Palette tool laser prototype.

ash/common/system/chromeos/palette/tools/laser_pointer_view.cc

+// 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/common/system/chromeos/palette/tools/laser_pointer_view.h"
+
+#include <memory>
+
+#include "ash/common/shell_window_ids.h"
+#include "ash/common/wm_root_window_controller.h"
+#include "ash/common/wm_shell.h"
+#include "ash/common/wm_window.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "third_party/skia/include/core/SkPaint.h"
+#include "third_party/skia/include/core/SkRect.h"
+#include "ui/compositor/layer.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/transform.h"
+#include "ui/wm/core/coordinate_conversion.h"
+
+namespace ash {
+namespace {
+
+const double kMouselaserUiStartRadius = 4;
+const double kMouselaserUiEndRadius = 0.25;
+const int kMouselaserUiStartOpacityValue = 200;
+const int kMouselaserUiEndOpacityValue = 0;
+
+views::Widget* CreateLaserPointerWidget() {
+  views::Widget* widget = 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;
+  WmShell::Get()
+      ->GetRootWindowForNewWindows()
+      ->GetRootWindowController()
+      ->ConfigureWidgetInitParamsForContainer(
+          widget, kShellWindowId_OverlayContainer, &params);
+
+  widget->Init(params);
+  widget->SetOpacity(1.f);

[jdufault, 2016/08/12 19:58:00]

Is this needed?

[sammiequon, 2016/08/16 17:00:06]

Done.

+  return widget;
+}
+
+float DistanceBetweenPoints(const gfx::Point& point1,

[jdufault, 2016/08/12 19:57:59]

I feel like this is defined somewhere in the code base. If not, please only
define it once in the CL.

[sammiequon, 2016/08/16 17:00:06]

I couldn't find it but I changed it to use base functions.

+                            const gfx::Point& point2) {
+  float deltaX = point1.x() - point2.x();
+  float deltaY = point1.y() - point2.y();
+  return deltaX * deltaX + deltaY * deltaY;
+}
+
+void PaintLaser(gfx::Canvas* canvas,
+                const LaserPointerPoints& points,
+                const gfx::Rect& widget_bounds) {
+  SkPaint paint;
+  paint.setStyle(SkPaint::kStroke_Style);
+  paint.setAntiAlias(true);
+  paint.setStrokeJoin(SkPaint::kBevel_Join);
+  SkColor paintColor;
+
+  if (!points.IsEmpty()) {

[jdufault, 2016/08/12 19:58:00]

Just do an early return, so at the start of the fn add

  if (points.IsEmpty())
    return;

[sammiequon, 2016/08/16 17:00:06]

Done.

+    base::Time oldest = points.GetOldest().creationTime;
+    base::Time most_recent = points.GetMostRecent().creationTime;
+    gfx::Point last_point, current_point;
+    int point_count = 0;
+    int num_points = points.GetNumberOfPoints();
+    for (auto it = points.PointsStart(); it != points.PointsEnd();
+         it++, point_count++) {
+      float normalized;
+      // Only one point, the regular normalization will return undefined for
+      // this case.
+      if (oldest == most_recent)
+        normalized = 1.0;
+      else {  // Normalize the distance.
+        normalized = float{(it->creationTime - oldest).InMillisecondsF()} /

[jdufault, 2016/08/12 19:58:00]

Store normalized as a double to eliminate all of the casts.

[sammiequon, 2016/08/16 17:00:06]

Done.

+                     float{(most_recent - oldest).InMillisecondsF()};
+        normalized = 1.0 - normalized;
+      }
+
+      float radius =
+          float{kMouselaserUiStartRadius} -
+          normalized * float{kMouselaserUiStartRadius - kMouselaserUiEndRadius};
+      int opacity = kMouselaserUiStartOpacityValue -
+                    int{normalized * float{kMouselaserUiStartOpacityValue -
+                                           kMouselaserUiEndOpacityValue}};
+      gfx::Vector2d center = it->location - widget_bounds.origin();
+      current_point = gfx::Point(center.x(), center.y());
+      paintColor = SkColorSetARGB(opacity, 255, 0, 0);

[jdufault, 2016/08/12 19:58:00]

Move constants to anonymous namespace.

[sammiequon, 2016/08/16 17:00:06]

Done.

+      paint.setColor(paintColor);
+      paint.setStrokeWidth(radius * 2);
+      if (point_count == 0) {
+        last_point = current_point;
+      } else if (DistanceBetweenPoints(last_point, current_point) >
+                 radius * 4 * radius) {

[jdufault, 2016/08/12 19:57:59]

What's radius * 4 * radius?

[sammiequon, 2016/08/16 17:00:06]

Done.

+        canvas->DrawLine(last_point, current_point, paint);
+        last_point = current_point;
+      } else if (point_count == num_points - 1) {
+        canvas->DrawLine(last_point, current_point, paint);
+      }
+    }
+    paintColor = SkColorSetARGB(kMouselaserUiStartOpacityValue, 255, 0, 0);

[jdufault, 2016/08/12 19:57:59]

Move constant to anonymous namespace

[sammiequon, 2016/08/16 17:00:06]

Done.

+    paint.setColor(paintColor);
+    paint.setStyle(SkPaint::kFill_Style);
+    canvas->DrawCircle(current_point, kMouselaserUiStartRadius, paint);
+  }
+}
+}  // namespace
+
+////////////////////////////////////////////////////////////////////////////////
+
+// LaserPointerView
+LaserPointerView::LaserPointerView()
+    : views::View(), laser_points_(base::TimeDelta()) {
+  gfx::Rect newBoundingBox;
+  newBoundingBox.SetRect(0, 0, 1388, 768);

[jdufault, 2016/08/12 19:58:00]

?

[sammiequon, 2016/08/16 17:00:06]

Done.

+  widget_.reset(CreateLaserPointerWidget());
+  widget_->SetBounds(newBoundingBox);
+  widget_->Show();
+  widget_->SetContentsView(this);
+}
+
+LaserPointerView::~LaserPointerView() {
+  Stop();
+}
+
+void LaserPointerView::Stop() {
+  laser_points_.Clear();
+  SetNewPoints(laser_points_);
+}
+
+void LaserPointerView::SetNewPoints(const LaserPointerPoints& laser_points) {
+  laser_points_ = laser_points;
+  gfx::Rect oldBoundingBox, newBoundingBox;

[jdufault, 2016/08/12 19:57:59]

old_bounding_box, new_bounding_box

[sammiequon, 2016/08/16 17:00:06]

Done.

+  oldBoundingBox = laser_points.GetBoundingBox();
+  newBoundingBox.SetRect(
+      oldBoundingBox.x() - kMouselaserUiStartRadius,
+      oldBoundingBox.y() - kMouselaserUiStartRadius,
+      oldBoundingBox.width() + 2 * kMouselaserUiStartRadius,
+      oldBoundingBox.height() + 2 * kMouselaserUiStartRadius);
+  widget_->SetBounds(newBoundingBox);
+  SchedulePaint();
+}
+
+void LaserPointerView::OnPaint(gfx::Canvas* canvas) {
+  canvas->Save();
+  PaintLaser(canvas, laser_points_, widget_->GetWindowBoundsInScreen());
+  canvas->Restore();
+}
+}  // namespace ash