Export to SVG 1.1 includes non-standard rgba colors

Preflight Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Describe the bug Export to SVG 1.1 includes non-standard rgba colors, when rgb colors would be more appropriate.

In SVG 1.1 colors are expressed as rgb values, while opacity is expressed in a separate attribute. In the candidate SVG 2.0 version, rgba colors are allowed. Usage of rgba color values are non-standard, even though many browsers support it, but browsers are not the only applications that read SVG images.

To Reproduce Steps to reproduce the behavior:

1. Create a draw.io diagram, containing a rectangle.
2. Export to SVG
3. SVG file contains rgba(*, *, *, 1) color elements (* = wildcard).

Expected behavior Minimum: Color values rgba(r, g, b, 1) should be replaced with rgb(r, g, b).

In SVG 1.1, the alpha value should be moved to the attribute *-opacity.

You may want to differentiate between SVG 1.1 and (future) SVG 2.0. In SVG 2.0 the existing behavior is fine (perhaps desired).

draw.io version (In the Help->About menu of the draw.io editor):

• draw.io version 15.8.6

Desktop (please complete the following information):

• OS: macOS
• Browser Safari
• Version 15.0

[alderg]

The next release will use rgb() values.

[mbrannstrom]

Does it work if you change an example to use rgba(#RRGGBBAA) hex notation?

No, it does not work.

The attribute "fill" represents an invalid CSS value ("rgba(#000000ff)").
Original message:
Invalid RGB color: 000000ff.

My current workaround is to run the SVG through sed (BSD syntax here):

sed -E -i~ -e 's/rgba\(([0-9]+) *, *([0-9]+) *, *([0-9]+) *, *1 *\)/rgb(\1, \2, \3)/g' images/*.svg