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How to tell if an image contains a "handwritten signature"?


How to tell if an image contains a "handwritten signature"?

By : sgalloway
Date : November 21 2020, 09:01 AM
I wish did fix the issue. This is the code I've used in the past for checking for a signature. It assumes that an image has a Bytes per pixel of 3.
The MAX_BLACK_VALUE number comes from the max value for a colour of a pixel (255) multiplied by 3 (because there is a bytes per pixel of 3) then halved.
code :
private const int MAX_BLACK_VALUE = 382; // ((255 * 3) / 2) rounded down

private bool CheckForSignature(string SignatureFile, int MinPixelCount)
{
    using (Bitmap bitmap = new Bitmap(SignatureFile))
    {
        int nBytesPerPixel = Bitmap.GetPixelFormatSize(bitmap.PixelFormat) / 8;
        System.Drawing.Imaging.BitmapData bitmapData = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, bitmap.PixelFormat);
        try
        {
            byte[] baPixels = new byte[bitmapData.Stride * bitmap.Height];
            System.Runtime.InteropServices.Marshal.Copy(bitmapData.Scan0, baPixels, 0, baPixels.Length);

            int nBlackPixels = 0;
            for (int h = 0; h < bitmap.Height; h++)
            {
                int nCurrentLine = h * bitmapData.Stride;
                for (int w = 0; w < (bitmap.Width * nBytesPerPixel); w += nBytesPerPixel)
                {
                    int nBlue = baPixels[nCurrentLine + w];
                    int nGreen = baPixels[nCurrentLine + w + 1];
                    int nRed = baPixels[nCurrentLine + w + 2];

                    if (nBlue + nGreen + nRed <= MAX_BLACK_VALUE)
                    {
                        nBlackPixels++;
                        if (nBlackPixels >= MinPixelCount)
                            return true;
                    }
                }
            }
        }
        finally
        {
            bitmap.UnlockBits(bitmapData);
        }
    }

    return false;
}


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Gmail: Image Signature "Images are not displayed" Issue

Gmail: Image Signature "Images are not displayed" Issue


By : tgomes
Date : March 29 2020, 07:55 AM
This might help you At the moment, you can't set Gmail to display all images from any sender; you must do this on a per-contact basis.
source: http://support.google.com/mail/bin/answer.py?hl=en&answer=8833
How to make "MessageDigest SHA-1 and Signature NONEwithRSA" equivalent to "Signature SHA1withRSA "

How to make "MessageDigest SHA-1 and Signature NONEwithRSA" equivalent to "Signature SHA1withRSA "


By : Autumn
Date : March 29 2020, 07:55 AM
Hope that helps I am interested in applying a SHA-1 hash with RSA signature to some data, but I need to do it in two steps - apply hash first and then sign the data. The Signature.sign() function appears to create a more complex (ASN.1?) data structure that is ultimately signed (see this question). How can I make the two equivalent without using any external libraries like BouncyCastle? , I was able to solve this by doing the following:
Alloy terminology: signature "declaration" and signature "introduces" atoms

Alloy terminology: signature "declaration" and signature "introduces" atoms


By : Cookie
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further "Declaration" is a standard term in programming or spec languages for introducing (-;) a variable without giving it a value. I used the term "introduces" rather than "creates" to avoid the implication that there is an immediate operational effect (since the set of atoms is determined by constraint solving).
Method "DefaultAdapter" with signature "" on interface "org.bluez.Manager" doesn't exist i

Method "DefaultAdapter" with signature "" on interface "org.bluez.Manager" doesn't exist i


By : shixing leo
Date : March 29 2020, 07:55 AM
I hope this helps you . I had the same issue with org.bluez.Manager
There is also org.freedesktop.DBus.ObjectManager. This should get you those objects (from https://github.com/Douglas6/blueplayer/blob/master/blueplayer.py):
code :
import dbus

SERVICE_NAME = "org.bluez"
OBJECT_IFACE =  "org.freedesktop.DBus.ObjectManager"
ADAPTER_IFACE = SERVICE_NAME + ".Adapter1"
DEVICE_IFACE = SERVICE_NAME + ".Device1"
PROPERTIES_IFACE = "org.freedesktop.DBus.Properties"
bus = dbus.SystemBus()
manager = dbus.Interface(bus.get_object("org.bluez", "/"), "org.freedesktop.DBus.ObjectManager")
objects = manager.GetManagedObjects()
for path, ifaces in objects.iteritems():
    adapter = ifaces.get(ADAPTER_IFACE)
    if adapter is None:
        continue
    obj = bus.get_object(SERVICE_NAME, path)
    adapter = dbus.Interface(obj, ADAPTER_IFACE)
"non-existent directory or file for FILEOPEN operation" when generating signature of an image in oracle 11g?

"non-existent directory or file for FILEOPEN operation" when generating signature of an image in oracle 11g?


By : pkbellamy
Date : November 04 2020, 04:01 AM
wish help you to fix your issue After creating a directory for media elements in "c:\work" I declared the directory in sqlplus
code :
ORDSYS.ORDImage.init('FILE', 'FILE_DIR','tess.jpg')
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