MgraAlloc

Board	Supported
Host System	Yes
V4L2	Yes
Clarity UHD	Yes
Concord PoE	No
GenTL	Yes
GevIQ	Yes
GigE Vision	Yes
Indio	No
Iris GTX	Yes
Radient eV-CL	Yes
Rapixo CL	Yes
Rapixo CoF	Yes
Rapixo CXP	Yes
USB3 Vision	Yes

Allocate a 2D graphics context.

Syntax

AIL_ID MgraAlloc(
    AIL_ID   SysId,           //in
    AIL_ID * ContextGraIdPtr  //out
)

Description

This function allocates a 2D graphics context on the specified system. A 2D graphics context is required to use Aurora Imaging Library graphics to perform annotations. Whenever an annotation is done, 2D graphics context settings are inherited by the graphics. Different contexts can coexist; use their identifier to specify which to use or change.

To modify or inquire 2D graphics context settings, use MgraControl and MgraInquire.

Note that, upon allocation of an application, a default 2D graphics context is automatically allocated. Rather than using MgraAlloc to allocate a 2D graphics context, you can use this default 2D graphics context, by specifying M_DEFAULT wherever a 2D graphics context identifier is required. Note that there is a different default 2D graphics context for each thread.

When the 2D graphics context is no longer required, release it usingMgraFreeunless M_UNIQUE_ID was specified during allocation; if M_UNIQUE_ID was specified, the smart identifier manages the 2D graphics context's lifetime and you must not manually free it.

Parameters

SysId (in, AIL_ID)

Specifies the system on which to allocate the 2D graphics context.

For specifying the system

Value	Description
M_DEFAULT_HOST	Specifies the default Host system of the current Aurora Imaging Library application.
System identifier	Specifies a valid system identifier, previously allocated using MsysAlloc.

ContextGraIdPtr *(out, AIL_ID)

Specifies the address of the variable in which to write the 2D graphics context identifier or specifies the data type that the function should use to return the 2D graphics context identifier.

For retrieving the identifier or specifying how to return it

Value	Description
M_NULL	Specifies that you will use this function's return value to obtain the identifier of the allocated 2D graphics context; in this case, a standard Aurora Imaging Library identifier of type AIL_ID is returned.
M_UNIQUE_ID	Specifies that you will use this function's return value to obtain the identifier of the allocated 2D graphics context; in this case, an Aurora Imaging Library smart identifier of type _AIL_UNIQUE_GRA_ID_is returned instead of a standard Aurora Imaging Library identifier.This setting is only available when using C++11 (or later).An Aurora Imaging Library smart identifier manages the lifespan of the Aurora Imaging Library object it owns (similar to a std::unique_ptr). Note, you can use an Aurora Imaging Library smart identifier as though it were a standard Aurora Imaging Library identifier, except that you cannot use it to manually free the 2D graphics context (it is freed automatically). For more information, see Aurora Imaging Library smart identifiers.
Address in which to write the identifier	Specifies the address of an AIL_ID in which to write the identifier of the allocated 2D graphics context.

If allocation fails, M_NULL is written as the identifier. |

Return Value

Type: AIL_ID

The returned value is the 2D graphics context identifier either as a standard identifier (AIL_ID) or a smart identifier (AIL_UNIQUE_GRA_ID). If allocation fails, M_NULL is returned (or nullptr ifM_UNIQUE_ID was specified).