libCZI::ScopedBitmapLocker< tBitmap > Class Template Reference

#include <libCZI_Pixels.h>

Inheritance diagram for libCZI::ScopedBitmapLocker< tBitmap >:

Public Member Functions
	ScopedBitmapLocker (tBitmap bmData)
	ScopedBitmapLocker (const ScopedBitmapLocker< tBitmap > &other)
	ScopedBitmapLocker (ScopedBitmapLocker< tBitmap > &&other) noexcept
	move constructor
ScopedBitmapLocker< tBitmap > &	operator= (ScopedBitmapLocker< tBitmap > &&other) noexcept
	move assignment

Additional Inherited Members
Public Attributes inherited from libCZI::BitmapLockInfo
void *	ptrData
	Not currently used, to be ignored.
void *	ptrDataRoi
	The pointer to the first (top-left) pixel of the bitmap.
std::uint32_t	stride
	The stride of the bitmap data (pointed to by ptrDataRoi).
std::uint64_t	size
	The size of the bitmap data (pointed to by ptrDataRoi) in bytes.

Detailed Description

template<typename tBitmap>
class libCZI::ScopedBitmapLocker< tBitmap >

A helper class used to scope the lock state of a bitmap.

It is intended to be used like this:

libCZI::IBitmapData* bm = ... // assume that we have a pointer to a bitmap
 
// this example assumes that the pixel type is Gray8 and nothing else...
if (bm->GetPixelType() != libCZI::PixelType::Gray8) throw std::exception();
 
{
    // access the bitmap's pixels directly within this scope
    libCZI::ScopedBitmapLocker<libCZI::IBitmapData*> lckBm{ bm };   // <- will call bm->Lock here
    for (std::uint32_t y  = 0; y < bm->GetHeight(); ++y)
    {
        const std::uint8_t* ptrLine = ((const std::uint8_t*)lckBm.ptrDataRoi) + y * lckBm.stride;
        for (std::uint32_t x  = 0; x < bm->GetWidth(); ++x)
        {
            auto pixelVal = ptrLine[x];
            // do something with the pixel...
        }
    }
    
    // when lckBm goes out of scope, bm->Unlock will be called
 }

For convenience two typedef are provided: ScopedBitmapLockerP and ScopedBitmapLockerSP for use with the types IBitmapData* and std::shared_ptr<IBitmapData>.

typedef ScopedBitmapLocker<IBitmapData*> ScopedBitmapLockerP;
typedef ScopedBitmapLocker<std::shared_ptr<IBitmapData>> ScopedBitmapLockerSP;

So in above sample we could have used

libCZI::ScopedBitmapLockerP lckBm{ bm };

This utility is intended to help adhering to the RAII-pattern, since it makes writing exception-safe code easier - in case of an exception (within the scope of the ScopedBitmapLocker object) the bitmap's Unlock method will be called (which is cumbersome to achieve otherwise).

Constructor & Destructor Documentation

ScopedBitmapLocker() [1/2]

template<typename tBitmap >

libCZI::ScopedBitmapLocker< tBitmap >::ScopedBitmapLocker ( tBitmap  bmData )

inlineexplicit

Constructor taking the object for which we provide the scope-guard.

Parameters

bmData

The object for which we are to provide the scope-guard.

ScopedBitmapLocker() [2/2]

template<typename tBitmap >

libCZI::ScopedBitmapLocker< tBitmap >::ScopedBitmapLocker ( const ScopedBitmapLocker< tBitmap > &  other )

inline

Copy-Constructor .

Parameters

other

The other object.

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The documentation for this class was generated from the following file:

• libCZI/libCZI_Pixels.h