References ▼
#include "lttwn.h"
L_LTTWN_API L_INT L_TwainGetJPEGCompression(hSession, pTwJpegComp, uFlag)
Gets the current or default JPEG compression settings for the session.
Handle to an existing TWAIN session. This handle is obtained by calling the L_TwainInitSession or L_TwainInitSession2 function.
Pointer to a TW_JPEGCOMPRESSION structure that contains the JPEG compression settings.
Flag that indicates which type of JPEG compression values to get. Possible values are:
| Value | Meaning |
|---|---|
| LTWAIN_GET_JPEG_COMPRESSION | [0x0001] Get the current JPEG compression settings |
| LTWAIN_GET_DEFAULT_JPEG_COMPRESSION | [0x0002] Get the default JPEG compression settings |
| Value | Meaning |
|---|---|
| SUCCESS | The function was successful. |
| < 1 | An error occurred. Refer to Return Codes. |
This function will get the current or default TWAIN JPEG compression settings, depending on which flag gets passed to the uFlag parameter.
For more information about TW_JPEGCOMPRESSION, refer to the TWAIN specification.
This function must be called after calling the L_TwainStartCapsNeg function and before calling the L_TwainEndCapsNeg function.
Required DLLs and Libraries
L_INT TwainGetJPEGCompressionExample(HTWAINSESSION hSession){L_INT nRet;nRet = L_TwainStartCapsNeg (hSession);if(nRet != SUCCESS)return nRet;TW_JPEGCOMPRESSION myJPEG;memset(&myJPEG, 0, sizeof(TW_JPEGCOMPRESSION));nRet = L_TwainGetJPEGCompression(hSession, &myJPEG, LTWAIN_GET_JPEG_COMPRESSION);if (nRet == SUCCESS){myJPEG.ColorSpace = TWPT_GRAY;myJPEG.SubSampling = 0x10001000;myJPEG.NumComponents = 1;myJPEG.RestartFrequency = 0;myJPEG.QuantMap[0] = 0;memset(&myJPEG.QuantTable[0], 0, sizeof(TW_MEMORY));myJPEG.HuffmanMap[0] = 0;memset(&myJPEG.HuffmanDC[0], 0, sizeof(TW_MEMORY));memset(&myJPEG.HuffmanAC[0], 0, sizeof(TW_MEMORY));nRet = L_TwainSetJPEGCompression (hSession, &myJPEG, LTWAIN_SET_JPEG_COMPRESSION);if (nRet == SUCCESS){MessageBox(NULL, TEXT("Setting JPEG compression options was successful"), TEXT("Notice!"), MB_OK);return nRet;}}nRet = L_TwainEndCapsNeg(hSession);if(nRet != SUCCESS)return nRet;return SUCCESS;}