[Scilab-users] ?= density in a grap

[Jean-Philippe Grivet]

Le 24/01/2020 à 08:45, Antoine Monmayrant a écrit :
> That's what I understood, but using lines, not polygons.
>
> Another approach than what I suggested previously would be to pixelate everything: ie make a big matrix for the whole graph and increment the value stored at a certain coordinate whenever it falls under one of the lines.
> You could then plot this matrix using matplot of sgrayplot... with a graycolormap (maybe reversed graycolormap).
> Far from ideal, but it would work.
>
> Antoine
>   
>   
> Le Jeudi, Janvier 23, 2020 21:27 CET, P M <p.muehlmann at gmail.com> a écrit:
>   
>> something like this...only in gray?
>> [image: test.png]
>>
>> Am Do., 23. Jan. 2020 um 19:08 Uhr schrieb Antoine Monmayrant <
>> amonmayr at laas.fr>:
>>
>>> Hello Jean-Philippe,
>>>
>>> I think I understand what you want to do, but there is no easy way to get
>>> this in scilab.
>>> The main issue is that scilab does not support transparency.
>>> Otherwise, you could just plot your lines in black with 1/32 alpha (or
>>> 255/32 alpha if 0 means transparent and 255 solid color).
>>> For this kind of plot, I usually plot everything in scilab with a dummy
>>> color (let's say blue), export in svg, edit the svg to replace the dummy
>>> color by the transparent one.
>>>
>>> Antoine
>>>
>>>
>>> Le Jeudi, Janvier 23, 2020 16:35 CET, Jean-Philippe Grivet <
>>> jean-philippe.grivet at wanadoo.fr> a écrit:
>>>
>>>> Dear all,
>>>>
>>>> I am drawing a graph in a gray scale (say from 1 to 32), using lines of
>>>> different density. I would like that, in the region of intersection of
>>>> two lines, the shade of gray be the sum of the densities of each line.
>>>> How can I manage that ?
>>>>
>>>> Thanks in advance for any hint
>>>>
>>>> JP Grivet
>>>>
>>>>
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This approach looks rather easy to me. Have you a suggestion on how I 
can define the pixels to be modified ?

Than you all for your suggestions

JP Grivet