wxScrolledWindow - The wxScrolled (not implemented in wx) 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.
Please see following description for synopsis
wxScrolledWindow(3) Erlang Module Definition wxScrolledWindow(3)
NAME
wxScrolledWindow - The wxScrolled (not implemented in wx) 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.
DESCRIPTION
There are two commonly used (but not the only possible!) specializa-
tions of this class:
Note: See wxScrolled::Create() (not implemented in wx) if you want to
use wxScrolled (not implemented in wx) with a custom class.
Starting from version 2.4 of wxWidgets, there are several ways to use a
?wxScrolledWindow (and now wxScrolled (not implemented in wx)). In par-
ticular, there are three ways to set the size of the scrolling area:
One way is to set the scrollbars directly using a call to setScroll-
bars/6. This is the way it used to be in any previous version of wxWid-
gets 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/3, or wxWindow:fitInside/1,
and setting the scrolling increments for it by calling setScrollRate/3.
Scrolling in some orientation is enabled by setting a non-zero incre-
ment 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 (not implemented in wx) with wxWindow:setSizer/3. 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/3. 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 setScroll-
bars/6 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 wxWin-
dow::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 wxWin-
dow::SetVirtualSizeHints() with wxWindow::SetMinVirtualSize() or simi-
lar and remove it entirely in future.
As with all windows, an application can draw onto a wxScrolled (not
implemented in wx) using a device context.
You have the option of handling the OnPaint handler or overriding the
wxScrolled::OnDraw() (not implemented in wx) function, which is passed
a pre-scrolled device context (prepared by doPrepareDC/2).
If you don't wish to calculate your own scrolling, you must call doPre-
pareDC/2 when not drawing from within OnDraw() (not implemented in wx),
to set the device origin for the device context according to the cur-
rent scroll position.
A wxScrolled (not implemented in wx) 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 spread-
sheet, you will normally only have to scroll the (usually white) cell
area, whereas the (usually grey) label area will scroll very differ-
ently. For this special purpose, you can call setTargetWindow/2 which
means that pressing the scrollbars will scroll a different window.
Note that the underlying system knows nothing about scrolling coordi-
nates, 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).
Styles
This class supports the following styles:
Note: Don't confuse wxScrollWinEvents generated by this class with
wxScrollEvent objects generated by wxScrollBar and wxSlider.
Remark: Use wxScrolled (not implemented in wx) for applications where
the user scrolls by a fixed amount, and where a 'page' can be inter-
preted to be the current visible portion of the window. For more
sophisticated applications, use the wxScrolled (not implemented in wx)
implementation as a guide to build your own scroll behaviour or use
wxVScrolledWindow (not implemented in wx) or its variants.
Since: The wxScrolled (not implemented in wx) template exists since
version 2.9.0. In older versions, only ?wxScrolledWindow (equivalent of
wxScrolled<wxPanel>) was available.
See: wxScrollBar, wxClientDC, wxPaintDC, wxVScrolledWindow (not imple-
mented in wx), wxHScrolledWindow (not implemented in wx), wxHVScrolled-
Window (not implemented in wx)
This class is derived (and can use functions) from: wxPanel wxWindow
wxEvtHandler
wxWidgets docs: wxScrolledWindow
EVENTS
Event types emitted from this class: scrollwin_top, scrollwin_bottom,
scrollwin_lineup, scrollwin_linedown, scrollwin_pageup, scrollwin_page-
down, scrollwin_thumbtrack, scrollwin_thumbrelease
DATA TYPES
wxScrolledWindow() = wx:wx_object()
EXPORTS
new() -> wxScrolledWindow()
Default constructor.
new(Parent) -> wxScrolledWindow()
Types:
Parent = wxWindow:wxWindow()
new(Parent, Options :: [Option]) -> wxScrolledWindow()
Types:
Parent = wxWindow:wxWindow()
Option =
{winid, integer()} |
{pos, {X :: integer(), Y :: integer()}} |
{size, {W :: integer(), H :: integer()}} |
{style, integer()}
Constructor.
Remark: The window is initially created without visible scroll-
bars. Call setScrollbars/6 to specify how big the virtual window
size should be.
calcScrolledPosition(This, Pt) -> {X :: integer(), Y :: integer()}
Types:
This = wxScrolledWindow()
Pt = {X :: integer(), Y :: integer()}
calcScrolledPosition(This, X, Y) ->
{Xx :: integer(), Yy :: integer()}
Types:
This = wxScrolledWindow()
X = Y = integer()
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 Calc-
ScrolledPosition(0, 10, xx, yy) will return 0 in yy.
See: calcUnscrolledPosition/3
calcUnscrolledPosition(This, Pt) ->
{X :: integer(), Y :: integer()}
Types:
This = wxScrolledWindow()
Pt = {X :: integer(), Y :: integer()}
calcUnscrolledPosition(This, X, Y) ->
{Xx :: integer(), Yy :: integer()}
Types:
This = wxScrolledWindow()
X = Y = integer()
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 CalcUn-
scrolledPosition(0, 0, xx, yy) will return 10 in yy.
See: calcScrolledPosition/3
enableScrolling(This, XScrolling, YScrolling) -> ok
Types:
This = wxScrolledWindow()
XScrolling = YScrolling = boolean()
Enable or disable use of wxWindow:scrollWindow/4 for scrolling.
By default, when a scrolled window is logically scrolled, wxWin-
dow:scrollWindow/4 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 argu-
ment, then this "physical scrolling" is disabled and the window
is entirely invalidated whenever it is scrolled by calling
wxWindow:refresh/2.
It should be rarely necessary to disable physical scrolling, so
this method shouldn't be called in normal circumstances.
getScrollPixelsPerUnit(This) ->
{XUnit :: integer(), YUnit :: integer()}
Types:
This = wxScrolledWindow()
Get the number of pixels per scroll unit (line), in each direc-
tion, as set by setScrollbars/6.
A value of zero indicates no scrolling in that direction.
See: setScrollbars/6, wxWindow:getVirtualSize/1
getViewStart(This) -> {X :: integer(), Y :: integer()}
Types:
This = wxScrolledWindow()
This is a simple overload of GetViewStart(int*,int*); see that
function for more info.
doPrepareDC(This, Dc) -> ok
Types:
This = wxScrolledWindow()
Dc = wxDC:wxDC()
Call this function to prepare the device context for drawing a
scrolled image.
It sets the device origin according to the current scroll posi-
tion. doPrepareDC/2 is called automatically within the default
wxEVT_PAINT event handler, so your OnDraw() (not implemented in
wx) override will be passed an already 'pre-scrolled' device
context. However, if you wish to draw from outside of OnDraw()
(not implemented in wx) (e.g. from your own wxEVT_PAINT han-
dler), you must call this function yourself.
For example:
Notice that the function sets the origin by moving it relatively
to the current origin position, so you shouldn't change the ori-
gin before calling doPrepareDC/2 or, if you do, reset it to (0,
0) later. If you call doPrepareDC/2 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.
prepareDC(This, Dc) -> ok
Types:
This = wxScrolledWindow()
Dc = wxDC:wxDC()
This function is for backwards compatibility only and simply
calls doPrepareDC/2 now.
Notice that it is not called by the default paint event handle
(doPrepareDC/2 is), so overriding this method in your derived
class is useless.
scroll(This, Pt) -> ok
Types:
This = wxScrolledWindow()
Pt = {X :: integer(), Y :: integer()}
This is an overload of scroll/3; see that function for more
info.
scroll(This, X, Y) -> ok
Types:
This = wxScrolledWindow()
X = Y = integer()
Scrolls a window so the view start is at the given point.
Remark: 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 ?wxDefault-
Coord (-1), that position will be ignored (no change in that
direction).
See: setScrollbars/6, getScrollPixelsPerUnit/1
setScrollbars(This, PixelsPerUnitX, PixelsPerUnitY, NoUnitsX,
NoUnitsY) ->
ok
Types:
This = wxScrolledWindow()
PixelsPerUnitX = PixelsPerUnitY = NoUnitsX = NoUnitsY = inte-
ger()
setScrollbars(This, PixelsPerUnitX, PixelsPerUnitY, NoUnitsX,
NoUnitsY,
Options :: [Option]) ->
ok
Types:
This = wxScrolledWindow()
PixelsPerUnitX = PixelsPerUnitY = NoUnitsX = NoUnitsY = inte-
ger()
Option =
{xPos, integer()} | {yPos, integer()} | {noRefresh, bool-
ean()}
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 scroll-
bar in scroll steps, which sets the size of the virtual window.
xPos and yPos optionally specify a position to scroll to immedi-
ately.
For example, the following gives a window horizontal and verti-
cal scrollbars with 20 pixels per scroll step, and a size of 50
steps (1000 pixels) in each direction:
wxScrolled (not implemented in wx) 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.
See: wxWindow:setVirtualSize/3
setScrollRate(This, Xstep, Ystep) -> ok
Types:
This = wxScrolledWindow()
Xstep = Ystep = integer()
Set the horizontal and vertical scrolling increment only.
See the pixelsPerUnit parameter in setScrollbars/6.
setTargetWindow(This, Window) -> ok
Types:
This = wxScrolledWindow()
Window = wxWindow:wxWindow()
Call this function to tell wxScrolled (not implemented in wx) 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 con-
tents window must be derived from wxScrolled (not implemented in
wx), 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, GetSizeAvailableForScroll-
Target() (not implemented in wx) method must be overridden.
destroy(This :: wxScrolledWindow()) -> ok
Destroys the object.
wxWidgets team. wx 2.1.1 wxScrolledWindow(3)