Fix PDF generation failure on blank SVG files.

[cbalint13]

In continuation of #82 & #83 this fix broken PDF generation as of last log.

• Silently discards blank SVG conversions (there are many blanks).
• Additional latex UTF-8 char mappings to build full documentation.

Cc @proppy

Thanks, ~Cristian.

[proppy]

Silently discards blank SVG conversions (there are many blanks).

@mithro do you know if that's expected? should we log those in a separate bug?

[cbalint13]

Silently discards blank SVG conversions (there are many blanks).

@mithro do you know if that's expected? should we log those in a separate bug?

@proppy , @mithro

My investigation:

• those are not a bugs, in the repo there are many SVG carrying no drawing at all inside.
• sphinx ImageMagick backend can convert such SVG to a blank .PNG only using -quiet bypass.

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Here is such a blank SVG to have a look (using convert CLI tool):

convert /home/cbalint/work/GITHUB/gf180mcu/docs/digital/standard_cells/gf180mcu_fd_sc_mcu7t5v0/cells/endcap/gf180mcu_fd_sc_mcu7t5v0__endcap.schematic.svg test.png
convert: negative or zero image size `/home/cbalint/work/GITHUB/gf180mcu/docs/digital/standard_cells/gf180mcu_fd_sc_mcu7t5v0/cells/endcap/gf180mcu_fd_sc_mcu7t5v0__endcap.schematic.svg' @ error/image.c/SetImageExtent/2698.
convert: no decode delegate for this image format `/home/cbalint/work/GITHUB/gf180mcu/docs/digital/standard_cells/gf180mcu_fd_sc_mcu7t5v0/cells/endcap/gf180mcu_fd_sc_mcu7t5v0__endcap.schematic.svg' @ error/svg.c/RenderRSVGImage/534.
convert: no images defined `test.png' @ error/convert.c/ConvertImageCommand/3229.

But it pass and resulted test.png is fine (have legit size and etc) with the -quiet bypass.

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[mithro]

We should create a GitHub issue to fix the SVGs with no drawings inside (either removing them or adding the proper contents).