gnome-shell/js/ui/slider.js

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/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
/* exported Slider */
const { Atk, Clutter, GObject } = imports.gi;
const BarLevel = imports.ui.barLevel;
var SLIDER_SCROLL_STEP = 0.02; /* Slider scrolling step in % */
var Slider = GObject.registerClass({
Signals: {
'drag-begin': {},
'drag-end': {},
},
}, class Slider extends BarLevel.BarLevel {
_init(value) {
super._init({
value,
style_class: 'slider',
can_focus: true,
reactive: true,
accessible_role: Atk.Role.SLIDER,
x_expand: true,
});
this._releaseId = 0;
this._dragging = false;
this._customAccessible.connect('get-minimum-increment', this._getMinimumIncrement.bind(this));
}
vfunc_repaint() {
super.vfunc_repaint();
// Add handle
let cr = this.get_context();
let themeNode = this.get_theme_node();
let [width, height] = this.get_surface_size();
let handleRadius = themeNode.get_length('-slider-handle-radius');
let handleBorderWidth = themeNode.get_length('-slider-handle-border-width');
let [hasHandleColor, handleBorderColor] =
themeNode.lookup_color('-slider-handle-border-color', false);
const ceiledHandleRadius = Math.ceil(handleRadius + handleBorderWidth);
const handleX = ceiledHandleRadius +
(width - 2 * ceiledHandleRadius) * this._value / this._maxValue;
const handleY = height / 2;
let color = themeNode.get_foreground_color();
Clutter.cairo_set_source_color(cr, color);
cr.arc(handleX, handleY, handleRadius, 0, 2 * Math.PI);
cr.fillPreserve();
if (hasHandleColor && handleBorderWidth) {
Clutter.cairo_set_source_color(cr, handleBorderColor);
cr.setLineWidth(handleBorderWidth);
cr.stroke();
}
cr.$dispose();
}
vfunc_button_press_event() {
return this.startDragging(Clutter.get_current_event());
}
startDragging(event) {
if (this._dragging)
return Clutter.EVENT_PROPAGATE;
this._dragging = true;
let device = event.get_device();
let sequence = event.get_event_sequence();
this._grab = global.stage.grab(this);
this._grabbedDevice = device;
this._grabbedSequence = sequence;
// We need to emit 'drag-begin' before moving the handle to make
// sure that no 'notify::value' signal is emitted before this one.
this.emit('drag-begin');
let absX, absY;
[absX, absY] = event.get_coords();
this._moveHandle(absX, absY);
return Clutter.EVENT_STOP;
}
_endDragging() {
if (this._dragging) {
if (this._releaseId) {
this.disconnect(this._releaseId);
this._releaseId = 0;
}
if (this._grab) {
this._grab.dismiss();
this._grab = null;
}
this._grabbedSequence = null;
this._grabbedDevice = null;
this._dragging = false;
this.emit('drag-end');
}
return Clutter.EVENT_STOP;
}
vfunc_button_release_event() {
if (this._dragging && !this._grabbedSequence)
return this._endDragging();
return Clutter.EVENT_PROPAGATE;
}
vfunc_touch_event() {
let event = Clutter.get_current_event();
let sequence = event.get_event_sequence();
if (!this._dragging &&
event.type() == Clutter.EventType.TOUCH_BEGIN) {
this.startDragging(event);
return Clutter.EVENT_STOP;
} else if (this._grabbedSequence &&
sequence.get_slot() === this._grabbedSequence.get_slot()) {
if (event.type() == Clutter.EventType.TOUCH_UPDATE)
return this._motionEvent(this, event);
else if (event.type() == Clutter.EventType.TOUCH_END)
return this._endDragging();
}
return Clutter.EVENT_PROPAGATE;
}
scroll(event) {
let direction = event.get_scroll_direction();
let delta;
if (event.is_pointer_emulated())
return Clutter.EVENT_PROPAGATE;
if (direction == Clutter.ScrollDirection.DOWN) {
delta = -SLIDER_SCROLL_STEP;
} else if (direction == Clutter.ScrollDirection.UP) {
delta = SLIDER_SCROLL_STEP;
} else if (direction == Clutter.ScrollDirection.SMOOTH) {
let [, dy] = event.get_scroll_delta();
// Even though the slider is horizontal, use dy to match
// the UP/DOWN above.
delta = -dy * SLIDER_SCROLL_STEP;
}
this.value = Math.min(Math.max(0, this._value + delta), this._maxValue);
return Clutter.EVENT_STOP;
}
vfunc_scroll_event() {
return this.scroll(Clutter.get_current_event());
}
vfunc_motion_event() {
if (this._dragging && !this._grabbedSequence)
return this._motionEvent(this, Clutter.get_current_event());
return Clutter.EVENT_PROPAGATE;
}
_motionEvent(actor, event) {
let absX, absY;
[absX, absY] = event.get_coords();
this._moveHandle(absX, absY);
return Clutter.EVENT_STOP;
}
vfunc_key_press_event(keyPressEvent) {
let key = keyPressEvent.keyval;
if (key == Clutter.KEY_Right || key == Clutter.KEY_Left) {
let delta = key == Clutter.KEY_Right ? 0.1 : -0.1;
this.value = Math.max(0, Math.min(this._value + delta, this._maxValue));
return Clutter.EVENT_STOP;
}
return super.vfunc_key_press_event(keyPressEvent);
}
_moveHandle(absX, _absY) {
let relX, sliderX;
[sliderX] = this.get_transformed_position();
relX = absX - sliderX;
let width = this._barLevelWidth;
let handleRadius = this.get_theme_node().get_length('-slider-handle-radius');
let newvalue;
if (relX < handleRadius)
newvalue = 0;
else if (relX > width - handleRadius)
newvalue = 1;
else
newvalue = (relX - handleRadius) / (width - 2 * handleRadius);
this.value = newvalue * this._maxValue;
}
_getMinimumIncrement() {
return 0.1;
}
});