[WWdevel] Re: [webwork-user] Re: pdf generation problem and image problem

[Sam H. <sh...@ma...>]

On Aug 29, 2005, at 20:02, Davide P.Cervone wrote:

>>> If you change -bgTransparent to -bgtransparent (i.e., remove the  
>>> capitalization)
>>>
>>
>> Is this a bug in Constants.pm?
>
> No, it's a bug in MSIE.  :-)
>
> In dvipng prior to version 1.6, both forms meant the same thing.   
> In 1.6 and later, the first gets you alpha-channel transparency  
> while the second gets your single-bit transparency.  While every  
> other modern browser handles alpha-channel transparency, MSIE only  
> does this if you include a horrible proprietary call to a special  
> image filter that references the alpha image and link the source  
> image to a blank image file (if I remember correctly).  I would  
> love to switch to alpha-channel transparency so that the background  
> colors work better, but as long as we are saddled with the  
> lumbering and decrepit beast known as MSIE, we have to dump down to  
> its (in-)capabilities.  Not that I'm upset by this.  >:-p
>
> The upshot is, though, that Constants.pm probably should have the  
> lower-case transparency to avoid the alpha-channel problem.

Right, that's what I meant. -bgTransparent is not a valid switch to  
dvipng, so Constants.pm is wrong.
  -sam