ZoomConstraint is a simple interface that describes a limitation on the available zoom sizes for a view, for example based on cache strategy or a (processing) window-size limitation. More...

#include <ZoomConstraint.h>

Inheritance diagram for ZoomConstraint:

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Public Types
enum	RoundingDirection { RoundDown, RoundUp, RoundNearest }

Public Member Functions
virtual	~ZoomConstraint ()

virtual int	getNearestBlockSize (int requestedBlockSize, RoundingDirection=RoundNearest) const
	Given the "ideal" block size (frames per pixel) for a given zoom level, return the nearest viable block size for this constraint. More...

virtual int	getMaxZoomLevel () const
	Return the maximum zoom level within range for this constraint. More...

Detailed Description

ZoomConstraint is a simple interface that describes a limitation on the available zoom sizes for a view, for example based on cache strategy or a (processing) window-size limitation.

The default ZoomConstraint imposes no actual constraint except for a nominal maximum.

Definition at line 30 of file ZoomConstraint.h.

Member Enumeration Documentation

◆ RoundingDirection

enum ZoomConstraint::RoundingDirection

Enumerator
RoundDown
RoundUp
RoundNearest

Definition at line 35 of file ZoomConstraint.h.

Constructor & Destructor Documentation

◆ ~ZoomConstraint()

virtual ZoomConstraint::~ZoomConstraint ( )

inlinevirtual

Definition at line 33 of file ZoomConstraint.h.

Member Function Documentation

◆ getNearestBlockSize()

virtual int ZoomConstraint::getNearestBlockSize	(	int	requestedBlockSize,
		RoundingDirection	= `RoundNearest`
	)		const

inlinevirtual

Given the "ideal" block size (frames per pixel) for a given zoom level, return the nearest viable block size for this constraint.

For example, if a block size of 1523 frames per pixel is requested but the underlying model only supports value summaries at powers-of-two block sizes, return 1024 or 2048 depending on the rounding direction supplied.

Reimplemented in PowerOfSqrtTwoZoomConstraint, and PowerOfTwoZoomConstraint.

Definition at line 51 of file ZoomConstraint.h.

References getMaxZoomLevel().