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wxWidgets/interface/wx/scrolwin.h
Vadim Zeitlin 673ea07284 Document that window must be created in ShowScrollbars() 
Calling it before creating the window actually works under MSW, but not
under the other platforms.
2018-01-14 18:31:29 +01:00

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/////////////////////////////////////////////////////////////////////////////
// Name: scrolwin.h
// Purpose: interface of wxScrolled template
// Author: wxWidgets team
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/**
Possible values for the second argument of wxScrolled::ShowScrollbars().
*/
enum wxScrollbarVisibility
{
wxSHOW_SB_NEVER = -1, ///< Never show the scrollbar at all.
wxSHOW_SB_DEFAULT, ///< Show scrollbar only if it is needed.
wxSHOW_SB_ALWAYS ///< Always show scrollbar, even if not needed.
};
/**
The wxScrolled class manages scrolling for its client area, transforming
the coordinates according to the scrollbar positions, and setting the
scroll positions, thumb sizes and ranges according to the area in view.
There are two commonly used (but not the only possible!) specializations of
this class:
- ::wxScrolledWindow, aka wxScrolled<wxPanel>, is equivalent to
::wxScrolledWindow from earlier versions. Derived from wxPanel, it shares
wxPanel's behaviour with regard to TAB traversal and focus handling. Use
this if the scrolled window will have child controls.
- ::wxScrolledCanvas, aka wxScrolled<wxWindow>, derives from wxWindow and
so doesn't handle children specially. This is suitable e.g. for
implementing scrollable controls such as tree or list controls.
Starting from version 2.4 of wxWidgets, there are several ways to use a
::wxScrolledWindow (and now wxScrolled). In particular, there are
three ways to set the size of the scrolling area:
One way is to set the scrollbars directly using a call to SetScrollbars().
This is the way it used to be in any previous version of wxWidgets and it
will be kept for backwards compatibility.
An additional method of manual control, which requires a little less
computation of your own, is to set the total size of the scrolling area by
calling either wxWindow::SetVirtualSize(), or wxWindow::FitInside(), and
setting the scrolling increments for it by calling SetScrollRate().
Scrolling in some orientation is enabled by setting a non-zero increment
for it.
The most automatic and newest way is to simply let sizers determine the
scrolling area. This is now the default when you set an interior sizer into
a wxScrolled with wxWindow::SetSizer(). The scrolling area will be
set to the size requested by the sizer and the scrollbars will be assigned
for each orientation according to the need for them and the scrolling
increment set by SetScrollRate(). As above, scrolling is only enabled in
orientations with a non-zero increment. You can influence the minimum size
of the scrolled area controlled by a sizer by calling
wxWindow::SetVirtualSizeHints(). (Calling SetScrollbars() has analogous
effects in wxWidgets 2.4 -- in later versions it may not continue to
override the sizer.)
Note that if maximum size hints are still supported by
wxWindow::SetVirtualSizeHints(), use them at your own dire risk. They may
or may not have been removed for 2.4, but it really only makes sense to set
minimum size hints here. We should probably replace
wxWindow::SetVirtualSizeHints() with wxWindow::SetMinVirtualSize() or
similar and remove it entirely in future.
@todo review docs for this class replacing SetVirtualSizeHints() with
SetMinClientSize().
As with all windows, an application can draw onto a wxScrolled using a
@ref overview_dc "device context".
You have the option of handling the OnPaint handler or overriding the
wxScrolled::OnDraw() function, which is passed a pre-scrolled device
context (prepared by wxScrolled::DoPrepareDC()).
If you don't wish to calculate your own scrolling, you must call
DoPrepareDC() when not drawing from within OnDraw(), to set the device
origin for the device context according to the current scroll position.
A wxScrolled will normally scroll itself and therefore its child windows
as well. It might however be desired to scroll a different window than
itself: e.g. when designing a spreadsheet, you will normally only have to
scroll the (usually white) cell area, whereas the (usually grey) label area
will scroll very differently. For this special purpose, you can call
SetTargetWindow() which means that pressing the scrollbars will scroll a
different window.
Note that the underlying system knows nothing about scrolling coordinates,
so that all system functions (mouse events, expose events, refresh calls
etc) as well as the position of subwindows are relative to the "physical"
origin of the scrolled window. If the user insert a child window at
position (10,10) and scrolls the window down 100 pixels (moving the child
window out of the visible area), the child window will report a position
of (10,-90).
@beginStyleTable
@style{wxHSCROLL}
If this style is specified and ::wxVSCROLL isn't, the window will be
scrollable only in horizontal direction (by default, i.e. if neither
this style nor ::wxVSCROLL is specified, it scrolls in both
directions).
@style{wxVSCROLL}
If this style is specified and ::wxHSCROLL isn't, the window will be
scrollable only in vertical direction (by default, i.e. if neither
this style nor ::wxHSCROLL is specified, it scrolls in both
directions).
@style{wxALWAYS_SHOW_SB}
Since wxWidgets 2.9.5, specifying this style makes the window always
show its scrollbars, even if they are not used. See ShowScrollbars().
@style{wxRETAINED}
Uses a backing pixmap to speed refreshes. Motif only.
@endStyleTable
@beginEventEmissionTable{wxScrollWinEvent}
@event{EVT_SCROLLWIN(func)}
Process all scroll events.
@event{EVT_SCROLLWIN_TOP(func)}
Process @c wxEVT_SCROLLWIN_TOP scroll-to-top events.
@event{EVT_SCROLLWIN_BOTTOM(func)}
Process @c wxEVT_SCROLLWIN_BOTTOM scroll-to-bottom events.
@event{EVT_SCROLLWIN_LINEUP(func)}
Process @c wxEVT_SCROLLWIN_LINEUP line up events.
@event{EVT_SCROLLWIN_LINEDOWN(func)}
Process @c wxEVT_SCROLLWIN_LINEDOWN line down events.
@event{EVT_SCROLLWIN_PAGEUP(func)}
Process @c wxEVT_SCROLLWIN_PAGEUP page up events.
@event{EVT_SCROLLWIN_PAGEDOWN(func)}
Process @c wxEVT_SCROLLWIN_PAGEDOWN page down events.
@event{EVT_SCROLLWIN_THUMBTRACK(func)}
Process @c wxEVT_SCROLLWIN_THUMBTRACK thumbtrack events
(frequent events sent as the user drags the thumbtrack).
@event{EVT_SCROLLWIN_THUMBRELEASE(func)}
Process @c wxEVT_SCROLLWIN_THUMBRELEASE thumb release events.
@endEventTable
@note
Don't confuse wxScrollWinEvents generated by this class with
wxScrollEvent objects generated by wxScrollBar and wxSlider.
@remarks
Use wxScrolled for applications where the user scrolls by a fixed amount,
and where a 'page' can be interpreted to be the current visible portion of
the window. For more sophisticated applications, use the wxScrolled
implementation as a guide to build your own scroll behaviour or use
wxVScrolledWindow or its variants.
@since The wxScrolled template exists since version 2.9.0. In older versions,
only ::wxScrolledWindow (equivalent of wxScrolled<wxPanel>) was
available.
@library{wxcore}
@category{miscwnd}
@see wxScrollBar, wxClientDC, wxPaintDC,
wxVScrolledWindow, wxHScrolledWindow, wxHVScrolledWindow,
*/
template<class T>
class wxScrolled : public T
{
public:
/// Default constructor.
wxScrolled();
/**
Constructor.
@param parent
Parent window.
@param id
Window identifier. The value @c wxID_ANY indicates a default value.
@param pos
Window position. If a position of ::wxDefaultPosition is specified
then a default position is chosen.
@param size
Window size. If a size of ::wxDefaultSize is specified then the
window is sized appropriately.
@param style
Window style. See wxScrolled.
@param name
Window name.
@remarks The window is initially created without visible scrollbars.
Call SetScrollbars() to specify how big the virtual window
size should be.
*/
wxScrolled(wxWindow* parent, wxWindowID id = -1,
const wxPoint& pos = wxDefaultPosition,
const wxSize& size = wxDefaultSize,
long style = wxHSCROLL | wxVSCROLL,
const wxString& name = "scrolledWindow");
/**
Translates the logical coordinates to the device ones. For example, if
a window is scrolled 10 pixels to the bottom, the device coordinates of
the origin are (0, 0) (as always), but the logical coordinates are (0,
10) and so the call to CalcScrolledPosition(0, 10, xx, yy) will return
0 in yy.
@beginWxPerlOnly
In wxPerl this method takes two parameters and returns a
2-element list (xx, yy).
@endWxPerlOnly
@see CalcUnscrolledPosition()
*/
void CalcScrolledPosition(int x, int y, int* xx, int* yy) const;
wxPoint CalcScrolledPosition(const wxPoint& pt) const;
/**
Translates the device coordinates to the logical ones. For example, if
a window is scrolled 10 pixels to the bottom, the device coordinates of
the origin are (0, 0) (as always), but the logical coordinates are (0,
10) and so the call to CalcUnscrolledPosition(0, 0, xx, yy) will return
10 in yy.
@beginWxPerlOnly
In wxPerl this method takes two parameters and returns a
2-element list (xx, yy).
@endWxPerlOnly
@see CalcScrolledPosition()
*/
void CalcUnscrolledPosition(int x, int y, int* xx, int* yy) const;
wxPoint CalcUnscrolledPosition(const wxPoint& pt) const;
/**
Creates the window for two-step construction. Derived classes
should call or replace this function. See wxScrolled::wxScrolled()
for details.
*/
bool Create(wxWindow* parent, wxWindowID id = -1,
const wxPoint& pos = wxDefaultPosition,
const wxSize& size = wxDefaultSize,
long style = wxHSCROLL | wxVSCROLL,
const wxString& name = "scrolledWindow");
/**
Disable use of keyboard keys for scrolling.
By default cursor movement keys (including Home, End, Page Up and Down)
are used to scroll the window appropriately. If the derived class uses
these keys for something else, e.g. changing the currently selected
item, this function can be used to disable this behaviour as it's not
only not necessary then but can actually be actively harmful if another
object forwards a keyboard event corresponding to one of the above keys
to us using ProcessWindowEvent() because the event will always be
processed which can be undesirable.
@since 2.9.1
*/
void DisableKeyboardScrolling();
/**
Call this function to prepare the device context for drawing a scrolled
image.
It sets the device origin according to the current scroll position.
DoPrepareDC() is called automatically within the default @c wxEVT_PAINT
event handler, so your OnDraw() override will be passed an already
'pre-scrolled' device context. However, if you wish to draw from
outside of OnDraw() (e.g. from your own @c wxEVT_PAINT handler), you
must call this function yourself.
For example:
@code
void MyWindow::OnEvent(wxMouseEvent& event)
{
wxClientDC dc(this);
DoPrepareDC(dc);
dc.SetPen(*wxBLACK_PEN);
float x, y;
event.Position(&x, &y);
if (xpos > -1 && ypos > -1 && event.Dragging())
{
dc.DrawLine(xpos, ypos, x, y);
}
xpos = x;
ypos = y;
}
@endcode
Notice that the function sets the origin by moving it relatively to the
current origin position, so you shouldn't change the origin before
calling DoPrepareDC() or, if you do, reset it to (0, 0) later. If you
call DoPrepareDC() immediately after device context creation, as in the
example above, this problem doesn't arise, of course, so it is
customary to do it like this.
*/
void DoPrepareDC(wxDC& dc);
/**
Enable or disable use of wxWindow::ScrollWindow() for scrolling.
By default, when a scrolled window is logically scrolled,
wxWindow::ScrollWindow() is called on the underlying window which
scrolls the window contents and only invalidates the part of the window
newly brought into view. If @false is passed as an argument, then this
"physical scrolling" is disabled and the window is entirely invalidated
whenever it is scrolled by calling wxWindow::Refresh().
It should be rarely necessary to disable physical scrolling, so this
method shouldn't be called in normal circumstances.
@param xScrolling
If @true, enables physical scrolling in the x direction.
@param yScrolling
If @true, enables physical scrolling in the y direction.
*/
void EnableScrolling(bool xScrolling, bool yScrolling);
/**
Set the scrollbar visibility.
By default the scrollbar in the corresponding direction is only shown
if it is needed, i.e. if the virtual size of the scrolled window in
this direction is greater than the current physical window size. Using
this function the scrollbar visibility can be changed to be:
- wxSHOW_SB_ALWAYS: To always show the scrollbar, even if it is
not needed currently (wxALWAYS_SHOW_SB style can be used during
the window creation to achieve the same effect but it applies
in both directions).
- wxSHOW_SB_NEVER: To never show the scrollbar at all. In this case
the program should presumably provide some other way for the
user to scroll the window.
- wxSHOW_SB_DEFAULT: To restore the default behaviour described
above.
Note that the window must be created before calling this method.
@param horz
The desired visibility for the horizontal scrollbar.
@param vert
The desired visibility for the vertical scrollbar.
@since 2.9.0
*/
void ShowScrollbars(wxScrollbarVisibility horz, wxScrollbarVisibility vert);
/**
Get the number of pixels per scroll unit (line), in each direction, as
set by SetScrollbars(). A value of zero indicates no scrolling in that
direction.
@param xUnit
Receives the number of pixels per horizontal unit.
@param yUnit
Receives the number of pixels per vertical unit.
@beginWxPerlOnly
In wxPerl this method takes no parameters and returns a
2-element list (xUnit, yUnit).
@endWxPerlOnly
@see SetScrollbars(), GetVirtualSize()
*/
void GetScrollPixelsPerUnit(int* xUnit, int* yUnit) const;
/**
Get the position at which the visible portion of the window starts.
@param x
Receives the first visible x position in scroll units.
@param y
Receives the first visible y position in scroll units.
@remarks
If either of the scrollbars is not at the home position, @a x
and/or @a y will be greater than zero.
Combined with wxWindow::GetClientSize(), the application can use this
function to efficiently redraw only the visible portion of the window.
The positions are in logical scroll units, not pixels, so to convert
to pixels you will have to multiply by the number of pixels per scroll
increment.
@beginWxPerlOnly
In wxPerl this method takes no parameters and returns a
2-element list (x, y).
@endWxPerlOnly
@see SetScrollbars(), Scroll()
*/
void GetViewStart(int* x, int* y) const;
/**
This is a simple overload of GetViewStart(int*,int*); see that function
for more info.
*/
wxPoint GetViewStart() const;
/**
Gets the size in device units of the scrollable window area (as
opposed to the client size, which is the area of the window currently
visible).
@param x
Receives the length of the scrollable window, in pixels.
@param y
Receives the height of the scrollable window, in pixels.
@remarks Use wxDC::DeviceToLogicalX() and wxDC::DeviceToLogicalY() to
translate these units to logical units.
@beginWxPerlOnly
In wxPerl this method takes no parameters and returns a
2-element list (xUnit, yUnit).
@endWxPerlOnly
@see SetScrollbars(), GetScrollPixelsPerUnit()
*/
void GetVirtualSize(int* x, int* y) const;
/**
Motif only: @true if the window has a backing bitmap.
*/
bool IsRetained() const;
/**
Called by the default paint event handler to allow the application to
define painting behaviour without having to worry about calling
DoPrepareDC().
Instead of overriding this function you may also just process the paint
event in the derived class as usual, but then you will have to call
DoPrepareDC() yourself.
*/
virtual void OnDraw(wxDC& dc);
/**
This function is for backwards compatibility only and simply calls
DoPrepareDC() now. Notice that it is not called by the default paint
event handle (DoPrepareDC() is), so overriding this method in your
derived class is useless.
*/
void PrepareDC(wxDC& dc);
/**
Scrolls a window so the view start is at the given point.
@param x
The x position to scroll to, in scroll units.
@param y
The y position to scroll to, in scroll units.
@remarks The positions are in scroll units, not pixels, so to convert to
pixels you will have to multiply by the number of
pixels per scroll increment. If either parameter is
::wxDefaultCoord (-1), that position will be ignored (no change
in that direction).
@see SetScrollbars(), GetScrollPixelsPerUnit()
*/
void Scroll(int x, int y);
/**
This is an overload of Scroll(int,int); see that function for more info.
*/
void Scroll(const wxPoint& pt);
/**
Set the horizontal and vertical scrolling increment only. See the
pixelsPerUnit parameter in SetScrollbars().
*/
void SetScrollRate(int xstep, int ystep);
/**
Sets up vertical and/or horizontal scrollbars.
The first pair of parameters give the number of pixels per 'scroll
step', i.e. amount moved when the up or down scroll arrows are pressed.
The second pair gives the length of scrollbar in scroll steps, which
sets the size of the virtual window.
@a xPos and @a yPos optionally specify a position to scroll to
immediately.
For example, the following gives a window horizontal and vertical
scrollbars with 20 pixels per scroll step, and a size of 50 steps (1000
pixels) in each direction:
@code
window->SetScrollbars(20, 20, 50, 50);
@endcode
wxScrolled manages the page size itself, using the current client
window size as the page size.
Note that for more sophisticated scrolling applications, for example
where scroll steps may be variable according to the position in the
document, it will be necessary to derive a new class from wxWindow,
overriding OnSize() and adjusting the scrollbars appropriately.
@param pixelsPerUnitX
Pixels per scroll unit in the horizontal direction.
@param pixelsPerUnitY
Pixels per scroll unit in the vertical direction.
@param noUnitsX
Number of units in the horizontal direction.
@param noUnitsY
Number of units in the vertical direction.
@param xPos
Position to initialize the scrollbars in the horizontal direction,
in scroll units.
@param yPos
Position to initialize the scrollbars in the vertical direction, in
scroll units.
@param noRefresh
Will not refresh window if @true.
@see wxWindow::SetVirtualSize()
*/
void SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
int noUnitsX,
int noUnitsY,
int xPos = 0,
int yPos = 0,
bool noRefresh = false);
/**
Call this function to tell wxScrolled to perform the actual scrolling
on a different window (and not on itself).
This method is useful when only a part of the window should be
scrolled. A typical example is a control consisting of a fixed header
and the scrollable contents window: the scrollbars are attached to the
main window itself, hence it, and not the contents window must be
derived from wxScrolled, but only the contents window scrolls when the
scrollbars are used. To implement such setup, you need to call this
method with the contents window as argument.
Notice that if this method is used, GetSizeAvailableForScrollTarget()
method must be overridden.
*/
void SetTargetWindow(wxWindow *window);
wxWindow *GetTargetWindow() const;
void SetTargetRect(const wxRect& rect);
wxRect GetTargetRect() const;
int GetScrollPageSize(int orient) const;
void SetScrollPageSize(int orient, int pageSize);
int GetScrollLines( int orient ) const;
void SetScale(double xs, double ys);
double GetScaleX() const;
double GetScaleY() const;
virtual void AdjustScrollbars();
/**
Are we generating the autoscroll events?
*/
bool IsAutoScrolling() const;
/**
Stop generating the scroll events when mouse is held outside the
window.
*/
void StopAutoScrolling();
/**
This method can be overridden in a derived class to forbid sending the
auto scroll events - note that unlike StopAutoScrolling() it doesn't
stop the timer, so it will be called repeatedly and will typically
return different values depending on the current mouse position
The base class version just returns true.
*/
virtual bool SendAutoScrollEvents(wxScrollWinEvent& event) const;
protected:
/**
Function which must be overridden to implement the size available for
the scroll target for the given size of the main window.
This method must be overridden if SetTargetWindow() is used (it is
never called otherwise). The implementation should decrease the @a size
to account for the size of the non-scrollable parts of the main window
and return only the size available for the scrollable window itself.
E.g. in the example given in SetTargetWindow() documentation the
function would subtract the height of the header window from the
vertical component of @a size.
*/
virtual wxSize GetSizeAvailableForScrollTarget(const wxSize& size);
};
/**
Scrolled window derived from wxPanel.
See wxScrolled for a detailed description.
@note Note that because this class derives from wxPanel, it shares its
behaviour with regard to TAB traversal and focus handling (in
particular, it forwards focus to its children). If you don't want
this behaviour, use ::wxScrolledCanvas instead.
@note ::wxScrolledWindow is an alias for wxScrolled<wxPanel> since version
2.9.0. In older versions, it was a standalone class.
@library{wxcore}
@category{miscwnd}
@see wxScrolled, ::wxScrolledCanvas
*/
typedef wxScrolled<wxPanel> wxScrolledWindow;
/**
Alias for wxScrolled<wxWindow>. Scrolled window that doesn't have children
and so doesn't need or want special handling of TAB traversal.
@since 2.9.0
@library{wxcore}
@category{miscwnd}
@see wxScrolled, ::wxScrolledWindow
*/
typedef wxScrolled<wxWindow> wxScrolledCanvas;
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