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use bitflags::bitflags;
use std::borrow::Cow;
use std::ptr;
use crate::imgui::string::ImStr;
use crate::imgui::Ui;
// TODO: support size constraints
/// Combo box height mode.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum ComboBoxHeight {
/// Max ~4 items visible.
Small,
/// Max ~8 items visible.
Regular,
/// Max ~20 items visible.
Large,
/// As many fitting items as possible visible.
Largest,
}
/// Combo box preview mode.
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum ComboBoxPreviewMode {
/// Show only a box with the preview value
Label,
/// Show only an arrow button
ArrowButton,
/// Show a box with the preview value and an arrow button
Full,
}
bitflags!(
/// Flags for combo boxes
#[repr(transparent)]
pub struct ComboBoxFlags: u32 {
/// Align the popup toward the left by default
const POPUP_ALIGN_LEFT = crate::imgui_sys::ImGuiComboFlags_PopupAlignLeft;
/// Max ~4 items visible.
const HEIGHT_SMALL = crate::imgui_sys::ImGuiComboFlags_HeightSmall;
/// Max ~8 items visible (default)
const HEIGHT_REGULAR = crate::imgui_sys::ImGuiComboFlags_HeightRegular;
/// Max ~20 items visible
const HEIGHT_LARGE = crate::imgui_sys::ImGuiComboFlags_HeightLarge;
/// As many fitting items as possible
const HEIGHT_LARGEST = crate::imgui_sys::ImGuiComboFlags_HeightLargest;
/// Display on the preview box without the square arrow button
const NO_ARROW_BUTTON = crate::imgui_sys::ImGuiComboFlags_NoArrowButton;
/// Display only a square arrow button
const NO_PREVIEW = crate::imgui_sys::ImGuiComboFlags_NoPreview;
}
);
/// Builder for a combo box widget
#[derive(Copy, Clone, Debug)]
#[must_use]
pub struct ComboBox<'a> {
label: &'a ImStr,
preview_value: Option<&'a ImStr>,
flags: ComboBoxFlags,
}
impl<'a> ComboBox<'a> {
/// Constructs a new combo box builder.
#[doc(alias = "BeginCombo")]
pub const fn new(label: &'a ImStr) -> ComboBox<'a> {
ComboBox {
label,
preview_value: None,
flags: ComboBoxFlags::empty(),
}
}
/// Sets the preview value displayed in the preview box (if visible).
#[inline]
pub const fn preview_value(mut self, preview_value: &'a ImStr) -> Self {
self.preview_value = Some(preview_value);
self
}
/// Replaces all current settings with the given flags.
#[inline]
pub const fn flags(mut self, flags: ComboBoxFlags) -> Self {
self.flags = flags;
self
}
/// Enables/disables aligning the combo box popup toward the left.
///
/// Disabled by default.
#[inline]
pub fn popup_align_left(mut self, popup_align_left: bool) -> Self {
self.flags
.set(ComboBoxFlags::POPUP_ALIGN_LEFT, popup_align_left);
self
}
/// Sets the combo box height.
///
/// Default: `ComboBoxHeight::Regular`
#[inline]
pub fn height(mut self, height: ComboBoxHeight) -> Self {
self.flags
.set(ComboBoxFlags::HEIGHT_SMALL, height == ComboBoxHeight::Small);
self.flags.set(
ComboBoxFlags::HEIGHT_REGULAR,
height == ComboBoxHeight::Regular,
);
self.flags
.set(ComboBoxFlags::HEIGHT_LARGE, height == ComboBoxHeight::Large);
self.flags.set(
ComboBoxFlags::HEIGHT_LARGEST,
height == ComboBoxHeight::Largest,
);
self
}
/// Sets the combo box preview mode.
///
/// Default: `ComboBoxPreviewMode::Full`
#[inline]
pub fn preview_mode(mut self, preview_mode: ComboBoxPreviewMode) -> Self {
self.flags.set(
ComboBoxFlags::NO_ARROW_BUTTON,
preview_mode == ComboBoxPreviewMode::Label,
);
self.flags.set(
ComboBoxFlags::NO_PREVIEW,
preview_mode == ComboBoxPreviewMode::ArrowButton,
);
self
}
/// Creates a combo box and starts appending to it.
///
/// Returns `Some(ComboBoxToken)` if the combo box is open. After content has been
/// rendered, the token must be ended by calling `.end()`.
///
/// Returns `None` if the combo box is not open and no content should be rendered.
#[must_use]
pub fn begin<'ui>(self, ui: &Ui<'ui>) -> Option<ComboBoxToken<'ui>> {
let should_render = unsafe {
crate::imgui_sys::igBeginCombo(
self.label.as_ptr(),
self.preview_value.map(ImStr::as_ptr).unwrap_or(ptr::null()),
self.flags.bits() as i32,
)
};
if should_render {
Some(ComboBoxToken::new(ui))
} else {
None
}
}
/// Creates a combo box and runs a closure to construct the popup contents.
/// Returns the result of the closure, if it is called.
///
/// Note: the closure is not called if the combo box is not open.
pub fn build<T, F: FnOnce() -> T>(self, ui: &Ui, f: F) -> Option<T> {
self.begin(ui).map(|_combo| f())
}
}
create_token!(
/// Tracks a combo box that can be ended by calling `.end()`
/// or by dropping.
pub struct ComboBoxToken<'ui>;
/// Ends a combo box
drop { crate::imgui_sys::igEndCombo() }
);
/// # Convenience functions
impl<'a> ComboBox<'a> {
/// Builds a simple combo box for choosing from a slice of values
#[doc(alias = "BeginCombo")]
pub fn build_simple<T, L>(
self,
ui: &Ui,
current_item: &mut usize,
items: &[T],
label_fn: &L,
) -> bool
where
for<'b> L: Fn(&'b T) -> Cow<'b, ImStr>,
{
use crate::imgui::widget::selectable::Selectable;
let mut result = false;
let mut cb = self;
let preview_value = items.get(*current_item).map(label_fn);
if cb.preview_value.is_none() {
if let Some(preview_value) = preview_value.as_ref() {
cb = cb.preview_value(preview_value);
}
}
if let Some(_cb) = cb.begin(ui) {
for (idx, item) in items.iter().enumerate() {
let text = label_fn(item);
let selected = idx == *current_item;
if Selectable::new(&text).selected(selected).build(ui) {
*current_item = idx;
result = true;
}
}
}
result
}
/// Builds a simple combo box for choosing from a slice of strings
#[doc(alias = "BeginCombo")]
pub fn build_simple_string<S>(self, ui: &Ui, current_item: &mut usize, items: &[&S]) -> bool
where
S: AsRef<ImStr> + ?Sized,
{
self.build_simple(ui, current_item, items, &|&s| s.as_ref().into())
}
}