blurred shadow on images?

blurred shadow on images?

[Henning Hraban Ramm]

I'd like to place some plain photos rotated (say 12°) and with a  
blurred shadow above some colored elements, i.e. the shadow must use  
transparency.
I guess I could get such using ImageMagick, but is there a possibility  
using ConTeXt or one of its favourite friends?
I'd prefer a solution that works with CMYK data.
If there isn't - is the transparency of PNG usable?

Since all of the pictures will have almost the same size, I could  
probably also use the shadow as a single PDF picture and place that  
behind with a small offset.

Greetlings from Lake Constance!
Hraban
---
http://www.fiee.net/texnique/
http://wiki.contextgarden.net
https://www.cacert.org (I'm an assurer)

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: blurred shadow on images?

[Taco Hoekwater]

Henning Hraban Ramm wrote:
> I'd like to place some plain photos rotated (say 12°) and with a blurred 
> shadow above some colored elements, i.e. the shadow must use transparency.
> I guess I could get such using ImageMagick, but is there a possibility 
> using ConTeXt or one of its favourite friends?
> I'd prefer a solution that works with CMYK data.

Creating a semi-transparent backdrop with metapost is quite simple,
but I am not sure whether that works with cmyk, you'll have to try
yourself. Code goes something like this:

\startuniqueMPgraphic{texthole}
for dx = 0 upto 40:
   dy := dx;
   wa := 10 + dx;
   wb := \overlaywidth - dx - 10;
   ha := dy + 10;
   hb := \overlayheight - dy - 10;
   fill (wa,ha)--(wb,ha)--(wb,hb)--(wa,hb)--cycle
       withcolor transparent("normal", .04,white);
endfor;
\stopuniqueMPgraphic


> If there isn't - is the transparency of PNG usable?

Sure, and may use less resources than mp drawings, but that is
definitely RGB

Best wishes,
Taco
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: blurred shadow on images?

[Henning Hraban Ramm]

Am 2010-06-21 um 08:42 schrieb Taco Hoekwater:

> Henning Hraban Ramm wrote:
>> I'd like to place some plain photos rotated (say 12°) and with a  
>> blurred shadow above some colored elements, i.e. the shadow must  
>> use transparency.
>> I guess I could get such using ImageMagick, but is there a  
>> possibility using ConTeXt or one of its favourite friends?
>> I'd prefer a solution that works with CMYK data.
>
> Creating a semi-transparent backdrop with metapost is quite simple,
> but I am not sure whether that works with cmyk, you'll have to try
> yourself. Code goes something like this:

Thank you, I'll try.
Seems like I should learn MetaPost finally...

>> If there isn't - is the transparency of PNG usable?
>
> Sure, and may use less resources than mp drawings, but that is
> definitely RGB


Yes, of course. Since I only need to output on a color laser printer,  
it will probably work.
Processing time matters.


Greetlings from Lake Constance!
Hraban
---
http://www.fiee.net/texnique/
http://wiki.contextgarden.net
https://www.cacert.org (I'm an assurer)

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: blurred shadow on images?

[Henning Hraban Ramm]

Am 2010-06-21 um 08:42 schrieb Taco Hoekwater:
> Creating a semi-transparent backdrop with metapost is quite simple,
> but I am not sure whether that works with cmyk, you'll have to try
> yourself. Code goes something like this:

For the records: This is, how I'll use it:

\startuniqueMPgraphic{texthole}
for dx = 0 upto 40:
	 dy := dx;
	 wa := 10 + dx;
	 wb := \overlaywidth - dx - 10;
	 ha := dy + 10;
	 hb := \overlayheight - dy - 10;
	 fill (wa,ha)--(wb,ha)--(wb,hb)--(wa,hb)--cycle
		withcolor transparent("normal", .04, black);
endfor;
\stopuniqueMPgraphic

\defineoverlay[shaded][\useMPgraphic{texthole}]

\starttext

\rotate[rotation=12]{%
\framed[height=50mm, width=50mm, frame=off, background=shaded,  
backgroundoffset=5mm, align=middle]%
{\offset[x=1mm,y=-2mm]{\externalfigure[koe][width=50mm]}}%
}

\stoptext

I'm glad I found \offset, because framed's offset parameter can't  
distinguish x and y offset.
Positive offset moves right and down, negative offset moves just up -  
I guess that's a buglet.


Greetlings from Lake Constance!
Hraban
---
http://www.fiee.net/texnique/
http://wiki.contextgarden.net
https://www.cacert.org (I'm an assurer)

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: blurred shadow on images?

[Wolfgang Schuster]

Am 30.06.10 14:39, schrieb Henning Hraban Ramm:
> Am 2010-06-21 um 08:42 schrieb Taco Hoekwater:
>> Creating a semi-transparent backdrop with metapost is quite simple,
>> but I am not sure whether that works with cmyk, you'll have to try
>> yourself. Code goes something like this:
>
> For the records: This is, how I'll use it:
>
> \startuniqueMPgraphic{texthole}
> for dx = 0 upto 40:
>      dy := dx;
>      wa := 10 + dx;
>      wb := \overlaywidth - dx - 10;
>      ha := dy + 10;
>      hb := \overlayheight - dy - 10;
>      fill (wa,ha)--(wb,ha)--(wb,hb)--(wa,hb)--cycle
>         withcolor transparent("normal", .04, black);
> endfor;
> \stopuniqueMPgraphic
>
> \defineoverlay[shaded][\useMPgraphic{texthole}]
>
> \starttext
>
> \rotate[rotation=12]{%
> \framed[height=50mm, width=50mm, frame=off, background=shaded, 
> backgroundoffset=5mm, align=middle]%
> {\offset[x=1mm,y=-2mm]{\externalfigure[koe][width=50mm]}}%
> }
>
> \stoptext
>
> I'm glad I found \offset, because framed's offset parameter can't 
> distinguish x and y offset.
> Positive offset moves right and down, negative offset moves just up - 
> I guess that's a buglet.

You can change the boundingbox in the metapost graphic (the white 
background was required
for the cow figure because it has a transparent background)

\startuniqueMPgraphic{shadow}
for dx = 0 upto 40:
      dy := dx ;
      wa := dx - 10 ;
      wb := \overlaywidth - dx + 10 ;
      ha := dy - 10 ;
      hb := \overlayheight - dy + 10 ;
      fill (wa,ha)--(wb,ha)--(wb,hb)--(wa,hb)--cycle
         withcolor transparent("normal", .04, black);
endfor;
setbounds currentpicture to OverlayBox ;
\stopuniqueMPgraphic

\defineoverlay[shadow][\useMPgraphic{shadow}]

\starttext
\externalfigure[cow][width=50mm,background={shadow,color},backgroundcolor=white]
\stoptext

Wolfgang

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: blurred shadow on images?

[Henning Hraban Ramm]

Am 2010-06-30 um 22:47 schrieb Wolfgang Schuster:

> You can change the boundingbox in the metapost graphic (the white  
> background was required
> for the cow figure because it has a transparent background)

Thank you! I used an opaque picture for my tests.

I played a bit with different shapes, I like my rounded rectangle best:

\startuniqueMPgraphic{mpshadow}
ox := -7 ; % offset x
oy := -7 ; % offset y
bx := 5 ; % bleed x
by := 5 ; % bleed y
rx := 7 ; % corner radius x
ry := 7 ; % corner radius y
for dx = 0 upto 40:
	dy := dx ;
	xa := dx + ox - bx/2;
	xb := \overlaywidth - dx + ox + bx/2;
	ya := dy + oy - by/2;
	yb := \overlayheight - dy + oy + by/2;

%	% rectangle
%	fill (xa,ya)--(xb,ya)--(xb,yb)--(xa,yb)--cycle
%		withcolor transparent("normal", .04, black) ;

	% rounded rectangle
	fill (xa, ya + ry)---
		(xa, yb - ry)..
		(xa + rx, yb)---
		(xb - rx, yb)..
		(xb, yb - ry)---
		(xb, ya + ry)..
		(xb - rx, ya)---
		(xa + rx, ya)..cycle
		withcolor transparent("normal", .04, black) ;
	
%	% super ellipse
%	hx := xb / 2;
%	hy := yb / 2;
%	fill (xa + rx, ya + ry)...
%		(xa, ya + hy)...
%		(xa + rx, yb - ry)...
%		(xa + hx, yb)...
%		(xb - rx, yb - ry)...
%		(xb, ya + hy)...
%		(xb - rx, ya + ry)...
%		(xa + hx, ya)...cycle
%		withcolor transparent("normal", .04, black) ;
endfor;
setbounds currentpicture to OverlayBox ;
\stopuniqueMPgraphic

\defineoverlay[shadow][\useMPgraphic{mpshadow}]

\starttext

\rotate[rotation=12]{%
\externalfigure[koe][width=50mm,background=shadow]
}

\stoptext




Greetlings from Lake Constance!
Hraban
---
http://www.fiee.net/texnique/
http://wiki.contextgarden.net
https://www.cacert.org (I'm an assurer)

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________