I'm running this with ImageMagick and would like to speed it up slightly by switching to GraphicsMagick if possible. In this, case I'm blending 30% of image1.png and 70% of image2.png together into result.png.
composite -blend 70 -geometry +0+22.86 image1.png image2.png result.png
I think you have to go with dissolve in GraphicsMagick but I'm not too sure how to go about achieving the same affect.
gm composite -dissolve 30 image1 image2 result
Related
I've got an 540x540 image of 54x54 color squares (same sizes).
When I resize it to 54x54px it looks horrible (blurred), shouldn't a resize like this be perfectly done with imagemagick?
is I possible to get it perfect?
I've tested convert source.png -resize destination.png and -adaptive-resize but the result is the same..
I see what your confusion is now... the problem is not that the process is lossy, rather it is because the -resize is doing more sophisticated processing than you want in order to make an attractive job that you would want for, say, photographs. You want a very simple point sampling process which will produce simple blocks of pure, uncombined colour.
I'll make a start image:
magick -size 10x10 xc:red +noise random -scale 540x540 start.png
And scale it down, by taking a point sample in each block:
magick start.png -sample 10x10 small.png
And back up:
magick result.png -scale 540x540 reincarnated.png
I am converting many 3D textures with imagemagick for a video game. My source files are png, my target files are png, too. But I notice that whenever the alpha channel drops to 0.0 my color information are gone (and I need them). I just want to scale all channels as they are. I guess there is a small switch that fixes that problem, but the deadline is near and I cannot find anything about that.
Simple command to reproduce this:
convert source-with-alpha.png -scale 2014 target.png (I also tried -resize and it also didn't work).
Doing just convert source-with-alpha.png target.png works fine though (but has no scaledown).
Thank you for your help.
I guess ImageMagick is trying to optimise something but not sure what/why. Maybe the idea is that if something is transparent you can't see it, so we might as well make it black so it compresses well.
Anyway, try separating the channels so they are all just treated as independent channels, then resizing and recombining:
convert input.png -channel RGBA -separate -resize XxY -combine result.png
I am not sure I understand your problem. I have no issue resizing a transparent PNG image with ImageMagick 6.9.10.28 Q16 Mac OSX with libpng 1.6.36. Perhaps you need to upgrade one or both.
Image:
Make white into transparent:
convert logo.png -transparent white logot.png
Resize it:
convert logot.png -resize 25% logot_small.png
I tried Mark Setchell answer with two different versions of Windows imagemagick but I still have this issue.
RGB becomes 0 if alpha is 0 when resizing.
A workaround was to add alpha a little bit so it becomes non-zero:
magic.exe input.tga -channel a -evaluate add 0.2% -channel RGBA -separate -filter Quadratic -resize -resize XxY! -combine result.tga
or also (same result)
magick.exe ( input.tga -alpha off -filter Quadratic -resize XxY! ) ( input.tga -filter Quadratic -resize XxY! -alpha extract -evaluate add 0.2% ) -compose Copy_Alpha -composite result.tga
("-filter Quadratic" is optional)
Post one of your tga files so we can test with it. What is your ImageMagick version? There should be no need for any switch. This works fine for me on IM 6.9.10.65 Q16 Mac OSX.
Make a transparent TGA:
convert logo: -transparent white logo.tga
transparent tga image
Resize by 50%
convert logo.tga -resize 50% logo2.tga
resized transparent tga image
I want to get the mean of a sequence of images by using Imagemagick. Therefore I use the following command:
convert *.png -evaluate-sequence mean MEAN.png
Each of my images does contain an alpha channel. What I want is: Combine all the images by ignoring the alpha channel.
When I combine the images, the alpha channel is considered in the "mean" method and my final image has transparency. That isn't what I want.
Result:
I tried to add the parameter -alpha off, but then Imagemagick converts the alpha channel to black.
convert *.png -alpha off -evaluate-sequence mean MEAN.png
Result:
Photoshop does it right. I load all images in a stack and create a smart object. When I use the "mean" method in Photoshop, the alpha channel is not considdered in the final result.
Result that I want with Imagemagick:
Does someone have an idea how to do that with Imagemagick?
What you need to do is to use the alpha channels as weighting images for each image. The total fraction of white values at each pixel from all the alpha channels would be the weight to use for the average. So something like this should do what you want or at least be close.
First, cd to your directory of images. Then run the following.
convert *.png -evaluate-sequence mean \
\( -clone 0 -alpha off \) \
\( -clone 0 -alpha extract \) \
-delete 0 +swap -compose divide -composite result.png
This will work if there is some image texture at each pixel coming from al least one image. That is at a given pixel all images are not totally black (transparent).
compare -metric rmse result.png mean_photoshop.png null:
125.167 (0.00190993)
So this shows that there is about 0.2% difference between my result and what you got from photoshop
Maybe this way of working will help you get there - or at least explain the problem:
convert xc:"rgba(255,0,0,1)" xc:"rgba(0,0,0,1)" xc:"rgba(0,0,0,0)" -depth 8 -evaluate-sequence mean txt:
Output
# ImageMagick pixel enumeration: 1,1,65535,srgba
0,0: (21845,0,0,43690) #550000AA srgba(85,0,0,0.666667)
Using IM 6.8.9.4 Q16 or IM 7.0.5.5 Q16 Mac OSX Sierra, this seems to work fine for me:
Make transparent image
convert logo: -transparent white logot.png
Get mean
convert logot.png logot.png logot.png -alpha off -evaluate-sequence mean result.png
magick logot.png logot.png logot.png -alpha off -evaluate-sequence mean result.png
This also seems to work:
convert logot.png logot.png logot.png -channel rgb -evaluate-sequence mean -alpha off result.png
So perhaps you need to upgrade your ImageMagick (and/or libpng?)
Can you post a zip file of some of your input images, so we can test with your images?
One problem that I see is that the PNG images that you provided have black under the transparent areas and not image texture. So when you disable alpha as in my commands above, you see black and the black gets averaged into the final result. Did you use these same PNG images in Photoshop or did you have Photoshop PSD images or some other images that you used and then exported to PNG, which may have put black under the transparent areas. Have you tried using the same PNG images in Photoshop to do the average?
In fact, you have 8-bit color (palette) images, which have one color (black) assigned to be the transparent color.
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.