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nih-plug/nih_plug_egui/src/widgets/param_slider.rs
2022-10-22 00:14:13 +02:00

350 lines
13 KiB
Rust

use std::sync::Arc;
use egui::{vec2, Key, Response, Sense, Stroke, TextEdit, TextStyle, Ui, Vec2, Widget, WidgetText};
use lazy_static::lazy_static;
use nih_plug::prelude::{Param, ParamSetter};
use parking_lot::Mutex;
use super::util;
/// When shift+dragging a parameter, one pixel dragged corresponds to this much change in the
/// noramlized parameter.
const GRANULAR_DRAG_MULTIPLIER: f32 = 0.0015;
lazy_static! {
static ref DRAG_NORMALIZED_START_VALUE_MEMORY_ID: egui::Id = egui::Id::new((file!(), 0));
static ref DRAG_AMOUNT_MEMORY_ID: egui::Id = egui::Id::new((file!(), 1));
static ref VALUE_ENTRY_MEMORY_ID: egui::Id = egui::Id::new((file!(), 2));
}
/// A slider widget similar to [`egui::widgets::Slider`] that knows about NIH-plug parameters ranges
/// and can get values for it. The slider supports double click and control click to reset,
/// shift+drag for granular dragging, text value entry by clicking on the value text.
///
/// TODO: Vertical orientation
/// TODO: Check below for more input methods that should be added
/// TODO: Decouple the logic from the drawing so we can also do things like nobs without having to
/// repeat everything
/// TODO: Add WidgetInfo annotations for accessibility
#[must_use = "You should put this widget in an ui with `ui.add(widget);`"]
pub struct ParamSlider<'a, P: Param> {
param: &'a P,
setter: &'a ParamSetter<'a>,
draw_value: bool,
slider_width: Option<f32>,
/// Will be set in the `ui()` function so we can request keyboard input focus on Alt+click.
keyboard_focus_id: Option<egui::Id>,
}
impl<'a, P: Param> ParamSlider<'a, P> {
/// Create a new slider for a parameter. Use the other methods to modify the slider before
/// passing it to [`Ui::add()`].
pub fn for_param(param: &'a P, setter: &'a ParamSetter<'a>) -> Self {
Self {
param,
setter,
draw_value: true,
slider_width: None,
keyboard_focus_id: None,
}
}
/// Don't draw the text slider's current value after the slider.
pub fn without_value(mut self) -> Self {
self.draw_value = false;
self
}
/// Set a custom width for the slider.
pub fn with_width(mut self, width: f32) -> Self {
self.slider_width = Some(width);
self
}
fn plain_value(&self) -> P::Plain {
self.param.plain_value()
}
fn normalized_value(&self) -> f32 {
self.param.normalized_value()
}
fn string_value(&self) -> String {
self.param.to_string()
}
/// Enable the keyboard entry part of the widget.
fn begin_keyboard_entry(&self, ui: &Ui) {
ui.memory().request_focus(self.keyboard_focus_id.unwrap());
// Always initialize the field to the current value, that seems nicer than having to
// being typing from scratch
let value_entry_mutex = ui
.memory()
.data
.get_temp_mut_or_default::<Arc<Mutex<String>>>(*VALUE_ENTRY_MEMORY_ID)
.clone();
*value_entry_mutex.lock() = self.string_value();
}
fn keyboard_entry_active(&self, ui: &Ui) -> bool {
ui.memory().has_focus(self.keyboard_focus_id.unwrap())
}
fn begin_drag(&self) {
self.setter.begin_set_parameter(self.param);
}
fn set_normalized_value(&self, normalized: f32) {
// This snaps to the nearest plain value if the parameter is stepped in some way.
// TODO: As an optimization, we could add a `const CONTINUOUS: bool` to the parameter to
// avoid this normalized->plain->normalized conversion for parameters that don't need
// it
let value = self.param.preview_plain(normalized);
if value != self.plain_value() {
self.setter.set_parameter(self.param, value);
}
}
/// Begin and end drag still need to be called when using this. Returns `false` if the string
/// could no tbe parsed.
fn set_from_string(&self, string: &str) -> bool {
match self.param.string_to_normalized_value(string) {
Some(normalized_value) => {
self.set_normalized_value(normalized_value);
true
}
None => false,
}
}
/// Begin and end drag still need to be called when using this..
fn reset_param(&self) {
self.setter
.set_parameter(self.param, self.param.default_plain_value());
}
fn granular_drag(&self, ui: &Ui, drag_delta: Vec2) {
// Remember the intial position when we started with the granular drag. This value gets
// reset whenever we have a normal itneraction with the slider.
let start_value = if Self::get_drag_amount_memory(ui) == 0.0 {
Self::set_drag_normalized_start_value_memory(ui, self.normalized_value());
self.normalized_value()
} else {
Self::get_drag_normalized_start_value_memory(ui)
};
let total_drag_distance = drag_delta.x + Self::get_drag_amount_memory(ui);
Self::set_drag_amount_memory(ui, total_drag_distance);
self.set_normalized_value(
(start_value + (total_drag_distance * GRANULAR_DRAG_MULTIPLIER)).clamp(0.0, 1.0),
);
}
fn end_drag(&self) {
self.setter.end_set_parameter(self.param);
}
fn get_drag_normalized_start_value_memory(ui: &Ui) -> f32 {
ui.memory()
.data
.get_temp(*DRAG_NORMALIZED_START_VALUE_MEMORY_ID)
.unwrap_or(0.5)
}
fn set_drag_normalized_start_value_memory(ui: &Ui, amount: f32) {
ui.memory()
.data
.insert_temp(*DRAG_NORMALIZED_START_VALUE_MEMORY_ID, amount);
}
fn get_drag_amount_memory(ui: &Ui) -> f32 {
ui.memory()
.data
.get_temp(*DRAG_AMOUNT_MEMORY_ID)
.unwrap_or(0.0)
}
fn set_drag_amount_memory(ui: &Ui, amount: f32) {
ui.memory().data.insert_temp(*DRAG_AMOUNT_MEMORY_ID, amount);
}
fn slider_ui(&self, ui: &mut Ui, response: &mut Response) {
// Handle user input
// TODO: Optionally (since it can be annoying) add scrolling behind a builder option
if response.drag_started() {
// When beginning a drag or dragging normally, reset the memory used to keep track of
// our granular drag
self.begin_drag();
Self::set_drag_amount_memory(ui, 0.0);
}
if let Some(click_pos) = response.interact_pointer_pos() {
if ui.input().modifiers.command {
// Like double clicking, Ctrl+Click should reset the parameter
self.reset_param();
response.mark_changed();
// // FIXME: This releases the focus again when you release the mouse button without
// // moving the mouse a bit for some reason
// } else if ui.input().modifiers.alt && self.draw_value {
// // Allow typing in the value on an Alt+Click. Right now this is shown as part of the
// // value field, so it only makes sense when we're drawing that.
// self.begin_keyboard_entry(ui);
} else if ui.input().modifiers.shift {
// And shift dragging should switch to a more granulra input method
self.granular_drag(ui, response.drag_delta());
response.mark_changed();
} else {
let proportion =
egui::emath::remap_clamp(click_pos.x, response.rect.x_range(), 0.0..=1.0)
as f64;
self.set_normalized_value(proportion as f32);
response.mark_changed();
Self::set_drag_amount_memory(ui, 0.0);
}
}
if response.double_clicked() {
self.reset_param();
response.mark_changed();
}
if response.drag_released() {
self.end_drag();
}
// And finally draw the thing
if ui.is_rect_visible(response.rect) {
// We'll do a flat widget with background -> filled foreground -> slight border
ui.painter()
.rect_filled(response.rect, 0.0, ui.visuals().widgets.inactive.bg_fill);
let filled_proportion = self.normalized_value();
if filled_proportion > 0.0 {
let mut filled_rect = response.rect;
filled_rect.set_width(response.rect.width() * filled_proportion);
let filled_bg = if response.dragged() {
util::add_hsv(ui.visuals().selection.bg_fill, 0.0, -0.1, 0.1)
} else {
ui.visuals().selection.bg_fill
};
ui.painter().rect_filled(filled_rect, 0.0, filled_bg);
}
ui.painter().rect_stroke(
response.rect,
0.0,
Stroke::new(1.0, ui.visuals().widgets.active.bg_fill),
);
}
}
fn value_ui(&self, ui: &mut Ui) {
let visuals = ui.visuals().widgets.inactive;
let should_draw_frame = ui.visuals().button_frame;
let padding = ui.spacing().button_padding;
// Either show the parameter's label, or show a text entry field if the parameter's label
// has been clicked on
let keyboard_focus_id = self.keyboard_focus_id.unwrap();
if self.keyboard_entry_active(ui) {
let value_entry_mutex = ui
.memory()
.data
.get_temp_mut_or_default::<Arc<Mutex<String>>>(*VALUE_ENTRY_MEMORY_ID)
.clone();
let mut value_entry = value_entry_mutex.lock();
ui.add(
TextEdit::singleline(&mut *value_entry)
.id(keyboard_focus_id)
.font(TextStyle::Monospace),
);
if ui.input().key_pressed(Key::Escape) {
// Cancel when pressing escape
ui.memory().surrender_focus(keyboard_focus_id);
} else if ui.input().key_pressed(Key::Enter) {
// And try to set the value by string when pressing enter
self.begin_drag();
self.set_from_string(&value_entry);
self.end_drag();
ui.memory().surrender_focus(keyboard_focus_id);
}
} else {
let text = WidgetText::from(self.string_value()).into_galley(
ui,
None,
ui.available_width() - (padding.x * 2.0),
TextStyle::Button,
);
let response = ui.allocate_response(text.size() + (padding * 2.0), Sense::click());
if response.clicked() {
self.begin_keyboard_entry(ui);
}
if ui.is_rect_visible(response.rect) {
if should_draw_frame {
let fill = visuals.bg_fill;
let stroke = visuals.bg_stroke;
ui.painter().rect(
response.rect.expand(visuals.expansion),
visuals.rounding,
fill,
stroke,
);
}
let text_pos = ui
.layout()
.align_size_within_rect(text.size(), response.rect.shrink2(padding))
.min;
text.paint_with_visuals(ui.painter(), text_pos, &visuals);
}
}
}
}
impl<P: Param> Widget for ParamSlider<'_, P> {
fn ui(mut self, ui: &mut Ui) -> Response {
let slider_width = self
.slider_width
.unwrap_or_else(|| ui.spacing().slider_width);
ui.horizontal(|ui| {
// Allocate space, but add some padding on the top and bottom to make it look a bit slimmer.
let height = ui
.text_style_height(&TextStyle::Body)
.max(ui.spacing().interact_size.y * 0.8);
let slider_height = ui.painter().round_to_pixel(height * 0.8);
let mut response = ui
.vertical(|ui| {
ui.allocate_space(vec2(slider_width, (height - slider_height) / 2.0));
let response = ui.allocate_response(
vec2(slider_width, slider_height),
Sense::click_and_drag(),
);
let (kb_edit_id, _) =
ui.allocate_space(vec2(slider_width, (height - slider_height) / 2.0));
// Allocate an automatic ID for keeping track of keyboard focus state
// FIXME: There doesn't seem to be a way to generate IDs in the public API, not sure how
// you're supposed to do this
self.keyboard_focus_id = Some(kb_edit_id);
response
})
.inner;
self.slider_ui(ui, &mut response);
if self.draw_value {
self.value_ui(ui);
}
response
})
.inner
}
}