makepad/widgets/src/view.rs

use {
    crate::makepad_draw::event::FingerLongPressEvent,
    crate::{
        animator::*,
        makepad_derive_widget::*,
        makepad_draw::*,
        makepad_script::{script_err_wrong_value, ScriptFnRef},
        scroll_bars::ScrollBars,
        widget::*,
        widget_async::{
            CxWidgetToScriptCallExt, ScriptAsyncCalls, ScriptAsyncId, ScriptAsyncResult,
        },
        widget_tree::CxWidgetExt,
    },
};

script_mod! {
    use mod.prelude.widgets_internal.*

    mod.widgets.ViewBase = set_type_default() do #(View::register_widget(vm))
}

// maybe we should put an enum on the bools like

#[derive(Script, ScriptHook, Clone, Copy)]
pub enum ViewOptimize {
    #[pick]
    None,
    DrawList,
    Texture,
}

impl Default for ViewOptimize {
    fn default() -> Self {
        Self::None
    }
}

#[derive(Script, ScriptHook)]
pub enum EventOrder {
    Down,
    #[pick]
    Up,
    #[live(Default::default())]
    List(Vec<LiveId>),
}

impl ViewOptimize {
    fn is_texture(&self) -> bool {
        if let Self::Texture = self {
            true
        } else {
            false
        }
    }
    fn is_draw_list(&self) -> bool {
        if let Self::DrawList = self {
            true
        } else {
            false
        }
    }
    fn needs_draw_list(&self) -> bool {
        return self.is_texture() || self.is_draw_list();
    }
}

#[derive(Script, Animator, WidgetRef, WidgetSet, WidgetRegister)]
pub struct View {
    #[uid]
    uid: WidgetUid,
    #[source]
    pub source: ScriptObjectRef,
    // draw info per UI element
    #[live]
    pub draw_bg: DrawQuad,

    #[live(false)]
    pub show_bg: bool,

    #[layout]
    pub layout: Layout,

    #[walk]
    pub walk: Walk,

    //#[live] use_cache: bool,
    #[live]
    dpi_factor: Option<f64>,

    #[live(false)]
    pub new_batch: bool,

    #[live(false)]
    pub texture_caching: bool,

    #[rust]
    optimize: ViewOptimize,
    #[live]
    event_order: EventOrder,

    #[live(true)]
    pub visible: bool,
    #[live(false)]
    skip_widget_tree_search: bool,

    #[live(true)]
    grab_key_focus: bool,
    #[live(false)]
    block_signal_event: bool,
    #[live]
    pub cursor: Option<MouseCursor>,
    #[live(false)]
    capture_overload: bool,
    #[live]
    scroll_bars: ScriptObjectRef,

    #[live(false)]
    design_mode: bool,

    #[live(false)]
    pub debug_stream: bool,

    #[live]
    on_render: ScriptFnRef,

    #[rust]
    script_async: ScriptAsyncCalls,

    #[rust]
    scroll_bars_obj: Option<Box<ScrollBars>>,
    #[rust]
    view_size: Option<Vec2d>,
    // Forces the next Texture-mode draw to re-render its offscreen pass instead of cache-hitting.
    // Set on a repopulate or optimize-mode flip, since neither moves the rect that will_redraw sees.
    #[rust]
    force_texture_redraw: bool,
    // Caps the offscreen texture's height (in Texture mode only) so a huge Fit-height view never
    // allocates a render target past the GPU's max texture size. Content past the cap is clipped.
    #[rust]
    texture_max_height: Option<f64>,

    #[rust]
    area: Area,
    #[rust]
    draw_list: Option<DrawList2d>,

    #[rust]
    texture_cache: Option<ViewTextureCache>,
    #[rust]
    defer_walks: SmallVec<[(LiveId, DeferredWalk); 1]>,
    #[rust]
    draw_state: DrawStateWrap<DrawState>,
    #[rust]
    pub children: SmallVec<[(LiveId, WidgetRef); 2]>,
    #[rust]
    live_update_order: SmallVec<[LiveId; 1]>,

    #[apply_default]
    animator: Animator,
}

struct ViewTextureCache {
    pass: DrawPass,
    _depth_texture: Texture,
    color_texture: Texture,
}

impl ScriptHook for View {
    fn on_before_apply(
        &mut self,
        _vm: &mut ScriptVm,
        apply: &Apply,
        _scope: &mut Scope,
        _value: ScriptValue,
    ) {
        if apply.is_reload() {
            self.live_update_order.clear();
        }
    }

    fn on_after_apply(
        &mut self,
        vm: &mut ScriptVm,
        apply: &Apply,
        scope: &mut Scope,
        value: ScriptValue,
    ) {
        // Handle children from the object's vec
        // Skip for eval applies - eval should only affect this widget's own properties,
        // not propagate to children (which would use inherited vec from prototype)
        if !apply.is_eval() {
            if let Some(obj) = value.as_object() {
                let mut anon_index = 0usize;
                vm.vec_with(obj, |vm, vec| {
                    for kv in vec {
                        // Determine the id: use prefixed id if available, otherwise use numbered id for anonymous children
                        let id = if let Some(id) = kv.key.as_id() {
                            Some(id)
                        } else if kv.key.is_nil() {
                            // Anonymous child widget - use numbered id
                            let id = LiveId(anon_index as u64);
                            anon_index += 1;
                            Some(id)
                        } else {
                            None
                        };

                        if let Some(id) = id {
                            if !WidgetRef::value_is_newable_widget(vm, kv.value) {
                                continue;
                            }

                            if apply.is_reload() {
                                self.live_update_order.push(id);
                            }

                            if let Some((_, node)) =
                                self.children.iter_mut().find(|(id2, _)| *id2 == id)
                            {
                                node.script_apply(vm, apply, scope, kv.value);
                            } else {
                                let widget =
                                    WidgetRef::script_from_value_scoped(vm, scope, kv.value);
                                self.children.push((id, widget));
                            }
                        }
                    }
                });
            }
        }

        if apply.is_reload() {
            // update/delete children list
            // Only reorder and truncate if we actually processed items from the vec.
            // If vec was empty but children exist, this is likely an incomplete parse
            // during streaming - preserve existing children.
            if !self.live_update_order.is_empty() || self.children.is_empty() {
                for (idx, id) in self.live_update_order.iter().enumerate() {
                    if let Some(pos) = self.children.iter().position(|(i, _v)| *i == *id) {
                        self.children.swap(idx, pos);
                    }
                }
                self.children.truncate(self.live_update_order.len());
            }
        }

        if self.texture_caching {
            self.optimize = ViewOptimize::Texture;
        } else if self.new_batch {
            self.optimize = ViewOptimize::DrawList;
        }

        if self.optimize.needs_draw_list() && self.draw_list.is_none() {
            self.draw_list = Some(DrawList2d::script_new(vm));
        }
        if !self.scroll_bars.is_zero() {
            if self.scroll_bars_obj.is_none() {
                self.scroll_bars_obj = Some(Box::new(ScrollBars::script_from_value(
                    vm,
                    self.scroll_bars.as_object().into(),
                )));
            }
        }

        vm.cx_mut().widget_tree_mark_dirty(self.uid);
    }
}

#[derive(Clone, Debug, Default)]
pub enum ViewAction {
    #[default]
    None,
    FingerDown(FingerDownEvent),
    FingerUp(FingerUpEvent),
    FingerLongPress(FingerLongPressEvent),
    FingerMove(FingerMoveEvent),
    FingerHoverIn(FingerHoverEvent),
    FingerHoverOut(FingerHoverEvent),
    KeyDown(KeyEvent),
    KeyUp(KeyEvent),
}

impl View {
    /// Build the object `on_render` appends its children to. It is re-applied to this
    /// View with `Apply::Reload`, so whatever isn't reachable on its prototype chain
    /// reverts to the base widget's defaults.
    ///
    /// It therefore protos off the *instance* source — the declaration site — not the
    /// instance's template. Protoing off `source.proto` skipped the declaration level
    /// and silently dropped every property set there: `results := ScrollYView{height: 610}`
    /// re-applied as the base `height: Fill`, which a `Fit` parent defers to zero, so
    /// the view (and every rendered row in it) vanished after the first `render()`.
    ///
    /// `script_result` restores `self.source` afterwards, so the chain stays
    /// `me -> declaration` instead of growing a link per render. `no_vec` leaves `me`'s
    /// own vec empty so `on_render` fully owns the child list.
    fn make_render_me(&self, vm: &mut ScriptVm) -> ScriptValue {
        if self.source.is_zero() {
            return NIL;
        }

        vm.bx
            .heap
            .new_with_proto_no_vec(self.source.as_object().into())
            .into()
    }

    pub fn set_debug_dump(&mut self, cx: &mut Cx, debug: bool) {
        if let Some(draw_list) = &self.draw_list {
            cx.draw_lists[draw_list.id()].debug_dump = debug;
        }
    }

    pub fn repaint(&mut self, cx: &mut Cx) {
        if let Some(draw_list) = &self.draw_list {
            if let Some(pass_id) = cx.draw_lists[draw_list.id()].draw_pass_id {
                cx.repaint_pass(pass_id);
            }
        }
    }
}

impl ViewRef {
    pub fn set_debug_dump(&self, cx: &mut Cx, debug: bool) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.set_debug_dump(cx, debug);
        }
    }

    pub fn repaint(&self, cx: &mut Cx) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.repaint(cx);
        }
    }

    /// Forces the next Texture-mode draw to re-render its offscreen texture. Call after
    /// repopulating a texture-cached view whose content changed.
    pub fn redraw_texture_cache(&self) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.redraw_texture_cache();
        }
    }

    /// Caps the offscreen texture's height in Texture mode (`None` = uncapped). See the `View`
    /// method for details.
    pub fn set_texture_max_height(&self, max: Option<f64>) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.set_texture_max_height(max);
        }
    }

    pub fn finger_down(&self, actions: &Actions) -> Option<FingerDownEvent> {
        if let Some(item) = actions.find_widget_action(self.widget_uid()) {
            if let ViewAction::FingerDown(fd) = item.cast() {
                return Some(fd);
            }
        }
        None
    }

    pub fn finger_up(&self, actions: &Actions) -> Option<FingerUpEvent> {
        if let Some(item) = actions.find_widget_action(self.widget_uid()) {
            if let ViewAction::FingerUp(fd) = item.cast() {
                return Some(fd);
            }
        }
        None
    }

    pub fn finger_move(&self, actions: &Actions) -> Option<FingerMoveEvent> {
        if let Some(item) = actions.find_widget_action(self.widget_uid()) {
            if let ViewAction::FingerMove(fd) = item.cast() {
                return Some(fd);
            }
        }
        None
    }

    pub fn finger_hover_in(&self, actions: &Actions) -> Option<FingerHoverEvent> {
        if let Some(item) = actions.find_widget_action(self.widget_uid()) {
            if let ViewAction::FingerHoverIn(fd) = item.cast() {
                return Some(fd);
            }
        }
        None
    }

    pub fn finger_hover_out(&self, actions: &Actions) -> Option<FingerHoverEvent> {
        if let Some(item) = actions.find_widget_action(self.widget_uid()) {
            if let ViewAction::FingerHoverOut(fd) = item.cast() {
                return Some(fd);
            }
        }
        None
    }

    pub fn key_down(&self, actions: &Actions) -> Option<KeyEvent> {
        if let Some(item) = actions.find_widget_action(self.widget_uid()) {
            if let ViewAction::KeyDown(fd) = item.cast() {
                return Some(fd);
            }
        }
        None
    }

    pub fn key_up(&self, actions: &Actions) -> Option<KeyEvent> {
        if let Some(item) = actions.find_widget_action(self.widget_uid()) {
            if let ViewAction::KeyUp(fd) = item.cast() {
                return Some(fd);
            }
        }
        None
    }

    pub fn animator_cut(&self, cx: &mut Cx, state: &[LiveId; 2]) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.animator_cut(cx, state);
        }
    }

    pub fn animator_play(&self, cx: &mut Cx, state: &[LiveId; 2]) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.animator_play(cx, state);
        }
    }

    pub fn animator_play_with(&self, cx: &mut Cx, state: &[LiveId; 2], play: Play) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.animator_play_with(cx, state, play);
        }
    }

    pub fn toggle_state(
        &self,
        cx: &mut Cx,
        is_state_1: bool,
        animate: Animate,
        state1: &[LiveId; 2],
        state2: &[LiveId; 2],
    ) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.animator_toggle(cx, is_state_1, animate, state1, state2);
        }
    }

    pub fn set_visible(&self, cx: &mut Cx, visible: bool) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.set_visible(cx, visible)
        }
    }

    pub fn visible(&self) -> bool {
        if let Some(inner) = self.borrow() {
            inner.visible()
        } else {
            false
        }
    }

    pub fn set_texture(&self, slot: usize, texture: &Texture) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.draw_bg.set_texture(slot, texture);
        }
    }

    pub fn set_uniform(&self, cx: &Cx, uniform: LiveId, value: &[f32]) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.draw_bg.set_uniform(cx, uniform, value);
        }
    }

    pub fn set_scroll_pos(&self, cx: &mut Cx, v: Vec2d) {
        if let Some(mut inner) = self.borrow_mut() {
            inner.set_scroll_pos(cx, v)
        }
    }

    pub fn area(&self) -> Area {
        if let Some(inner) = self.borrow_mut() {
            inner.area
        } else {
            Area::Empty
        }
    }

    pub fn cached_texture_id(&self) -> Option<TextureId> {
        self.borrow().and_then(|inner| {
            inner
                .texture_cache
                .as_ref()
                .map(|cache| cache.color_texture.texture_id())
        })
    }

    pub fn child_count(&self) -> usize {
        if let Some(inner) = self.borrow_mut() {
            inner.children.len()
        } else {
            0
        }
    }

    pub fn set_key_focus(&self, cx: &mut Cx) {
        if let Some(inner) = self.borrow_mut() {
            inner.set_key_focus(cx);
        }
    }
}

impl ViewSet {
    pub fn animator_cut(&self, cx: &mut Cx, state: &[LiveId; 2]) {
        for item in self.iter() {
            item.animator_cut(cx, state)
        }
    }

    pub fn animator_play(&self, cx: &mut Cx, state: &[LiveId; 2]) {
        for item in self.iter() {
            item.animator_play(cx, state);
        }
    }

    pub fn animator_play_with(&self, cx: &mut Cx, state: &[LiveId; 2], play: Play) {
        for item in self.iter() {
            item.animator_play_with(cx, state, play);
        }
    }

    pub fn toggle_state(
        &self,
        cx: &mut Cx,
        is_state_1: bool,
        animate: Animate,
        state1: &[LiveId; 2],
        state2: &[LiveId; 2],
    ) {
        for item in self.iter() {
            item.toggle_state(cx, is_state_1, animate, state1, state2);
        }
    }

    pub fn set_visible(&self, cx: &mut Cx, visible: bool) {
        for item in self.iter() {
            item.set_visible(cx, visible)
        }
    }

    pub fn set_texture(&self, slot: usize, texture: &Texture) {
        for item in self.iter() {
            item.set_texture(slot, texture)
        }
    }

    pub fn set_uniform(&self, cx: &Cx, uniform: LiveId, value: &[f32]) {
        for item in self.iter() {
            item.set_uniform(cx, uniform, value)
        }
    }

    pub fn redraw(&self, cx: &mut Cx) {
        for item in self.iter() {
            item.redraw(cx);
        }
    }

    pub fn finger_down(&self, actions: &Actions) -> Option<FingerDownEvent> {
        for item in self.iter() {
            if let Some(e) = item.finger_down(actions) {
                return Some(e);
            }
        }
        None
    }

    pub fn finger_up(&self, actions: &Actions) -> Option<FingerUpEvent> {
        for item in self.iter() {
            if let Some(e) = item.finger_up(actions) {
                return Some(e);
            }
        }
        None
    }

    pub fn finger_move(&self, actions: &Actions) -> Option<FingerMoveEvent> {
        for item in self.iter() {
            if let Some(e) = item.finger_move(actions) {
                return Some(e);
            }
        }
        None
    }

    pub fn key_down(&self, actions: &Actions) -> Option<KeyEvent> {
        for item in self.iter() {
            if let Some(e) = item.key_down(actions) {
                return Some(e);
            }
        }
        None
    }

    pub fn key_up(&self, actions: &Actions) -> Option<KeyEvent> {
        for item in self.iter() {
            if let Some(e) = item.key_up(actions) {
                return Some(e);
            }
        }
        None
    }
}

impl WidgetNode for View {
    fn widget_uid(&self) -> WidgetUid {
        self.uid
    }
    fn walk(&mut self, _cx: &mut Cx) -> Walk {
        self.walk
    }

    fn area(&self) -> Area {
        self.area
    }

    fn set_scroll_pos(&mut self, cx: &mut Cx, v: Vec2d) {
        self.set_scroll_pos(cx, v);
    }

    fn redraw(&mut self, cx: &mut Cx) {
        self.area.redraw(cx);
        if let Some(draw_list) = &self.draw_list {
            draw_list.redraw(cx);
        }
        for (_, child) in &mut self.children {
            child.redraw(cx);
        }
    }

    fn children(&self, visit: &mut dyn FnMut(LiveId, WidgetRef)) {
        for (id, child) in &self.children {
            visit(*id, child.clone());
        }
    }

    fn skip_widget_tree_search(&self) -> bool {
        self.skip_widget_tree_search
    }

    fn find_widgets_from_point(&self, cx: &Cx, point: DVec2, found: &mut dyn FnMut(&WidgetRef)) {
        for (_, child) in &self.children {
            child.find_widgets_from_point(cx, point, found);
        }
    }

    fn selection_text_len(&self) -> usize {
        for (_, child) in &self.children {
            let v = child.selection_text_len();
            if v > 0 {
                return v;
            }
        }
        0
    }

    fn selection_point_to_char_index(&self, cx: &Cx, abs: DVec2) -> Option<usize> {
        for (_, child) in &self.children {
            if let Some(v) = child.selection_point_to_char_index(cx, abs) {
                return Some(v);
            }
        }
        None
    }

    fn selection_set(&mut self, anchor: usize, cursor: usize) {
        for (_, child) in &self.children {
            child.selection_set(anchor, cursor);
        }
    }

    fn selection_clear(&mut self) {
        for (_, child) in &self.children {
            child.selection_clear();
        }
    }

    fn selection_select_all(&mut self) {
        for (_, child) in &self.children {
            child.selection_select_all();
        }
    }

    fn selection_get_text_for_range(&self, start: usize, end: usize) -> String {
        for (_, child) in &self.children {
            let v = child.selection_get_text_for_range(start, end);
            if !v.is_empty() {
                return v;
            }
        }
        String::new()
    }

    fn selection_get_full_text(&self) -> String {
        for (_, child) in &self.children {
            let v = child.selection_get_full_text();
            if !v.is_empty() {
                return v;
            }
        }
        String::new()
    }

    fn set_visible(&mut self, cx: &mut Cx, visible: bool) {
        if self.visible != visible {
            self.visible = visible;
            // A view that has never drawn has an empty area, so its own
            // redraw is a no-op and the visibility change only lands on
            // the next unrelated full repaint (the classic "appears after
            // hot reload" bug). Escalate to a full redraw in that case.
            if visible && matches!(self.area, Area::Empty) {
                cx.redraw_all();
            } else {
                self.redraw(cx);
            }
        }
    }

    fn visible(&self) -> bool {
        self.visible
    }
}

impl Widget for View {
    fn script_call(
        &mut self,
        vm: &mut ScriptVm,
        method: LiveId,
        args: ScriptValue,
    ) -> ScriptAsyncResult {
        if method == live_id!(render) {
            let me = self.make_render_me(vm);
            return vm.with_cx_mut(|cx| {
                cx.widget_to_script_async_call_fwd(
                    self.uid,
                    &mut self.script_async,
                    me,
                    self.source.clone(),
                    self.on_render.clone(),
                    args,
                    id!(render),
                )
            });
        }
        if method == live_id!(set_visible) {
            if let Some(args_obj) = args.as_object() {
                let trap = vm.bx.threads.cur().trap.pass();
                let value = vm.bx.heap.vec_value(args_obj, 0, trap);
                let visible = value
                    .as_bool()
                    .or_else(|| value.as_number().map(|n| n != 0.0));
                match visible {
                    Some(visible) => {
                        vm.with_cx_mut(|cx| {
                            if self.visible != visible {
                                self.visible = visible;
                                self.redraw(cx);
                            }
                        });
                    }
                    // Never guess on a bad argument: a silent default (especially
                    // `true`) turns script bugs into invisible misbehavior. Keep
                    // the current visibility and surface an error instead.
                    None => {
                        return ScriptAsyncResult::Return(script_err_wrong_value!(
                            vm.trap(),
                            "set_visible expects a bool (or number), got {:?}",
                            value.value_type()
                        ));
                    }
                }
            }
            return ScriptAsyncResult::Return(NIL);
        }
        ScriptAsyncResult::MethodNotFound
    }

    fn script_result(&mut self, vm: &mut ScriptVm, id: ScriptAsyncId, result: ScriptValue) {
        let Some(call) = self.script_async.take(id) else {
            return;
        };

        if call.method() == id!(render) {
            if result.is_err() {
                // An error mid-closure abandons every child emitted before it
                // and used to do so with ZERO diagnostics — the "on_render
                // silently renders nothing" family cost days to bisect. Say
                // what happened.
                let msg = vm.bx.heap.temp_string_with(|heap, out| {
                    heap.cast_to_string(result, out);
                    out.to_string()
                });
                error!("on_render closure failed; discarding its output: {msg}");
                return;
            }
            if let Some(me_obj) = call.me().as_object() {
                // The closure's FINAL statement becomes its return value (the
                // parser converts the last commit into a RETURN), so a widget
                // emitted last would otherwise vanish. Commit it as the last
                // child; non-widget values are skipped downstream anyway.
                if let Some(ret_obj) = result.as_object() {
                    if ret_obj != me_obj {
                        // Unchecked: `me` is this render's own throwaway
                        // object (make_render_me), never frozen.
                        vm.bx.heap.vec_push_unchecked(me_obj, NIL, result);
                    }
                }
                // `#[source]` is reassigned by any non-eval script apply, so this Reload
                // would leave `source` pointing at `me`. Keep it on the declaration object:
                // the next `make_render_me` protos off it (see there), and `me` is a
                // throwaway whose children already hold their own refs.
                let declaration = self.source.clone();
                self.script_apply(vm, &Apply::Reload, &mut Scope::empty(), me_obj.into());
                self.source = declaration;
                self.redraw(vm.cx_mut());
            }
        }
    }

    fn is_interactive(&self) -> bool {
        self.cursor.is_some() || self.animator.is_defined
    }

    fn handle_event(&mut self, cx: &mut Cx, event: &Event, scope: &mut Scope) {
        if !self.visible && event.requires_visibility() {
            return;
        }

        let uid = self.widget_uid();
        if self.animator_handle_event(cx, event).must_redraw() {
            self.redraw(cx);
        }

        if self.block_signal_event {
            if let Event::Signal = event {
                return;
            }
        }
        if let Event::ClearHover = event {
            if self.animator.is_defined {
                self.animator_play(cx, ids!(hover.off));
                self.animator_play(cx, ids!(down.off));
            }
        }
        // A press that catches an in-progress momentum fling stops the scroll and is consumed:
        // it must not also activate a child widget under the finger, as on iOS, Android, and
        // macOS. So when the scroll bars report a caught fling, skip dispatching this press to
        // children. This runs before the child loop below, since children would otherwise
        // capture the press first.
        let mut fling_caught = false;
        if let Some(scroll_bars) = &mut self.scroll_bars_obj {
            let mut actions = Vec::new();
            scroll_bars.handle_main_event(cx, event, scope, &mut actions);
            if actions.len() > 0 {
                cx.redraw_area_and_children(self.area);
            };
            fling_caught = scroll_bars.catch_fling_on_press(cx, event);
        }

        if !fling_caught {
            match &self.event_order {
                EventOrder::Up => {
                    for (_id, child) in self.children.iter_mut().rev() {
                        child.handle_event(cx, event, scope);
                    }
                }
                EventOrder::Down => {
                    for (_id, child) in self.children.iter_mut() {
                        child.handle_event(cx, event, scope);
                    }
                }
                EventOrder::List(list) => {
                    for id in list {
                        if let Some((_, child)) =
                            self.children.iter_mut().find(|(id2, _)| id2 == id)
                        {
                            child.handle_event(cx, event, scope);
                        }
                    }
                }
            }
        }

        event.hit_tweak_ray(self.area(), self.widget_uid());

        // Also skip this View's own press-driven hit handling when a fling was caught, so the
        // catching press is fully consumed (it neither activates a child nor fires this
        // View's own FingerDown/animator). `fling_caught` is only ever true on a press event
        // over a flinging scroll view, so key/hover handling is unaffected.
        if !fling_caught && (self.visible && self.cursor.is_some() || self.animator.is_defined) {
            match event.hits_with_capture_overload(cx, self.area(), self.capture_overload) {
                Hit::FingerDown(e) => {
                    if self.grab_key_focus {
                        cx.set_key_focus(self.area());
                    }
                    cx.widget_action(uid, ViewAction::FingerDown(e));
                    if self.animator.is_defined {
                        self.animator_play(cx, ids!(down.on));
                    }
                }
                Hit::FingerMove(e) => cx.widget_action(uid, ViewAction::FingerMove(e)),
                Hit::FingerLongPress(e) => cx.widget_action(uid, ViewAction::FingerLongPress(e)),
                Hit::FingerUp(e) => {
                    cx.widget_action(uid, ViewAction::FingerUp(e));
                    if self.animator.is_defined {
                        self.animator_play(cx, ids!(down.off));
                    }
                }
                Hit::FingerHoverIn(e) => {
                    cx.widget_action(uid, ViewAction::FingerHoverIn(e));
                    if let Some(cursor) = &self.cursor {
                        cx.set_cursor(*cursor);
                    }
                    if self.animator.is_defined {
                        self.animator_play(cx, ids!(hover.on));
                    }
                }
                Hit::FingerHoverOut(e) => {
                    cx.widget_action(uid, ViewAction::FingerHoverOut(e));
                    if self.animator.is_defined {
                        self.animator_play(cx, ids!(hover.off));
                    }
                }
                Hit::KeyDown(e) => cx.widget_action(uid, ViewAction::KeyDown(e)),
                Hit::KeyUp(e) => cx.widget_action(uid, ViewAction::KeyUp(e)),
                _ => (),
            }
        }

        if let Some(scroll_bars) = &mut self.scroll_bars_obj {
            scroll_bars.handle_scroll_event(cx, event, scope, &mut Vec::new());
        }
    }

    fn draw_walk(&mut self, cx: &mut Cx2d, scope: &mut Scope, walk: Walk) -> DrawStep {
        // the beginning state
        if self.draw_state.begin(cx, DrawState::Drawing(0, false)) {
            if !self.visible {
                self.draw_state.end();
                return DrawStep::done();
            }

            self.defer_walks.clear();

            match self.optimize {
                ViewOptimize::Texture => {
                    let walk = self.walk_from_previous_size(walk);
                    // A repopulate or optimize-mode flip forces one real re-render: the size-based
                    // cache check can't see content changes on a recycled/toggled view.
                    let force = std::mem::take(&mut self.force_texture_redraw);
                    // Re-render whenever the on-screen rect changes (position or size) or a
                    // repopulate/mode-flip forced it; only a truly unchanged view cache-hits.
                    if !force && !cx.will_redraw(self.draw_list.as_mut().unwrap(), walk) {
                        if let Some(texture_cache) = &self.texture_cache {
                            self.draw_bg
                                .draw_vars
                                .set_texture(0, &texture_cache.color_texture);
                            let mut rect = cx.walk_turtle_with_area(&mut self.area, walk);
                            // NOTE(eddyb) see comment lower below for why this is
                            // disabled (it used to match `set_pass_scaled_area`).
                            if false {
                                rect.size *= 2.0 / self.dpi_factor.unwrap_or(1.0);
                            }
                            self.draw_bg.draw_abs(cx, rect);
                            self.area = self.draw_bg.area();
                            /*if false {
                                // FIXME(eddyb) this was the previous logic,
                                // but the only tested apps that use `CachedView`
                                // are sized correctly (regardless of `dpi_factor`)
                                // *without* extra scaling here.
                                cx.set_pass_scaled_area(
                                    &texture_cache.pass,
                                    self.area,
                                    2.0 / self.dpi_factor.unwrap_or(1.0),
                                );
                            } else {*/
                            cx.set_pass_area(&texture_cache.pass, self.area);
                            //}
                        }
                        return DrawStep::done();
                    }
                    // lets start a pass
                    if self.texture_cache.is_none() {
                        self.texture_cache = Some(ViewTextureCache {
                            pass: DrawPass::new(cx),
                            _depth_texture: Texture::new(cx),
                            color_texture: Texture::new(cx),
                        });
                        let texture_cache = self.texture_cache.as_mut().unwrap();
                        //cache.pass.set_depth_texture(cx, &cache.depth_texture, PassClearDepth::ClearWith(1.0));
                        texture_cache.color_texture = Texture::new_with_format(
                            cx,
                            TextureFormat::RenderBGRAu8 {
                                size: TextureSize::Auto,
                                initial: true,
                            },
                        );
                        texture_cache.pass.set_color_texture(
                            cx,
                            &texture_cache.color_texture,
                            DrawPassClearColor::ClearWith(vec4(0.0, 0.0, 0.0, 0.0)),
                        );
                    }
                    let texture_cache = self.texture_cache.as_mut().unwrap();
                    cx.make_child_pass(&texture_cache.pass);
                    cx.begin_pass(&texture_cache.pass, self.dpi_factor);
                    self.draw_list.as_mut().unwrap().begin_always(cx)
                }
                ViewOptimize::DrawList => {
                    let walk = self.walk_from_previous_size(walk);
                    if self
                        .draw_list
                        .as_mut()
                        .unwrap()
                        .begin(cx, walk)
                        .is_not_redrawing()
                    {
                        cx.walk_turtle_with_area(&mut self.area, walk);
                        return DrawStep::done();
                    }
                }
                _ => (),
            }

            // ok so.. we have to keep calling draw till we return LiveId(0)
            let scroll = if let Some(scroll_bars) = &mut self.scroll_bars_obj {
                scroll_bars.begin_nav_area(cx);
                scroll_bars.get_scroll_pos()
            } else {
                self.layout.scroll
            };

            // Only Texture mode allocates an offscreen render target sized to this turtle, so cap
            // its height there. None/DrawList render into the parent turtle and must stay uncapped.
            let walk = if self.optimize.is_texture() {
                self.walk_with_texture_max_height(walk)
            } else {
                walk
            };

            if self.show_bg {
                /*if let Some(image_texture) = &self.image_texture {
                    self.draw_bg.draw_vars.set_texture(0, image_texture);
                }*/
                self.draw_bg
                    .begin(cx, walk, self.layout.with_scroll(scroll)); //.with_scale(2.0 / self.dpi_factor.unwrap_or(2.0)));
            } else {
                cx.begin_turtle(walk, self.layout.with_scroll(scroll)); //.with_scale(2.0 / self.dpi_factor.unwrap_or(2.0)));
            }
        }

        while let Some(DrawState::Drawing(step, resume)) = self.draw_state.get() {
            if step < self.children.len() {
                //let id = self.draw_order[step];
                if let Some((id, child)) = self.children.get_mut(step) {
                    if child.visible() {
                        let walk = child.walk(cx);
                        if resume {
                            child.draw_walk(cx, scope, walk)?;
                        } else if let Some(fw) = cx.defer_walk_turtle(walk) {
                            self.defer_walks.push((*id, fw));
                        } else {
                            self.draw_state.set(DrawState::Drawing(step, true));
                            child.draw_walk(cx, scope, walk)?;
                        }
                    }
                }
                self.draw_state.set(DrawState::Drawing(step + 1, false));
            } else {
                self.draw_state.set(DrawState::DeferWalk(0));
            }
        }

        while let Some(DrawState::DeferWalk(step)) = self.draw_state.get() {
            if step < self.defer_walks.len() {
                let (id, dw) = &mut self.defer_walks[step];
                if let Some((_id, child)) = self.children.iter_mut().find(|(id2, _)| id2 == id) {
                    let walk = dw.resolve(cx);
                    child.draw_walk(cx, scope, walk)?;
                }
                self.draw_state.set(DrawState::DeferWalk(step + 1));
            } else {
                if let Some(scroll_bars) = &mut self.scroll_bars_obj {
                    scroll_bars.draw_scroll_bars(cx);
                };

                if self.show_bg {
                    if self.optimize.is_texture() {
                        panic!("dont use show_bg and texture caching at the same time");
                    }
                    self.draw_bg.end(cx);
                    self.area = self.draw_bg.area();
                } else {
                    cx.end_turtle_with_area(&mut self.area);
                };

                if let Some(scroll_bars) = &mut self.scroll_bars_obj {
                    scroll_bars.set_area(self.area);
                    scroll_bars.end_nav_area(cx);
                };

                // Track measured size in every mode. The None path must update it too, or a later
                // Texture draw sizes its offscreen turtle to a stale height and clips the content.
                self.view_size = Some(self.area.rect(cx).size);

                if self.optimize.needs_draw_list() {
                    let rect = self.area.rect(cx);
                    self.draw_list.as_mut().unwrap().end(cx);

                    if self.optimize.is_texture() {
                        let texture_cache = self.texture_cache.as_mut().unwrap();
                        cx.end_pass(&texture_cache.pass);
                        /*if cache.pass.id_equals(4){
                            self.draw_bg.draw_vars.set_uniform(cx, id!(marked),&[1.0]);
                        }
                        else{
                            self.draw_bg.draw_vars.set_uniform(cx, id!(marked),&[0.0]);
                        }*/
                        self.draw_bg
                            .draw_vars
                            .set_texture(0, &texture_cache.color_texture);
                        self.draw_bg.draw_abs(cx, rect);
                        let area = self.draw_bg.area();
                        let texture_cache = self.texture_cache.as_mut().unwrap();
                        /* if false {
                            // FIXME(eddyb) this was the previous logic,
                            // but the only tested apps that use `CachedView`
                            // are sized correctly (regardless of `dpi_factor`)
                            // *without* extra scaling here.
                            cx.set_pass_scaled_area(
                                &texture_cache.pass,
                                area,
                                2.0 / self.dpi_factor.unwrap_or(1.0),
                            );
                        } else {*/
                        cx.set_pass_area(&texture_cache.pass, area);
                        //}
                    }
                }
                self.draw_state.end();
            }
        }
        DrawStep::done()
    }
}

trait EventTweakRayExt {
    fn hit_tweak_ray(&self, area: Area, widget_uid: WidgetUid);
}

impl EventTweakRayExt for Event {
    fn hit_tweak_ray(&self, area: Area, widget_uid: WidgetUid) {
        if let Event::TweakRay(e) = self {
            if !area.is_empty() {
                e.hit_widget_uids.borrow_mut().push(widget_uid.0);
            }
        }
    }
}

#[derive(Clone)]
enum DrawState {
    Drawing(usize, bool),
    DeferWalk(usize),
}

impl View {
    pub fn swap_child(&mut self, pos_a: usize, pos_b: usize) {
        self.children.swap(pos_a, pos_b);
    }

    pub fn child_index(&mut self, comp: &WidgetRef) -> Option<usize> {
        if let Some(pos) = self.children.iter().position(|(_, w)| w == comp) {
            Some(pos)
        } else {
            None
        }
    }

    pub fn child_at_index(&mut self, index: usize) -> Option<&WidgetRef> {
        if let Some(f) = self.children.get(index) {
            Some(&f.1)
        } else {
            None
        }
    }

    pub fn set_scroll_pos(&mut self, cx: &mut Cx, v: Vec2d) {
        if let Some(scroll_bars) = &mut self.scroll_bars_obj {
            scroll_bars.set_scroll_pos(cx, v);
        } else {
            self.layout.scroll = v;
        }
    }

    pub fn area(&self) -> Area {
        self.area
    }

    /// Switch this view's draw optimization at runtime (e.g. toggle texture caching per frame).
    /// Allocates the backing draw_list on demand when promoting to a draw-list-backed mode.
    pub fn set_optimize(&mut self, cx: &mut Cx, optimize: ViewOptimize) {
        // A mode flip (e.g. None<->Texture) is a guaranteed content/layout change, and the None
        // path never updates view_size, so force one fresh texture re-render on the change.
        if core::mem::discriminant(&self.optimize) != core::mem::discriminant(&optimize) {
            self.redraw_texture_cache();
        }
        self.optimize = optimize;
        if self.optimize.needs_draw_list() && self.draw_list.is_none() {
            self.draw_list = Some(DrawList2d::new(cx));
        }
    }

    /// Forces the next Texture-mode draw to re-render its offscreen texture instead of compositing
    /// the cached one, and drops the stale measured size so the re-render sizes to the new content.
    /// Call after repopulating a texture-cached view's children.
    pub fn redraw_texture_cache(&mut self) {
        self.force_texture_redraw = true;
        self.view_size = None;
    }

    /// Caps the offscreen texture's height when this view is in Texture mode. `None` (the default)
    /// leaves it uncapped. Only useful for a Fit-height cached view whose content can be taller than
    /// the GPU's max texture size; content past the cap is clipped.
    pub fn set_texture_max_height(&mut self, max: Option<f64>) {
        if self.texture_max_height != max {
            self.texture_max_height = max;
            self.redraw_texture_cache();
        }
    }

    fn walk_with_texture_max_height(&self, walk: Walk) -> Walk {
        match self.texture_max_height {
            Some(max) if !walk.height.is_fill() => Walk { height: Size::Fixed(max), ..walk },
            _ => walk,
        }
    }

    pub fn walk_from_previous_size(&self, walk: Walk) -> Walk {
        // Fill and Fixed sizes are already known before drawing, so keep them live —
        // a Fixed size can be fresh truth for this frame (e.g. a deferred fill the
        // parent just resolved), and pinning it to the previous frame's measurement
        // would make the cached-draw dirty check miss a pure size change. Only
        // content-driven sizes fall back to the previous measurement, since they
        // cannot be known before the children draw.
        let view_size = self.view_size.unwrap_or(Vec2d::default());
        Walk {
            abs_pos: walk.abs_pos,
            width: if walk.width.is_fill() || walk.width.is_fixed() {
                walk.width
            } else {
                Size::Fixed(view_size.x)
            },
            height: if walk.height.is_fill() || walk.height.is_fixed() {
                walk.height
            } else {
                Size::Fixed(view_size.y)
            },
            margin: walk.margin,
            metrics: Metrics::default(),
        }
    }

    pub fn child_count(&self) -> usize {
        self.children.len()
    }

    pub fn debug_print_children(&self) {
        // Debug output removed
    }

    pub fn debug_props(&self) -> String {
        format!(
            "walk=({:?},{:?}) flow={:?} show_bg={} visible={} padding=({},{},{},{}) spacing={:?}",
            self.walk.width,
            self.walk.height,
            self.layout.flow,
            self.show_bg,
            self.visible,
            self.layout.padding.left,
            self.layout.padding.top,
            self.layout.padding.right,
            self.layout.padding.bottom,
            self.layout.spacing
        )
    }

    pub fn debug_dump_tree(&self, depth: usize) -> String {
        let mut out = String::new();
        let indent = "  ".repeat(depth);
        out.push_str(&format!("{}View {{ {} }}\n", indent, self.debug_props()));
        for (id, child) in &self.children {
            out.push_str(&format!("{}  [id={:?}] ", indent, id));
            if let Some(view) = child.borrow_mut::<View>() {
                out.push_str(&format!("\n{}", view.debug_dump_tree(depth + 2)));
            } else {
                let text = child.text();
                if text.is_empty() {
                    out.push_str("<widget>\n");
                } else {
                    out.push_str(&format!("<widget text={:?}>\n", text));
                }
            }
        }
        out
    }

    pub fn set_key_focus(&self, cx: &mut Cx) {
        cx.set_key_focus(self.draw_bg.area());
    }
}