Are you able to load and save the bitmap to a file?
On Fri, Aug 29, 2008 at 2:13 PM, Jared Miller <[EMAIL PROTECTED]> wrote:
> Hello,
>
> I am having trouble figuring out how to successfully write an image to the
> SQLite database as a Blob, using C++.
>
> I have an HBITMAP that I would like to be able to store to and retrieve from
> the DB. If I understand what I have read correctly, I am supposed to write
> out the actual byte data to the DB. Here is what I have done so far.
>
> I pass in pbyBitmap as the bmBytes parameter to this function:
> ImportPageImage(CPage* pPage, BYTE* bmBytes, DWORD bmSize), which calls the
> code below. . .
>
> //prepare query
> static const WCHAR tblInsertBlob[] = _T("Insert into [tblBlob] ([Data])
> values (?)");
> SQL_HANDLE blobHandle = m_pSqliteDB->PrepareQuery16(tblInsertBlob); //calls
> sqlite3_prepare16()
>
> //bind blob
> m_pSqliteDB->BindBlob(blobHandle, 1, (void *)bmBytes, bmSize); //calls
> sqlite3_bind_blob (bmBytes is the pData param)
>
> Then I call StepQuery to execute it, and then I close the query.
> sqlite3_bind_blob() returns SQLITE_OK when I run it, so it does not seem to
> be encountering an error there.
>
> Something apparently gets written to the database, but it does not seem to be
> correct. When I try to retrieve and display my image, it is all black (which
> is how bitmaps look when there is no data).
>
> I think that the problem is coming from writing the BLOB to the database, but
> I am not entirely sure. Just in case it is getting written properly and I am
> not reading it from the database correctly, I will show you how I pulled it
> from the DB.
>
> //prepare blob
> sqlite3_blob* pBlob = NULL;
> sqlite3_blob_open(m_sqliteDB, "main", "tblBlob", "Data", iBlobID, FALSE,
> &pBlob);
>
> BLOB_HANDLE hBlob = pBlob;
> int size = sqlite3_blob_bytes(hBlob); //works correctly, returns 998058
> BYTE* pBuffer = g_MemMgr.AllocDataBuffer(size);
>
> sqlite3_blob_read(hBlob, pBuffer, size, 0); //returns SQLITE_OK
> sqlite3_blob_close(hBlob);
>
> I then try to make a bitmap out of the bytes in pBuffer, but when I do, it
> turns out all black (as I mentioned earlier).
>
> Do I have the concept correct? And if so, what part of my current code should
> I change to be able to use my DB to store image data?
>
> Thanks a lot.
>
>
>
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