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Next: An Embedded Image Example Up: No Title Previous: Mathematics

Figures and Image Conversion

LATEX2HTML converts equations, special accents, external PostScript files, and LATEX environments it cannot directly translate into inlined images. This section describes how it is possible to control the final appearance of such images. For purposes of discussion ...

The size of all ``small images'' depends on a configuration variable $MATH_SCALE_FACTOR which specifies how much to enlarge or reduce them in relation to their original size in the PostScript version of the document. For example a scale-factor of 0.5 will make all images half as big, while a scale-factor of 2 will make them twice as big. Larger scale-factors result in longer processing times and larger intermediate image files. A scale-factor will only be effective if it is greater than 0. The configuration variable $FIGURE_SCALE_FACTOR performs a similar function for ``figures''. Both of these variables are initially set to have value 1.6.

A further variable $DISP_SCALE_FACTOR is used with `displayed math' equations and formulas; this value multiplies the $MATH_SCALE_FACTOR to give the actual scaling used. With the improved clarity of anti-aliased images, a scaling of 1.6 may be a little excessive for inline images. Accordingly this manual actually uses values of 1.4 and 1.2 respectively, for $MATH_SCALE_FACTOR and $DISP_SCALE_FACTOR. These go well with the browser's text-font set at 14pt. The next larger size of 17pt is then used for the <LARGE> tags in displayed equations.


A further variable $EXTRA_IMAGE_SCALE allows images to be created at a larger size than intended for display. The browser itself scales them down to the intended size, but has the extra information available for a better quality print. This feature is also available with single images. It is discussed, with examples, on the next page.
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\htmlimage{ <options>}

For finer control, several parameters affecting the conversion of a single image can be controlled with the command \htmlimage, which is defined in html.sty.
With version V97.1 use of this command has been extended to allow it to control whether an image is generated or not for some environments, as well as specifying effects to be used when creating this image.

If an \htmlimage command appears within any environment for which creating an image is a possible strategy (though not usual, due to loading of extensions, say), then an image will indeed be created. Any effects requested in the <options> argument will be used. Having empty <options> still causes the image to be generated.

This ability has been used within this manual, for example with the mathematics images in the previous section.
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The <options> argument is a string separated by commas.  
Allowable options are:

In order to be effective the \htmlimage command and its options must be placed inside the environment on which it will operate. Environments for alignment and changing the font size do not generate images of their contents. Any \htmlimage command may affect the surrounding environment instead; e.g. within a table or figure environment, but does not apply to a minipage.

When the \htmlimage command occurs in an inappropriate place, the following message is printed among the warnings at the end of processing. The actual command is shown, with its argument; also the environment name and identifying number, if there is one.

The command "\htmlimage" is only effective inside an environment 
which may generate an image (e.g. "{figure}", "{equation}")
 center92: \htmlimage{ ... }

next up previous contents index
Next: An Embedded Image Example Up: No Title Previous: Mathematics