en:software:qview:qview_6:qcl_library:vi10begindrawbuffer

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en:software:qview:qview_6:qcl_library:vi10begindrawbuffer [2017/02/27 17:28] – created qem103en:software:qview:qview_6:qcl_library:vi10begindrawbuffer [2019/08/29 17:01] (current) – external edit 127.0.0.1
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 +====== VI10BeginDrawBuffer ======
 +
 +**V = **//Vector//
 +
 +**I = **//Image//
 +
 +Function that is used to manage the Vector Image feature (object that resides on some versions of Qpaint).
 +
 +The VI10BeginDrawBuffer function has the task of preparing the buffer to next add paint operations.
 +The function also checks for errors and then places them in the variable given as the second argument. 
 +
 +Before you start building the buffer content, if you want to start a new drawing, you must call this function or function [[.:VI10InitBuffer]].
 +
 +===== IMPLEMENTATION =====
 +
 +**VI10BeginDrawBuffer (awBuffer, gwError)**
 +
 +Parameters:
 +
 +^IN/OUT^VARIABLE TYPE^EXAMPLE NAME^DIM^^
 +|  IN  |  ARRSYS /\\ ARRGBL  |  awBuffer  |  W  |Array that serves as a buffer for instructions/data|
 +|  OUT  |  SYSTEM /\\ GLOBAL  |  gwError  |  W  |Error variable|
 +
 +=== Example ===
 +
 +//TASK_00//
 +<code QCl>
 +MAIN:
 +  IF gfDraw
 +    VI11WaitBufferReadyUsingWAIT(awBuffer)
 +    VI10BeginDrawBuffer(awBuffer, gwError)
 +    IF gwError
 +      ; Error report
 +    ELSE
 +      ...
 +      VI10DrawBuffer(awBuffer)
 +    ENDIF
 +    gfDraw = 0
 +  ENDIF
 +END
 +</code>
 +
 +=== Note ===
 +In case the error variable already has a value other than zero, it __will not be overwritten__.