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.
Related
I want to distort with perspective an image and i want to set it on specific coordinates. I expect him to stand on them, but only the upper left corner stands correctly. Is it possible to make all the corners stand on the coordinates that I specify?
My code:
convert roof.jpg -matte -background none -virtual-pixel background \
-distort Perspective '0,0,541,286 0,1428,82,542 2000,1428,1137,549 2000,0,1306,203' \
roof-pers.png
Example for output:
You need to use +distort in ImageMagick to make it work. Note you can use %[fx:w-1] and %[fx:h-1] for the input.
convert roof.png -background none -virtual-pixel background +distort Perspective "0,0 541,286 0,%[fx:h-1] 82,542 %[fx:w-1],%[fx:h-1] 1137,549 %[fx:w-1],0 1306,203" roof-pers.png
I want to generate an image out of 3 images. One of these images is the background, one the shape mask and one the color of the shape.
Here are the images:
shape.png
(transparent background, white circle in the middle and black circle inside and gray circle inside the black one)
shapecolor.png
background.png
The background.png should be the overall background. On top of that is the shape and all white parts (and also the white in the gray parts) should be in the color of shapecolor.png
I used simple mono color images to make it easier but I use some textures in reality ^^
I have no idea how to solve this problem in Imagemagick, the tool is very powerful and the documentation is not so easy to understand. Tried to solve this for 3h, but did not get the result, which should look like this:
Can anyone help please?
Here is one way to do it in Imagemagick. In the second line, extract the alpha channel from omg.png and save it in an mpr: in-memory image and then delete the clone. Then I use the mpr: image later in the last step.
convert red.png img.png \
\( +clone -alpha extract -write mpr:alpha +delete \) \
-compose multiply -composite \
green.png +swap mpr:alpha -compose over -composite \
result.png
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
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.
I'm trying to take an image, blur it with a 10px radius (both -blur and -gaussian-blur should work fine), then give it a 50% opacity, and finally overlay the blurred transparent image with the original. Here's what I've got so far:
convert sample.png \( sample.png -gaussian-blur 10 -matte -channel A
-evaluate set 50% \) -composite dreamy.png
Here's the original image:
And here is what it should look like after the effect is applied:
However, what I get with the command above just looks very similar to the original. Anyone have any ideas how to achieve the effect I want? If I do what I originally described in an image manipulation program, I get the desired effect, so something is probably wrong with the command I'm using.
Edit:
-adaptive-blur seems to get me closer to the desired effect, but still I'd like to use -blur.
Edit 2:
convert round-face-winslet.jpg \( +clone -blur 0x10 \) -compose Screen -composite round-face-winslet_soft.jpg
...gets me yet closer to the result, but no matter what kind of -compose method I choose, the result still does not look like the desired image. It's either too light or too dark. What should be a simple 50% opacity blended with the underlying original picture, for some reason doesn't want to work...
I think the effect you are looking for can be found in the ImageMagick compose examples in the "Softened Blurring" section.
convert face.png -morphology Convolve Gaussian:0x3 face_strong_blur.png
convert face.png face_strong_blur.png \
-compose Blend -define compose:args=60,40% -composite \
face_soft_blur.png
Looks like this:
An older tutorial on this technique (here) suggests lightening the blurred layer and blending in Multiply mode. I expect that darkening the blurred layer and blending with Screen would also work. Don't use a standard 50/50 blend - it doesn't have the same glowing appearance.
In your sample, the shadows of the processed image are lighter. Multiplying can only make an image darker, so I'm guessing they took the darken-Screen approach.