# 像素级验证轮盘扇形间隙宽度（任意半径处应恒定 ≈ 10px）
$ErrorActionPreference = 'Stop'
Add-Type -AssemblyName System.Drawing

foreach ($name in 'wheel-light', 'wheel-dark') {
    $path = "artifacts\$name.png"
    $bmp = [System.Drawing.Bitmap]::FromFile((Resolve-Path $path))
    $cx = [int]($bmp.Width / 2); $cy = [int]($bmp.Height / 2)
    Write-Output "=== $name ($($bmp.Width)x$($bmp.Height)) ==="

    foreach ($radius in 100, 145, 200) {
        $steps = 7200
        $transparentRuns = New-Object System.Collections.Generic.List[double]
        $opaqueRuns = New-Object System.Collections.Generic.List[double]
        $runSteps = 0; $prevTransparent = $false
        for ($i = 0; $i -le $steps; $i++) {
            $ang = ($i / $steps) * 2 * [Math]::PI
            $x = [int][Math]::Round($cx + $radius * [Math]::Cos($ang))
            $y = [int][Math]::Round($cy + $radius * [Math]::Sin($ang))
            $px = $bmp.GetPixel($x, $y)
            $transparent = $px.A -lt 30
            if ($i -gt 0 -and $transparent -ne $prevTransparent) {
                $pxArc = $runSteps / $steps * 2 * [Math]::PI * $radius
                if ($prevTransparent) { $transparentRuns.Add($pxArc) } else { $opaqueRuns.Add($pxArc) }
                $runSteps = 0
            }
            $runSteps++; $prevTransparent = $transparent
        }
        $gaps = @($transparentRuns | Where-Object { $_ -gt 1 -and $_ -lt 40 })
        $sectors = @($opaqueRuns | Where-Object { $_ -gt 40 })
        $gapAvg = -1; $gapMin = -1; $gapMax = -1
        if ($gaps.Count -gt 0) {
            $gapAvg = ($gaps | Measure-Object -Average).Average
            $gapMin = ($gaps | Measure-Object -Minimum).Minimum
            $gapMax = ($gaps | Measure-Object -Maximum).Maximum
        }
        $line = '半径 {0}: 扇形段数={1}, 间隙段数={2}, 间隙宽度 均值={3:F2}px 最小={4:F2}px 最大={5:F2}px (期望≈10px 且处处相等)' -f $radius, $sectors.Count, $gaps.Count, $gapAvg, $gapMin, $gapMax
        Write-Output $line
    }
    $bmp.Dispose()
}