Fix valid unicode in clipboard paste being filtered by special key filter

[dougbinks]

Note: This PR is based on docking branch, but I can create a master branch PR if required.

Currently pasting a valid unicode character (such as when using an icon font) can result in it being filtered by the lines:

    // Filter private Unicode range. GLFW on OSX seems to send private characters for special keys like arrow keys (FIXME)
    if (c >= 0xE000 && c <= 0xF8FF)
        return false;

Since pastes originate from the clipboard, they are likely valid unicode and do not originate from these special keys, thus my proposed solution is a flag which hints the data source is from a clipboard, rather than from key presses:

    // Filter private Unicode range. GLFW on OSX seems to send private characters for special keys like arrow keys (FIXME)
    if ( !(flags & ImGuiInputTextFlags_FromClipboard) && c >= 0xE000 && c <= 0xF8FF)
        return false;

This is a 3 line change (actually 4 since there is a separator needed on the last flag), with limited surface area. Since it's fairly simple it may be easiest for you to modify the code directly rather than accept this PR.

[ocornut]

Thank you Doug, this makes sense!

I'm tempted to avoid leaking this into flags since it really only applies to the helper InputTextFilterCharacter() function. My suggestion would be to add a ImGuiInputSource_Clipboard value in ImGuiInputSource and add the parameter to InputTextFilterCharacter().

I can apply this very easily, do you mind if I perform the change (and attribute the commit to you) or do you prefer doing it on your side?

[dougbinks]

If it's easier for you to do then go ahead, if not let me know and I can handle it later on today. I'm not worried about attribution :)

[ocornut]

Reworked and merged (see f08566b), thank you!

[dougbinks]

Thanks!