From: Tim Hunter <cyclists@...>
Date: 2006-03-19T08:38:48+09:00
Subject: Re: text to images using RMagick

Ray wrote:
> Hi Tim, thanks for your quick response. I'm very new to this, Im on Mac
> OSX 10.4.5, how do I check the version of ImageMagick installed?
> 
> Also, when I do get it working, can all text formatting (eg: bold,
> italic, colours, etc) work with the caption parameter?
> 
> Ta, Ray
> 
Enter this command in irb:

irb -r RMagick
puts Magick::Long_version

The doc on the "caption" builtin format[1] says that you can use these 
options with caption:

antialias
background_color
border_color
density
fill
font
gravity
pointsize

font_style and font_weight aren't on the list, so you can't specify 
italic or bold with caption. You could specify a bold or italic font by 
name instead. (This is a limitation of ImageMagick, not RMagick.) To 
specify those kinds of attributes you're going to have to use the 
Draw#text method[2] or RVG::Text[3] or the Draw#annotate method[4]. The 
annotate method will handle strings with embedded newlines, the other 
two don't.

Keep in mind that ImageMagick will not alter a font (the way Windows 
slants a font to fake italics, for example) to match the attributes you 
specify. It simply searches its list of fonts (which may not include all 
the fonts you have on your system) to find the closest match and uses 
that. If you ask for a bold Arial and it doesn't have Arial Bold on its 
list, it'll just give you Arial. If you absolutely need a certain  font, 
the best thing to do is to specify the full path to the font. Anthony 
Thyssen has a great set of ImageMagick examples, including one about 
fonts[5]. The examples use the ImageMagick commands but it's not hard to 
map them into the RMagick API. (If you do need help translating the 
commands into RMagick send me an email and I'll see what I can do.)

[1]http://www.simplesystems.org/RMagick/doc/imusage.html#builtin_formats
[2]http://www.simplesystems.org/RMagick/doc/draw.html#text
[3]http://www.simplesystems.org/RMagick/doc/rvgtext.html
[4]http://www.simplesystems.org/RMagick/doc/draw.html#annotate
[5]http://www.cit.gu.edu.au/~anthony/graphics/imagick6/text/