ash/wm/partial_screenshot_view.cc

// Copyright (c) 2012 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/wm/partial_screenshot_view.h"

#include "ash/screenshot_delegate.h"
#include "ash/shell.h"
#include "ash/shell_window_ids.h"
#include "ash/wm/overlay_event_filter.h"
#include "ui/aura/root_window.h"
#include "ui/base/cursor/cursor.h"
#include "ui/base/events/event.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/rect.h"
#include "ui/views/view.h"
#include "ui/views/widget/widget.h"

namespace ash {

PartialScreenshotView::PartialScreenshotView(
    ScreenshotDelegate* screenshot_delegate)
    : is_dragging_(false),
      screenshot_delegate_(screenshot_delegate) {
}

PartialScreenshotView::~PartialScreenshotView() {
  screenshot_delegate_ = NULL;
}

// static
void PartialScreenshotView::StartPartialScreenshot(
    ScreenshotDelegate* screenshot_delegate) {
  views::Widget* widget = new views::Widget;
  PartialScreenshotView* view = new PartialScreenshotView(
      screenshot_delegate);
  aura::RootWindow* root_window = Shell::GetActiveRootWindow();
  views::Widget::InitParams params(
      views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
  params.transparent = true;
  params.delegate = view;
  // The partial screenshot rectangle has to be at the real top of
  // the screen.
  params.parent = Shell::GetContainer(
      root_window,
      internal::kShellWindowId_OverlayContainer);

  widget->Init(params);
  widget->SetContentsView(view);
  widget->SetBounds(root_window->bounds());
  widget->GetNativeView()->SetName("PartialScreenshotView");
  widget->StackAtTop();
  widget->Show();
  // Captures mouse events in case that context menu already captures the
  // events.  This will close the context menu.
  widget->GetNativeView()->SetCapture();

  Shell::GetInstance()->overlay_filter()->Activate(view);
}

gfx::NativeCursor PartialScreenshotView::GetCursor(
    const ui::MouseEvent& event) {
  // Always use "crosshair" cursor.
  return ui::kCursorCross;
}

void PartialScreenshotView::Cancel() {
  Shell::GetInstance()->overlay_filter()->Deactivate();
  views::Widget* widget = GetWidget();
  if (widget)
    widget->Close();
}

bool PartialScreenshotView::IsCancelingKeyEvent(ui::KeyEvent* event) {
  return event->key_code() == ui::VKEY_ESCAPE;
}

aura::Window* PartialScreenshotView::GetWindow() {
  return GetWidget()->GetNativeWindow();
}

void PartialScreenshotView::OnPaint(gfx::Canvas* canvas) {
  if (is_dragging_) {
    // Screenshot area representation: black rectangle with white
    // rectangle inside.  To avoid capturing these rectangles when mouse
    // release, they should be outside of the actual capturing area.
    gfx::Rect screenshot_rect = GetScreenshotRect();
    screenshot_rect.Inset(-1, -1, -1, -1);
    canvas->DrawRect(screenshot_rect, SK_ColorWHITE);
    screenshot_rect.Inset(-1, -1, -1, -1);
    canvas->DrawRect(screenshot_rect, SK_ColorBLACK);
  }
}

void PartialScreenshotView::OnMouseCaptureLost() {
  Cancel();
}

bool PartialScreenshotView::OnMousePressed(const ui::MouseEvent& event) {
  start_position_ = event.location();
  return true;
}

bool PartialScreenshotView::OnMouseDragged(const ui::MouseEvent& event) {
  current_position_ = event.location();
  SchedulePaint();
  is_dragging_ = true;
  return true;
}

bool PartialScreenshotView::OnMouseWheel(const ui::MouseWheelEvent& event) {
  // Do nothing but do not propagate events futhermore.
  return true;
}

void PartialScreenshotView::OnMouseReleased(const ui::MouseEvent& event) {
  Cancel();
  if (!is_dragging_)
    return;

  is_dragging_ = false;
  if (screenshot_delegate_) {
    aura::RootWindow *root_window = Shell::GetPrimaryRootWindow();
    screenshot_delegate_->HandleTakePartialScreenshot(
        root_window, root_window->bounds().Intersect(GetScreenshotRect()));
  }
}

gfx::Rect PartialScreenshotView::GetScreenshotRect() const {
  int left = std::min(start_position_.x(), current_position_.x());
  int top = std::min(start_position_.y(), current_position_.y());
  int width = ::abs(start_position_.x() - current_position_.x());
  int height = ::abs(start_position_.y() - current_position_.y());
  return gfx::Rect(left, top, width, height);
}

}  // namespace ash