate::Event::MouseMoved { position, .. } => { |
| 466 | // A mouse event over the dragbar should set the cursor |
| 467 | let Some(z_index) = self.z_index() else { |
| 468 | log::warn!("self.z_index() was None in `Resizable`"); |
| 469 | return false; |
| 470 | }; |
| 471 | let hovering_dragbar = self.is_mouse_hovering_dragbar(ctx, *position); |
| 472 | let was_already_hovering = |
| 473 | mem::replace(&mut self.hovering_dragbar, hovering_dragbar); |
| 474 | |
| 475 | if hovering_dragbar && !was_already_hovering { |
| 476 | let cursor = match self.direction { |
| 477 | ResizeDirection::Horizontal => Cursor::ResizeLeftRight, |
| 478 | ResizeDirection::Vertical => Cursor::ResizeUpDown, |
| 479 | }; |
| 480 | ctx.set_cursor(cursor, z_index); |
| 481 | } else if !hovering_dragbar && was_already_hovering { |
| 482 | ctx.reset_cursor(); |
| 483 | } |
| 484 | |
| 485 | return true; |
| 486 | } |
| 487 | _ => {} |
| 488 | } |
| 489 | child_handled |
| 490 | } |
| 491 | |
| 492 | fn size(&self) -> Option<Vector2F> { |
| 493 | self.child.size() |
| 494 | } |
| 495 | |
| 496 | fn origin(&self) -> Option<Point> { |
| 497 | self.child.origin() |
| 498 | } |
| 499 | } |
| 500 | |
| 501 | fn dispatch_callback(callback: Option<&mut Handler>, ctx: &mut EventContext, app: &AppContext) { |
| 502 | if let Some(callback) = callback { |
| 503 | callback(ctx, app); |
| 504 | } |
| 505 | } |
| 506 |