drop shadows with metapost/ metafun

drop shadows with metapost/ metafun

[Garulfo]

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Which process would you advice to add « drop shadows » to any kind of metafun / metapost figures like:
picture p;
p := textext("MetaPost is fun!") shifted (10cm,10cm);

My current understanding of the required steps :


1- fill p with the shadow color

2- write it to an external metapost file (with savebuffer ?) ready for png export (outputformat := "png »;)

3- with lua, os.execute, and imagemagick prepare the shadow
  - extent the png file with a transparent background, to have room for blurring 
  - blur it

4- import this png in context / Metapost (externalfigure), and center it with p figure

5- shift it according to the desired shadows distance and angle

6- apply the initial bounding box of p to the shadow, draw the shadow, draw the p picture 


Actually, all this seems long and tedious, and contrasts with the already existing links between MetaPost / MetaFun and cairo + libpng.

Thanks again for your help.

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Re: drop shadows with metapost/ metafun

[Aditya Mahajan]

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On Tue, 29 Dec 2020, Garulfo wrote:

> Which process would you advice to add « drop shadows » to any kind of metafun / metapost figures like:
> picture p;
> p := textext("MetaPost is fun!") shifted (10cm,10cm);
> 
> My current understanding of the required steps :
> 
> 
> 1- fill p with the shadow color
> 
> 2- write it to an external metapost file (with savebuffer ?) ready for png export (outputformat := "png »;)
> 
> 3- with lua, os.execute, and imagemagick prepare the shadow
>   - extent the png file with a transparent background, to have room for blurring 
>   - blur it
> 
> 4- import this png in context / Metapost (externalfigure), and center it with p figure
> 
> 5- shift it according to the desired shadows distance and angle
> 
> 6- apply the initial bounding box of p to the shadow, draw the shadow, draw the p picture 
> 
> 
> Actually, all this seems long and tedious, and contrasts with the already existing links between MetaPost / MetaFun and cairo + libpng.

There was a drops module by Peter Rolf, which provides exactly these features:

https://mailman.ntg.nl/pipermail/ntg-context/2016/084242.html

It is not part of modules.contextgarden.net and the url in the previous post is no longer valid. 

I am CC:ing Peter and perhaps he can point to the updated location for the module. 

Aditya

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Re: drop shadows with metapost/ metafun

[Aditya Mahajan]

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On Fri, 1 Jan 2021, Aditya Mahajan wrote:

> On Tue, 29 Dec 2020, Garulfo wrote:
> 
> > Which process would you advice to add « drop shadows » to any kind of metafun / metapost figures like:
>
> > Actually, all this seems long and tedious, and contrasts with the already existing links between MetaPost / MetaFun and cairo + libpng.
> 
> There was a drops module by Peter Rolf, which provides exactly these features:
> 
> https://mailman.ntg.nl/pipermail/ntg-context/2016/084242.html
> 
> It is not part of modules.contextgarden.net and the url in the previous post is no longer valid. 
> 
> I am CC:ing Peter and perhaps he can point to the updated location for the module. 

Also, if you don't want the shadows to be too nice, you can also translate the fake shadows used by tikz to metapost:

https://adityam.github.io/context-blog/post/drop-shadow-with-lifted-corners/

Aditya

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Re: drop shadows with metapost/ metafun

[Henning Hraban Ramm]

> Am 29.12.2020 um 22:56 schrieb Garulfo <garulfo@azules.eu>:
> 
> Which process would you advice to add « drop shadows » to any kind of metafun / metapost figures like:
> picture p;
> p := textext("MetaPost is fun!") shifted (10cm,10cm);
> 
> 
> My current understanding of the required steps :
> 
> 
> 1- fill p with the shadow color
> 
> 2- write it to an external metapost file (with savebuffer ?) ready for png export (outputformat := "png »;)
> 
> 3- with lua, os.execute, and imagemagick prepare the shadow
>   - extent the png file with a transparent background, to have room for blurring 
>   - blur it
> 
> 4- import this png in context / Metapost (externalfigure), and center it with p figure
> 
> 5- shift it according to the desired shadows distance and angle
> 
> 6- apply the initial bounding box of p to the shadow, draw the shadow, draw the p picture 
> 
> 
> Actually, all this seems long and tedious, and contrasts with the already existing links between MetaPost / MetaFun and cairo + libpng.

I don’t know if that helps, but I’m using a stack of transparent objects to simulate drop shadows:
https://wiki.contextgarden.net/Drop_shadows

No pixel images required. But I’d like to have a real text shadow instead of that box shadow.


Happy New Year!
Hraban
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