I have this image:
I need to count how many red pixels there are vertically on x 60 which would be the red line on the right containing 4 pixels.
I tried this:
img.png -alpha off -fuzz 2% -fill white -opaque "#FF0000" -fill black +opaque white -gravity west -crop 61x+0+0 -format "%[fx:round(mean*w*h)]\n" info:
but it also counts all the red pixels left to x 60
Try:
magick ... -crop 1x+61+0 ...
to crop a full-height, 1px wide column starting at 61,0.
Related
There is a small sprite:
# mario sprite in base64 writing to file:
magick 'inline:data:image/png;base64,
iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAYAAACNiR0NAAAACXBIWXMAAA7EAAAO
xAGVKw4bAAAA00lEQVQ4ja1UwRGDMAyTe7zLJmWUzMoodBO6gHmkhsRWcukVvYID
kiKbiKoqbsTjTjIAmLq7IvXzwGHahJ5sUKBJKKhf3rcVAPB8pZ5BTihyEcxLomuD
Fxhqyryk06WtDZ93LSB+bMqYvBtPBsQYA2FP3YPl2XUIAIpcsCZ5eRM18slvALyL
CoFAu5EApCn7tsbx+hY0U55llmkYG7NefuhzKAVFUv1Mm8L+EgKWa5zDQbIWqiNn
riuvID8g1r4c2Hi6Ghvg6sg/mqEIDv+9v2+/sQ8vtmAvY/Wf0QAAAABJRU5ErkJg
gg==' mario.png
I want to scale it 8x:
convert -scale 800% -quality 100 mario.png mario-big.png
But scale with padding between pixels. To have an indent of 1 pixel between four adjacent eight times larger pixels. Or overlay a grid over the enlarged image.
How can I do this, please tell me?
Example:
As an alternative approach, how about using -fx to make a grid? For example:
convert -size 64x64 canvas: -fx "i % 9 == 0 | j % 9 == 0" x.png
Will set a pixel white when either the column (that's i) or row number (that's j) is on a multiple of 9. I see:
Now using Mark's suggestion, just expand your sprite by 9 with nearest neighbor, then use a ternary operator to pick either the image (image pixels are u) or white (1.0):
convert mario.png \
-scale 900% \
-fx "(i % 9 == 0 | j % 9 == 0) ? 1.0 : u" \
result.png
With this test image:
I see:
It'll work for any size image, though it'll be pretty slow if the image is large.
Updated Answer
I'm not sure how to change the 2px spacing to 1px in my original answer. Here's another method which we can probably speed up and improve if it gets the results you want. I'm using my image below as it's a an easier size to see, but you can adjust the numbers to match your own image. I am also using the "wrong" colours so you can see where each one ends up, but again, you can change my mad colours to white:
Chop into rows, each row being 50px tall
Iterate over rows, chopping each into 50px wide chunks and recombining with 1px yellow spacing
Smush the new rows together vertically with 1px cyan spacing
The code looks like this:
#!/bin/bash
# Chop into rows, each row being 50px tall
magick artistic-swirl.jpg -crop x50 row-%02d.png
# Iterate over rows, chopping each into 50px wide chunks and recombining with 1px spacing
for f in row-*png ; do
echo $f
magick "$f" -crop 50x -background yellow +smush 1 "$f"
done
# Smush the new rows together vertically with 1px spacing
magick row-*png -background cyan -smush 1 result.png
Note that +smush N joins images side-by-side with N px spacing in the background colour, but that -smush N joins images above-and-below with N px spacing.
Here's what I get applying that to your image:
#!/bin/bash
# Chop into rows, each row being 50px tall
magick mario.png -scale 800% -crop x8 row-%02d.png
# Iterate over rows, chopping each into 50px wide chunks and recombining with 1px spacing
for f in row-*png ; do
echo $f
magick "$f" -crop 8x -background yellow +smush 1 "$f"
done
# Smush the new rows together vertically with 1px spacing
magick row-*png -background cyan -smush 1 -bordercolor blue -border 1 result.png
Original Answer
Not at a computer to test, but if you scale your image up to the correct size as you are currently doing, you should then be able to crop the image into tens/hundreds of individual 8x8 images and pipe them to a montage command to lay them out on a white background with a 1px spacing between all the individual 8x8 blocks.
Something like:
magick 'inline:data:...' -scale 800% -crop 8x8 miff:- | magick montage -background white -geometry +1+1 -tile Nx miff:- result.png
where N is the number of 8x8 blocks you want in each row.
Note that miff:- is an ImageMagick internal lossless transmission format.
Back at a computer, I'll do something similar with this image:
magick artistic-swirl.jpg -scale 500x500 -crop 50x50 miff:- | magick montage -background yellow -geometry +5+5 -tile 10x miff:- result.png
Following this approach, deskewing works great, how do I autocrop so it the outer border comes in until it finds a mostly white contiguous rectangle, so it could be auto-cropped after deskewing?
If you are using Imagemagick 7, you can do an extreme trim using the new -define trim:percent-background=0% to remove all the background from the image. See https://imagemagick.org/script/command-line-options.php#trim
Input:
magick skewed_1500.jpeg -background black -deskew 60% -background black -define trim:percent-background=0% -fuzz 1% -trim +repage x.jpg
Result:
ADDITION:
You can trim even more by trimming before the deskew. I had to use a large fuzz value to remove the bottom white. There must be some slight gray spot somewhere down there that I cannot see. But if there is no black border to start, you may trim too much white all around. That is the downside.
magick skewed_1500.jpeg -bordercolor white -border 1 -fuzz 75% -trim +repage -background black -deskew 60% -background black -define trim:percent-background=0% -fuzz 1% -trim +repage x.jpg
Result:
This is an example PNG image:
it's 50x40 but enlarged here to see it better.
The hex of bottom left and bottom right pixels is F9E4B7
I need to know how many pixels there are on vertical edges from the bottom left and right with almost this color, like 1% fuzz because they are not all exactly F9E4B7 but some are very slightly different.
In this case it would be 20px of each side:
I'll mark the areas which need to be counted just to make it perfectly clear:
I also need to be able to count how many pixels are exactly F9E4B7, which in this case would be 15 left and 20 right, I'll mark the slightly different areas so it's clear where the counter needs to stop:
The way to do that in Imagemagick is to use fuzz to change all your pixels close to that color to white and the rest black. The crop the first or last column and use -fx to get the count from mean*width*height. So for example for the left full column of the whole image, one has
Unix Imagemagick 6 syntax:
convert tan.png -alpha off \
-fuzz 1% -fill white -opaque "#F9E4B7" -fill black +opaque white \
-gravity west -crop 1x+0+0 -format "%[fx:round(mean*w*h)]\n" info:
Windows Imagemagick Syntax:
convert tan.png -alpha off ^
-fuzz 1% -fill white -opaque "#F9E4B7" -fill black +opaque white ^
-gravity west -crop 1x+0+0 -format "%[fx:round(mean*w*h)]\n" info:
Result:
108
To get the right side, use -gravity east.
For exact count, use -fuzz 0
For Imagemagick 7, change convert to magick
Is there a way to add 5 or any number of white/transparent pixels at the top and left borders of an image with the magick command in Linux?
Use the -splice operator. First make a solid magenta rectangle:
magick -size 100x50 xc:magenta image.png
Now splice on a yellow chunk (so you can see it) 10 wide and 20 tall:
magick image.png -background yellow -gravity northwest -splice 10x20 result.png
Change yellow to none for transparent pixels.
Change magick to convert for v6 ImageMagick.
If you just want to splice to the East side:
magick image.png -background yellow -gravity east -splice 10x east.png
If you just want to splice to the South side:
magick image.png -background yellow -gravity south -splice x10 south.png
Using imagemagick, I want to clean the left side of an image, i.e. make white without cropping. For example cleaning the left-most vertical strip of 25 pixels wide. I figured out how to crop to a given geometry, but I couldn't figure out how to clean without cropping.
Here is my start image, made like this:
convert -size 256x256 gradient:cyan-yellow image.png
Method 1
One way to do it would be to use -fx and set all pixels where the x-coordinate is less than 25 to 1.0 (i.e. white) and leave all other pixels as they are:
convert image.png -fx "i<25?1:u" result.png
Method 2
Another, faster way to do it might be to clone the original image, and scale it down to 25 pixels wide, fill it with white and composite that over the original image:
convert image.png \
\( +clone -scale 25x! -fill white -colorize 100 \) \
-composite result.png
The result is the same.
Method 3
A third way to do it might be to crop the image 25 pixels in from the left side, then splice 25 white pixels back on the left side:
convert image.png -crop +25+0 -background white -gravity west -splice 25x result.png
Method 4
Bit of a kludge, but nearer to what you asked. Here, I guess that your image height doesn't exceed 10,000 pixels and draw a rectangle:
convert image.png -fill white -draw "rectangle 0,0 24,9999" result.png
I guess the proper way to do this is to get the height first then use it:
#!/bin/bash
h=$(convert image.png -format "%[fx:h-1]" info:)
convert image.png -fill white -draw "rectangle 0,0 24,$h" result.png