cs:pdf_to_pictures
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cs:pdf_to_pictures [2019/02/07 15:16] paolo_bolzoni Add border parameter |
cs:pdf_to_pictures [2019/02/11 14:40] paolo_bolzoni Add a note to keep convert memory usage under control |
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| ======= Convert PDF to pictures ======= | ======= Convert PDF to pictures ======= | ||
| - | Seldom printers fail to print a PDF file, a is converting the file to a sequence of pictures; basically doing the whole process to decide where the inks should go in your computer before sending the result to the printer. | + | Seldom printers fail to print a PDF file, a possible solution is to convert the file to a sequence of pictures; basically this means to do the whole process that decides where the inks should go in your computer; before sending the result to the printer. |
| - | Ghostscript does most of the hard work creating the pictures, however it does not apply any kind of antialiasing so when creating a picture in the printing resolution (usually 300 DPI) the result will be poor. | + | Ghostscript does most of the hard work creating the pictures, however it does not apply any kind of smoothing to the curves so when creating a picture in the printing resolution (usually 300 DPI) the result will be poor. |
| To workaround this problem we use a trick similar to videogames antialiasing. We create the picture 4 times larger and we resize it later to the correct size applying smoothing algorithms. | To workaround this problem we use a trick similar to videogames antialiasing. We create the picture 4 times larger and we resize it later to the correct size applying smoothing algorithms. | ||
| - | Finally we losslessy put all the pictures in a new PDF. The resulting PDF will have no text, no fonts or anything a part of pictures. So it lost much of its convenience and the resulting file will be much larger, however printers will not fail to print it. | + | Finally we losslessy put all the pictures in a new PDF. The resulting PDF will have no text, no fonts or anything a part of pictures. So it loses much of its convenience and the resulting file will be much larger, however printers will not fail to print it. |
| Software used: | Software used: | ||
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| $ gs -sDEVICE=pngalpha -o output-%04d.png -r1200 input.pdf | $ gs -sDEVICE=pngalpha -o output-%04d.png -r1200 input.pdf | ||
| - | Please note that 1200 is four time the wanted resolution, we want to print to 300DPI. | + | Please note that 1200 is four times the wanted resolution, we want to print to 300DPI. |
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| $ img2pdf --pagesize a4 --border 0 --output easy2print_output.pdf soutput-*png | $ img2pdf --pagesize a4 --border 0 --output easy2print_output.pdf soutput-*png | ||
| + | It is possible to use greater resolutions to print for example with 600DPI, just use ''-r2400''. But the ''convert'' step may require too much memory to resize the output ''.png'' files. It is the case, it is possible to limit the amount of memory using environment variables: | ||
| + | MAGICK_TEMPORARY_PATH=. MAGICK_AREA_LIMIT=1024mb convert ... | ||
| + | | ||
| + | ''convert'' will store its temporary files in the current directory and avoid using more than 1Gb of memory. The process might be slower, but it will end correctly. | ||
| + | | ||
| + | Here is [[https://www.imagemagick.org/script/resources.php#environment|the list of environment variables that ImageMagick understands]]. | ||
cs/pdf_to_pictures.txt ยท Last modified: 2019/02/11 16:30 by paolo_bolzoni
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