Problems proportioning an image

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troyd1
Posts: 73
Joined: 2007-07-29T17:13:19-07:00

Problems proportioning an image

Post by troyd1 »

I have created 2 blank graphics using:
convert -size 500x250 xc:white blanks.bmp
convert -size 1975x938 xc:white blankl.bmp

I did:
convert blanks.bmp -fill black -pointsize 16 -font ARIAL.TTF -size 310 -gravity center -background #00000000 caption:"This is a test for proportioning" -gravity northwest -geometry +180+30 -composite small.bmp

Then I did:
convert blankl.bmp -fill black -pointsize 60 -font ARIAL.TTF -size 1240 -gravity center -background #00000000 caption:"This is a test for proportioning" -gravity northwest -geometry +675+112 -composite large.bmp

The font almost looks bold.
I then did:
convert -resize 500x250 large.bmp resize.bmp

The resize.bmp font is completely different as it almost looks bold.

The large.bmp is the size I need to print at 300 dpi, but the fonts do not proportion right. to create the large, I multplied all the arguments by 3.75 (500x3.75) = 1975. pointsize 16x3.75 is 60.

I also the tried:
convert -resize 1975x938 small.bmp largeresize.bmp

and that was not right either.

Please help.

Thanks, Troy

Lithium

Re: Problems proportioning an image

Post by Lithium »

I think it is a feature of TrueType font renderer. TrueType glyph is not only a set of curves, it may contain multiple levels of detalisations and instructions that adjust point coordinates according to output size in pixels, which is more visible for small size in pixels. Because of that, small text looks different (and more clear, one can notice) than shrinked large text.

troyd1
Posts: 73
Joined: 2007-07-29T17:13:19-07:00

Re: Problems proportioning an image

Post by troyd1 »

That makes some sense, but then how do printers print at high dpi's? when I add this text at 16 point, it looks much different than if I add it at 80 point. if I am entering text at 16 point at 100 dpi, how do I get the same image at 500 dpi without using 80 point font and creating it?

User avatar
anthony
Posts: 8884
Joined: 2004-05-31T19:27:03-07:00
Authentication code: 8675308
Location: Brisbane, Australia

Re: Problems proportioning an image

Post by anthony »

the number of 'pixels' a font has to handle is controld not just by 'pointsize' but also the 'denstity' or resolution. Printers have a 300dpi or higher resolution, so get more pixels per 'pointsize'.

See IM examples
Resolution, Pointsize, and Actual Font Size
http://imagemagick.org/Usage/text/#pointsize
Anthony Thyssen -- Webmaster for ImageMagick Example Pages
https://imagemagick.org/Usage/

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