The native scrollbars of the matrices a worksheet shows in a viewport. More...

#include <MatrixScrollbars.h>

Inheritance diagram for MatrixScrollbars:

Collaboration diagram for MatrixScrollbars:

Public Member Functions
	MatrixScrollbars (wxScrolled< wxWindow > *worksheet)

	MatrixScrollbars (const MatrixScrollbars &)=delete

MatrixScrollbars &	operator= (const MatrixScrollbars &)=delete

wxCoord	ScrollbarThickness () const override
	How thick a native scrollbar is, in worksheet pixels.

void	MatrixDrawn (MatrCell *matrix) override
	A matrix that needs scrollbars has just been drawn.

void	BeginPaint ()
	To be called before a paint draws any cell.

void	EndPaint (const wxRegion &updateRegion)
	To be called once a paint has drawn all it is going to.

void	Sync ()
	Creates, moves, shows and hides scrollbars as the last paint found.

size_t	VisibleScrollbars () const
	How many scrollbars are visible right now (for tests)

Detailed Description

The native scrollbars of the matrices a worksheet shows in a viewport.

A MatrCell in Configuration::OversizedMatrices::scroll mode knows where its scrollbars belong, but owns no window: see MatrixScrollHost for why. This is the worksheet's side of that arrangement. It keeps one real wxScrollBar per scrollbar a matrix needs, as a child window of the worksheet, and keeps them in line with the matrices:

Every matrix that needs scrollbars reports in (MatrixDrawn()) each time it is drawn. A paint handler must not create, move or show windows, so that only notes the fact; EndPaint() then schedules Sync() for after the paint, which does the actual work.
A matrix that goes away – deleted, re-evaluated, folded away, its output hidden – simply stops being drawn. So a scrollbar is hidden when the place its matrix was last drawn at gets repainted without the matrix, and destroyed once the matrix itself has been (CellPtr notices that).
The worksheet's own scrolling needs nothing from here: wxScrolled moves its child windows along with its contents.

Moving a matrix's scrollbar scrolls the matrix (MatrCell::ScrollTo()) and redraws just it; no relayout is needed. The mouse wheel over the matrix still scrolls the worksheet, so a matrix never traps the wheel, and the scrollbars never keep the keyboard focus: typing always goes to the worksheet.

Member Function Documentation

◆ EndPaint()

void MatrixScrollbars::EndPaint ( const wxRegion & updateRegion )

To be called once a paint has drawn all it is going to.

Parameters

updateRegion what the paint repainted, in window coordinates

◆ MatrixDrawn()

void MatrixScrollbars::MatrixDrawn ( MatrCell * matrix )

overridevirtual

A matrix that needs scrollbars has just been drawn.

Called from MatrCell::Draw(), i.e. from inside the paint handler, so the host must not create, move or show windows here – only note what is needed, and act once the paint is over.

Implements MatrixScrollHost.

◆ ScrollbarThickness()

wxCoord MatrixScrollbars::ScrollbarThickness ( ) const