Double precision support

[lycium]

Sorry if this has been mentioned before (seems quite an obvious request, though I couldn't find any mention of it), but would it be possible to support double precision as well? For example, in addition to:

bool ImGui::SliderFloat(const char* label, float* v, float v_min, float v_max, const char* display_format, float power)

there would also be:

bool ImGui::SliderDouble(const char* label, double* v, double v_min, double v_max, const char* display_format, double power)

I'm aware that it could potentially lead to lots of code duplication, though maybe this can be avoided by templating the code. On the other hand, without double precision support in imgui, it becomes extremely awkward to edit our double precision internal data / very frustrating to work around.

I'm also aware that games typically don't use much double precision, but sometimes they might, and for other applications it can also be useful.

It's pretty easy to hack up this support myself and submit the pull request, but I'm first curious to know if it would be considered at all.

Thanks for your awesome library!

[lycium]

I've found this previous issue now after searching more deeply: #320

Apparently the preferred way to handle this is via string processing on the inputs, but that opens a whole can of worms (validation, fast and accurate string <=> double conversion, ...) and generally breaks the main nice thing about ImGui, that you can just drop it in to make your data editable.

[ocornut]

I'd like to solve this problem eventually. As you pointed out one of the problem is the explosion of API entry points.

Apparently the preferred way to handle this is via string processing on the inputs, but that opens a whole can of worms (validation, fast and accurate string <=> double conversion, ...) and generally breaks the main nice thing about ImGui, that you can just drop it in to make your data editable.

Creating an InputDouble function in your code (within ImGui namespace) that uses sprintf+InputText+sscanf should be fairly easy and only a few lines of code.

[IsaacWoods]

This seems like a common enough thing to want to do to justify adding to ImGui proper. Through either templating or just creating those functions, it would be nice to see this. Our entire codebase uses double and it would be nice to use some of the more advanced widgets.

[ocornut]

@lycium, @IsaacWoods Sorry I didn't get to react earlier and with more details on this.

1. I have added a InputDouble() function recently.

2. As you pointed out, we will probably end up something sort sort of generic mechanism internally to make it easier to expose more function, so I still plan to add the SliderFloat, DragFloat functions at some point. Will work on making that possible, as there's a little more work involved for slider and drag as they are designed around float (even the int path uses float, which is occasionally problematic).

[lycium]

That's awesome, thank you!

[ocornut]

FYI, I have added functions in a branch to work with float, double, 32/64 bits, signed and unsigned (and in a proper lossless manner, as previously some functions didn't work great with big integers).
See #643 for details.