If the page parameter is set, conversion of PDF files at a given density outputs blank pages.
"convert -units PixelsPerInch -density 300 $myfiles -page A4 -gravity center test.pdf"
If I omit page parameter from the command, I get appropriate output but at 72dpi default resolution.
Any idea?
A4 page size is 595 x 842. So in ImageMagick you could try
convert -units PixelsPerInch -density 300 $myfiles +repage -resize 595x842 test.pdf
That will make an A4 pixel dimension image with 300 dpi. You could also do
convert -units PixelsPerInch -density 300 $myfiles +repage -resize 595x842 -density XX test.pdf
Where XX is the dpi you want when printing the image of that size.
I added +repage to remove any input image virtual canvas, since you did not specify what format images you are using for $myfiles. Without +repage, that could have caused a large bit of white space at the top of your result.
Note it is always best and most helpful to provide your ImageMagick version and platform when asking questions about its use.
While I was trying to tweak the command I found that a set density (i.e, density 300) with a given page parameter actually sets the density of the -page A4 but not the converted object on page as the set density can't actually determine resolution of the -page A4 to which it shall be applicable. As a result, the command returns blurry or blank image on set page.
However, extent parameter is what, which actually outputs the appropriate image as it is possible to set the page resolution with this parameter at a predefined density. The following example will make it absolutely clear.
Resolution of A4 size page at 300 dpi is 2480x3508, thus correct command for a set density like 300 dpi shall be:
"convert -units PixelsPerInch -density 300 $myfiles -gravity center -extent 2480x3508 test.pdf"
Resolution of A4 size page at 72 dpi is 595x842, thus correct command for a set density like 72 dpi shall be:
"convert -units PixelsPerInch -density 72 $myfiles -gravity center -extent 595x842 test.pdf"
Related
I was trying to resize a pdf file to 8.5x11 with ImageMagick and in doing so, I am loosing the quality of my pdf file.
I was using convert source.pdf -extent 612x792 destination.pdf command.
Can someone please help me with this one?
Imagemagick is rasterizing the PDF, then scaling it, then producing an output PDF of differing dimensions, which contains raster data only.
Scale a PDF to fit directly like this:
cpdf -scale-to-fit "612 792" in.pdf -o out.pdf
This keeps the PDF's original vector artwork and fonts intact.
Imagemagick uses Ghostscript and will rasterize your PDF. It will not maintain its vectors. If you want higher quality, use a higher -density to rasterize and then resize back to whatever you want. For example, I use a density 4x the default of 72 or 288 and then resize by 25%=1/4 to get back to the nominal size.
convert -density 288 -units pixelsperinch image.pdf -resize 25% result.pdf
You can then include your -density 72 -gravity XX -extent 612x792 before the output.
Or you can compute do -density 288 etc and then just resize to 612x792.
I've tried this and it worked.
convert -density 300 -define pdf:fit-page=Letter -gravity Center source.pdf output.pdf
In order to make applying blur faster I'm first scaling my image down and then scale it back up:
convert - -scale 10% -blur 0x2.5 -resize 1000% RGB:-
This works most of the time but sometimes the output resolution is slightly different from the original input. Is there a way to force the pipeline to be size-preserving?
You should be able to access the original geometry of the image via %G, so you can do:
convert input.jpg -scale 10% -blur 0x2.5 -resize '%G!' RGB:-
If you are using Windows, you probably want "%G!" in double rather than single quotes.
If you are using v7 ImageMagick, replace convert with magick.
I think you are getting errors because if you take 10% of 72 pixels (say), you will get a whole number of pixels, i.e. 7 pixels and then when you scale back up by a factor of 10 you'll get 70 rather than your initial 72.
If you are using Imagemagick 7, you can do the following:
magick input.jpg -set option:wd "%w" -set option:ht "%h" -scale "%[fx:wd/10]x%[fx:ht/10]" -blur 0x2.5 -resize "%[fx:wd]x%[fx:ht]\!" RGB:-
This stores the input width and height. Then uses the stored values to scale by 1/10 of those dimensions, then does the blur, then resizes exactly back to the origin input size. Note the ! that forces the resize to the exact dimensions.
or simpler without storing the input width and height:
magick lena.jpg -scale "%[fx:w/10]x%[fx:h/10]" -blur 0x2.5 -resize "%[fx:w]x%[fx:h]\!" lena_x.jpg
At a high density like 300 dpi other than the default density 72 dpi the following ImageMagick convert command outputs blank pages. It looks strange to me.
"convert -units PixelsPerInch -density 300 $myfiles -page A4 -gravity center test.pdf"
Anyone like to exchange idea?
gravity parameter here isn't effective appropriately
(unable to align the object)
as it can't recognize the position & resolution of A4 page at 300 dpi. This is why the questioned command is outputting blank pages at 300 dpi.
We should avoid using page parameter if density is already defined. ImageMagick has a parameter called extent that can be used to define the resolution of a page at a given density (here 300 dpi). Thus we should use extent instead of page in this case in order to achieve the desired output.
For example,
resolution of A4 size page at 300 dpi is 2480x3508, thus correct command for a set density like 300 dpi shall be:
"convert -units PixelsPerInch -density 300 $myfiles -gravity center -extent 2480x3508 test.pdf"
Here, resolution of extent parameter should be proportionately equal to the set density for any specific page size.
I want to convert pdf pages to images of same size(aspect ratio maintained) irrespective of the pdf quality. Say A4 size. I am using convert from Imagemagick for this but struggling to get the fixed size of images for different pdfs of different quality.
Can anyone help me?
Something like:
convert -density 288 document.pdf -resize 2480x3508 result.png
The density must come before the PDF to ensure the rasterisation is done at sufficient quality/resolution.
If you want that centred on a piece of A4 and padded with white to fill the page:
convert -density 288 document.pdf -resize 2480x3508 -background white -gravity center -extent 2480x3508 result.png
I want to convert different image formats (bmp,jpg,gif,png,tiff-incluging multipaged) into a PDF format with A4 page size and with images fit to page (resized if necessary). Image should be positioned at the center of the page and I'd like to define an offset.
I tried the code below but there is no offset at the top and the image quality is really poor.
convert png.png -gravity North -resize 500x500 -quality 100 -page a4x5x5 myout.pdf
Is there any way to do that?
Thanks in advance for any help,
Mariusz
If you want to keep the original resolution (lossless) you can try the following command:
convert png.png -background white -page a4 myoutput.pdf
Based on a comment posted before: https://stackoverflow.com/a/24573341/6747994
#m4tx This command only makes sense if the picture has a resolution above 500x800px, it does not zoom in, to avoid pixelated thumbnails.
You can convert to pdf using ImageMagick
convert png.png myout.pdf
but use pdfjam instead of ImageMagick to adjust the page size
pdfjam --paper a4paper --outfile myoutA4.pdf myout.pdf
pdfjam offers other options, which may fit your needs.
Found this somewhere on stackoverflow:
convert *.jpg -resize 1240x1753 \
-extent 1240x1753 -gravity center \
-units PixelsPerInch -density 150x150 multipage.pdf
Thanks to the ImageMagick support forum I was able to find a solution:
convert image.tif -resize 575x823^> -gravity center -background white -extent 595x842 image.pdf
If you get an error try:
convert image.tif -resize 595x842^\> -gravity center -background white -extent 595x842 image.pdf
You need to specify the density:
convert -density 80 -page a4 input_A.jpg input_B.jpg output.pdf
Otherwise, there can be an issue when printing with "actual size" instead of "fit". I have used a public printer where I could not choose "fit" and had to choose "actual size", in which case the printed page was only a part of the page which I wanted to print.