DataFlex Requires Chilkat v11.7.0+

QR Code Quiet Zone, Padding and Rotation

See more QR Code Examples

Demonstrates the space around a QR code and its rotation. The quiet zone is the blank margin a reader needs around the symbol. It is measured in modules, the QR standard requires 4, and QrCode will make it larger but not smaller. Padding is extra space outside the quiet zone, measured in the render units (pixels by default). Rotation turns the whole image by 90, 180 or 270 degrees. A QR code reads the same at any rotation. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vJson
    Handle hoJson
    Handle hoFmt
    Variant vJsonOut
    Handle hoJsonOut
    String sTemp1
    Integer iTemp1
    Integer iTemp2
    Integer iTemp3
    Integer iTemp4

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Get ComUpdateString Of hoJson "payload.text" "https://www.chilkatsoft.com/" To iSuccess
    Get ComUpdateInt Of hoJson "render.moduleSize" 6 To iSuccess

    //  A quiet zone of 6 modules on every side instead of the standard 4.
    Get ComUpdateInt Of hoJson "render.quietZone.left" 6 To iSuccess
    Get ComUpdateInt Of hoJson "render.quietZone.top" 6 To iSuccess
    Get ComUpdateInt Of hoJson "render.quietZone.right" 6 To iSuccess
    Get ComUpdateInt Of hoJson "render.quietZone.bottom" 6 To iSuccess

    //  10 more pixels of background around that.
    Get ComUpdateInt Of hoJson "render.padding" 10 To iSuccess

    //  Turn the image a quarter turn clockwise.
    Get ComUpdateInt Of hoJson "render.rotation" 90 To iSuccess

    Get ComUpdateString Of hoJson "output.path" "qa_output/qr_margins.png" To iSuccess
    Get ComUpdateBool Of hoJson "output.overwrite" True To iSuccess
    Get ComUpdateString Of hoJson "output.return" "none" To iSuccess

    Get Create (RefClass(cComChilkatFormats)) To hoFmt
    If (Not(IsComObjectCreated(hoFmt))) Begin
        Send CreateComObject of hoFmt
    End
    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonOut
    If (Not(IsComObjectCreated(hoJsonOut))) Begin
        Send CreateComObject of hoJsonOut
    End
    Get pvComObject of hoJson to vJson
    Get pvComObject of hoJsonOut to vJsonOut
    Get ComQrCode Of hoFmt "generate" vJson vJsonOut To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoFmt To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComIntOf Of hoJsonOut "measurements[0].pitch" To iTemp1
    Showln "module: " iTemp1 " pixels"
    Get ComIntOf Of hoJsonOut "measurements[0].symbolWidth" To iTemp1
    Get ComIntOf Of hoJsonOut "measurements[0].symbolHeight" To iTemp2
    Get ComIntOf Of hoJsonOut "measurements[0].symbolX" To iTemp3
    Get ComIntOf Of hoJsonOut "measurements[0].symbolY" To iTemp4
    Showln "symbol: " iTemp1 " x " iTemp2 " pixels at (" iTemp3 "," iTemp4 ")"
    Get ComIntOf Of hoJsonOut "measurements[0].quietZonePx.left" To iTemp1
    Showln "quiet zone: " iTemp1 " pixels"
    Get ComIntOf Of hoJsonOut "measurements[0].paddingPx" To iTemp1
    Showln "padding: " iTemp1 " pixels"
    Get ComIntOf Of hoJsonOut "measurements[0].rotation" To iTemp1
    Showln "rotation: " iTemp1
    Get ComIntOf Of hoJsonOut "measurements[0].canvasWidth" To iTemp1
    Get ComIntOf Of hoJsonOut "measurements[0].canvasHeight" To iTemp2
    Showln "image: " iTemp1 " x " iTemp2 " pixels"

    //  The image, enlarged, with the quiet zone and the padding tinted here to show where they are.
    //  In the image itself both are plain white.  A QR code has no finder pattern (the large squares)
    //  in its bottom right corner.  After the quarter turn that corner is at the bottom left:

    //  

    //  Sample output:

    //  module: 6 pixels
    //  symbol: 174 x 174 pixels at (46,46)
    //  quiet zone: 36 pixels
    //  padding: 10 pixels
    //  rotation: 90
    //  image: 266 x 266 pixels


End_Procedure