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laser_pointer_view.cc
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laser_pointer_view.cc
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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ash/laser/laser_pointer_view.h"
#include <memory>
#include "ash/laser/laser_pointer_points.h"
#include "ash/public/cpp/shell_window_ids.h"
#include "ash/shell.h"
#include "base/timer/timer.h"
#include "third_party/skia/include/core/SkColor.h"
#include "third_party/skia/include/core/SkPaint.h"
#include "ui/aura/window.h"
#include "ui/events/event.h"
#include "ui/gfx/canvas.h"
#include "ui/views/widget/widget.h"
namespace ash {
namespace {
// Variables for rendering the laser. Radius in DIP.
const double kPointInitialRadius = 5;
const double kPointFinalRadius = 0.25;
const int kPointInitialOpacity = 200;
const int kPointFinalOpacity = 0;
const SkColor kPointColor = SkColorSetRGB(255, 0, 0);
float DistanceBetweenPoints(const gfx::Point& point1,
const gfx::Point& point2) {
return (point1 - point2).Length();
}
double LinearInterpolate(double initial_value,
double final_value,
double progress) {
return initial_value + (final_value - initial_value) * progress;
}
} // namespace
////////////////////////////////////////////////////////////////////////////////
// LaserPointerView
LaserPointerView::LaserPointerView(base::TimeDelta life_duration,
aura::Window* root_window)
: laser_points_(life_duration) {
widget_.reset(new views::Widget);
views::Widget::InitParams params;
params.type = views::Widget::InitParams::TYPE_WINDOW_FRAMELESS;
params.name = "LaserOverlay";
params.accept_events = false;
params.activatable = views::Widget::InitParams::ACTIVATABLE_NO;
params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
params.parent =
Shell::GetContainer(root_window, kShellWindowId_OverlayContainer);
widget_->Init(params);
widget_->Show();
widget_->SetContentsView(this);
set_owned_by_client();
}
LaserPointerView::~LaserPointerView() {}
void LaserPointerView::Stop() {
laser_points_.Clear();
SchedulePaint();
}
aura::Window* LaserPointerView::GetRootWindow() {
return widget_->GetNativeView()->GetRootWindow();
}
void LaserPointerView::ReparentWidget(aura::Window* new_root_window) {
if (GetRootWindow() != new_root_window) {
// TODO(sammiequon): Investigate if we should stop (which removes all
// points) or keep the old points. See http://crbug.com/647793.
Stop();
views::Widget::ReparentNativeView(
widget_->GetNativeView(),
Shell::GetContainer(new_root_window, kShellWindowId_OverlayContainer));
}
}
void LaserPointerView::AddNewPoint(const gfx::Point& new_point) {
laser_points_.AddPoint(new_point);
OnPointsUpdated();
}
void LaserPointerView::UpdateTime() {
// Do not add the point but advance the time if the view is in process of
// fading away.
laser_points_.MoveForwardToTime(base::Time::Now());
OnPointsUpdated();
}
void LaserPointerView::OnPointsUpdated() {
// The bounding box should be relative to the screen.
gfx::Point screen_offset =
widget_->GetNativeView()->GetRootWindow()->GetBoundsInScreen().origin();
// Expand the bounding box so that it includes the radius of the points on the
// edges.
gfx::Rect bounding_box;
bounding_box = laser_points_.GetBoundingBox();
bounding_box.Offset(-kPointInitialRadius, -kPointInitialRadius);
bounding_box.Offset(screen_offset.x(), screen_offset.y());
bounding_box.set_width(bounding_box.width() + (kPointInitialRadius * 2));
bounding_box.set_height(bounding_box.height() + (kPointInitialRadius * 2));
widget_->SetBounds(bounding_box);
SchedulePaint();
}
void LaserPointerView::OnPaint(gfx::Canvas* canvas) {
if (laser_points_.IsEmpty())
return;
SkPaint paint;
paint.setStyle(SkPaint::kStroke_Style);
paint.setAntiAlias(true);
paint.setStrokeJoin(SkPaint::kBevel_Join);
// Compute the offset of the current widget.
gfx::Point widget_offset =
widget_->GetNativeView()->GetBoundsInRootWindow().origin();
gfx::Point previous_point(
(laser_points_.GetOldest().location - widget_offset).x(),
(laser_points_.GetOldest().location - widget_offset).y());
gfx::Point current_point;
int num_points_ = laser_points_.GetNumberOfPoints();
int point_count = 0;
int current_opacity = 0;
for (const LaserPointerPoints::LaserPoint& point :
laser_points_.laser_points()) {
// Set the radius and opacity based on the distance.
double current_radius =
LinearInterpolate(kPointInitialRadius, kPointFinalRadius, point.age);
current_opacity = int{LinearInterpolate(
double{kPointInitialOpacity}, double{kPointFinalOpacity}, point.age)};
gfx::Vector2d center = point.location - widget_offset;
current_point = gfx::Point(center.x(), center.y());
// If we draw laser_points_ that are within a stroke width of each other,
// the result will be very jagged, unless we are on the last point, then we
// draw regardless.
point_count++;
float distance_threshold = float{current_radius * 2};
if (DistanceBetweenPoints(previous_point, current_point) <=
distance_threshold &&
point_count != num_points_) {
continue;
}
paint.setColor(SkColorSetA(kPointColor, current_opacity));
paint.setStrokeWidth(current_radius * 2);
canvas->DrawLine(previous_point, current_point, paint);
previous_point = current_point;
}
// Draw the last point as a circle.
paint.setColor(SkColorSetA(kPointColor, current_opacity));
paint.setStyle(SkPaint::kFill_Style);
canvas->DrawCircle(current_point, kPointInitialRadius, paint);
}
} // namespace ash