I am trying to do a simple conversion from a transparent PNG file to EPS with transparency and currently my command looks like this:
convert "image1.png" "image1.eps"
It looks like all I am getting is a black image. Any ideas?
Thanks!
Converting a PNG to an EPS is more than just a simple format conversion. Its changing from a raster image to a vector image, so the raster image has to be "traced". The popular command line tool for doing this is potrace. With potrace installed (and its component tool mkbitmap) you could do it with something like this:
convert image1.png image1.bmp
mkbitmap image1.bmp -o image1.pgm
potrace image1.pgm -e -o image1.eps
The call to mkbitmap converts the color image to a graymap more suitable for tracing.
This will yield an eps with black lines on a white background. If you need a full color trace, inkskape is a GUI tool for doing this, and an inkscape user homebrewed a command line tool to do it, which can be found here
Related
Using the Google cwebp utility (https://developers.google.com/speed/webp/docs/cwebp) and the ImageMagick convert utility, I am unable to preserve transparency in png images when converted to webp.
Using convert I've tried using alpha-compression=0 and alpha-quality=100, without positive result. See: https://imagemagick.org/script/webp.php
The images I am working with have transparent corners for a rounded icon image.
Script being used (in Fish shell):
for file in *.png;
cwebp $file -o (basename $file .png).webp;
end;
and
for file in *.png;
convert $file (basename $file .png).webp;
end;
Never mind. It was my image editor which was not displaying the transparency properly. Transparency was still there. Now filing a bug report at https://github.com/linuxmint/pix/issues
I wanted to batch-convert some JPG images to PNG, so I used the following ImageMagick command:
convert before.jpg after.png
However, things didn't go as smooth as I planned. See two images below - first is before.jpg, second is after.png:
You can see that the second one is quite darker than the original.
I'm using ImageMagick 6.9.9-19.
Opening JPEG image in GIMP and exporting it as PNG gives expected result - output image is identical to original.
What am I doing wrong?
Edit: re-saving after.png with GIMP also makes the image identical to original.
Edit: even after I saved after.png with GIMP, re-converting with ImageMagick breaks colors again (convert after-gimp.png after-gimp-and-im.png).
Edit: converting to sRGB or CMYK TIFF, or even again to JPG, does not give this problem. However, I still need PNG.
The two images you posted are identical according to IM 6.9.9.20 Q16 Mac OSX compare -metric rmse GBooF.jpg geDxn.png null: Which produces: 0 (0). It is possible your viewers may display jpg and png differently, since neither have an sRGB profile. Though, png is usually assumed to be sRGB.
Also my viewer shows both of your images as the same --- no difference, in your post on Mac Safari and using Mac Preview.
Try adding an sRGB profile to your jpg. Then convert.
convert GBooF.jpg -profile path2/sRGB.icc GBooF2.jpg
convert GBooF2.jpg GBooF2.png
See if those view the same.
New to Juypter, trying to use it with Latex. Everything works fine except for the images. I used this tutorial: https://www.youtube.com/watch?v=m3o1KXA1Rjk&t=149s
Png Images are fine in markdown, i.e
But LaTex cannot determine size of png images. If I save the image as pdf I get the same issue. If I save the image as eps then LaTex complains that it cannot convert eps to pdf.
Has anyone had this issue? Anyone know how to solve it?
PNG images always contain the size in pixels.
Optionally, they can include a chunk of data named pHYs. This contains the resolution of the image. If this chuck is present, you should be able to find the actual text pHYs in the file.
If this chunk is missing from the PNG file, the scale of the image can not be found.
If you are on a UNIX-like operating system you could use grep or hexdump to check for the text pHYs in the PNG file. The identify program from the ImageMagick suite also can display the resolution of PNG images.
Note that there is an error in the video. The author first uses latex and then pdflatex three times. That is not a good idea, since they have different capabilities w.r.t. graphics. Stick with pdflatex.
I'm trying to edit a pdf file with 100 pages, all of them images I need to export as png, setting their image mode as greyscale, and setting also their resolution, width and heigth.
How can I write a scheme (or python) script that perform this actions so that i could apply them by gimp in batch mode?
I've searched in the internet but didn't find simpy stated instructions.
ImageMagick's convert will do all this in one call in a command prompt:
convert -density 200 -colorspace Gray input.pdf -geometry 1000 ouput.png
will produce 1000px-wide grayscale PNGs (output-0 to output-(N-1).png) using a 200DPI rendering of the PDF.
You can also use Gimp scripting but you'll have a lot more to learn and AFAIK the API for the PDF loader only loads at 100DPI.
A slightly more manual method could be to:
Load (manually) the image in Gimp (you can specifiy the DPI in that case). This loads all the pages as layers.
Image>Mode>RGB to convert the image to grayscale.
Image>Scale image to set the size of all the pages
Save the individual layers to PNG (there are scripts for this, for instance this one)
I'm using ImageMagick to convert PDF files to PNGs. (Lots of text, so I'd rather use PNG over JPEG.) I'm doing this on OS X, 10.8.2.
I tried using Ghostscript, then ImageMagick, as was done here and I got a gray background. I shortened it to one line, since ImageMagick can work with PDFs and tried this:
convert -background transparent -transparent white \
Background-Page01.pdf TestClearX1.png
I've tried that with PNG files and JPEG files. (And with and without -transparent white as well.)
If it's a JPEG, I can get a white background (which is probably clear, but in my viewer, I can't tell), but with a PNG, I always get a dark background. I thought about, as a test, trying to generate a BMP, then converting that to PNG, but it won't generate BMP files.
How can I get a transparent background for a PNG file?
And if that's not possible, since JPEG files are not good for text, is there a better alternative?
This isn't an answer, but the format of the comment section doesn't allow sensible formatting, so I am offering it here instead.
You alluded to the fact that Preview in OS X doesn't show transparency properly, and that is correct. To get around that, I made the following script, which overlays the files you want to view onto a checkerboard pattern like Photoshop does. I save it as preview and then use chmod +x preview on it to make it executable. Here is the script:
#!/bin/bash
################################################################################
# preview
# Preview images using OSX "open" but overlay images on top of checkerboard
# first so you can see transparency/transparent pixels, since Preview renders
# them grey :-(
################################################################################
for f in "$#"
do
base=$(basename "$f")
composite -compose Dst_Over -tile pattern:checkerboard "$f" "/tmp/$base"
open -g "/tmp/$base"
done
That enables you to do:
/.preview file1.png file2.gif
and the -g option also means Preview doesn't steal focus too :-)
So, instead of looking like this:
it looks like this:
There's two ways to export a PDF in LibreOffice, and one way does not provide any warnings. The other way provides a warning that PDF/A cannot have transparent objects. The problem is you're using PDF/A files that don't support transparent objects—this results in your PNG always having a background colour.