Am 06.12.2012 um 19:05 schrieb Aditya Mahajan :

On Thu, 6 Dec 2012, Peter Rolf wrote:

...

Hi all,

a first version of the 'drops'-module (MkIV only) is available at

https://www.wuala.com/indiego/public/ConTeXt/drops/?key=caiCGLasLFmJ

Taken from the included documentation.. [..] 'drops' is a small extension for ConTeXt, that allows you to add drop shadows to rectangular regions (so called boxshadows). A working installation of ImageMagick (IM) is required to create the shadow graphics. The supported color spaces are CMYK, RGB and Gray, the file formats are limited to PNG and JPG. [..] Read the manual for detailed information.

Nice.

The module would be cleaner with a MkIV rewrite and I would drop the option to accept each module parameter with \usemodule. I would also create a new namespace for the \setupdrops command because currently it uses the “module” namespace. \def\dosetupdrops[#1]% {\iffirstargument\getparameters[\??module drops:][#1,{\c!setup=}]\else % never parameter 'setup' \ctxlua{thirddata.drops.resetdrops()}\fi} % reset all parameters to their default, when no argument is given Wolfgang

Am 07.12.2012 um 13:01 schrieb Peter Rolf :

...

I would also create a new namespace for the \setupdrops command because currently it uses the “module” namespace.

\def\dosetupdrops[#1]% {\iffirstargument\getparameters[\??module drops:][#1,{\c!setup=}]\else % never parameter 'setup' \ctxlua{thirddata.drops.resetdrops()}\fi} % reset all parameters to their default, when no argument is given

Ok. Can you explain why that is a problem?

It’s bad style to misuse internal namespaces and and you can’t be sure the namespaces changes which lead to problems with the simple slides module which used the \setavariables namespace for a while. Wolfgang

On 12/6/2012 7:35 PM, Marco wrote:

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;

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).

I think drops are somewhat different as they might follow different rules than circular or linear shades

...

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.

Yes. Of course we can make shading more clever, but to be honest I never had the need. Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

On 2012–12–07 Peter Rolf wrote:

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.

Thanks for pointing that out. I will have a look into my code again. I was (and actually I still am) confused by the different shading methods provided by MetaFun. I admit that I never read the PDF reference which means that I don't know the shading internals. I experimented a little and came up with a working solution to add some eye-candy to presentations.

And to repeat myself: there is nothing wrong with bitmaps.

I agree. Even Knuth designed his fonts as bitmaps (at least the output is a bitmap). However, bitmaps always have a fixed size and thus are not scalable.

Take the best from both worlds ;-)

ACK And thanks for this nice module and especially for the well-written documentation. Marco

On 12/6/2012 7:05 PM, Aditya Mahajan wrote:

On Thu, 6 Dec 2012, Peter Rolf wrote:

...

Hi all,

a first version of the 'drops'-module (MkIV only) is available at

https://www.wuala.com/indiego/public/ConTeXt/drops/?key=caiCGLasLFmJ

Taken from the included documentation.. [..] 'drops' is a small extension for ConTeXt, that allows you to add drop shadows to rectangular regions (so called boxshadows). A working installation of ImageMagick (IM) is required to create the shadow graphics. The supported color spaces are CMYK, RGB and Gray, the file formats are limited to PNG and JPG. [..] Read the manual for detailed information.

Nice.

...

The attached example is just a small test file for the 'rotation' parameter (a compensation for the object rotation, so that the shadow stays at the given direction). You will find other examples in the documentation and there is also a 'pile' example with the complete source. The 'presets' pdf contains the predefined setups for different shadow (or frame) types and it's source is a good starting point for your own experiments.

This is a first draft, but most things work quite stable. If you want to help, test as much as possible. :-)

*You need a recent version of ImageMagick for this module.*

I always thought that shadows were possible to do in PDF (after all TikZ does it using some type of PDF primitives). Since you are the PDF expert, I am interested in knowing why you choose to go the ImageMagic route.

Some tricks are possible with functions that repeat bitmap patterns in clever ways but I lost the code that does it. If Peter can tell us what graphics are needed we can also make them directly as the img library has that possibility (we use it in mojca's gnuplot module) Anyhow, as you are the math magician, here's a start: \starttext \startluacode local format = string.format function document.TestBitmap(nx,ny) local r = { } local s = 1/nx for i=1,ny do local c = { } for j=1,nx/2 do c[#c+1] = format("%02x",j*s*255) end for j=nx/2,1,-1 do c[#c+1] = format("%02x",j*s*255) end c = table.concat(c,"",1,nx) r[#r+1] = c end r = table.concat(r,"\r",1,ny) print(r) context(r) end \stopluacode \startMPcode draw textext("\bitmapimage[x=100,y=100,color=gray]{\ctxlua{document.TestBitmap(100,100)}}") xsized 10cm ; \stopMPcode \stoptext So, what's needed is some edge related jugling. Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

Am 06.12.2012 19:05, schrieb Aditya Mahajan:

On Thu, 6 Dec 2012, Peter Rolf wrote:

...

Hi all,

a first version of the 'drops'-module (MkIV only) is available at

https://www.wuala.com/indiego/public/ConTeXt/drops/?key=caiCGLasLFmJ

Taken from the included documentation.. [..] 'drops' is a small extension for ConTeXt, that allows you to add drop shadows to rectangular regions (so called boxshadows). A working installation of ImageMagick (IM) is required to create the shadow graphics. The supported color spaces are CMYK, RGB and Gray, the file formats are limited to PNG and JPG. [..] Read the manual for detailed information.

Nice.

...

The attached example is just a small test file for the 'rotation' parameter (a compensation for the object rotation, so that the shadow stays at the given direction). You will find other examples in the documentation and there is also a 'pile' example with the complete source. The 'presets' pdf contains the predefined setups for different shadow (or frame) types and it's source is a good starting point for your own experiments.

This is a first draft, but most things work quite stable. If you want to help, test as much as possible. :-)

*You need a recent version of ImageMagick for this module.*

I always thought that shadows were possible to do in PDF (after all TikZ does it using some type of PDF primitives). Since you are the PDF expert, I am interested in knowing why you choose to go the ImageMagic route.

Because it's relative simple (I use a working function) , fast (in terms of rendering speed) and the footprint of the shadow graphics is not that big (png: one color, only alpha channel differs). Quality is (as you can see) also not an issue. Mh, there is nothing wrong with bitmaps ;-) See Type4/Type5 Shadings (Free-Form Gouraud-Shaded Triangle Meshes) on page 314 of the PDF Reference for the PDF alternative. The problems to solve are the calculation of the mesh points (think about rounded squares) and also to find a proper shading function (which sets the colors). See 'Shadow Internals' at http://www.imagemagick.org/Usage/blur/#shadow%20internals Far from trivial (and I'm only an amateur with limited time). Also: you can 'draw' (command of IM) any shape in IM (SVG paths are supported) and use the 'shadow' function on that. Theoretically you can extent drops to support any shape (path or drawing). That's one reason why I used the more general name 'drops' instead of the currently better fitting 'boxshadow'. The other reason is, that Hans would never use the stupid name 'drops' internally. :-D

In terms of interface, wouldn't it be better if this somehow interfaced with the background/overlay mechanism. For example,

\definedropshadow[identifier][...options...]

which will define an overlay that will call ImageMagic with appropriate parameters (and caching the results if speed is a concern),

and then

\externalfigure[name][background=identifier]

should draw a dropped shadow around the image

Needs some thinking

Aditya ___________________________________________________________________________________

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On 12/7/2012 7:02 PM, Otared Kavian wrote:

Hi Peter,

Thank you for your very nice module. For your information, I wanted just to report an issue I noticed with Adobe Reader (Version: 11.0.0 (11.0.0)) on Mac OS X 10.8: when I try to open the file « pile.pdf » (which is in your « examples » directory) Adobe Reader crashes and there is no way to open that file with it. However th eother file, « rotate.pdf » opens without any problem…

I Noticed the same on Windows 8 / Acrobat 11.0 so it's in the pdf. Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------