Cloud functions Circle Image Imagemagick - firebase

Question

I would like to convert uploaded pictures to Firebase Storage into circled images using Cloud functions and resize them.
Having a look at the documentation of ImageMagick I am wondering about the syntax to use for this task. Using the below to resize the image which works like a charm. But how would I add the commands into this and which ones to use best?
return spawn('convert', [tmpFilePath, '-resize', '250x250', tmpFilePath]);

Answer 1

I don't know what a 'circle image' means, but perhaps applying Vignette effect?
convert -size 250x250 plasma: -background white -vignette 0x0 output.png
So your command may be...
return spawn('convert', [
tmpFilePath,
'-resize', '250x250',
'-background', 'white',
'-vignette', '0x0',
tmpFilePath
]);

Answer 2

emcconville probably has the simplest method. You may just need to make the background transparent and replace the plasma image with a real image.
If you want the outside to be transparent, be sure to save your output to PNG or TIFF and not JPG. JPG does not support transparency.
Input:
convert lena.jpg -background none -vignette 0x0 output.png
However, the circle's perimeter will not extend to the edges of the image.
To make it do that, you have to change the arguments as follows:
convert lena.jpg -background none -vignette 0x0+0+0 output2.png
But here is another method that is a bit longer and more complex (assuming you have a square image).
If by "circled images" you mean make the outside of a circle the size of the image transparent, you can do that in ImageMagick command line as follows:
1) Read the image (and somehow get its size)
2) Then create a new image the same size and fill with black and draw a white circle supplying the center point and any point on the perimeter
3) Put the circle image into the alpha channel of the original
Original:
Unix Syntax. (For Windows remove the \s in the following)
convert lena.jpg \( -size 256x256 xc:black -fill white -draw "circle 128,128 128,255" \) -alpha off -compose copy_opacity -composite result.png
In Unix syntax one can get the dimensions of the input image as follows:
WxH=`convert -ping lena.jpg -format "%wx%h" info:`
ww=`echo $WxH | cut -dx -f1`
hh=`echo $WxH | cut -dx -f2`
ww2=`convert xc: -format "%[fx:$ww/2]" info:`
hh2=`convert xc: -format "%[fx:$hh/2]" info:`
hhm1=$((hh-1))
convert lena.jpg \( -size ${ww}x${hh} xc:black -fill white -draw "circle $ww2,$hh2 $ww2,$hhm1" \) -alpha off -compose copy_opacity -composite result2.png
If you do not have a square image, then you must use the minimum dimension of the input image as the circle diameter. This also works for a square image.
Input:
dim=`convert -ping monet2.jpg -format "%[fx:min(w,h)]" info:`
dim2=`convert xc: -format "%[fx:$dim/2]" info:`
dimm1=$((dim-1))
convert monet2.jpg \( -size ${dim}x${dim} xc:black -fill white -draw "circle $dim2,$dim2 $dim2,$dimm1" \) -alpha off -gravity center -compose copy_opacity -composite result4.png
If we use the vignette method on a non-square image, then you will get an elliptical region.
convert monet2.jpg -background none -vignette 0x0+0+0 output3.png