reflect NUM_FRACTION_DIGITS to SVG path data

[tushuhei]

Motivation

Fix #5734. toSVG does not consider NUM_FRACTION_DIGITS in exporting path data, which makes the resulting SVG (and JSON eventually) unnecessarily large.

Description

util.path.joinPath() seriarizes SVG path data by joining commands. This change is to extend the function by additing the fractionDigits argument, which represents the number of fraction digits for the serialized SVG path data.

Changes

• BREAKING: Added a new argument to the joinPath function. If no argument is passed toFixed will round it to an int
• Call the joinPath function with config.NUM_FRACTION_DIGITS.
• Add a unit test for the joinPath function.

In Action

<canvas id="fabric"></canvas>
<p id="output"></p>
<div id="reconstructed"></div>
<script src="https://unpkg.com/fabric@5.3.0/dist/fabric.js"></script>
<script>
const canvas = new fabric.Canvas('fabric');
const path = new fabric.Path('M55.23 82.29a11.13 11.13 0 0 0-10.46 0L23.55 95.12c-2.88 1.74-4.61.49-3.84-2.78l5.65-24.15a11.16 11.16 0 0 0-3.23-9.95L3.36 42c-2.54-2.2-1.88-4.23 1.47-4.51l24.71-2.09A11.11 11.11 0 0 0 38 29.27l9.63-22.85c1.3-3.1 3.44-3.1 4.74 0L62 29.27a11.11 11.11 0 0 0 8.46 6.15l24.71 2.09c3.35.29 4 2.31 1.47 4.51L77.87 58.24a11.16 11.16 0 0 0-3.23 9.95l5.65 24.15c.76 3.27-1 4.52-3.84 2.78Z');
canvas.add(path);
fabric.Object.NUM_FRACTION_DIGITS = 0;
document.getElementById("output").textContent = canvas.toSVG();
document.getElementById("reconstructed").innerHTML = canvas.toSVG();
</script>

Before:

After:

[ShaMan123]

Thanks
Good job
Add a changelog please

[ShaMan123]

And run npm run prettier:write and commit the changes

Read the CONTRIBUTING.md for more details on how to finish up the PR

[ShaMan123]

Passing undefined to toFixed rounds the number entirely so that doesn't support what was before.
So I guess we should make the arg non optional as you did but I am not sure.
It is used only by the _toSVG method so I think it doesn't really matter.
@asturur thoughts?

[asturur]

This is fine.
But in the changelog we need to write BREAKING.

[asturur]

Please add BREAKING in front of the changelog line

[tushuhei]

Sure thing, done.

[asturur]

@ShaMan123 your question was collapsed for me and i didn't see.
Sorry @tushuhei @ShaMan123 is right. While joinPath is used once, is still an external utility. Forcing the use of toFixed means making impossible to keep the original values.
(please corret me if i m mistaken)

so for joinPath toFixed was good as an optional parameter, and if is isn't passed should not truncte the numbers

[Exlord]

Hi, I am using the custom build version which is 5.2. Is this update available there ?

[ShaMan123]

No.
V6 only.
You can patch if you must.

[Exlord]

Is version 6 production ready ?

[ShaMan123]

beta
much better than v5