adding legend for slideView()

[r-spatial]

adding legend for slideView()

[tim-salabim]

Sorry for the long silence on this. After talking to @swoellauer I think we have a plan of action now that should enable legends in both slideView and plainView.

[tim-salabim]

Thanks @fdetsch ! The issue of bad font rendering of the legend under windows seemed to have been antialiasing. I have now set antialiasing = "none" which seems to resolve this. See a73462c

[tim-salabim]

In general, I do like the idea, however, in your example you are referring to RGB images for which a legend does not make much sense in my opinion.

@swoellauer would you have some time to look into this? 2 separate divs on each side with their own legends. I guess we could simply hijack leaflet legends for this.

[danklotz]

well yeah, but one gets the gist.

[tim-salabim]

@swoellauer I have just pushed an update that passes the filename of the legend png via the htmlwidget in plainview - RasterLayer method. Can you please check whether that is sufficient for adding a legend this way.

library(mapview)
plainview(poppendorf[[5]], legend = TRUE)

This should produce a valid x.leg_fl on the JS side which points to the legend png.

This is a rough implementation so far as the dimensions of the png are fixed (500 x 200 pixels height and width). I am yet to come up with a clever way to estimate the ratio properly (this is mainly depending on the values of the ticks - in the example above these are largish numbers so should be fine in most occasions, but still...). Also, this means that there is some white space (actually transparent space) around the legend, meaning we will need to find a way to crop/clip the png. This could easily be done on the R side using the magick package, yet I am a bit reluctant towards adding another dependency to mapview if not really needed. So, if there is a way to crop the image in JS (without adding another library dependency) then this would be great. If there isn't, then I guess importing the relevant function from magick is something we need to consider.

@danklotz this is currently only a test implemented in plainview for the easiest case of rendering a RatserLayer but if this works, adding the same to slideview should be straight forward.

[tim-salabim]

@danklotz We have a first working legend for plainview can you please let us know if this is what you are after? plainview(poppendorf[[5]])

@swoellauer can we make this flexible, so that plainview(poppendorf[[5]], legend = FALSE) doesn't throw an error?

[danklotz]

Sorry for the late reply.

The first commit (~8 days ago) did not work, but the current dev-version does! It looks a bit rough around the edges (as you said) but would be exactly what I would like to have (if implemented in slideview). Thank you very much 💃 💃 💃

[tim-salabim]

@danklotz could you be more specific regarding 'a bit rough around the edges'? So we can try to smooth things... ;-)

[danklotz]

Oh... Well this might be picky, but the rendering/transparency of the font seems off. One can see slight white pixels around it.

[tim-salabim]

@danklotz what OS are you using? I don't see any rendering issues on Linux...

@swoellauer I have just updated the R side of cube and plainview to include laegends. Can you adjust JS side to enable legend rendering?

[danklotz]

used windows. Will check it on mac os to then

[tim-salabim]

@danklotz slideview and cubeview now also have legends (for numeric data). Testing welcome. Regarding the rough look, I can replicate that on windows and will look into that. Linux seems to render fine. Did get a chance to try on mac?

[tim-salabim]

Here's what it looks like on linux

[danklotz]

Mac rendering looks fine to! Attached a screenshot of the plainview example from above.

[fdetsch]

plainview works like a charm on Windows as well: