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FW: Re: Using ImageMagick to overlay text
by Ted.Harding＠manchester.ac.uk 01 Dec '09

01 Dec '09

Apologies -- I just noticed that at the end of the message below which I recently posted, I said "the length of "This is my Text" in inches, when printed in Helvetica-Bold in point-size 15." That was incorrect, since everything preceding was done in terms of Courier-Bold! To see what it comes to in terms of Helvetica-Bold, substitute "HB" for "CB" in the commands. Thus: echo "\f[HB]\w'This is my Text'\s0\fP" | troff -Tps | awk '/^t/{sub(/t/,""); print $0/72000}' results in 0.988889 the length in inches of "This is my Text" in Helvetica-Bold in the default point-size of 10 points, while echo "\f[HB]\w'\s[15]This is my Text'\s0\fP" | troff -Tps | awk '/^t/{sub(/t/,""); print $0/72000}' results in 1.48333 the length in inches of "This is my Text" in Helvetica-Bold in 15-point (1.5 times as long as in 10-point). Also note (which I forgot to mention) that this length takes account of kerning (the slight left-shift of some letters relative to a preceding letter -- e.g. in "Text" the "ext" is moved left so tht the "e" is slightly overlapped by the preceding "T"). Kerning can be suppressed. Also, of course, the length is computed in terms of the font-metrics in the font files referred to by troff, and in other applications different font files may be used; however, the result is unlikely to be greatly different. Sorry for the sloppiness! Ted. -----FW: <XFMail.091201122319.Ted.Harding(a)manchester.ac.uk>----- Date: Tue, 01 Dec 2009 12:23:19 -0000 (GMT) Sender: main-bounces(a)lists.alug.org.uk From: (Ted Harding) <Ted.Harding(a)manchester.ac.uk> To: main(a)lists.alug.org.uk Subject: Re: [ALUG] Using ImageMagick to overlay text On 01-Dec-09 09:06:14, Mark Rogers wrote: > MJ Ray wrote: >> I'd either run identify on the image beforehand, or test PHP's libgd >> module to see if it was good enough for this. > > I will try GD today and see what the results are like (the results from > ImageMagick are pretty amazing, to be honest). > > I'm not sure what you mean about using identify though - I can see how > I'd use it to work out the size of the image but I can't see how I'd > use > that information to calculate the pointsize to use with my text? > > -- > Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 Your basic problem here is to find the printed length of a given text string, in a given font, at a given point size! You could incorporate something like the following in a script: echo "\f[CB]\w'This is my Text'\fP" | troff -Tps from which the output (to screen, when I entered the above on the command line) is; x T ps x res 72000 1 1 x init C p1 x font 6 CB f6 s10000 V12000 H72000 md DFd t90000 n12000 0 x trailer V792000 x stop The key line in there is t90000 which is the evaluation of the width ("\w'...'")of the string "This is my Text" in point-size 10 (the default) using font Courier-Bold ("\f[CB]"). The numerical result "90000" is the length of the text in units of (1 point)/1000, i.e. 1/72000 of an inch, so the physical printed length would be 90000/72000 = 1.25 inches You could feed that to 'awk' to do the sums (and this time I'll feed in an explicit point-size 15 ("\s[15]...\s0") as well): echo "\f[CB]\s[15]\w'This is my Text'\s0\fP" | troff -Tps | awk '/^t'/ results in: t135000 while echo "\f[CB]\s[15]\w'This is my Text'\s0\fP" | troff -Tps | awk '/^t/{sub(/t/,""); print $0}' results in 135000 so, finally, echo "\f[CB]\w'\s[15]This is my Text'\s0\fP" | troff -Tps | awk '/^t/{sub(/t/,""); print $0/72000}' results in 1.875 which is (15/10)*1.25, the length of "This is my Text" in inches, when printed in Helvetica-Bold in point-size 15. There may be some discrepancy, depending on how spaces are handled in the output. You can probably exploit the above ideas to get what you want! Hoping this helps, Ted. -------------------------------------------------------------------- E-Mail: (Ted Harding) <Ted.Harding(a)manchester.ac.uk> Fax-to-email: +44 (0)870 094 0861 Date: 01-Dec-09 Time: 12:23:16 ------------------------------ XFMail ------------------------------ _______________________________________________ main(a)lists.alug.org.uk http://www.alug.org.uk/ http://lists.alug.org.uk/mailman/listinfo/main Unsubscribe? See message headers or the web site above! --------------End of forwarded message------------------------- -------------------------------------------------------------------- E-Mail: (Ted Harding) <Ted.Harding(a)manchester.ac.uk> Fax-to-email: +44 (0)870 094 0861 Date: 01-Dec-09 Time: 14:22:46 ------------------------------ XFMail ------------------------------

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Using ImageMagick to overlay text
by Mark Rogers 01 Dec '09

01 Dec '09

I'm playing with ImageMagick's "convert" program to add text to an image. I have something like this (which works): convert "infile.png" -font "font.ttf" -gravity 'south' \ -stroke '#fffc' -strokewidth '3' -pointsize '300' \ -annotate 0 "Test" "outfile.png" However, the only way I can find to size the text is using the -pointsize option. What I want to do is make the text proportional to the image size, eg have the text work out to 50% of the available width, or similar. I can't find any good way to do this - and nor can I find a suitable query for Google to assist me. The "convert" program is being called as part of a PHP script so I can be quite flexible in what I do if I need to be (eg if I need to create dummy images to see what sizes they come out as, etc). Suggestions for other programs I can use instead welcome. I know ImageMagick and I know I can trust it with high quality images if I need to (and will need to here) which is why I stated there. -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) @ 13 Clarke Rd, Milton Keynes, MK1 1LG

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Re: [ALUG] Using ImageMagick to overlay text
by Mark Rogers 01 Dec '09

01 Dec '09

James Taylor wrote: > I think there is a question about whether swapping from inside PHP to > ImageMagick and back is a good thing or not - why spawn a separate > process to do essentially the same work? > > Another possibility is: > > 1) Load image. > 2) Create new image to store text in > 3) Render text (make it vector based if possible) > 4) Resize-text-image to being correct size/proportion > 5) Merge text-image over image > The actual processing is slower than the spawning, so it's not particularly a problem, but I am moving towards using the Imagick PHP libraries which will bring the processing inside PHP rather than spawning a new process. Spawning a process has the advantage that I can experiment at the commandline first (and can seek advice from a wider range of people), but the options are pretty straightforward to convert between library and commandline. -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) @ 13 Clarke Rd, Milton Keynes, MK1 1LG

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