Re: drops module (draft)

[Peter Rolf <indiego@gmx.net>]

Am 06.12.2012 19:35, schrieb Marco:
> On 2012–12–06 Aditya Mahajan wrote:
> 
>> I always thought that shadows were possible to do in PDF (after all
>> TikZ does it using some type of PDF primitives).
> 
> It is. I use MetaPost to draw the shadows using the shading
> mechanism:
> 
>   withshading("circular", urcorner bottom_left, urcorner bottom_left, radius, 0)
>   withfromshadecolor \MPcolor{c:transparent}
>   withtoshadecolor   col;
>

Don't mix Type2/3 with Type 4/5 shadings (see my answer to Aditya). They
are all called 'shadings', but only the latter can be used for the
creation of realistic looking drop shadows.

And to repeat myself: there is nothing wrong with bitmaps. Take the best
from both worlds ;-)


> and it works well if placed in an overlay. However, I did not manage
> to get it working in TikZ, it could not display shadings to
> transparent colours (which is very handy for slides where the
> shadings might overlay graphics with a non-uniform colour).
> 
>> Since you are the PDF expert, I am interested in knowing why you
>> choose to go the ImageMagic route.
> 
> From my experience shadows made from MetaPost shadings (which uses
> PDF shadings, I assume) are quite low level. It's harder to get the
> angle, distance and shadow size correctly implemented. I think the
> ImageMagick shadings are more high level and ready to use.
> 
> 
> Marco
> 
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