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Fix of the Flash description for Flash == OFF #356

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Oct 10, 2018
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Fix of the Flash description for Flash == OFF #356

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3 changes: 2 additions & 1 deletion Source/com/drew/metadata/exif/ExifDescriptorBase.java
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Original file line number Diff line number Diff line change
Expand Up @@ -844,7 +844,8 @@ public String getFlashDescription()
sb.append(", return not detected");
}

if ((value & 0x10) != 0)
// If 0x10 is set and the lowest byte is not zero - then flash is Auto
if ((value & 0x10) != 0 && (value & 0x0F) != 0)
sb.append(", auto");
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Do you have a reference for this change? (On phone right now.)

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@Gorbush Gorbush Oct 9, 2018 •
edited by drewnoakes
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The reference is here:
Hi,

sorry missed this email.
By reference did you mean why I think this change is right?

Here is the clarification:
com/drew/metadata/exif/ExifDirectoryBase.java:333
Basing on the description of this field

/**
 * 0x0  = 0000000 = No Flash
 * 0x1  = 0000001 = Fired
 * 0x5  = 0000101 = Fired, Return not detected
 * 0x7  = 0000111 = Fired, Return detected
 * 0x9  = 0001001 = On
 * 0xd  = 0001101 = On, Return not detected
 * 0xf  = 0001111 = On, Return detected
 * 0x10 = 0010000 = Off
 * 0x18 = 0011000 = Auto, Did not fire
 * 0x19 = 0011001 = Auto, Fired
 * 0x1d = 0011101 = Auto, Fired, Return not detected
 * 0x1f = 0011111 = Auto, Fired, Return detected
 * 0x20 = 0100000 = No flash function
 * 0x41 = 1000001 = Fired, Red-eye reduction
 * 0x45 = 1000101 = Fired, Red-eye reduction, Return not detected
 * 0x47 = 1000111 = Fired, Red-eye reduction, Return detected
 * 0x49 = 1001001 = On, Red-eye reduction
 * 0x4d = 1001101 = On, Red-eye reduction, Return not detected
 * 0x4f = 1001111 = On, Red-eye reduction, Return detected
 * 0x59 = 1011001 = Auto, Fired, Red-eye reduction
 * 0x5d = 1011101 = Auto, Fired, Red-eye reduction, Return not detected
 * 0x5f = 1011111 = Auto, Fired, Red-eye reduction, Return detected
 *        6543210 (positions)
 *
 * This is a bitmask.
 * 0 = flash fired
 * 1 = return detected
 * 2 = return able to be detected
 * 3 = unknown
 * 4 = auto used
 * 5 = unknown
 * 6 = red eye reduction used
 */

Auto is everywhere where bit is set 0x10 but requires that the lower 4 bits
are not zero:

 * 0x10 = 0010000 = Off

 * 0x18 = 0011000 = Auto, Did not fire
 * 0x19 = 0011001 = Auto, Fired
 * 0x1d = 0011101 = Auto, Fired, Return not detected
 * 0x1f = 0011111 = Auto, Fired, Return detected

 * 0x59 = 1011001 = Auto, Fired, Red-eye reduction
 * 0x5d = 1011101 = Auto, Fired, Red-eye reduction, Return not detected
 * 0x5f = 1011111 = Auto, Fired, Red-eye reduction, Return detected

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Thanks for following up. This looks great.


if ((value & 0x40) != 0)
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