• NAME
• SYNOPSIS
• FUNCTION DESCRIPTIONS
• AcquireCacheView
• CloseCacheView
• GetCacheView
• GetCacheViewIndexes
• GetCacheViewPixels
• OpenCacheView
• SetCacheView
• SyncCacheView

NAME

cache_view - Working with Cache Views

SYNOPSIS

const PixelPacket * AcquireCacheView( const ViewInfo *view, const long x, const long y, const unsigned long columns, const unsigned long rows, ExceptionInfo *exception );

void CloseCacheView( ViewInfo *view );

PixelPacket * GetCacheView( ViewInfo *view, const long x, const long y, const unsigned long columns, const unsigned long rows );

IndexPacket * GetCacheViewIndexes( const ViewInfo *view );

PixelPacket * GetCacheViewPixels( const ViewInfo *view );

ViewInfo * OpenCacheView( Image *image );

PixelPacket * SetCacheView( ViewInfo *view, const long x, const long y, const unsigned long columns, const unsigned long rows );

unsigned int SyncCacheView( ViewInfo *view );

FUNCTION DESCRIPTIONS

AcquireCacheView

Method AcquireCacheView gets pixels from the in-memory or disk pixel cache as defined by the geometry parameters. A pointer to the pixels is returned if the pixels are transferred, otherwise a NULL is returned.

The format of the AcquireCacheView method is:

const PixelPacket *AcquireCacheView ( const ViewInfo *view, const long x, const long y, const unsigned long columns, const unsigned long rows, ExceptionInfo *exception );

A description of each parameter follows:

pixels:

Method GetCacheView returns a null pointer if an error occurs, otherwise a pointer to the view pixels.

view:

The address of a structure of type ViewInfo.

x,y,columns,rows:

These values define the perimeter of a region of pixels.

exception:

Return any errors or warnings in this structure.

CloseCacheView

CloseCacheView() closes the specified view returned by a previous call to OpenCacheView ( ) .

The format of the CloseCacheView method is:

void CloseCacheView ( ViewInfo *view );

A description of each parameter follows:

view:

The address of a structure of type ViewInfo.

GetCacheView

GetCacheView() gets pixels from the in-memory or disk pixel cache as defined by the geometry parameters. A pointer to the pixels is returned if the pixels are transferred, otherwise a NULL is returned.

The format of the GetCacheView method is:

PixelPacket *GetCacheView ( ViewInfo *view, const long x, const long y, const unsigned long columns, const unsigned long rows );

A description of each parameter follows:

pixels:

Method GetCacheView returns a null pointer if an error occurs, otherwise a pointer to the view pixels.

view:

The address of a structure of type ViewInfo.

x,y,columns,rows:

These values define the perimeter of a region of pixels.

GetCacheViewIndexes

Method GetCacheViewIndexes returns the indexes associated with the specified view.

The format of the GetCacheViewIndexes method is:

IndexPacket *GetCacheViewIndexes ( const ViewInfo *view );

A description of each parameter follows:

indexes:

Method GetCacheViewIndexes returns the indexes associated with the specified view.

view:

The address of a structure of type ViewInfo.

GetCacheViewPixels

GetCacheViewPixels() returns the pixels associated with the specified specified view.

The format of the GetCacheViewPixels method is:

PixelPacket *GetCacheViewPixels ( const ViewInfo *view );

A description of each parameter follows:

view:

The address of a structure of type ViewInfo.

OpenCacheView

OpenCacheView() opens a view into the pixel cache.

The format of the OpenCacheView method is:

ViewInfo *OpenCacheView ( Image *image );

A description of each parameter follows:

image:

The image.

SetCacheView

SetCacheView() gets pixels from the in-memory or disk pixel cache as defined by the geometry parameters. A pointer to the pixels is returned if the pixels are transferred, otherwise a NULL is returned.

The format of the SetCacheView method is:

PixelPacket *SetCacheView ( ViewInfo *view, const long x, const long y, const unsigned long columns, const unsigned long rows );

A description of each parameter follows:

view:

The address of a structure of type ViewInfo.

x,y,columns,rows:

These values define the perimeter of a region of pixels.

SyncCacheView

SyncCacheView() saves the view pixels to the in-memory or disk cache. The method returns True if the pixel region is synced, otherwise False.

The format of the SyncCacheView method is:

unsigned int SyncCacheView ( ViewInfo *view );

A description of each parameter follows:

view:

The address of a structure of type ViewInfo.