[Autofill] Move functions from the AutofillPopupController to AutofillPopupLayoutModel

chrome/browser/ui/autofill/popup_view_utils.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 "chrome/browser/ui/autofill/popup_view_utils.h"
+
+#include <algorithm>
+#include <utility>
+
+#include "ui/gfx/display.h"
+#include "ui/gfx/geometry/point.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/vector2d.h"
+#include "ui/gfx/screen.h"
+
+namespace autofill {
+namespace view_utils {
+
+namespace {
+
+std::pair<int, int> CalculatePopupXAndWidth(const gfx::Display& left_display,
+                                            const gfx::Display& right_display,
+                                            int popup_required_width,
+                                            const gfx::Rect element_bounds,
+                                            bool is_rtl) {
+  int leftmost_display_x = left_display.bounds().x();
+  int rightmost_display_x =
+      right_display.GetSizeInPixel().width() + right_display.bounds().x();
+
+  // Calculate the start coordinates for the popup if it is growing right or
+  // the end position if it is growing to the left, capped to screen space.
+  int right_growth_start = std::max(
+      leftmost_display_x, std::min(rightmost_display_x, element_bounds.x()));
+  int left_growth_end =
+      std::max(leftmost_display_x,
+               std::min(rightmost_display_x, element_bounds.right()));
+
+  int right_available = rightmost_display_x - right_growth_start;
+  int left_available = left_growth_end - leftmost_display_x;
+
+  int popup_width =
+      std::min(popup_required_width, std::max(right_available, left_available));
+
+  std::pair<int, int> grow_right(right_growth_start, popup_width);
+  std::pair<int, int> grow_left(left_growth_end - popup_width, popup_width);
+
+  // Prefer to grow towards the end (right for LTR, left for RTL). But if there
+  // is not enough space available in the desired direction and more space in
+  // the other direction, reverse it.
+  if (is_rtl) {
+    return left_available >= popup_width || left_available >= right_available
+               ? grow_left
+               : grow_right;
+  }
+  return right_available >= popup_width || right_available >= left_available
+             ? grow_right
+             : grow_left;
+}
+
+// Calculates the height of the popup and the y position of it. These values
+// will stay on the screen.
+std::pair<int, int> CalculatePopupYAndHeight(const gfx::Display& top_display,
+                                             const gfx::Display& bottom_display,
+                                             int popup_required_height,
+                                             const gfx::Rect element_bounds) {
+  int topmost_display_y = top_display.bounds().y();
+  int bottommost_display_y =
+      bottom_display.GetSizeInPixel().height() + bottom_display.bounds().y();
+
+  // Calculate the start coordinates for the popup if it is growing down or
+  // the end position if it is growing up, capped to screen space.
+  int top_growth_end = std::max(
+      topmost_display_y, std::min(bottommost_display_y, element_bounds.y()));
+  int bottom_growth_start =
+      std::max(topmost_display_y,
+               std::min(bottommost_display_y, element_bounds.bottom()));
+
+  int top_available = bottom_growth_start - topmost_display_y;
+  int bottom_available = bottommost_display_y - top_growth_end;
+
+  // TODO(csharp): Restrict the popup height to what is available.
+  if (bottom_available >= popup_required_height ||
+      bottom_available >= top_available) {
+    // The popup can appear below the field.
+    return std::make_pair(bottom_growth_start, popup_required_height);
+  } else {
+    // The popup must appear above the field.
+    return std::make_pair(top_growth_end - popup_required_height,
+                          popup_required_height);
+  }
+}
+
+}  // namespace
+
+gfx::Rect PopupViewUtils::CalculatePopupBounds(int desired_width,
+                                               int desired_height,
+                                               const gfx::Rect& element_bounds,
+                                               gfx::NativeView container_view,
+                                               bool is_rtl) {
+  // This is the top left point of the popup if the popup is above the element
+  // and grows to the left (since that is the highest and furthest left the
+  // popup go could).
+  gfx::Point top_left_corner_of_popup =
+      element_bounds.origin() +
+      gfx::Vector2d(element_bounds.width() - desired_width, -desired_height);
+
+  // This is the bottom right point of the popup if the popup is below the
+  // element and grows to the right (since the is the lowest and furthest right
+  // the popup could go).
+  gfx::Point bottom_right_corner_of_popup =
+      element_bounds.origin() +
+      gfx::Vector2d(desired_width, element_bounds.height() + desired_height);
+
+  gfx::Display top_left_display =
+      GetDisplayNearestPoint(top_left_corner_of_popup, container_view);
+  gfx::Display bottom_right_display =
+      GetDisplayNearestPoint(bottom_right_corner_of_popup, container_view);
+
+  std::pair<int, int> popup_x_and_width =
+      CalculatePopupXAndWidth(top_left_display, bottom_right_display,
+                              desired_width, element_bounds, is_rtl);
+  std::pair<int, int> popup_y_and_height = CalculatePopupYAndHeight(
+      top_left_display, bottom_right_display, desired_height, element_bounds);
+
+  return gfx::Rect(popup_x_and_width.first, popup_y_and_height.first,
+                   popup_x_and_width.second, popup_y_and_height.second);
+}
+
+gfx::Display PopupViewUtils::GetDisplayNearestPoint(
+    const gfx::Point& point,
+    gfx::NativeView container_view) {
+  return gfx::Screen::GetScreenFor(container_view)
+      ->GetDisplayNearestPoint(point);
+}
+
+}  // namespace view_utils
+}  // namespace autofill