Class: HumanReadableImageGenerator

• Inheritance
• Description
• Class protocol
  • defaults
  • image specs
  • instance creation
  • support
• Instance protocol
  • accessing
  • initialization
  • private
  • public
• Examples

Inheritance:

   Object
   |
   +--HumanReadableImageGenerator

Package:

stx:goodies/webServer

Category:

Net-Communication-HTML-Misc

Version:

rev: 1.10 date: 2009/04/23 09:18:35

user: sr

file: HumanReadableImageGenerator.st directory: goodies/webServer

module: stx stc-classLibrary: webServer

Author:

Claus Gittinger

Description:

Generate a form containing a string for the user to type into a web-form
as confirmation that he is really human.
I.e. the forms image is designed to make it hard for an OCR program to
extract the characters.
At least, we hope that it is so.

Sometimes, the picture is hard to decipher, even for a real human;
therefore, add some 'try another picture' button to the web page.

Caveat: this is a dirty hack

[usage:]
    HumanReadableImageGenerator new generate inspect

Class protocol:

 characterMapCharacters

 numberOfCharMaps

 charMapImage1

character bitmaps (needed ebcause the webServer has no Display for drawing)

 charMapImage1_height

 charMapImage1_width

 charMapImage2

character bitmaps (needed ebcause the webServer has no Display for drawing)

 charMapImage2_height

 charMapImage2_width

 charMapImage3

character bitmaps (needed ebcause the webServer has no Display for drawing)

 charMapImage3_height

 charMapImage3_width

 getCharMapImage: idx

 new

 fonts

 generateFontMaps

generates the methods:
charMapImage1,
charMapImage2,
...
one for each font

 generateImageMethod: selector with: image forFont: aFont

Instance protocol:

 characterSet: something

 colors: something

 extent: something

 maxAngle: something

 minAngle: something

 numberOfRandomDots: something

 numberOfRandomLines: something

 string

 string: something

 stringLength: something

 computeExtent

 generateString

 initialize

 randomCharacter

 generate

 generateFormUsingDisplay

 generateImageWithoutUsingDisplay

 generateImage

Examples:

    |gen image|

    gen := HumanReadableImageGenerator new.
    gen numberOfRandomDots:10000.
    gen numberOfRandomLines:25.
    gen minAngle:-45.
    gen maxAngle:45.
    gen string inspect.
    image := gen generate.
    image inspect.