How to resize a watermark in proportion to the original image? [#1293092]

How to resize the overlay image (watermark) based on the original image size?
For example, my watermark image is 200px.
I overlay this watermark image on an original image of 400px.
What if I have an original image of 800px? My watermark should follow the same proportion and be automatically resized to twice its original size.
How can this be done?

Comments

Comment #1

dman commented 28 September 2011 at 07:07

Category:

support

» feature

I understand what you are wanting.
Right now, there is no clean or effective way of getting this effect. I have encountered it myself - galleries of normally huge images which is resized down to 1200x*, then get a proportional large watermark. usually that's OK. However, running this process on a stray 640x480 does not upsize ('coz that looks crap) and then gets a watermark that overpowers the image.

At the time I couldn't see a good, tight way to address it without a number of confusing config options. I tried to imagine a generic sensible way of dealing with the general case. It did not occur to me.
At the time, running the built-in resize function on an alpha-channelled png watermark introduced really bad artifacts. This is fixed now in patches I added to imageapi later

I'd put this on the wish-list, but am open to code suggestions and patches - but they must be imageapi-compatible atomic actions and re-usable code.