I have 100s of screenshots taken from website of varying height. I would like to crop header of the images by 50px from the top irrespective of the height of the image.
convert -crop autoxauto+0x50 image-input.png image-output.png
If you start with this image where the two bars are both 50 pixels tall:
You probably mean:
convert start.png -crop x50+0+0 top.png
Or:
convert start.png -crop x50+0+50 bottom.png
I agree with #Mark's answer, however I found a simpler solution:
convert image-input.png -chop 0x50 image-output.png
Related
I'm trying to crop image by height with this command line:
convert 1053257.png -gravity South -crop 2910x3312+0+0 -background black +repage image-cropped-top.png
The generated image is not cropped correctly, as the dimensions after running the command are 2791 x 3312.
The width is cropped as well!
Can anyone help with this?
The general form is:
convert input.jpg -crop WIDTHxHEIGHT+0+0 result.jpg
If you want to crop to a specific width, say 1024, leaving the height unaffected:
convert image.jpg -crop 1024x+0+0 result.jpg
If you want to crop to a specific height, say 768, leaving the width unaffected - note the height is after the x:
convert image.jpg -crop x768+0+0 result.jpg
If you want to crop to a maximum width and height, say 1024 wide by 768 tall without distorting the aspect ratio:
convert image.jpg -crop 1024x768+0+0 result.jpg
If you want to crop to a specific width and height, say 1024 wide by 768 tall and are happy to allow gross distortions:
convert image.jpg -crop 1024x768+0+0\! result.jpg
Think of the exclamation mark as meaning "just do it!". Note that the backslash is only needed on Linux/Unix/macOS to escape the exclamation mark, you omit the backslash on Windows.
Note, if you are saving the cropped image in PNG format, you probably want to reset the page afterwards so the image "forgets" it used to be part of a larger image:
convert input.jpg -crop 1024x768+0+0 +repage result.png
With ImageMagick a problem like that can occur if you've done a "-trim" to the image before the crop. When you "-trim" an image it can still remember the original page dimensions from before the trim, then when you crop it, it uses those page dimensions as the starting reference for the crop. You probably need to "+repage" before the crop to start with fresh paging information. Try something like this...
convert 1053257.png -gravity South +repage -crop 2910x3312+0+0 +repage image-cropped-top.png
I have a few images I want to convert in batch using ImageMagick.
All images should be converted to a specific width, lets say 500px.
If an image's width is larger than 500px, scale it down and preserve the aspect ratio.
If an image's width is less than 500px, add borders to the sides to make it 500px wide.
The first one is possible using magick mogrify -resize 500x *, but this also scales images with a smaller width up. How can I prevent that from happening and add borders instead?
I figured I could just add -background black -gravity center but I don't know how to prevent upscaling.
Solved it using two separate commands for now:
Resize images larger than 500px wide:
magick mogrify -resize '500x>' *
Add borders to images smaller than 500px wide:
magick mogrify -gravity center -extent '735x<' *
I have a lot of images. Size of images are different.
I need to write the one imagemagick commandline operation to crop the borders of each image (for example, 10px of each edge).
Basic usage of -crop reuire to know the image geometry - it's not usefull.
Use -shave
convert montage.png -shave 10x10 montage.png
I have images of unknown size and ratios. I wish to take a centred 16:9 crop.
If all the images were known 4:3, then it's easy: 9/16 รท 3/4 = 0.75 so I simply set the height to 75% of the original like this:
convert photo.jpg -gravity center -crop '100%x75%' +repage photo16x9.jpg
However, if the photo is already 16:9 (or even wider), I don't want to crop it, and if it is 'taller' than 16:9 I want to crop it only by the amount necessary to achieve a 16:9 crop.
This would be also easier if I wanted to scale to a known width or height (example question for that). But I'm looking to leave as much of the original image data in place as poss.
Therefore I'm looking for a way to crop the height to a factor of the image's width, with a cut-off.
I hoped this might work
convert photo.jpg -gravity center \
-crop '100%x[fx:9/16*w]' +repage photo16x9.jpg
but alas it seems the [fx:...] is not allowed in a -crop argument.
Hacking a bit I found somewhere that I could not for the life of me understand(!) also failed, but I'll list it here to show research effort!
convert photo.jpg -set option:distort:viewport \
'[fx: w]x[fx: w*9/16 ]+0+0' -filter point \
-distort SRT 0 +repage photo16x9.jpg
(I realise that neither attempts above cover the case when the image is already wider than 16:9, but if the [fx:...] thing worked I could achieve that by using the ternary operator, so I kept the examples simple.)
Maybe you can just calculate the aspect ratio and use that to make a decision. Create two test images, one 15x9 and one 17x9:
convert -size 15x9 xc:black 15x9.png
convert -size 17x9 xc:black 17x9.png
Now ask ImageMagick to tell you if the aspect ratio is wider than 16:9 or less than or equal to 16:9:
convert 15x9.png -format "%[fx:(w/h)>16/9]" info:
0
convert 17x9.png -format "%[fx:(w/h)>16/9]" info:
1
i'm having a large jpg, which has a resolution of x * 256 / x * 256. I want to cut this image into 256x256 tiles with a naming convention {zoom}-{x}-{y}.jpg. In the past i've used ZoomifyExpress Converter which does the cutting and zooming. I also want 6 different zoom levels. I've started so far with this command:
convert example.jpg -crop 256x256 +gravity -set filename:tile
./tiles/%[fx:page.x/256]-%[fx:page.y/256] %[filename:tile].jpg
This produces a lot of x-y.jpg tiles.I don't know how i can add different zoomlevels. I'm relativly new to ImageMagick and this feels like a basic thing to do. Hopefully somebody can help me out. Thanks in advance.
I found the solution:
I just resize the image to the appropriate size and then crop it. The first number in the filename is the zoom level.
convert example.jpg -resize 256x256 -crop 256x256 -set filename:tile
./tiles/0-%[fx:page.x/256]-%[fx:page.y/256] %[filename:tile].jpg
convert example.jpg -resize 512x512 -crop 256x256 -set filename:tile
./tiles/1-%[fx:page.x/(256)]-%[fx:page.y/(256)] %[filename:tile].jpg
.. and so on until i reach the highest resolution.