Convert Inline Data-URL Images to Related Parts

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Demonstrates the Chilkat Email.ConvertInlineImages method, which converts images embedded inline within HTML (as base64 data URLs) into multipart/related MIME parts referenced from the HTML by cid:. This example sets an HTML body containing a data-URL image and converts it.

Background: HTML can embed an image two ways: as a data: URL (the base64 bytes sit right in the src attribute) or as a related part referenced by cid:. Many email clients don't render data: URLs for security reasons, so converting them to proper multipart/related parts — the traditional email way to embed images — greatly improves how reliably the images display.

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#include <C_CkEmail.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkEmail email;

    success = FALSE;

    //  Demonstrates the ConvertInlineImages method, which converts images embedded inline within
    //  HTML (as base64 data URLs) into multipart/related MIME parts referenced from the HTML by
    //  CID.

    email = CkEmail_Create();
    CkEmail_putSubject(email,"Convert inline images");

    //  An HTML body with a base64 data-URL image (a 1x1 PNG).
    CkEmail_SetHtmlBody(email,"<html><body><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==\"/></body></html>");

    printf("NumRelatedItems before = %d\n",CkEmail_getNumRelatedItems(email));

    //  Convert the inline data-URL image(s) to multipart/related parts referenced by CID.

    success = CkEmail_ConvertInlineImages(email);
    if (success == FALSE) {
        printf("%s\n",CkEmail_lastErrorText(email));
        CkEmail_Dispose(email);
        return;
    }

    printf("NumRelatedItems after = %d\n",CkEmail_getNumRelatedItems(email));


    CkEmail_Dispose(email);

    }