[texhax] Using .png, .jpg, .gif

[Uwe Lück]

Supplement: `The command in the fourth argument' meant `The command in the 
fourth argument of \DeclareGraphicsRule.' -- Uwe.

At 08:38 05.08.09, Uwe Lück wrote:
>Bev,
>
>sorry, I did not pay proper attention to the aspect of your posting 
>concerning `convert' in \DeclareGraphicsRule:
>
>At 05:43 02.07.09, Beverley Eyre wrote:
>>I'd like to get \DeclareGraphicsRule to work, but it seems more trouble 
>>to use than just converting each image file by hand.
>>
>>For example, if I want to use a .png file:
>>\DeclareGraphicsExtensions{.png, .eps}
>>\DeclareGraphicsRule{.png}{eps}{*}{`convert #1}      %% (the last arg 
>>I've done in many different ways, e.g. {`convert #1 eps:- } )
>>
>>then, in the body:
>>
>>\includegraphics[width=1in]{myimage}   %% (which is myimage.png)
>>
>>I get an error msg telling me that I there is no bounding box. So in 
>>order to use it, I have to determine the bounding box for the image 
>>first, and then include that info into one or the other command.   But, 
>>if I just do:
>>
>> > convert myimage.png myimage.eps
>>
>>on the command line, it converts it without having to know the bounding 
>>box info. I'm not sure why convert needs the bounding box info in one 
>>case (latex) but not the other (command line).
>
>It is important to recognize that importing a graphics file with LaTeX has 
>two parts: 1. the LaTeX run (building a .dvi), 2. previewing or printing 
>(executing \special commands from the .dvi).
>
>The LaTeX run only needs to know the dimensions of the image. This is 
>where the famous `bounding box' error occurs. LaTeX does not care about 
>other contents of the graphics file. This other content is only used at 
>getting visible output from the .dvi.
>
>The command in the fourth argument is only used at the second step, 
>creating a screen display or printout from the .dvi. This is too late to 
>tell LaTeX the bounding box info!
>
>Repeating:
>
>>But, if I just do:
>>
>> > convert myimage.png myimage.eps
>>
>>on the command line, it converts it without having to know the bounding 
>>box info.
>
>It is wrong to say `convert' doesn't need knowledge of the bounding box. 
>The truth is that `convert' is able to extract the bounding box 
>information from myimage.png while LaTeX is not.
>
>>  I'm not sure why convert needs the bounding box info in one case 
>> (latex) but not the other (command line).
>
>It is also wrong to say `convert' needs the bounding box info `in the 
>LaTeX case'. The error message comes from LaTeX when it looks for that 
>info in building the .dvi. As I said, `convert' is not involved at this 
>first step.
>
>HTH -- Uwe.
>
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