1// Copyright © SixtyFPS GmbH <info@slint.dev>
2// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
3
4//! Remove the rectangles that serves no purposes
5//!
6//! Rectangles which do not draw anything and have no x or y don't need to be in
7//! the item tree, we can just remove them.
8
9use crate::langtype::ElementType;
10use crate::object_tree::*;
11use std::rc::Rc;
12
13pub fn optimize_useless_rectangles(root_component: &Rc<Component>) {
14 recurse_elem_including_sub_components(root_component, &(), &mut |parent_, _| {
15 let mut parent = parent_.borrow_mut();
16 let children = std::mem::take(&mut parent.children);
17
18 for elem in children {
19 if !can_optimize(&elem) {
20 parent.children.push(elem);
21 continue;
22 }
23
24 parent.children.extend(std::mem::take(&mut elem.borrow_mut().children));
25 if let Some(last) = parent.debug.last_mut() {
26 last.element_boundary = true;
27 }
28 parent.debug.extend(std::mem::take(&mut elem.borrow_mut().debug));
29
30 let enclosing = parent.enclosing_component.upgrade().unwrap();
31
32 for popup in enclosing.popup_windows.borrow_mut().iter_mut() {
33 if Rc::ptr_eq(&popup.parent_element, &elem) {
34 // parent element is use for x/y, and the position of the removed element is 0,0
35 popup.parent_element = parent_.clone();
36 }
37 }
38
39 enclosing.optimized_elements.borrow_mut().push(elem);
40 }
41 });
42}
43
44/// Check that this is a element we can optimize
45fn can_optimize(elem: &ElementRc) -> bool {
46 let e = elem.borrow();
47 if e.is_flickable_viewport || e.has_popup_child || e.is_component_placeholder {
48 return false;
49 };
50
51 if e.child_of_layout {
52 // The `LayoutItem` still has reference to this component, so we cannot remove it
53 return false;
54 }
55
56 let base_type = match &e.base_type {
57 ElementType::Builtin(base_type) if base_type.name == "Rectangle" => base_type,
58 ElementType::Builtin(base_type) if base_type.native_class.class_name == "Empty" => {
59 base_type
60 }
61 _ => return false,
62 };
63
64 let analysis = e.property_analysis.borrow();
65 for coord in ["x", "y"] {
66 if e.bindings.contains_key(coord) || analysis.get(coord).is_some_and(|a| a.is_set) {
67 return false;
68 }
69 }
70 if analysis.get("absolute-position").is_some_and(|a| a.is_read) {
71 return false;
72 }
73
74 // Check that no Rectangle property are set
75 !e.bindings.keys().chain(analysis.iter().filter(|(_, v)| v.is_set).map(|(k, _)| k)).any(|k| {
76 !e.property_declarations.contains_key(k.as_str())
77 && base_type.properties.contains_key(k.as_str())
78 }) && e.accessibility_props.0.is_empty()
79}
80