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// Copyright 2018 The xi-editor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! A button widget.
use crate::theme;
use crate::widget::prelude::*;
use crate::widget::{Click, ControllerHost, Label, LabelText};
use crate::{Affine, Data, Insets, LinearGradient, Point, Rect, RenderContext, UnitPoint, Widget};
// the minimum padding added to a button.
// NOTE: these values are chosen to match the existing look of TextBox; these
// should be reevaluated at some point.
const LABEL_INSETS: Insets = Insets::uniform_xy(8., 2.);
/// A button with a text label.
pub struct Button<T> {
label: Label<T>,
label_size: Size,
}
impl<T: Data> Button<T> {
/// Create a new button with a text label.
///
/// Use the `.on_click` method to provide a closure to be called when the
/// button is clicked.
///
/// # Examples
///
/// ```
/// use druid::widget::Button;
///
/// let button = Button::new("Increment").on_click(|_ctx, data: &mut u32, _env| {
/// *data += 1;
/// });
/// ```
pub fn new(text: impl Into<LabelText<T>>) -> Button<T> {
Button {
label: Label::new(text),
label_size: Size::ZERO,
}
}
/// Provide a closure to be called when this button is clicked.
pub fn on_click(
self,
f: impl Fn(&mut EventCtx, &mut T, &Env) + 'static,
) -> ControllerHost<Self, Click<T>> {
ControllerHost::new(self, Click::new(f))
}
}
impl<T: Data> Widget<T> for Button<T> {
fn event(&mut self, ctx: &mut EventCtx, event: &Event, _data: &mut T, _env: &Env) {
match event {
Event::MouseDown(_) => {
ctx.set_active(true);
ctx.request_paint();
}
Event::MouseUp(_) => {
if ctx.is_active() {
ctx.set_active(false);
ctx.request_paint();
}
}
_ => (),
}
}
fn lifecycle(&mut self, ctx: &mut LifeCycleCtx, event: &LifeCycle, data: &T, env: &Env) {
if let LifeCycle::HotChanged(_) = event {
ctx.request_paint();
}
self.label.lifecycle(ctx, event, data, env)
}
fn update(&mut self, ctx: &mut UpdateCtx, old_data: &T, data: &T, env: &Env) {
self.label.update(ctx, old_data, data, env)
}
fn layout(
&mut self,
layout_ctx: &mut LayoutCtx,
bc: &BoxConstraints,
data: &T,
env: &Env,
) -> Size {
bc.debug_check("Button");
let padding = Size::new(LABEL_INSETS.x_value(), LABEL_INSETS.y_value());
let label_bc = bc.shrink(padding).loosen();
self.label_size = self.label.layout(layout_ctx, &label_bc, data, env);
// HACK: to make sure we look okay at default sizes when beside a textbox,
// we make sure we will have at least the same height as the default textbox.
let min_height = env.get(theme::BORDERED_WIDGET_HEIGHT);
bc.constrain(Size::new(
self.label_size.width + padding.width,
(self.label_size.height + padding.height).max(min_height),
))
}
fn paint(&mut self, ctx: &mut PaintCtx, data: &T, env: &Env) {
let is_active = ctx.is_active();
let is_hot = ctx.is_hot();
let size = ctx.size();
let rounded_rect = Rect::from_origin_size(Point::ORIGIN, size)
.to_rounded_rect(env.get(theme::BUTTON_BORDER_RADIUS));
let bg_gradient = if is_active {
LinearGradient::new(
UnitPoint::TOP,
UnitPoint::BOTTOM,
(env.get(theme::BUTTON_DARK), env.get(theme::BUTTON_LIGHT)),
)
} else {
LinearGradient::new(
UnitPoint::TOP,
UnitPoint::BOTTOM,
(env.get(theme::BUTTON_LIGHT), env.get(theme::BUTTON_DARK)),
)
};
let border_color = if is_hot {
env.get(theme::BORDER_LIGHT)
} else {
env.get(theme::BORDER_DARK)
};
ctx.stroke(
rounded_rect,
&border_color,
env.get(theme::BUTTON_BORDER_WIDTH),
);
ctx.fill(rounded_rect, &bg_gradient);
let label_offset = (size.to_vec2() - self.label_size.to_vec2()) / 2.0;
ctx.with_save(|ctx| {
ctx.transform(Affine::translate(label_offset));
self.label.paint(ctx, data, env);
});
}
}