Seeking to set a folder of PNG line drawings to background transparent and getting lost in examples and options recommended for other cases. Essentially when I find a line of command that seems to fit I don't know how to apply it to an entire folder. Also getting lost in options like fuzz and anti-alias which I'm not even sure would benefit my images, below. I'm on a Mac running v7 of Magick and really appreciate your kind help.
Simplest Sample
Most Complex Sample
This should do what you want in Imagemagick 7. You should use magick mogrify to process a whole folder of images. To convert white to transparent in an image you can use -fuzz XX% -transparent white, where XX is a percent tolerance for nearby colors. For JPG, typically about 15% seems to work due to jpg compression change of flat colors. So I put your images into a folder called drawings and create a new empty folder called drawings2 to hold the output image, which need to be PNG (or TIFF) so use transparency.
cd
cd desktop/drawings
magick mogrify -path ../drawings2 -format png -fuzz 15% -transparent white *.jpg
Results:
See https://imagemagick.org/Usage/basics/#mogrify
Related
I am looking to batch resize pictures to a specific pixel size while maintaining the aspect ratio. Is their a way that the picture aspect can be preserved and the rest of the space can be filled in with white? For example, I resize an image to 200 x 200 and due to preserving the aspect ratio it is changed to 200 x 194. I would like the actual image to remain 200 x 194 and white space to fill in the remaining area to create an image that is 200 x 200 px. Thank you in advance!
You can do that with ImageMagick which is included in most Linux distros and is available for macOS and Windows.
Just in Terminal, or Command Prompt on Windows:
magick input.jpg -background white -resize 200x200 -gravity center -extent 200x200 result.jpg
If you have many files to do, you may be better using ImageMagick's mogrify command, which will do them all in one go for you! So make a new directory called processed for the output files and then use this to process all PNG files in the current directory:
magick mogrify -path processed -background white -resize 200x200 -gravity center -extent 200x200 '*.png'
I don't know if you are on Windows or not, so you may or may not need the single quotes around the filenames at the end of that command. Basically, it determines whether the expansion of the filename list is done by the shell (which has limitations on the number of files), or internally by ImageMagick (which does not).
If you are running anything older than v7, the commands become:
convert input.jpg ...
or
mogrify ...
I searched everywhere but couldn't find an answer to this.
I would like to output all images of a folder in 50Kb exactly and maintain the original aspect ratio.
I tried ImageMagick and resizing to 250x250 e.g but it is not working for me, what it does is change the first dimension and adapt the other, so output images have not the same size.
for image in `ls $#*.jpg`; do
mogrify "${image}" -resize 250x250 "${image}"
done
How do it? Thanks
Updated Answer
If you want the file size of the images to be limited to 50kB, use:
convert input.jpg -define jpeg:extent=50KB output.jpg
Original Answer
Use mogrify, but be careful it will overwrite all your images:
mogrify -resize 250x250! *.jpg
In general, when using mogrify I like to use the -path option to specify an output directory for results, like this to avoid originals getting overwritten:
mkdir results
mogrify -path results ...
Your script will work if you add the ! after the resize which forces the resize even if it distorts the shape of the picture.
If you want a way to do something similar with Python, I wrote an answer that works pretty well here. It does a binary search for a JPEG quality that satisfies a maximum size requirement.
I'm playing with this creative script here: http://www.fmwconcepts.com/imagemagick/transitions/. The plan is to mimic what happens with the script with ffmpeg and generate video with transition effects between pictures. My current understanding is this:
I have two pictures A and B.
I need in between a couple of pictures (say 15) that are partially A and partially B.
To do that I use the composite -compose src-over A.jpg B.jpg mask-n.jpg out.jpg command.
During the process, the mask-n.jpg gets generated automatically that gradually change from all black to all white.
Depends on the mathematically equations, the way the transition effect looks is different.
In one of the example, Fred the author gave this:
convert -size 128x128 gradient: maskfile.jpg
This will generate a image like this:
This is partially black and partially white. For the transition to work, I'll need an all white one and an all black one and a couple of others in between. What's the magical command to do that?
I have re-read your question and I am still not sure I understand, but maybe you want a dark grey to light grey gradient:
convert -size 128x128 gradient:"rgb(40,40,40)-rgb(200,200,200)" greygrad.png
Not sure I understand what you are trying to achieve, but if you want an all black one, use:
convert -size 128x128 xc:black black.jpg
and an all white one:
convert -size 128x128 xc:white white.jpg
and a grey one:
convert -size 128x128 xc:gray40 gray40.jpg
If you want to join them for transitions, use
convert im1.jpg im2.jpg -append result.jpg
or use +append to join side by side instead of above and below.
Consider using PNG instead of JPEG throughout.
Fred tells you how the script works at the bottom of the page you have linked to with some example code.
According to his explanation there is only the one mask images as:
The mask images is gradually made lighter
I have a bunch of images that are rectangular and I need them to be square, i.e. 1000x1000, so I've decided to use ImageMagick to pad the sides of the image with the amount of whitespace necessary to make the image square.
I've found the code from the following link useful (see next paragraph). But this requires me to process each image individually, to set the filename and then the -thumbnail dimensions. How can I use this same process to process an entire folder?
Here's the code and the link to it:
http://imagemagick.org/Usage/thumbnails/#pad
convert -define jpeg:size=200x200 hatching_orig.jpg -thumbnail '100x100>' \
-background white -gravity center -extent 100x100 pad_extent.gif
It is not very clear from your question what you actually have (i.e. how big your images are? what format are they?), nor what you actually want (you only provide an example that doesn't do what you want. But I'll take your question at the face-vale of the title and hope you can work out anything missing from there.
If you want to do ImageMagick in bulk, you either need to use a loop in bash, like this:
#!/bin/bash
for f in *.jpg; do
convert "%f" ...
done
or use IM's mogrify command. That is quite a powerful command, so make a backup of your images before you even think of trying to use it.
Let's assume you want to place all JPEG images in the current directory onto a white 1000x1000 pixel background. You would do this:
mogrify -background white -gravity center -extent 1000x1000 *.jpg
Updated Answer
It should be possible to do the resizing and the white padding in a single ImageMagick command without needing to use SIPS as well, like this if you now want 1200x1200 square images padded with white:
mogrify -background white -gravity center -resize 1200x1200\> -extent 1200x1200 *.jpg
We have an in-house tool that does some operations on windows icon files. Turns out that it only really supports the type of .ico files that are generated by ImageMagick. Should be no big deal because we currently use ImageMagick anyway to generate sizes not supplied in the original image. My plan was to always use ImageMagick to generate images, even when the original .ico file contained an image with the correct resolution, to ensure the image was of the correct format.
So far, so good. However in practice this does not seem to work the way I expect it to. Specifically I'm after a 256x256 icon. The original file contains (I believe) a 256x256 version as it looks high res when viewed from the browser. However, the output file from ImageMagick is obviously a low-resolution one scaled up.
The command line I'm using is:
convert.exe orig.ico -background #FFFFFFFFFFFF0101 -compose Copy \
-gravity Center -scale 256x256! -depth 8 temp2.ico
Question: is there some better set of commands to use, which might start from the 256x256 icon?
Your orig.ico file probably contains multiple dimensions. They will also be stored in the output file. This means a dimension of 16x16 will be upscaled to 256x256 and that produces an ugly image. The 256x256 resolution is most likely the first dimension. You can see all the dimensions with the following command:
identify.exe orig.ico
With the command below you can get a specific dimension/image by specifying the index (starts at zero):
convert.exe orig.ico[0] -background #FFFFFFFFFFFF0101 -compose Copy ^
-gravity Center -scale 256x256! -depth 8 temp2.ico
If the 256x256 dimension is the last image you should set the index to -1:
convert.exe orig.ico[-1] -background #FFFFFFFFFFFF0101 -compose Copy ^
-gravity Center -scale 256x256! -depth 8 temp2.ico