461bc42fab
git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@8114 8e941d3f-bd1b-0410-a28a-d453659cc2b4
63 lines
2.5 KiB
Plaintext
63 lines
2.5 KiB
Plaintext
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Visual CAPTCHA component for Lazarus
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Description
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-----------
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The component TCaptchaLabel descends from TGraphicControl and contains its own
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drawing routine. Just place it on the form and use it. It displays a random
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string with slanted characters and overlaid lines.
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The method Verify() checks whether a user-provided string matches the
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captcha string and returns true.
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There are several properties to define its behaviour:
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* NumChars: Number of characters in the captcha
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* NumLines: Number of lines drawn over the captcha
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* Font1, Font2: two fonts to be mixed within the captcha randomly
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* MaxAngle: maximum rotation angle for the characters which are rotated by a
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random angle between -MaxAngle and +MaxAngle
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* Color: the background color of the area of the control covered by the captcha.
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Character and line colors are selected such that a minimum brightness difference
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to the background color is achieved.
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* Options: This is a set of the following options which can be combined:
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* coAlphaUpper: Use uppercase characters as defined by the the UppercaseChars string
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* coAlphaLower: Use lowercase characters as defined by the LowercaseChars string
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* coNumeric: Use numeric characters as defined by the NumericChars string
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(the characters which are hard to distinguish are skipped,
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zero vs uppercase O, lowercase L vs upper case I)
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* coCustom: Use special characters as defined by the CustomChars string
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* coRotated: Characters are rotated
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* coFont1: Font1 is used
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* coFont2: Font2 is used
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* coLines: Lines are drawn over the captcha
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* NewCaptchaEvent: Enumerated property for how to quickly select of a new captcha
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string at runtime:
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* nceNone: deactivated; captcha can only be changed by code.
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* nceClick: a new captcha is created when the user clicks on the control
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* nceDblClick: a new captcha is created when the user double-clicks on the control.
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Installation
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------------
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* Load the package file captcha_pkg.lpk into the Lazarus Package Editor and
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click "Use" > "Install" to rebuild the Lazarus IDE. When Lazarus restarts you
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find the new component in the palette "Misc".
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License
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-------
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LGPL with linking exception, like the Lazarus LCL.
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See the file COPYING.modifiedLGPL.txt, included in the Lazarus distribution,
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for details about the license.
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