Display Text as Image

ruby-talk
1

Hello,

I have a String, which I want to display as a bitmap image. What is the
best way to do this?

I tried f.e. the code below (RMagick), but the image displayed did not
contain the whole Text I stored in the variable myText. What can I do to
get the whole text displayed in an image? Or is there another, better
approach to do this?

Best Regards

Adriana

img = Image.read("caption:"+myText) do
         self.size = "2000"
         self.height=1000
         self.pointsize = 20
        self.font = "Tahoma"

       end

img[0].display

···

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2

Quoting Adriana Mikolaskova (lists@ruby-forum.com):

Hello,

I have a String, which I want to display as a bitmap image. What is the
best way to do this?

I tried f.e. the code below (RMagick), but the image displayed did not
contain the whole Text I stored in the variable myText. What can I do to
get the whole text displayed in an image? Or is there another, better
approach to do this?

Best Regards

Adriana

img = Image.read("caption:"+myText) do
         self.size = "2000"
         self.height=1000
         self.pointsize = 20
        self.font = "Tahoma"

       end

I am not sure I understand what you would like to obtain.

Here is the way to create a RMagick Image object, composed of given pixels
passed in a string:

def make_image(x,y,pixels)
  im=Magick::Image::new(x,y)
  im.import_pixels(0,0,x,y,'RGB',pixels)
  im
end

The string must be made up of x*y*3 bytes - the RGB values for each
pixel.

But from your example, it seems that you want to make an image which
includes a given message (characters to be read). This requires
something more complex:

def make_image_with_text(x,y,backg_col,foreg_col,text,font,pointsize)
  im=Magick::Image::new(x,y) do
    self.background_color=backg_col
  end
  gc=Magick::Draw::new()
  gc.annotate(im,x,y,0,0,text) do
    self.font_family=font
    self.fill=foreg_col
    self.stroke=foreg_col
    self.pointsize=pointsize
    self.gravity=Magick::CenterGravity
  end
  im
end

To have a 2000x1000 black image with "This is a test" written in
20point Tahoma in red in it you should call the above as follows:

im=make_image_with_text(2000,1000,'black','red','This is a test','Tahoma',20)
im.display

Of course you can do the two things in sequence - first draw some
pixels, and then superimpose some text...

Have a look at

http://studio.imagemagick.org/RMagick/doc/draw.html#annotate

Remember to destroy Image objects after using them, with

im.destroy!

Otherwise they are not garbage-collected, and if you generate many
images you soon end up with a full ram...

Carlo

···

Subject: Display Text as Image
  Date: Mon 05 Nov 12 01:17:13AM +0900

--
  * Se la Strada e la sua Virtu' non fossero state messe da parte,
* K * Carlo E. Prelz - fluido@fluido.as che bisogno ci sarebbe
  * di parlare tanto di amore e di rettitudine? (Chuang-Tzu)

3

Thank you very much for the detailled description and the code!!!it was
the second I'm looking for!

···

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4

Hello,

your code worked fine for me, just one little problem occured.
When there are no linebreaks in the text, all the text is displayed on
one line (that means invisible).

I found different solutions, just wanted to ask here: is it really
necassary to figure out, how many characters a image-with can hold and
insert the line-breaks in the text? Or did I miss some easier method for
inserting line-breaks at the end of the image-width?

Best regards

Adriana

···

def make_image_with_text(x,y,backg_col,foreg_col,text,font,pointsize)
  im=Magick::Image::new(x,y) do
    self.background_color=backg_col
  end
  gc=Magick::Draw::new()
  gc.annotate(im,x,y,0,0,text) do
    self.font_family=font
    self.fill=foreg_col
    self.stroke=foreg_col
    self.pointsize=pointsize
    self.gravity=Magick::CenterGravity
  end
  im
end

To have a 2000x1000 black image with "This is a test" written in
20point Tahoma in red in it you should call the above as follows:

im=make_image_with_text(2000,1000,'black','red','This is a
test','Tahoma',20)
im.display

O

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5

Quoting Adriana Mikolaskova (lists@ruby-forum.com):

your code worked fine for me, just one little problem occured.
When there are no linebreaks in the text, all the text is displayed on
one line (that means invisible).

I found different solutions, just wanted to ask here: is it really
necassary to figure out, how many characters a image-with can hold and
insert the line-breaks in the text? Or did I miss some easier method for
inserting line-breaks at the end of the image-width?

From what I know, no. Note that, for fonts that are not monospaced, it
is not simply a question of how many characters, because glyphs may
have different widths.

You can split your phrase in words, add one word at a time, measure
the width (with get_multiline_type_metrics) and insert a newline
before the word that would overflow. Not very difficult, but as far as
I know there is nothing pre-made in Magick.

Carlo

···

Subject: Re: Display Text as Image
  Date: Tue 06 Nov 12 05:51:21AM +0900

--
  * Se la Strada e la sua Virtu' non fossero state messe da parte,
* K * Carlo E. Prelz - fluido@fluido.as che bisogno ci sarebbe
  * di parlare tanto di amore e di rettitudine? (Chuang-Tzu)