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// Copyright 2008, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef CHROME_VIEWS_SCROLLBAR_H__
#define CHROME_VIEWS_SCROLLBAR_H__
#include "chrome/views/view.h"
#include "chrome/views/event.h"
namespace ChromeViews {
class ScrollBar;
/////////////////////////////////////////////////////////////////////////////
//
// ScrollBarController
//
// ScrollBarController defines the method that should be implemented to
// receive notification from a scrollbar
//
/////////////////////////////////////////////////////////////////////////////
class ScrollBarController {
public:
// Invoked by the scrollbar when the scrolling position changes
// This method typically implements the actual scrolling.
//
// The provided position is expressed in pixels. It is the new X or Y
// position which is in the GetMinPosition() / GetMaxPosition range.
virtual void ScrollToPosition(ScrollBar* source, int position) = 0;
// Returns the amount to scroll. The amount to scroll may be requested in
// two different amounts. If is_page is true the 'page scroll' amount is
// requested. The page scroll amount typically corresponds to the
// visual size of the view. If is_page is false, the 'line scroll' amount
// is being requested. The line scroll amount typically corresponds to the
// size of one row/column.
//
// The return value should always be positive. A value <= 0 results in
// scrolling by a fixed amount.
virtual int GetScrollIncrement(ScrollBar* source,
bool is_page,
bool is_positive) = 0;
};
/////////////////////////////////////////////////////////////////////////////
//
// ScrollBar
//
// A View subclass to wrap to implement a ScrollBar. Our current windows
// version simply wraps a native windows scrollbar.
//
// A scrollbar is either horizontal or vertical
//
/////////////////////////////////////////////////////////////////////////////
class ScrollBar : public View {
public:
virtual ~ScrollBar();
// Return whether this scrollbar is horizontal
bool IsHorizontal() const;
// Set / Get the controller
void SetController(ScrollBarController* controller);
ScrollBarController* GetController() const;
// Update the scrollbar appearance given a viewport size, content size and
// current position
virtual void Update(int viewport_size, int content_size, int current_pos);
// Return the max and min positions
int GetMaxPosition() const;
int GetMinPosition() const;
// Returns the position of the scrollbar.
virtual int GetPosition() const = 0;
// Get the width or height of this scrollbar, for use in layout calculations.
// For a vertical scrollbar, this is the width of the scrollbar, likewise it
// is the height for a horizontal scrollbar.
virtual int GetLayoutSize() const = 0;
protected:
// Create new scrollbar, either horizontal or vertical. These are protected
// since you need to be creating either a NativeScrollBar or a
// BitmapScrollBar.
ScrollBar(bool is_horiz);
private:
const bool is_horiz_;
// Current controller
ScrollBarController* controller_;
// properties
int max_pos_;
};
}
#endif
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