Font texture styling - demo window and metric/debug

[nahkhiir]

When using the Light style, the font texture displayed in the demo window (Widgets/Images) and the Metrics/Debug window is white on a light background and nearly unreadable (especially the magnified part under the mouse cursor)

This is caused by a fixed white tint being applied to the font texture image which is fine for the Dark and Classic styles but is not suitable for the Light style.

ImVec4 tint_col = ImVec4(1.0f, 1.0f, 1.0f, 1.0f);

Changing the tint_col to use the styles text colour fixes the image display for the Light style and leaves the Dark and Classic styles unchanged as their font colour is light

ImVec4 tint_col = ImGui::GetStyleColorVec4(ImGuiCol_Text);

Result with fixed applied

Dark style unaffected - before -

After -

[ocornut]

Hello,

Thanks for the PR.
Unfortunately the atlas can also contains RGBA contents (e.g. #3369 or custom glyph/icons added by application) so tinting is not always appropriate.

I've made this optional in ShowFontAtlas() with a checkbox: dd21cab and haven't touched the demo section because of that.
Thanks!

EDIT Also also the checkbox in Demo, in 2efebe3