HellionChat/HellionChat/Ui/StyleEngine/Metrics.cs

using Dalamud.Bindings.ImGui;
using Dalamud.Interface.Utility;
using HellionChat.Util;

namespace HellionChat.Ui.StyleEngine;

// Layout values, authored at 100% display scaling. Draw code reads the scaled
// properties; the Raw constants exist only for the few places that must store or
// compare an unscaled value (Sidebar.GetWidth, the width slider bounds).
//
// Deliberately NOT part of ThemeLayout: that record is serialised into theme
// JSON, and layout customisation is deliberately out of scope.
internal static class Metrics
{
    // --- Sidebar ---
    internal const float SidebarIconOnlyWidthRaw = 38f;
    internal const float SidebarMinWidthRaw = 40f;
    internal const float SidebarMaxWidthRaw = 300f;
    internal const float SidebarRowHeightRaw = 32f;
    internal const float SidebarPopOutHitWidthRaw = 22f;
    internal const float SidebarGreetedHitWidthRaw = 22f;
    internal const float SidebarHitSlackRaw = 4f;
    internal const float SidebarMinDrawWidthRaw = 2f;
    internal const float SidebarUnreadRadiusRaw = 4f;
    internal const float SidebarGlyphInsetRaw = 4f;

    // --- Input bar ---
    internal const float InputBarHeightRaw = 32f;

    // Two ghost buttons since v1.14.0 -- symbols and the more-menu. Everything
    // else moved into the menu, and the hundred-odd pixels went back to the
    // input field.
    internal const float InputQuickButtonsReserveRaw = 62f;

    // --- Honorific header ---
    internal const float HonorificHeightRaw = 30f;
    internal const float HonorificInsetRaw = 8f;
    internal const float HonorificBracketGapRaw = 6f;

    // --- Top tab bar ---
    internal const float TopTabUnreadInsetRaw = 4f;
    internal const float TopTabPaddingXRaw = 10f;
    internal const float TopTabUnderlineRaw = 2f;

    // --- Status bar ---
    internal const float StatusBorderThicknessRaw = 1f;
    internal const float StatusTopSpacerRaw = 2f;

    // --- Message list ---
    internal const float MessageDummyWidthRaw = 10f;

    private static float _cachedScale = 1f;
    private static int _cachedFrame = -1;

    // GlobalScale resolves to ImGui.GetIO().FontGlobalScale, which the Dalamud
    // settings slider moves on every frame while it is dragged. Pinning it once
    // per frame keeps a CalcSize and its matching Draw on the same value, and
    // saves three native calls per access.
    internal static float Scale
    {
        get
        {
            var frame = ImGui.GetFrameCount();
            if (frame == _cachedFrame)
                return _cachedScale;

            // Safe variant: GlobalScale throws while the interface manager is
            // still coming up, and Metrics reaches more call sites than it did.
            _cachedScale = ImGuiHelpers.GlobalScaleSafe;
            _cachedFrame = frame;
            return _cachedScale;
        }
    }

    internal static float SidebarIconOnlyWidth => MetricsMath.Scale(SidebarIconOnlyWidthRaw, Scale);
    internal static float SidebarRowHeight => MetricsMath.Scale(SidebarRowHeightRaw, Scale);
    internal static float SidebarPopOutHitWidth =>
        MetricsMath.Scale(SidebarPopOutHitWidthRaw, Scale);
    internal static float SidebarGreetedHitWidth =>
        MetricsMath.Scale(SidebarGreetedHitWidthRaw, Scale);
    internal static float SidebarHitSlack => MetricsMath.Scale(SidebarHitSlackRaw, Scale);
    internal static float SidebarMinDrawWidth => MetricsMath.Scale(SidebarMinDrawWidthRaw, Scale);
    internal static float SidebarUnreadRadius => MetricsMath.Scale(SidebarUnreadRadiusRaw, Scale);
    internal static float SidebarGlyphInset => MetricsMath.Scale(SidebarGlyphInsetRaw, Scale);

    internal static float InputBarHeight => MetricsMath.Scale(InputBarHeightRaw, Scale);
    internal static float InputQuickButtonsReserve =>
        MetricsMath.Scale(InputQuickButtonsReserveRaw, Scale);

    internal static float HonorificHeight => MetricsMath.Scale(HonorificHeightRaw, Scale);
    internal static float HonorificInset => MetricsMath.Scale(HonorificInsetRaw, Scale);
    internal static float HonorificBracketGap => MetricsMath.Scale(HonorificBracketGapRaw, Scale);

    internal static float TopTabUnreadInset => MetricsMath.Scale(TopTabUnreadInsetRaw, Scale);
    internal static float TopTabPaddingX => MetricsMath.Scale(TopTabPaddingXRaw, Scale);
    internal static float TopTabUnderline => MetricsMath.Scale(TopTabUnderlineRaw, Scale);

    // Measured, not scaled: the tab has to fit the text, and the font comes from
    // Config.FontSizeV2 which display scaling does not feed into.
    internal static float TopTabHeight => ImGui.GetTextLineHeight() + MathF.Round(10f * Scale);

    internal static float StatusBorderThickness =>
        MetricsMath.Scale(StatusBorderThicknessRaw, Scale);
    internal static float StatusTopSpacer => MathF.Round(StatusTopSpacerRaw * Scale);

    internal static float MessageDummyWidth => MetricsMath.Scale(MessageDummyWidthRaw, Scale);

    // Text-dependent heights are measured, never scaled: the font is built from
    // Config.FontSizeV2, which GlobalScale does not feed into. StatusBar.Height
    // has done it this way since 1.8.x.
    internal static float CenterY(float rowHeight) =>
        MetricsMath.CenterY(rowHeight, ImGui.GetTextLineHeight());
}