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// 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_LAYOUT_BOX_LAYOUT_H_
#define UI_VIEWS_LAYOUT_BOX_LAYOUT_H_
#include <map>
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "ui/gfx/insets.h"
#include "ui/views/layout/layout_manager.h"
namespace gfx {
class Rect;
class Size;
}
namespace views {
class View;
// A Layout manager that arranges child views vertically or horizontally in a
// side-by-side fashion with spacing around and between the child views. The
// child views are always sized according to their preferred size. If the
// host's bounds provide insufficient space, child views will be clamped.
// Excess space will not be distributed.
class VIEWS_EXPORT BoxLayout : public LayoutManager {
public:
enum Orientation {
kHorizontal,
kVertical,
};
// This specifies where along the main axis the children should be laid out.
// e.g. a horizontal layout of MAIN_AXIS_ALIGNMENT_END will result in the
// child views being right-aligned.
enum MainAxisAlignment {
MAIN_AXIS_ALIGNMENT_START,
MAIN_AXIS_ALIGNMENT_CENTER,
MAIN_AXIS_ALIGNMENT_END,
// TODO(calamity): Add MAIN_AXIS_ALIGNMENT_JUSTIFY which spreads blank space
// in-between the child views.
};
// This specifies where along the cross axis the children should be laid out.
// e.g. a horizontal layout of CROSS_AXIS_ALIGNMENT_END will result in the
// child views being bottom-aligned.
enum CrossAxisAlignment {
// This causes the child view to stretch to fit the host in the cross axis.
CROSS_AXIS_ALIGNMENT_STRETCH,
CROSS_AXIS_ALIGNMENT_START,
CROSS_AXIS_ALIGNMENT_CENTER,
CROSS_AXIS_ALIGNMENT_END,
};
// Use |inside_border_horizontal_spacing| and
// |inside_border_vertical_spacing| to add additional space between the child
// view area and the host view border. |between_child_spacing| controls the
// space in between child views.
BoxLayout(Orientation orientation,
int inside_border_horizontal_spacing,
int inside_border_vertical_spacing,
int between_child_spacing);
~BoxLayout() override;
void set_main_axis_alignment(MainAxisAlignment main_axis_alignment) {
main_axis_alignment_ = main_axis_alignment;
}
void set_cross_axis_alignment(CrossAxisAlignment cross_axis_alignment) {
cross_axis_alignment_ = cross_axis_alignment;
}
void set_inside_border_insets(const gfx::Insets& insets) {
inside_border_insets_ = insets;
}
void set_minimum_cross_axis_size(int size) {
minimum_cross_axis_size_ = size;
}
// Sets the flex weight for the given |view|. Using the preferred size as
// the basis, free space along the main axis is distributed to views in the
// ratio of their flex weights. Similarly, if the views will overflow the
// parent, space is subtracted in these ratios.
//
// A flex of 0 means this view is not resized. Flex values must not be
// negative.
void SetFlexForView(const View* view, int flex);
// Clears the flex for the given |view|, causing it to use the default
// flex.
void ClearFlexForView(const View* view);
// Sets the flex for views to use when none is specified.
void SetDefaultFlex(int default_flex);
// Overridden from views::LayoutManager:
void Installed(View* host) override;
void Uninstalled(View* host) override;
void ViewRemoved(View* host, View* view) override;
void Layout(View* host) override;
gfx::Size GetPreferredSize(const View* host) const override;
int GetPreferredHeightForWidth(const View* host, int width) const override;
private:
// Returns the flex for the specified |view|.
int GetFlexForView(const View* view) const;
// Returns the size and position along the main axis of |rect|.
int MainAxisSize(const gfx::Rect& rect) const;
int MainAxisPosition(const gfx::Rect& rect) const;
// Sets the size and position along the main axis of |rect|.
void SetMainAxisSize(int size, gfx::Rect* rect) const;
void SetMainAxisPosition(int position, gfx::Rect* rect) const;
// Returns the size and position along the cross axis of |rect|.
int CrossAxisSize(const gfx::Rect& rect) const;
int CrossAxisPosition(const gfx::Rect& rect) const;
// Sets the size and position along the cross axis of |rect|.
void SetCrossAxisSize(int size, gfx::Rect* rect) const;
void SetCrossAxisPosition(int size, gfx::Rect* rect) const;
// Returns the main axis size for the given view. |child_area_width| is needed
// to calculate the height of the view when the orientation is vertical.
int MainAxisSizeForView(const View* view, int child_area_width) const;
// Returns the cross axis size for the given view.
int CrossAxisSizeForView(const View* view) const;
// The preferred size for the dialog given the width of the child area.
gfx::Size GetPreferredSizeForChildWidth(const View* host,
int child_area_width) const;
// The amount of space the layout requires in addition to any space for the
// child views.
gfx::Size NonChildSize(const View* host) const;
const Orientation orientation_;
// Spacing between child views and host view border.
gfx::Insets inside_border_insets_;
// Spacing to put in between child views.
const int between_child_spacing_;
// The alignment of children in the main axis. This is
// MAIN_AXIS_ALIGNMENT_START by default.
MainAxisAlignment main_axis_alignment_;
// The alignment of children in the cross axis. This is
// CROSS_AXIS_ALIGNMENT_STRETCH by default.
CrossAxisAlignment cross_axis_alignment_;
// A map of views to their flex weights.
std::map<const View*, int> flex_map_;
// The flex weight for views if none is set. Defaults to 0.
int default_flex_;
// The minimum cross axis size for the layout.
int minimum_cross_axis_size_;
// The view that this BoxLayout is managing the layout for.
views::View* host_;
DISALLOW_IMPLICIT_CONSTRUCTORS(BoxLayout);
};
} // namespace views
#endif // UI_VIEWS_LAYOUT_BOX_LAYOUT_H_
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