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// Copyright (c) 2011 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.
#pragma once
#include <string>
#include "views/controls/scrollbar/scroll_bar.h"
namespace views {
// ScrollView class
// A ScrollView is used to make any View scrollable. The view is added to
// a viewport which takes care of clipping.
// In this current implementation both horizontal and vertical scrollbars are
// added as needed.
// The scrollview supports keyboard UI and mousewheel.
class VIEWS_EXPORT ScrollView : public View, public ScrollBarController {
static const char* const kViewClassName;
// Initialize with specific views. resize_corner is optional.
ScrollView(ScrollBar* horizontal_scrollbar,
ScrollBar* vertical_scrollbar,
View* resize_corner);
virtual ~ScrollView();
// Set the contents. Any previous contents will be deleted. The contents
// is the view that needs to scroll.
void SetContents(View* a_view);
View* GetContents() const;
// Overridden to layout the viewport and scrollbars.
virtual void Layout();
// Returns the visible region of the content View.
gfx::Rect GetVisibleRect() const;
// Scrolls the minimum amount necessary to make the specified rectangle
// visible, in the coordinates of the contents view. The specified rectangle
// is constrained by the bounds of the contents view. This has no effect if
// the contents have not been set.
// Client code should use ScrollRectToVisible, which invokes this
// appropriately.
void ScrollContentsRegionToBeVisible(const gfx::Rect& rect);
// ScrollBarController.
// NOTE: this is intended to be invoked by the ScrollBar, and NOT general
// client code.
// See also ScrollRectToVisible.
virtual void ScrollToPosition(ScrollBar* source, int position);
// Returns the amount to scroll relative to the visible bounds. This invokes
// either GetPageScrollIncrement or GetLineScrollIncrement to determine the
// amount to scroll. If the view returns 0 (or a negative value) a default
// value is used.
virtual int GetScrollIncrement(ScrollBar* source,
bool is_page,
bool is_positive);
// Keyboard events
virtual bool OnKeyPressed(const KeyEvent& event);
virtual bool OnMouseWheel(const MouseWheelEvent& e);
virtual std::string GetClassName() const;
// Retrieves the vertical scrollbar width.
int GetScrollBarWidth() const;
// Retrieves the horizontal scrollbar height.
int GetScrollBarHeight() const;
// Computes the visibility of both scrollbars, taking in account the view port
// and content sizes.
void ComputeScrollBarsVisibility(const gfx::Size& viewport_size,
const gfx::Size& content_size,
bool* horiz_is_shown,
bool* vert_is_shown) const;
ScrollBar* horizontal_scroll_bar() const { return horiz_sb_; }
ScrollBar* vertical_scroll_bar() const { return vert_sb_; }
// Initialize the ScrollView. resize_corner is optional.
void Init(ScrollBar* horizontal_scrollbar,
ScrollBar* vertical_scrollbar,
View* resize_corner);
// Shows or hides the scrollbar/resize_corner based on the value of
// |should_show|.
void SetControlVisibility(View* control, bool should_show);
// Update the scrollbars positions given viewport and content sizes.
void UpdateScrollBarPositions();
// Make sure the content is not scrolled out of bounds
void CheckScrollBounds();
// Make sure the content is not scrolled out of bounds in one dimension
int CheckScrollBounds(int viewport_size, int content_size, int current_pos);
// The clipping viewport. Content is added to that view.
View* viewport_;
// The current contents
View* contents_;
// Horizontal scrollbar.
ScrollBar* horiz_sb_;
// Vertical scrollbar.
ScrollBar* vert_sb_;
// Resize corner.
View* resize_corner_;
// VariableRowHeightScrollHelper is intended for views that contain rows of
// varying height. To use a VariableRowHeightScrollHelper create one supplying
// a Controller and delegate GetPageScrollIncrement and GetLineScrollIncrement
// to the helper. VariableRowHeightScrollHelper calls back to the
// Controller to determine row boundaries.
class VariableRowHeightScrollHelper {
// The origin and height of a row.
struct RowInfo {
RowInfo(int origin, int height) : origin(origin), height(height) {}
// Origin of the row.
int origin;
// Height of the row.
int height;
// Used to determine row boundaries.
class Controller {
// Returns the origin and size of the row at the specified location.
virtual VariableRowHeightScrollHelper::RowInfo GetRowInfo(int y) = 0;
// Creates a new VariableRowHeightScrollHelper. Controller is
// NOT deleted by this VariableRowHeightScrollHelper.
explicit VariableRowHeightScrollHelper(Controller* controller);
virtual ~VariableRowHeightScrollHelper();
// Delegate the View methods of the same name to these. The scroll amount is
// determined by querying the Controller for the appropriate row to scroll
// to.
int GetPageScrollIncrement(ScrollView* scroll_view,
bool is_horizontal, bool is_positive);
int GetLineScrollIncrement(ScrollView* scroll_view,
bool is_horizontal, bool is_positive);
// Returns the row information for the row at the specified location. This
// calls through to the method of the same name on the controller.
virtual RowInfo GetRowInfo(int y);
Controller* controller_;
// FixedRowHeightScrollHelper is intended for views that contain fixed height
// height rows. To use a FixedRowHeightScrollHelper delegate
// GetPageScrollIncrement and GetLineScrollIncrement to it.
class FixedRowHeightScrollHelper : public VariableRowHeightScrollHelper {
// Creates a FixedRowHeightScrollHelper. top_margin gives the distance from
// the top of the view to the first row, and may be 0. row_height gives the
// height of each row.
FixedRowHeightScrollHelper(int top_margin, int row_height);
// Calculates the bounds of the row from the top margin and row height.
virtual RowInfo GetRowInfo(int y);
int top_margin_;
int row_height_;
} // namespace views