Imagemagick - pngs onto png - imagemagick

i've a huge png image (4000x3000, big.png), and i've smaller images (1500x200, small_n.png) .
I'd like to put the small images onto the big.png based on a starting (x,y) parameter.
So, for instance I've the small_1.png with the starting point (300, 200), and this point should represent the top left corner of the image. How can I put the small_1.png onto the big.png knowing the starting point?
I'd like to use imagemagick, or if not possible, any linux commandline tool.
Thanks.

In ImageMagick, you can do that as follows:
convert large_image.png small_image.png -geometry +300+200 -compose over -composite result.png
If you have several small images, you can repeat the same process multiple times in the same command line.
convert large_image.png small_image1.png -geometry +X1+Y1 -compose over -composite small_image2.png -geometry +X2+Y2 -compose over -composite result.png
If using ImageMagick 7, replace convert with magick.
See https://imagemagick.org/Usage/layers/#convert

Related

ImageMagick: Replace All Image Tiles with Single Tile

I'm assuming ImageMagick is the best option for this, but please let me know if you have other recommendations that can be scripted.
I am trying to replace all the 32x32 tiles of an image with a single tile. This is an example for the original image:
This is the tile that I want to use to replace all tiles on the original image:
And this is what I want the output to be:
I've figured out from other posts on Stack Overflow that I can use ImageMagick's composite option to overlay the tile onto the original image:
$ convert original.png tile.png -composite overlay.png
Resulting in the following:
And I assume by knowing the original images dimensions I can overlay the tile manually multiple times. But is there a way to automate the process. In the example pictures I have given, I need to overlay the tile 8 times on the original 64x128 image.
How can I do this with ImageMagick or another software? And if ImageMagick, would the montage or composite command be a better option?
Edit: As an additional question, would it be possible to skip tiles that are completely transparent?
Input example:
Output example:
It isn't really important to be able to do this part, but would be nice.
If the tile image fits evenly into the dimensions of the original, a command like this should do most of what you want...
convert original.png tile.png -background none -virtual-pixel tile \
-set option:distort:viewport %[fx:u.w]x%[fx:u.h] -distort SRT 0 +swap \
-compose copyopacity -composite overlay.png
That reads in both images. Then it creates another canvas the size of the original and filled with multiple copies of the tile image. Then it uses the original as a transparency mask to create a copy of the new tiled image with the same transparent cells as the original.
I don't know why you would need to overlay the 8 tiles on the original. Just create it from scratch and name the output the same as your original
You could use Imagemagick montage to do that (unix syntax):
nx=`convert original.png -format "%[fx:w/32]" info:`
ny=`convert original.png -format "%[fx:h/32]" info:`
num=$((nx*ny-1))
montage tile.png -duplicate $num -tile ${nx}x${ny} -geometry +0+0 result.png
Here I use convert to duplicated the tile, but it uses a relatively current -duplicate feature. If you do not have a current enough version of Imagemagick, then just repeat the tile in montage as follows:
montage Ro1Lp.png Ro1Lp.png Ro1Lp.png Ro1Lp.png Ro1Lp.png Ro1Lp.png Ro1Lp.png Ro1Lp.png -tile 2x8 -geometry +0+0 result.png
As Fred (fmw42) says, "why don't you just create the whole image from scratch?".
Maybe your description isn't complete, so here are a couple more pieces that might help you work it out.
Given bluetiles.png and singlered.png:
you can position red ones as you wish like this:
convert bluetiles.png \
singlered.png -geometry +0+32 -composite \
singlered.png -geometry +32+96 -composite result.png
Given bluewithtransparent.png:
you can copy its transparency to the newly-created image like this:
convert bluetiles.png \
singlered.png -geometry +0+32 -composite \
singlered.png -geometry +32+96 -composite \
\( bluewithtransparent.png -alpha extract \) -compose copyopacity -composite result.png

ImageMagick: Distort and Overlay

I have several pictures of a landscape.
Using the ImageMagick CLI on OSX, I would like to distort and overlay them properly.
I have looked for distortion coordinates between several of the pictures and a reference picture. I fail to understand the diference between -distort and +distort and how it plays with +repage. When I use -distort, the output has the desired offset but it's incomplete (it needs to be bigger). When I use +distort, I get the full image but it's missing the offset.
Reading the documentation I understand that I could do without the offset if I did the overlay composition in the same command before the offset information is lost but what's happening is that the distort is being applied to both the reference and the distorted images.
This is the result of using -distort:
This is the result of using +distort:
The offset of the -distort result would work once I apply it as an overlay (here using the composite in a separate command, but it's missing a big chunk of the picture.
When I tried to consolidate it in a single command this is the result I get:
This is the command I'm currently using:
convert base.jpg overlay.jpg
-matte -virtual-pixel transparent -distort Perspective '961,1695 1856,2461 2279,1520 3185,2303 3564,2173 4441,2970 1547,2817 2441,3594'
-compose blend -define compose:args=50,100 -composite result.jpg
I understand I could use parenthesis there but I fail to see where should I put them.
Thanks!
Update: this is the result of the overlay when using +distort either in two steps or in a single step as recommended by Mark.
The solution was to use -flatten instead of -composite.
convert base.jpg \( b.jpg -matte -virtual-pixel transparent +distort Perspective '961,1695 1856,2461 2279,1520 3185,2303 3564,2173 4441,2970 1547,2817 2441,3594' \) -compose blend -define compose:args=100,50 -flatten result.jpg
Turns out that -composite ignores the image offsets whereas -flatten works with layers and uses the offset information.
The suggestion came from this thread: http://www.imagemagick.org/discourse-server/viewtopic.php?t=20157
This is the documentation to flatten (link broken in the discussion above): http://www.imagemagick.org/Usage/layers/#flatten
Not sure I understand the issues, but would suggest you try this (untested):
convert base.jpg \
\( overlay.jpg -matte -virtual-pixel transparent -distort Perspective '961,1695 1856,2461 2279,1520 3185,2303 3564,2173 4441,2970 1547,2817 2441,3594' \) \
-define compose:args=50,100 -compose blend -composite result.jpg
That would mean that the perspective distortion is only applied to the overlay, not the base. So, in the code above, the first line only processes the base image, the second line only processes the overlay, and the final line blends the two.

Imagemagick: distorting images on top of background?

I've got one background image: sky.jpg
And two transparent PNG images: gradient.png and tree.png
Now I want to draw the two images on the background with a perspective distortion, like this:
The destination coordinates of the two images are, in clockwise order (starting top left) :
gradient: 62,129 421,218 383,458 147,548
tree: 445,100 765,47 698,368 529,396
I cannot figure out how to start with one image (in this case the sky background) and then take another image and draw that with perspective distortion to specific destination coords within the background. Also doing this with more than one image at a time, within one convert command, troubles me.
For example, when I start with just one image (the gradient) and try this:
convert sky.jpg \( gradient.png -alpha set -virtual-pixel transparent \
+distort Perspective "0,0 62,129 255,0 421,218 255,255 383,458 0,255 147,548" \) \
-compose src-over -composite result.jpg
It gets correctly warped (so the coordinates are relatively correct) but it's drawn in the top left corner, not at the coordinates I specify.
Also I'm a bit unsure if my usage of -compose and -composite is correct (I took this from various IM manual examples).
One other thing that is unclear to me: in case of the 256x256 image, should I use 255,0 and 255,255 and 0,255 as the corner coordinates, or 256,0 and 256,256 and 0,256 ?
Any IM experts who can shed light on these issues?
Add a -geometry just before the -composite like this:
convert -size 800x600 xc:black \( -size 300x200 xc:red \) -geometry +90+10 -composite result.png

imagemagick composite two png and keep it's alpha

I want to add watermark to my_own_png.png file by using:
composite -dissolve 10% -gravity center -quality 100 watermark_350.png my_own_png.png result.png
The result.png is not what I what, I want to keep my_own_png.png's alpha.
Please help~Thank you.
There are a couple of ways of doing this...
Firstly, you could run with your current processing, which I presume you understand and are happy with, and then copy back your original image's alpha over the top of your result, like this:
# Your current processing
composite -dissolve 10% ... result.png
# Now add back the original image's alpha
convert result.png my_own_png.png -compose CopyOpacity -composite result.png
Or, you could do the whole lot in one go using convert rather than composite, and it will look something like this but it is hard to be sure without seeing what you are actually doing:
convert my_own_png.png \
\( +clone -gravity center watermark_350.png -compose dissolve -define compose:args='10' -composite \) \
+swap -compose CopyOpacity -composite result.png
That basically loads up your my_own_png.png and puts it to one side. It then copies it and does the dissolve with your watermark inside the parentheses. After the parentheses, the order of the images is swapped so that the watermarked image is first in the list and the original png is second in the list. It then copies the alpha from the original image and applies it to the watermarked image - hopefully :-)

Compositing premultiplied images using ImageMagick

I have two images. One is background with no alpha. The other is a white cloud. The alpha of the cloud image is premultiplied with black. When I composite them the white cloud has black in it, so it looks grey instead of white like it should. I'm doing:
convert -gravity Center bg.tga whitecloud.tga -composite comp.tga
Is there a way to composite premultiplied images in ImageMagick, or does the image have to be non-premultiplied? Can I make a premultiplied image non-premultiplied using ImageMagick?
Update:
Ok, here are the images as TGA for download:
http://acatysmoof.com/posting/problems/imagemagick/premultiplication/bg.tga
http://acatysmoof.com/posting/problems/imagemagick/premultiplication/whitecloud.tga
http://acatysmoof.com/posting/problems/imagemagick/premultiplication/aftereffects.tga
http://acatysmoof.com/posting/problems/imagemagick/premultiplication/imagemagick.tga
and in the same order as jpgs to view in your browser:
I tried all the modes provided, but none of them create the same result as After Effects.
It would be easier if you showed your images, but try adding -compose lighten before -composite in your command, like this:
convert a.tga b.tga -compose lighten -composite out.tga
Basically that will make ImageMagick choose the lighter pixel of the two images at every point.
If that doesn't work, try other blending modes
for b in $(identify -list compose); do
convert -label "$b" bg.tga whitecloud.tga -compose $b -composite miff:-
done | montage - -tile 5x out.png
I am kind of thinking Atop, Dissolve, SrcAtop and SrcOver might be your friends but have a look full-size and see what floats your boat. That would be
convert a.tga b.tga -compose Atop -composite out.tga
Here is an Imagemagick command that does what you want:
convert -gravity Center whitecloud.tga -fx "u/max(u.a, 1/255)" bg.tga +swap -composite -fx "u*u.a" comp.tga
What's happening here?
-fx command #1: Convert whitecloud.tga from premultiplied alpha to "normal". The max() operator is a special case to avoid dividing by zero.
+swap command: Make bg.tga the first image and the revised whitecloud.tga the second.
-composite these two regular, non-premultiplied images.
-fx command #2: take the result, and return to a premultiplied alpha format.
This gives exactly the same result as After Effects.
Note that, as I wrote it, it only works for an opaque bg.tga. You'd need to do some extra work to handle a transparent background image.
If you want to duplicate the After Effects result, then I believe what you want to do in ImageMagick is the following -- composite the background image with a white image using the cloud as a mask:
convert bg.tga \( -clone 0 -fill white -colorize 100 \) whitecloud.tga -compose over -composite cloud_blue.tga
I have posted a JPG result, but my .tga result is the same.

Resources