Macro Scheduler Floating Point DTWAIN Examples

Here are some examples of usage of Macro Scheduler and handling of floating point in DTWAIN:

Example 1: Set the current resolution value:

LibLoad> DTWAIN32.DLL,hLib

If> hLib <> 0

    // check if TWAIN is available

    LibFunc> hLib,DTWAIN_IsTwainAvailable,avail

    If> avail<> 0

        // Initialize the library

        LibFunc> hLib,DTWAIN_SysInitialize,ret

       // Select the source

        LibFunc> hLib,DTWAIN_SelectSource,TwainSource

        If> TwainSource <> 0

              LibFunc> hLib,DTWAIN_SetResolutionString,bOk,TwainSource,300.0

              If> bOk <> 0

                   // create a buffer that is 255 in length

                   Let> buffer_SIZE=255

                   LibFunc> hLib,DTWAIN_GetResolutionString,bOk,TwainSource,buffer

                   MessageModal>Window Text: %bOk_2%

              EndIf

        EndIf

        // Close Source and shutdown DTWAIN

        LibFunc> hLib,DTWAIN_SysDestroy,ret2

    EndIf

    // Unload the DLL

    LibFree> hLib

Endif

In Example 1, the function DTWAIN_SetResolutionString and DTWAIN_GetResolutionString act exactly the same as DTWAIN_SetResolution and DTWAIN_GetResolution, with the lone exception being that the last parameter of the DTWAIN_xxxString() function is a string value instead of a DTWAIN_FLOAT.  This allows Macro Scheduler programmers to use string values instead of floating point variables.  Note that for DTWAIN_GetResolutionString, the buffer must be sized before sending it to the DTWAIN function that gets the data.

In addition, the Macro Scheduler paradigm of returning values based on position (the bOk_2) is done to retrieve the resolution value.  Please consult the Macro Scheduler documentation on retrieving values from a DLL function.

Example 2:  Get all of the resolution values.  This example shows conversion of an array of floating point values to fixed point values.

Let> fixedPtArray = 0

Let> whole=0

Let> frac=0

Let> floatArrayRef=0

LibLoad> DTWAIN32.DLL,hLib

If> hLib <> 0

    // check if TWAIN is available

    LibFunc> hLib,DTWAIN_IsTwainAvailable,avail

   If> avail<> 0

        // Initialize the library

        LibFunc> hLib,DTWAIN_SysInitialize,ret

       // Select the source

        LibFunc> hLib,DTWAIN_SelectSource,TwainSource

        If> TwainSource <> 0

              // get the resolution values

              LibFunc> hLib,DTWAIN_EnumResolutionValues,floatArray,TwainSource,ref:floatArrayRef,1

              // get the number of resolution values

              LibFunc> hLib,DTWAIN_ArrayGetCount,numValues,floatArray_2

              If> numValues <> 0

                   // convert to fixed point array

                   LibFunc> hLib,DTWAIN_ArrayConvertFloatToFix32,fixedPtArray,floatArray_2

                   // output the values

                   Let> i=0

                   Let> strValue=

                   While> i < numValues

                            // whole and frac contain the values in the array

                           LibFunc> hLib,DTWAIN_ArrayFix32GetAt,numParts,fixedPtArray,i,ref:whole,ref:frac

                           LTrim> numParts_3,numParts_3

                           LTrim> numParts_4,numParts_4

                           ConCat> strValue,numParts_3

                           ConCat> strValue,.

                           ConCat> strValue,numParts_4

                           ConCat> strValue,CRLF

                           Add> i,1

                    EndWhile

                    MessageModal>Resolution Values: %CRLF% %strValue%

         EndIf

     Endif

      // Close Source and shutdown DTWAIN

      LibFunc> hLib,DTWAIN_SysDestroy,ret2

   EndIf

Endif

Note that the call to DTWAIN_ArrayConvertFloatToFix32 converts the array of 64-bit floating point values to an array of fixed point values (The device resolution values are potentially floating point value, thus the need to use floating point types to store this information).  Once that's done, to get the whole number and fractional portion of the fixed point number, the DTWAIN_ArrayFix32GetAt function returns the whole number and fractional portion of the desired number.