I'm creating sprites from 3d models in blender by rendering out the frames and then joining them together with ImageMagick. But when I run convert image.png -trim image.png on this one image the colours are being changed darker. How do I stop this or is it a bug?
Input File
Output File
Related
Task: i have an input png file (many actually, but i'll just loop the solution). It is 16x16 PNG, 32bit with partial transparency along edges.
It so happens that toolbar of a certain stupid platform requires 17x17 files. My problem is that imagemagick kills transparency when doing simple transformations.
So:
Sanity check:
convert add.png PNG32:add_COPIED.png
creates another 16x16#32bpp file. So far so good.
Transformation (gravity is fine):
convert add.png -extent 17x17 PNG32:add_17.png
creates a file with solid white background. That's not good.
What doesn't work:
I tried a serious number of combinations of transparent, transparent-color, background, alpha and flatten. Got nowhere.
What does work:
convert address_book.png -alpha Extract address_book_MASK.png
convert address_book.png -extent 17x17 PNG32:address_book_17.png
convert address_book_MASK.png -background black -extent 17x17 address_book_MASK17.png
composite -compose CopyOpacity address_book_MASK17.png address_book_17.png PNG32:address_book_FIN.png
While i have a working set of commands and I can get through the day, I honestly believe that this is the wrong way to do things - four commands that create 3 intermediate files that i need to delete later. Surely it can be done in a better way?
Set the background colour before changing the extent:
convert input.png -background none -extent WxH result.png
Currently, I have thousands of pictures where I want to get rid of white space around the object, but not inside the object. However, the white space is not constant. See pictures below.
Picture 1 :
Picture 2 :
Picture 3 :
Options like this don't work as they delete all white space in the images
convert image.png -fuzz 10% -transparent white output.png
Any suggestions?
What do you mean by getting rid of the white space? If you mean make it transparent, then in ImageMagick 6, you can do a whole folder of images using the mogrify command as follows:
The process involves padding the image with 1 pixel border of white to ensure white is all around. Then doing a fuzzy flood fill. Then remove the extra one pixel all around. I have assumed that the background color is nearly white. Change the fuzz value as desired.
Create a new directory to hold the output (or backup your input directory)
Change directory to the one holding your input images
mogrify -path path_to/outdirectory -format png -bordercolor white -border 1 -fuzz 20% -fill none -draw "matte 0,0 floodfill" -shave 1x1 *.png
Here are the resulting images.
Of course you will have to download them to see that they are transparent.
Note that the images that I downloaded were JPG. So if your images are jpg and not png as in your command, then change *.png to *.jpg. Or just use * to change all formats.
See
https://imagemagick.org/Usage/basics/#mogrify
https://imagemagick.org/Usage/draw/#matte
If using ImageMagick 7, change matte to alpha and change mogrify to magick mogrify.
How how would i generate an image of certain resolution containing black and white noise. I want to generate a number of images with each images noise being different. Prefer if done in console of either linux or windows but coding is ok if really have to.
Cheers
Like this with ImageMagick which is installed on most Linux distros and is available for macOS and Windows:
convert -size 512x512 xc:gray +noise random -colorspace gray noise.jpg
Replace convert with magick if using v7+ of ImageMagick.
If you mean pure black and white without shades of grey, and maybe would like a different size and a PNG format, use:
convert -size 600x400 xc:gray +noise random -colorspace gray -threshold 50% noise.png
If you want a different distribution of noise (gaussian, poisson, binomial) or to attenuate the noise, have a look at my other answer here.
I have an image in .jpg format with white background color. I want to remove the white background color to transparent in Imagemagick. I tried many ways but still the white background can not be removed. Can some one help me to solve this.
You cannot have transparent background colors in your JPEGs. The JPEG file format doesn't support transparency.
If you need transparent background, you need to convert the JPEG to
either PNG (high quality, filesize possibly larger than JPEG)
or GIF (in case you can tolerate low quality and a range of maximally 255 colors).
Example command:
convert your.jpg -transparent white your.png
First, you need to convert the image format from .jpg to .png format, because JPEG does not support transparency. Then use this command:
convert image1.png -fuzz 20% -transparent white result.png
The -fuzz option allows the specified percentage deviation from the pure white colour to be converted to transparent as well. This is useful, for example, when your image contains noise or subtle gradients.
I just found a very neat thing!
magicwand 1,1 -t 20 -f image -r outside -m overlay -o 0 image.jpg imgOutput.png
It is a Fred Weinhaus bash script that can be downloaded from here (for non commercial use only). Also there has about 250 scripts!! and this one is amazing! it did exactly the trick, to remove all background while keeping the inner image dots untouched!
At his page, there are several images as examples so you pick what you need to put on the command line!
The initial position 1,1 is a general guesser saying all the contour is background.
Pay attention that the output must be ".png"
This is my solution without magicwand (replace magick by convert for im < 7.0):
magick img.png -fuzz 20% -fill none -draw "alpha 1x1 floodfill" result.png
Get the background automatically and remove it :
bg=$(convert input.png -format "%[pixel:p{0,0}]" info:)
convert input.png -fuzz 20% -transparent "$bg" output.png
I want to save .gif conversions of other images with a specified colormap. The "-remap cmap.gif" option in Image Magick
example: convert -remap cmap.gif input.png output.gif
DOES process input.png using the specified colors from cmap.gif, but it changes the order in the output colormap. Is there a way to force Image Magick to used EXACTLY the same colormap?
I am attempting to add new images to an ancient display program that accepts .gif file input but uses a fixed colormap with no ability to alter the colormap for individual images.
Does it help to add the +dither parameter?
convert input.png -remap cmap.gif +dither output.gif