Legacy ImageMagick Discussions Archive

Hi guys,

I'm hitting a bit of a wall. I need to add a text watermark to images, however I don't know the size of these images so I end up with tet that isn't the appropriate size (tiny) on some images.
The command I use is:
Like I mentioned earlier, I need to find a way of resizing this watermark along with the image.

Thanks in advance for your help. I could probably resize the watermark using size $(convert etc...)x$(convert etc..) or something of the likes, but some images are really big and I would like to save computer ressources wherever possible

create an image of your text with transparent background by using label: to fit the image width. Then composite the text image over your background image.

See
http://www.imagemagick.org/Usage/text/#label_bestfit
http://www.imagemagick.org/Usage/layers/#convert

But I am resizing the background image using an area size, so how do I know what size to give my label?
I'd also rather not make a label the size of the original file if I could help it as it would be a waste of ressources. Given the amount of conversions our server has to make this is important for us

resize your background, get its size and then create and overlay the text image via label:

Unfortunately, that means multiple commands.

Or pre-compute the size of the resized image first, then create the label to that size and overlay. You will either know the resize width and/or height or know what percent factor you use. So either way, you can compute the width and/or height of the resized image ahead of time.

Otherwise, do everything at the full image size, overlay the text image and then resize.

I am not sure there is any other way.

Is there any way I could pipe the resized image and get it's resized height/width on the fly? If not I guess I'll have to compute height/width, I was kind of using area size to avoid it but hey.

pommeverte wrote:Is there any way I could pipe the resized image and get it's resized height/width on the fly? If not I guess I'll have to compute height/width, I was kind of using area size to avoid it but hey.

I do not believe that is possible in IM 6. But later in IM 7 I think that will be more feasible.

Unless you are using -resize with @ for file size, you can easily pre-compute the resized image width and height

Resurrecting this post from the dead,

I have attempted to run this code on a windows machine with the latest IM but the dissolve does not work (the watermark is fully opaque)

the code i am using is

convert in.tif -size 1555x2560 xc:none -gravity center -fill grey -font Arial \
-pointsize 227.25 -annotate 300x300+0+0 "Testing" -background none \
-compose dissolve -define compose:args=30,100 -composite out.tif

what if anything is wrong?

If i create a png image with the below code and composite it in a seperate process then it works just fine but i would like to get it in one go.

convert -size 1555x2560 xc:none -gravity center -fill grey -font Arial \
-pointsize 227.25 -annotate 300x300+0+0 "Testing" -background none watermark.png

Thanks

convert in.tif -size 1555x2560 xc:none -gravity center -fill grey -font Arial \
-pointsize 227.25 -annotate 300x300+0+0 "Testing" -background none \
-compose dissolve -define compose:args=30,100 -composite out.tif

Eek. That code will:

read in.tif
create a second image 1555x2560 with transparent background
annotate both images
dissolve them together.

You need parentheses, something like this:

convert in.tif \( -size 1555x2560 xc:none -gravity center -fill grey -font Arial \
-pointsize 227.25 -annotate 300x300+0+0 "Testing" \) -background none \
-compose dissolve -define compose:args=30,100 -composite out.tif

Now the annotate will only be done to the second image.