Monochrome text

[cja]

I want to create a monochrome bitmap with good quality text on it. Using a bit depth of 8, the text comes out very nicely. Making that into
a monochrome bitmap is terrible.

Commands I have been using (with variations):

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convert -background black -fill white -size x30 -density 192 label:"Text" sample.png

The above gives a good result, but bit-depth 8.

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convert -background black -fill white -size x30 -density 192 -monochrome label:"Text" sample_mono.png

The above gives a horrible result, but bit depth 1

I don't want to convert a grayscale image to monochrome, but instruct imagemagick to render the text directly in black/white. Looking at some freetype examples, that should give a good quality. But how to do that with imagemagick?

[snibgo]

"-monochrome" should come after label, not before.

By default, when IM reduces colours, it dithers. For this purpose, a better result comes when dithering is turned off.

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convert -size x30 label:"Text" +dither -monochrome x.png

[cja]

I do not see a difference when putting -monochrome behind the label option.
Switching dithering off is an improvement.

Thanx!

[snibgo]

Moving "-monochrome" makes no difference to this command. If the command was more complex, it would. The idea is to create an image, process it, and finally save it. Specifying the processing before creating the image sometimes works, but in general it doesn't.

[cja]

My thinking to put it 'before' the processing was to enable the rendering step for the text to take into account the output is monochroom. Thereby it could potentially optimize the output taking this into account.

For example, in freetype there is "FT_LOAD_TARGET_MONO" (1) that impacts the rasterization/rendering and gives great text output. I hoped to get the same quality with convert and avoid using freetype, or something simialr, directly.

(1) http://www.freetype.org/freetype2/docs/ ... TARGET_XXX

[snibgo]

Ah, I understand your thinking. You may be correct. I don't know.

[snibgo]

From the code in annotate.c, it seems that FT_LOAD_TARGET_MONO is activated when anti-aliasing is off. That option certainly should be before label:

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convert -size x30 +antialias label:"Text" x.png

[cja]

Yep. That seems to do the trick. Thanx!