On 2013–07–14 Wolfgang Schuster wrote:

Overlays are a framed feature (the page background is a frame too) and textbackgrounds are images which are drawn on the page like overlays.

MetaPost graphics can be hooked into the textbackground using the mp and method keys. So apparently there is a way to use arbitrary background graphics. It would be a natural consistent interface if overlays worked with the background key. But I assume it's due to the page break ability of textbackground that makes it more complicated to implement. BTW: Is there any documentation, except the source, about the mp and method keys? Marco

On 2013–07–15 Hans Hagen wrote:

On 7/14/2013 8:54 PM, Marco Patzer wrote:

...

Hi,

overlays are not displayed when used as a background for textbackground. Is this a bug or are overlays not supported?

in principle we can make it pluggable (given that there is some sensible way to pass info and real need for it)

No, I don't need it.

\definetextbackground [mybackgroundOverlay] [mp=mpos:region:whatever]

\startuseMPgraphic{mpos:region:whatever} for i=1 upto nofmultipars : draw textext("\externalfigure[cow.pdf]") rotated 10 shifted center multipars[i] ; endfor ; \stopuseMPgraphic

\starttext

\startmybackgroundOverlay \dorecurse{10}{\input knuth \par} \stopmybackgroundOverlay

\stoptext

Thanks for the example. Marco

Here is a trick (due to Hans, of course) to produce a watermark image. You can play with the idea in order to produce your own effect. \definecolor [percent] [s=1,a=1,t=.9] \externalfigure [cow] [background={foreground,color},backgroundcolor=percent] Alan On Wed, 18 May 2016 11:55:11 +0000 "Meer, Hans van der" wrote:

This code from three years back ia a reply to a question of placing an overlay background. Because the cow is very black I am curious if the \externalfigure can have a paramter to change the alpha of the cow, making it more transparent. By the way, it is not out of curiosity only. If possible it would forego the need to make separate pictures of different transparency beforehand.

...

On 15 Jul 2013, at 11:22, Hans Hagen wrote:

\definetextbackground [mybackgroundOverlay] [mp=mpos:region:whatever]

\startuseMPgraphic{mpos:region:whatever} for i=1 upto nofmultipars : draw textext("\externalfigure[cow.pdf]") rotated 10 shifted center multipars[i] ; endfor ; \stopuseMPgraphic

\starttext

\startmybackgroundOverlay \dorecurse{10}{\input knuth \par} \stopmybackgroundOverlay

\stoptext

Hans van der Meer