The ImageMagick documentation provides guidance on how to create torn page effects (https://www.imagemagick.org/Usage/thumbnails/#torn). However, in their implementation, all edges are torn. Suppose I wish to tear off only the bottom or top part of the image. How can I achieve such a thing using ImageMagick?
Simply grow the top & sides by using -extent operator.
convert zelda.png -background pink -extent 148x138-10-10 extent.png
(Adding pink background for visibility on stack)
Apply the effect from the Usage documentation.
convert extent.png \( +clone -alpha extract -virtual-pixel black \
-spread 10 -blur 0x3 -threshold 50% -spread 1 -blur 0x.7 \) \
-alpha off -compose Copy_Opacity -composite torn.png
Then crop back to original image size.
convert torn.png -crop 128x129+10+10 output.png
Update
If you do not want to use geometry, you can use a combination of -border, -shave & -chop.
convert zelda.png -bordercolor pink -border 10x10 -gravity South -chop 0x10 extent.png
convert extent.png \( +clone -alpha extract -virtual-pixel black \
-spread 10 -blur 0x3 -threshold 50% -spread 1 -blur 0x.7 \) \
-alpha off -compose Copy_Opacity -composite torn.png
convert torn.png -shave 10x -chop 0x10 output.png
.. And of course, this all can be done with one command.
convert zelda.png -bordercolor pink -border 10x10 -gravity South -chop 0x10 \
\( +clone -alpha extract -virtual-pixel black -spread 10 -blur 0x3 -threshold 50% \
-spread 1 -blur 0x.7 \) -gravity Forget -alpha off -compose Copy_Opacity -composite \
-shave 10x -chop 0x10 output.png
There are several ways to create a torn edge effect using ImageMagick. Here is another example command using IM version 6 and *nix syntax. This should apply a torn effect to just the top edge of any input image while keeping the original dimensions of the image.
convert input.png -alpha set -background black -fill white \
\( +clone -colorize 100 -gravity south -chop 0x6 -splice 0x6 \
-spread 6 -paint 2 +transparent white -blur 0x0.5 \) \
-background none -compose dstin -composite torn.png
That creates a white mask inside the parentheses. Then a small amount of the "torn" edge is chopped off and a black strip is spliced on to replace it. The random-ish torn edge is created using "-spread" and "-paint" between the white and black areas of the mask. After that, outside the parentheses, that mask is used to apply the transparent torn area to the input image.
To apply the effect to the bottom edge, just change the "-gravity north" to "-gravity south".
To make the torn edge on the left or right, change the gravity setting to "west" or "east", and change the values of the "-chop" and "-splice" operations from "0x6" to "6x0".
This should work the same way using ImageMagick version 7 by changing the "convert" command to "magick".
To use it in Windows, remove the backslashes that escape the parentheses from "\(...\)" to "(...)", and change the continued line backslashes "\" to carets "^".
Related
I'm trying to find a good way to add a 3px white stroke to a ton of png files, effectively to make them look like "stickers." I've got some sample code that does a decent job, but I can't seem to get the cropping right. Also, the stroke looks a bit pixelated and I wanted to know if it's possible to get cleaner edges!
I did a bunch of internet scouring, found some sample code, tweaked it around, and came to something that almost resembles what I'm looking for. The images are always going to be PNGs, so I looked into things like inkscape/gimp from the command line but realized I should be able to do this just using convert from the terminal.
convert in.png \
\( -clone 0 -alpha extract -threshold 0 \) \
\( -clone 1 -blur 10x65000 -threshold 0 \) \
\( -clone 2 -fill red -opaque white \) \
\( -clone 3 -clone 0 -clone 1 -alpha off -compose over -composite \) \
-delete 0,1,3 +swap -alpha off -compose copy_opacity -composite \
out.png
in:
out:
ideally:
Your main problem is it is that you do not have enough space bettween your object and the sides of the image. You just need to add your image with transparency and then remove any excess later.
In ImageMagick 6, this should do what you want.
1) read the input
2) add a larger border than you need to add
3) extract the alpha channel from the input and dilate it by the amount of border (in this case 10)
4) copy the previous image and color the white as red and the black as transparent
5) composite the original over the red/transparent image
6) delete the original and the red/transparent image
7) swap the composite with the dilated alpha channel and put the dilated alpha channel into the alpha channel of the previous image
8) trim the excess transparency from the border padding
9) save to output
convert img.png \
-bordercolor none -border 20 \
\( -clone 0 -alpha extract -morphology dilate diamond:10 \) \
\( -clone 1 -fuzz 30% -fill red -opaque white -fill none -opaque black \) \
\( -clone 2,0 -compose over -composite \) \
-delete 0,2 \
+swap -alpha off -compose copy_opacity -composite \
-trim +repage \
result.png
For ImageMagick 7, replace convert with magick.
If on a Unix-like system, you might be interested in my bash ImageMagick script, contour, at http://www.fmwconcepts.com/imagemagick/index.php
A better result can be achieved by replacing diamond:10 with disk:10
Follow up on “Diff” an image using ImageMagick
When you are working with forms (as opposed to images), the changes are very hard to see with this technique. I wanted to show some type of yellow highlight maybe 10-20 pixels "bigger" (padding) around the actual pixels that changed.
So instead of just this
Something more like this
It seems like I am just missing something here in the stack that can make this work.
convert '(' file1.png -flatten -grayscale Rec709Luminance ')' \
'(' file2.png -flatten -grayscale Rec709Luminance ')' \
... here ? ...
'(' -clone 0-1 -compose darken -composite ')' \
... or here ? ...
-channel RGB -combine diff.png
I can also run this as separate commands and does not need to be fast, most of this is going to be run offline.
I also tried studying the technique here (specifically how the thumbnail scaling gives you the effect I want as the pixels get expanded) but this code is using the library instead of the ImageMagick command line tools. Line 248 => "make the red as visible as possible"
https://github.com/vslavik/diff-pdf/blob/master/diff-pdf.cpp#L218
An example form is the standard W-9. I made 2 subtle changes
PART II .. moved the 2. left about 2 pixels
PART II .. on 4., moved word is to the right 2 pixels
and the compare pumps out this (changes in red that you can barely see)
Thank you for any help
You can use -morphology dilate in Imagemagick to increase the size of the red areas. For example, using your two forms:
convert JW0wZ.png 1nHWT.png -compose difference -composite -morphology dilate disk:10 +level-colors black,red result.gif
UPDATE:
If you want the background transparent, then try
convert JW0wZ.png 1nHWT.png -compose difference -composite -morphology dilate disk:10 +level-colors "black,red" -fuzz 20% -transparent black result.png
Or better
convert JW0wZ.png 1nHWT.png -compose difference -composite -morphology dilate disk:10 -alpha copy -background red -alpha shape result2.png
Update 2: Here is how to overlay a 50% yellow marking onto you two originals. Change the value as desired. I create a difference image and dilate the white. Then I create a 50% yellow image. Then I composite each of the originals with the yellow using the difference image as a mask. See https://www.imagemagick.org/Usage/compose/#compose
convert JW0wZ.png 1nHWT.png \
\( -clone 0,1 -compose difference -composite -morphology dilate disk:10 \) \
\( -clone 0 -fill yellow -colorize 100 -channel a -evaluate set 50% +channel \) \
\( -clone 0,3,2 -compose over -composite +write 1.png \) \
\( -clone 1,3,2 -compose over -composite +write 2.png \) \
null:
To view this, if on Unix and have X11 installed, you can do
animate -delay 20 -resize 50% 1.png 2.png
Hi I would like to create a mask image with "special corners" I am calling them special because I don't really know how to call them in english here is what I would like to achieve:
what I am using now is
convert xc:black -size 300x300 -fill white -draw "roundrectangle 3,3,296,296,5,5"
but this gives me rounded corners. Thank you in advance for any suggestions.
Here's one way of doing it.
convert -size 300x300 xc:none \
-shave 10 -bordercolor black -border 10 \
-fill black -draw "polyline 0,0 30,0 0,30" \
\( +clone -flip \) -gravity north -composite \
\( +clone -flop \) -gravity south -composite -background white -flatten result.png
That says... "Draw a rectangle your full size and transparent, shave 10 pixels off all round and add a 10 pixel black border (easier than doing the maths and making a 280x280 and adding 10 on each side). Draw a triangle in the top-left. Copy the whole shape and flip it and draw it on top of the original. Copy the whole shape and flop it and draw it again on the original. Now make all the transparent areas white."
Here is another way - maybe a little easier. Draw the original square, then copy it, enlarge it by square-root(2) (i.e. 141%), thicken the borders, rotate 45 degrees and composite it onto itself. Kinda depends how your brain works!
magick -size 300x300 xc:none -shave 10 -bordercolor black -border 10 \
\( +clone -scale 142% -shave 30 -border 30 -rotate 45 \) \
-gravity center -composite -background white -flatten result.png
Here is a link to a page showing how to do what you want along with other effects https://www.imagemagick.org/Usage/thumbnails/#rounded
This is the code from the page:
convert thumbnail.gif -alpha set -compose DstOut \
\( -size 20x15 xc:none -draw "polygon 0,0 0,14 19,0" \
-write mpr:triangle +delete \) \
\( mpr:triangle \) -gravity northwest -composite \
\( mpr:triangle -flip \) -gravity southwest -composite \
\( mpr:triangle -flop \) -gravity northeast -composite \
\( mpr:triangle -rotate 180 \) -gravity southeast -composite \
corner_cutoff.png
You should check out the examples as there is another method you could use for smaller images.
How do I replace a color in an image which contains transparency with ImageMagick, but afterwards retain the transparency of the original image.
This is very useful for batch-changing of colors in icons.
Updated Answer
Option 1
A simpler option might be like this:
convert start.png -alpha deactivate -fill blue -opaque red -alpha activate result.png
which changes this:
to this:
Option 2
Another option, which uses an in-memory copy of the image, can also avoid the need to create 2 processes and write an intermediate file to disk:
convert start.png -write MPR:orig \
-alpha off -fill blue -opaque red \
MPR:orig -compose CopyOpacity -composite result.png
Option 3
Yet another method, that uses clone instead of MPR:
convert start.png \
\( +clone -alpha off -fill blue -opaque red \) \
+swap -compose CopyOpacity -composite result.png
Original Answer
If I create an image that contains transparency like this:
convert -size 400x400 xc:none -fill red -draw "rectangle 10,10 100,100" -fill blue -draw "rectangle 200,200 300,300" -bordercolor black -border 5 start.png
I'll get this (I am showing it overlaid on a checkerboard just to visualise the transparency):
If I now run this
convert start.png -fill yellow -opaque red result.png
I'll get this (again overlaid on a checkerboard):
Not sure why you need a more complicated, 2-stage process - or have I misunderstood your question?
convert file-in.png -alpha off -fill REPLACEMENT -opaque COLOR file-out.png
then
convert file-out.png file-in.png -compose CopyOpacity -composite PNG32:file-final.png
I want to create a flare image using imagemagick and then add text on top of it. I was thinking that it was going to be quite easy, but I am having issues adding the text on top of the generated image.
This is so far what I have (keep in mind that the text as well as the dimension are dynamic):
FLARE:
\(
-fill transparent -size 300x1 xc: +noise Random -channel G -separate +channel \
-scale 300x300\! \
\( -size 300x300 gradient: -evaluate cos .5 \) \
-compose hardlight -composite \
-virtual-pixel HorizontalTileEdge -distort Polar -1
\)
TEXT
-fill red \
-gravity center \
-font Arial \
annotate:"Logo 12345678"
EDIT:
The text is showing, but I can't figure out how to overimpress the text on top of the image in a way that it will fill the image for the full width (from left to right, with some padding if possible)
Figured out:
convert \
\( -background transparent -size 300x1 xc: +noise Random -channel G -separate +channel -scale 300x300\! \( -size 300x300 gradient: -evaluate cos .5 \) -compose hardlight -composite -virtual-pixel HorizontalTileEdge -distort Polar -1 \) \
\( -background transparent -size 300x300 -fill blue -gravity center -font Arial caption:"Logo \\n13474899" \) \
-gravity center -composite /tmp/flare_2_final.png
Now I need to figure out how to change the background color of the flare from black to gray and I am done.