SQL Server Requires Chilkat v11.7.0+

QR Code Error Correction Levels

See more QR Code Examples

Demonstrates the four QR error-correction levels. L, M, Q and H allow a reader to recover the data when about 7%, 15%, 25% and 30% of the symbol is damaged or covered. More error correction leaves less room for data, so the same text needs a larger symbol at a higher level. The default is M. The example also shows boostErrorCorrection, which raises the level for free when the chosen version has room to spare. SQL Server

--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    DECLARE @iTmp1 int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  This example requires the Chilkat API to have been previously unlocked.
    --  See Global Unlock Sample for sample code.

    DECLARE @fmt int
    EXEC @hr = sp_OACreate 'Chilkat.Formats', @fmt OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @json int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @json OUT

    DECLARE @jsonOut int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @jsonOut OUT

    EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'payload.text', 'https://www.chilkatsoft.com/barcode_overview.asp'

    --  Encode the same text at each level.
    DECLARE @levels int
    EXEC @hr = sp_OACreate 'Chilkat.JsonArray', @levels OUT

    EXEC sp_OAMethod @levels, 'Load', @success OUT, '["L","M","Q","H"]'
    DECLARE @i int

    SELECT @i = 0
    WHILE @i <= 3
      BEGIN
        EXEC sp_OAMethod @levels, 'StringAt', @sTmp0 OUT, @i
        EXEC sp_OAMethod @json, 'UpdateString', @success OUT, 'encoding.qr.errorCorrection', @sTmp0
        EXEC sp_OAMethod @fmt, 'QrCode', @success OUT, 'generate', @json, @jsonOut
        IF @success = 0
          BEGIN
            EXEC sp_OAGetProperty @fmt, 'LastErrorText', @sTmp0 OUT
            PRINT @sTmp0
            EXEC @hr = sp_OADestroy @fmt
            EXEC @hr = sp_OADestroy @json
            EXEC @hr = sp_OADestroy @jsonOut
            EXEC @hr = sp_OADestroy @levels
            RETURN
          END

        EXEC sp_OAMethod @levels, 'StringAt', @sTmp0 OUT, @i

        EXEC sp_OAMethod @jsonOut, 'IntOf', @iTmp0 OUT, 'symbols[0].selectedEncoding.version'

        EXEC sp_OAMethod @jsonOut, 'IntOf', @iTmp1 OUT, 'symbols[0].dimensions.modulesWide'

        PRINT 'level ' + @sTmp0 + ': version ' + @iTmp0 + ', ' + @iTmp1 + ' modules wide'
        SELECT @i = @i + 1
      END

    --  The four symbols.  They hold the same text, and the higher the level, the larger the symbol:

    --  

    --  A symbol often has room left over.  boostErrorCorrection uses it: the level is raised
    --  as far as the same version allows, so the symbol is no larger but is more robust.
    DECLARE @json2 int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @json2 OUT

    EXEC sp_OAMethod @json2, 'UpdateString', @success OUT, 'payload.text', 'https://chilkatsoft.com'
    EXEC sp_OAMethod @json2, 'UpdateString', @success OUT, 'encoding.qr.errorCorrection', 'L'
    EXEC sp_OAMethod @fmt, 'QrCode', @success OUT, 'generate', @json2, @jsonOut
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @fmt, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @fmt
        EXEC @hr = sp_OADestroy @json
        EXEC @hr = sp_OADestroy @jsonOut
        EXEC @hr = sp_OADestroy @levels
        EXEC @hr = sp_OADestroy @json2
        RETURN
      END

    EXEC sp_OAMethod @jsonOut, 'IntOf', @iTmp0 OUT, 'symbols[0].selectedEncoding.version'

    EXEC sp_OAMethod @jsonOut, 'StringOf', @sTmp0 OUT, 'symbols[0].selectedEncoding.errorCorrection'
    PRINT 'level L requested: version ' + @iTmp0 + ', level ' + @sTmp0

    EXEC sp_OAMethod @json2, 'UpdateBool', @success OUT, 'encoding.qr.boostErrorCorrection', 1
    EXEC sp_OAMethod @fmt, 'QrCode', @success OUT, 'generate', @json2, @jsonOut
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @fmt, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @fmt
        EXEC @hr = sp_OADestroy @json
        EXEC @hr = sp_OADestroy @jsonOut
        EXEC @hr = sp_OADestroy @levels
        EXEC @hr = sp_OADestroy @json2
        RETURN
      END

    EXEC sp_OAMethod @jsonOut, 'IntOf', @iTmp0 OUT, 'symbols[0].selectedEncoding.version'

    EXEC sp_OAMethod @jsonOut, 'StringOf', @sTmp0 OUT, 'symbols[0].selectedEncoding.errorCorrection'
    PRINT 'level L with boost: version ' + @iTmp0 + ', level ' + @sTmp0

    --  Level L, and level M reached by the boost.  The two symbols are the same size:

    --  

    --  Sample output:

    --  level L: version 3, 29 modules wide
    --  level M: version 4, 33 modules wide
    --  level Q: version 5, 37 modules wide
    --  level H: version 6, 41 modules wide
    --  level L requested: version 2, level L
    --  level L with boost: version 2, level M

    EXEC @hr = sp_OADestroy @fmt
    EXEC @hr = sp_OADestroy @json
    EXEC @hr = sp_OADestroy @jsonOut
    EXEC @hr = sp_OADestroy @levels
    EXEC @hr = sp_OADestroy @json2


END
GO