ash: Make the touchy heads-up display more colorful/useful.

ash/touch/touch_observer_hud.cc

Index: ash/touch/touch_observer_hud.cc
diff --git a/ash/touch/touch_observer_hud.cc b/ash/touch/touch_observer_hud.cc
index d383c60343835f7f3912dd56b65cb44731545715..b7773a5acd390acf7426c8e7ca5f19f0ff840327 100644
--- a/ash/touch/touch_observer_hud.cc
+++ b/ash/touch/touch_observer_hud.cc
@@ -7,7 +7,14 @@
 #include "ash/shell_window_ids.h"
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
+#include "third_party/skia/include/core/SkPath.h"
+#include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/aura/event.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/monitor.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/screen.h"
+#include "ui/gfx/size.h"
 #include "ui/views/background.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/layout/box_layout.h"
@@ -16,11 +23,102 @@
 namespace ash {
 namespace internal {
 
+const int kMaxPaths = 15;
+const int kScale = 10;
+const int kColors[] = {
+  SK_ColorYELLOW,
+  SK_ColorGREEN,
+  SK_ColorRED,
+  SK_ColorBLUE,
+  SK_ColorMAGENTA,
+  SK_ColorCYAN,
+  SK_ColorWHITE,
+  SK_ColorBLACK
+};
+
+class TouchHudCanvas : public views::View {
+ public:
+  explicit TouchHudCanvas(TouchObserverHUD* owner)
+      : owner_(owner),
+        path_index_(0),
+        color_index_(0) {
+    gfx::Monitor monitor = gfx::Screen::GetPrimaryMonitor();
+    gfx::Rect bounds = monitor.bounds();
+    size_.set_width(bounds.width() / kScale);
+    size_.set_height(bounds.height() / kScale);
+  }
+
+  virtual ~TouchHudCanvas() {}
+
+  void Start(int id, const gfx::Point& point) {
+    paths_[path_index_].reset();
+    paths_[path_index_].moveTo(SkIntToScalar(point.x() / kScale),
+                      SkIntToScalar(point.y() / kScale));
+    colors_[path_index_] = kColors[color_index_];
+    color_index_ = (color_index_ + 1) % arraysize(kColors);
+
+    touch_id_to_path_[id] = path_index_;
+    path_index_ = (path_index_ + 1) % kMaxPaths;
+    SchedulePaint();
+  }
+
+  void Update(int id, gfx::Point& to) {
+    SkPoint last;
+    int path_id = touch_id_to_path_[id];
+    SkScalar x = SkIntToScalar(to.x() / kScale);
+    SkScalar y = SkIntToScalar(to.y() / kScale);
+    if (!paths_[path_id].getLastPt(&last) || x != last.x() || y != last.y())
+      paths_[path_id].lineTo(x, y);
+    SchedulePaint();
+  }
+
+ private:
+  // Overridden from views::View.
+  virtual gfx::Size GetPreferredSize() OVERRIDE {
+    return size_;
+  }
+
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
+    canvas->DrawColor(SK_ColorBLACK, SkXfermode::kClear_Mode);
+    canvas->DrawColor(SkColorSetARGB(25, 0, 0, 0));
+
+    SkPaint paint;
+    paint.setStrokeWidth(SkIntToScalar(2));
+    paint.setStyle(SkPaint::kStroke_Style);
+    for (size_t i = 0; i < arraysize(paths_); ++i) {
+      if (paths_[i].countPoints() == 0)
+        continue;
+      paint.setColor(colors_[i]);
+      if (paths_[i].countPoints() == 1) {
+        SkPoint point = paths_[i].getPoint(0);
+        canvas->sk_canvas()->drawPoint(point.x(), point.y(), paint);
+      } else {
+        canvas->DrawPath(paths_[i], paint);
+      }
+    }
+  }
+
+  TouchObserverHUD* owner_;
+  SkPath paths_[kMaxPaths];
+  SkColor colors_[kMaxPaths];
+
+  int path_index_;
+  int color_index_;
+
+  std::map<int, int> touch_id_to_path_;
+
+  gfx::Size size_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchHudCanvas);
+};
+
 TouchObserverHUD::TouchObserverHUD() {
   views::View* content = new views::View;
   content->SetLayoutManager(new views::BoxLayout(
       views::BoxLayout::kVertical, 0, 0, 0));
 
+  canvas_ = new TouchHudCanvas(this);
+  content->AddChildView(canvas_);
   for (int i = 0; i < kMaxTouchPoints; ++i) {
     touch_status_[i] = ui::ET_UNKNOWN;
     touch_labels_[i] = new views::Label;
@@ -37,6 +135,7 @@ TouchObserverHUD::TouchObserverHUD() {
       params(views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
   params.transparent = true;
   params.can_activate = false;
+  params.accept_events = false;
   params.bounds = gfx::Rect(content->GetPreferredSize());
   params.parent = Shell::GetInstance()->GetContainer(
       internal::kShellWindowId_OverlayContainer);
@@ -93,6 +192,10 @@ ui::TouchStatus TouchObserverHUD::PreHandleTouchEvent(
 
   if (event->type() != ui::ET_TOUCH_CANCELLED)
     touch_positions_[event->touch_id()] = event->root_location();
+  if (event->type() == ui::ET_TOUCH_PRESSED)
+    canvas_->Start(event->touch_id(), touch_positions_[event->touch_id()]);
+  else
+    canvas_->Update(event->touch_id(), touch_positions_[event->touch_id()]);
   touch_status_[event->touch_id()] = event->type();
   touch_labels_[event->touch_id()]->SetVisible(true);
   UpdateTouchPointLabel(event->touch_id());