Float: add unlocalized float to string

[Murmele]

Add possibility to cast a float to a string unlocalized.

This is required for the Path::command property

The problem is that Path::command float values must not be casted localized to string because the final svg string shall contain only "." as decimal separator

property <float> value: 5.;
Path {
        width: 100px;
        height: 100px;
        commands: "M 0 0 L 0 " + value.to-string-unlocalized() + " A 1 1 0 0 0 100 100 L 100 0 Z"; 
        stroke: red;
        stroke-width: 1px;
    }

• Rust
• C++
• Interpreter

[ogoffart]

I don't think this is the right approach, because it misses things where path are first assigned to a string property or stuff like that.

I think the way out is to check if the string contains the decimal separator in there:

slint/internal/core/graphics/path.rs

Line 307 in 8777f7f

PathData::Commands(commands) => {

and do a string replacement to . if that's the case.

[Murmele]

I don't think this is the right approach, because it misses things where path are first assigned to a string property or stuff like that.

I think the way out is to check if the string contains the decimal separator in there:

slint/internal/core/graphics/path.rs

Line 307 in 8777f7f

PathData::Commands(commands) => {

and do a string replacement to . if that's the case.

Yes this is true but for complex strings you have to iterate over all characters which would make it slow on embedded systems.

Approach	Comments
Search and replace in the string	Slow because iterating over the complete string
Ignore localization during creation	Fast, but if the command is assigned first to a string and then assigning to the command, we don't catch it

[tronical]

Yes this is true but for complex strings you have to iterate over all characters which would make it slow on embedded systems.

I don't think we need to be particularly concerned about dynamic path generation on MCU. And on MPU and higher I think that's just fine.

[ogoffart]

(can you please update the PR title and description?)

[ogoffart]

Looks good.

Just some notes regarding the documentation:

• The documentation of conversion from float to string could reference this function
• Not sure if we really need to mention it in the documentation of Path. @tronical what's your opinion?