Text in a shape

[badabou]

Hello,

Does the program imagemagick can put text in a form (eg a black and white mask) ?

I made a sketch to explain what I mean :


Thank you for your answers.

[snibgo]

In theory, yes, from SVG input. See http://www.w3.org/TR/2004/WD-SVG12-20041027/flow.html

[fmw42]

I cropped out your images.

Code: Select all

convert mask.png \( text.png -negate \) \( -clone 0 -negate \) -gravity center -compose over -composite text_in_heart.png

[badabou]

This is not quite what I want to do.

I want the text to be inserted inside the shape and follow the edges of the shape.

[fmw42]

You will need to write your text over the heart image in a way that conforms to the shape of the heart. That will require you to use for example PANGO and trial and error. See http://www.imagemagick.org/Usage/text/#pango

[snibgo]

The job is easily done with SVG, using inkscape for the rasterization. For example, here is an SVG file with a simpler path. I use Inkscape directly. Doubtless it could be done by using IM to call Inkscape.

flow.svg:

Code: Select all

<svg xmlns:svg="http://www.w3.org/2000/svg" version="1.2"
     xmlns:xlink="http://www.w3.org/1999/xlink" 
  width="100%" height="100%" viewBox="0 0 300 310">
  <title>Basic textflow</title>
  <rect x="0" y="0" width="100%" height="100%" fill="yellow" fill-opacity="0"/>
  <flowRoot font-size="16" >
    <flowRegion fill="none" fill-opacity="0" stroke-opacity="1" stroke="red">
      <path d="M90,40L40,270L260,270L210,40z"/>
    </flowRegion>
    <flowPara fill="blue" fill-opacity="1" stroke-opacity="1" stroke="red">
The job is easily done with SVG, using inkscape for the rasterization. For example, here is an SVG file with a simpler path. I use Inkscape directly. Doubtless it could be done by using IM to call Inkscape.
    </flowPara>
  </flowRoot>
  <path d="M90,40L40,270L260,270L210,40z" fill="none" fill-opacity="0" stroke-opacity="1" stroke="red" stroke-width="2"/>
</svg>

Command:

Code: Select all

inkscape -f flow.svg -e flow.png -y 1

flow.png:

[snibgo]

Yeah, "convert flow.svg flow2.png" works fine, now I've put the Inkscape directory into my path.

Another example:

Code: Select all

convert heartWords.svg -trim heartWords.png

Where heartWords.svg is:

Code: Select all

<svg xmlns:svg="http://www.w3.org/2000/svg" version="1.2"
     xmlns:xlink="http://www.w3.org/1999/xlink" 
  width="100%" height="100%" viewBox="0 0 744 1052">
  <title>Basic textflow</title>
  <rect x="0" y="0" width="100%" height="100%" fill="yellow" fill-opacity="0"/>
  <path d="m 300,169.50504 c 0,0 -111.53096,-11.5113 -114.28571,140 -1.42858,78.57143 116.42857,275.28572 223.65747,328.46079 107.22895,-54.68207 225.08605,-251.39636 223.65755,-329.96779 -2.7548,-151.5113 -114.2858,-140 -114.2858,-140 0,0 -105.7142,5.71429 -109.37175,117.89636 C 405.71428,175.21933 300,169.50504 300,169.50504 z"
 fill="black" fill-opacity="1" stroke-opacity="0" stroke="red" stroke-width="2"/>
  <flowRoot font-size="33" text-anchor="middle" >
    <flowRegion>
      <path d="m 300,169.50504 c 0,0 -111.53096,-11.5113 -114.28571,140 -1.42858,78.57143 116.42857,275.28572 223.65747,328.46079 107.22895,-54.68207 225.08605,-251.39636 223.65755,-329.96779 -2.7548,-151.5113 -114.2858,-140 -114.2858,-140 0,0 -105.7142,5.71429 -109.37175,117.89636 C 405.71428,175.21933 300,169.50504 300,169.50504 z"
/>
    </flowRegion>
    <flowPara fill="white" fill-opacity="1" stroke-opacity="0" stroke="red">The job is easily done with SVG, using inkscape for the rasterization. For example, here is an SVG file with a heart path. I can use Inkscape directly, or by using IM to call Inkscape.</flowPara>
  </flowRoot>
</svg>

And the resulting heartWords.png is:

I found the best font-size by trial and error.

[fmw42]

pretty neat!

how did you create the heart shape and get it vectorized?

One option would be to get a binary heart image, get its boundary (edge) and vectorize with autotrace, something like at http://www.imagemagick.org/Usage/transform/#edge_vector, but starting with the edge image.

Did you do something like that or just create it by hand?

[snibgo]

I just created it by hand in Inkscape. A heart shape, roughly symmetrical, with four points on the curve and eight control points. I wrote the result to an SVG file, and copied the path from there to my own file.

The result works, but I don't much like the solution, so I then simplified it.

A heart needs only two points on the curve, with four control points, two of which coincide. In Inkscape, I edited the points, then used a text editor to remove the fractional values and ensure it was exactly symmetrical. I also reorganised my SVG file so the path needs to be specified once even though it is used twice (once for the black shape, and once as a path in which to fit the text). So here is a simpler version:

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<svg xmlns:svg="http://www.w3.org/2000/svg" version="1.2"
     xmlns:xlink="http://www.w3.org/1999/xlink" 
  width="100%" height="100%" viewBox="0 0 900 650">
  <title>Text in a heart</title>
  <defs>
    <path id="heartPath"
       d="M 434,638
          C 868,183 434,72 434,287
            434,72 0,183 434,638
          z"
       />
  </defs>
  <use xlink:href="#heartPath"
       fill="black" stroke="none"
       fill-opacity="1" stroke-opacity="0" />
  <flowRoot font-size="30" text-anchor="middle" >
    <flowRegion>
      <use xlink:href="#heartPath" />
    </flowRegion>
    <flowPara fill="white" fill-opacity="1"
              stroke-opacity="0">The job is easily done with SVG,
 using Inkscape for the rasterization.
 For example, here is an SVG file with a heart path.
 I can use Inkscape directly, or call Inkscape via IM.</flowPara>
  </flowRoot>
</svg>

[snibgo]

Just for fun, we can define the heart-shape in SVG, rasterise that in IM (delegating to Inkscape), vectorise the result with Potrace, rasterise that, and compare the two raster images.

heart0.svg:

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<svg xmlns:svg="http://www.w3.org/2000/svg" version="1.2"
     xmlns:xlink="http://www.w3.org/1999/xlink" 
  width="900.000000pt" height="650.000000pt"  viewBox="0 0 900 650">
  <title>Text in a heart</title>
  <defs>
    <path id="heartPath"
       d="M 434,638
          C 868,183 434,72 434,287
            434,72 0,183 434,638
          z"
       />
  </defs>
  <use xlink:href="#heartPath"
       fill="black" stroke="none"
       fill-opacity="1" stroke-opacity="0" />
</svg>

Potrace needs PNM input.

Commands:

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convert -verbose -density 72 -depth 16 heart0.svg h0.pnm
c:\potrace\potrace.exe -s -o h1.svg h0.pnm
convert -verbose -density 72 -depth 16 h1.svg h1.pnm

compare -metric RMSE h0.pnm h1.pnm NULL:

The difference is ...

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769.815 (0.0117466)

... which is okay, and just visible. Potrace reports 18 points on the curve, rather than the elegant 2 that are actually needed.

[badabou]

Yeah, "convert flow.svg flow2.png" works fine, now I've put the Inkscape directory into my path.

Another example:

Code: Select all

convert heartWords.svg -trim heartWords.png

Where heartWords.svg is:

Code: Select all

<svg xmlns:svg="http://www.w3.org/2000/svg" version="1.2"
     xmlns:xlink="http://www.w3.org/1999/xlink" 
  width="100%" height="100%" viewBox="0 0 744 1052">
  <title>Basic textflow</title>
  <rect x="0" y="0" width="100%" height="100%" fill="yellow" fill-opacity="0"/>
  <path d="m 300,169.50504 c 0,0 -111.53096,-11.5113 -114.28571,140 -1.42858,78.57143 116.42857,275.28572 223.65747,328.46079 107.22895,-54.68207 225.08605,-251.39636 223.65755,-329.96779 -2.7548,-151.5113 -114.2858,-140 -114.2858,-140 0,0 -105.7142,5.71429 -109.37175,117.89636 C 405.71428,175.21933 300,169.50504 300,169.50504 z"
 fill="black" fill-opacity="1" stroke-opacity="0" stroke="red" stroke-width="2"/>
  <flowRoot font-size="33" text-anchor="middle" >
    <flowRegion>
      <path d="m 300,169.50504 c 0,0 -111.53096,-11.5113 -114.28571,140 -1.42858,78.57143 116.42857,275.28572 223.65747,328.46079 107.22895,-54.68207 225.08605,-251.39636 223.65755,-329.96779 -2.7548,-151.5113 -114.2858,-140 -114.2858,-140 0,0 -105.7142,5.71429 -109.37175,117.89636 C 405.71428,175.21933 300,169.50504 300,169.50504 z"
/>
    </flowRegion>
    <flowPara fill="white" fill-opacity="1" stroke-opacity="0" stroke="red">The job is easily done with SVG, using inkscape for the rasterization. For example, here is an SVG file with a heart path. I can use Inkscape directly, or by using IM to call Inkscape.</flowPara>
  </flowRoot>
</svg>

And the resulting heartWords.png is:

I found the best font-size by trial and error.

Hi snibgo,

Thank you so much for your examples, it's almost exactly what I want to do.

I did the test with your svg file :

Code: Select all

convert heartWords.svg -trim heartWords.png

but I is not the same result (the text is not displayed):


My imagemagick version :

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# convert -version
Version: ImageMagick 6.5.9-2 2010-02-03 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2010 ImageMagick Studio LLC
Features: OpenMP

I have another question: Is it possible that the text size is adjusted automatically according to the number of characters depending on the space available in the vector form (as with the "caption" option imagemagick program)?

[snibgo]

My tests were on IM v6.8.7-0, Inkscape 0.48 (the current version), on Windows 7.

Your version of IM is very old. I suggest you upgrade. What version of Inkscape are you on? That's more likely to make a difference. Is the Inkscape directory on your path? What happens when you run the Inkscape command?

A script could be written that could guess the best font-size, based on the proportion of the heart within the rectangle, and automated trial-and-error. But it wouldn't be easy. I can't see a simple test for the text being clipped.

[badabou]

My imagemagick version is old because when I update it, I have compatibility problems with php-imagick library (version 2.3.0) and all my scripts are written with it.

There's something I do not understand: In your second example, you seem not to use Inkscape to create the heart in PNG. So I simply used imagemagick "convert -trim heartWords.svg heartWords.png" with your heartWords.svg file, is it a mistake?

[snibgo]

My tests were done with the directory containing inkscape.exe on my PATH variable. This means that ImageMagick will use Inkscape to rasterise the SVG.

You could, instead, call inkscape directly.

[badabou]

It's good it works perfectly.

I must now find a way to adjust the text size in the vector shape.
I do not know how to know if the text out of the vector shape or not. If I knew that I could do more tests and derive the best font size.