Zend Framework

Captcha bad image quality

Details

  • Type: Improvement Improvement
  • Status: Resolved Resolved
  • Priority: Major Major
  • Resolution: Fixed
  • Affects Version/s: None
  • Fix Version/s: None
  • Component/s: Zend_Captcha, Zend_Form
  • Labels:
    None

Description

The image quality of Zend_Form_Element_Captcha('image' ... really needs improvement. We should be able at least to choose a %tage of image deformation, an image background, or no image deformation at all.
The black and white backgound image makes it often difficult to read.

Issue Links

This issue is related to:
ZF-10867 Captcha image background color Major Open

Activity

Ascending order - Click to sort in descending order
Hide
Permalink
Matthew Weier O'Phinney added a comment -

Assigning to Stas

Show
Matthew Weier O'Phinney added a comment - Assigning to Stas
Hide
Permalink
Ota Mares added a comment -

Yep also an option to define some colors would be nice.

Show
Ota Mares added a comment - Yep also an option to define some colors would be nice.
Hide
Permalink
Stanislav Malyshev added a comment -

I will look into making it more configurable - but also it would be really easy to use your own image generator (including amending the existing one) if you wanted to - just extend the Zend_Captcha_Image class and override _generateImage.

As for colors I'm not sure it's a good idea - having different colors rarely adds much since it is very easy for a robot to convert it back to b&w, but it often makes it easier to read characters - e.g. if noise and symbols have different colors, the robot could just filter the "noisy" color out automatically.

However, if you have an idea for using colors that you think would add strength - please share.

Show
Stanislav Malyshev added a comment - I will look into making it more configurable - but also it would be really easy to use your own image generator (including amending the existing one) if you wanted to - just extend the Zend_Captcha_Image class and override _generateImage. As for colors I'm not sure it's a good idea - having different colors rarely adds much since it is very easy for a robot to convert it back to b&w, but it often makes it easier to read characters - e.g. if noise and symbols have different colors, the robot could just filter the "noisy" color out automatically. However, if you have an idea for using colors that you think would add strength - please share.
Hide
Permalink
Ota Mares added a comment -

Hehe yeah you could but most of us dont have the time to create an own image generator and to think up some sin/cos mathematical stuff
So thanks for looking into it.

The color option was just an idea, there a cases where you want the captcha make more readable and a colored font adds to that option.
But you could create a gradient or color spots to the background to make it harder for robots.

Show
Ota Mares added a comment - Hehe yeah you could but most of us dont have the time to create an own image generator and to think up some sin/cos mathematical stuff So thanks for looking into it. The color option was just an idea, there a cases where you want the captcha make more readable and a colored font adds to that option. But you could create a gradient or color spots to the background to make it harder for robots.
Hide
Permalink
Stanislav Malyshev added a comment -

added setDotNoise() and setLineNoise() so that noise level can be configured. Also added setStartImage() so that image could be initialized with some non-empty image (should be PNG)

Show
Stanislav Malyshev added a comment - added setDotNoise() and setLineNoise() so that noise level can be configured. Also added setStartImage() so that image could be initialized with some non-empty image (should be PNG)

People

Vote (2)
Watch (2)

Dates

  • Created:
    Updated:
    Resolved:
Atlassian JIRA (v4.4.3#663-r165197) | Report a problem
Powered by a free Atlassian JIRA open source license for Zend Framework. Try JIRA - bug tracking software for your team.