ggsave() doesn't save geom_raster() layer to a file

[IKupriyanov-HORIS]

Code:

from lets_plot import *
from IPython.display import SVG

LetsPlot.setup_html()

data = {
    "x": [ -1.0, 1.0, -1.0, 1.0 ],
    "y": [ -1.0, -1.0, 1.0, 1.0 ],
    "z": [ 0.024, 0.094, 0.094, 0.024 ]
}
p = ggplot(data) + \
    geom_raster(aes(x='x', y='y', fill='z'), data=data) + \
    geom_point(aes(x='x', y='y'), size=5, data=data) + \
    scale_fill_gradient(low="#54278f", high="#f2f0f7")

print("Plot")
p.show()

print("Image")
plot_filename = ggsave(p, 'issue_ggsave_raster.svg')
display(SVG(plot_filename))

Result:

[alshan]

There is no "portable" RGB encoder:

lets-plot/plot-config-portable/src/commonMain/kotlin/jetbrains/datalore/plot/PlotSvgExportPortable.kt

Line 20 in fa86a9c

SvgToString(rgbEncoder = null) // data-frame --> rgb image is not supported (geom_raster)

[alshan]

Same issue when ggsaving geom_imshow (i.e. empty plot).