1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
// 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.
#ifndef UI_VIEWS_CONTROLS_SCROLLBAR_SCROLL_BAR_H_
#define UI_VIEWS_CONTROLS_SCROLLBAR_SCROLL_BAR_H_
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "ui/views/view.h"
#include "ui/views/views_export.h"
namespace views {
class ScrollBar;
/////////////////////////////////////////////////////////////////////////////
//
// ScrollBarController
//
// ScrollBarController defines the method that should be implemented to
// receive notification from a scrollbar
//
/////////////////////////////////////////////////////////////////////////////
class VIEWS_EXPORT 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 VIEWS_EXPORT ScrollBar : public View {
public:
~ScrollBar() override;
// Overridden from View:
void GetAccessibleState(ui::AXViewState* state) override;
// Returns whether this scrollbar is horizontal.
bool IsHorizontal() const;
void set_controller(ScrollBarController* controller) {
controller_ = controller;
}
ScrollBarController* controller() const { return controller_; }
// 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);
// Returns 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;
// Get the width or height for this scrollbar which overlaps with the content.
// Default is 0.
virtual int GetContentOverlapSize() const;
virtual void OnMouseEnteredScrollView(const ui::MouseEvent& event);
virtual void OnMouseExitedScrollView(const ui::MouseEvent& event);
protected:
// Create new scrollbar, either horizontal or vertical. These are protected
// since you need to be creating either a NativeScrollBar or a
// ImageScrollBar.
explicit ScrollBar(bool is_horiz);
private:
const bool is_horiz_;
ScrollBarController* controller_;
int max_pos_;
DISALLOW_COPY_AND_ASSIGN(ScrollBar);
};
} // namespace views
#endif // UI_VIEWS_CONTROLS_SCROLLBAR_SCROLL_BAR_H_
|
