71 lines
1.8 KiB
PowerShell
71 lines
1.8 KiB
PowerShell
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param(
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[Parameter(Mandatory=$true)][string]$InputPath,
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[Parameter(Mandatory=$true)][string]$OutputPath,
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[string]$BackupPath = "",
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[int]$AlphaThreshold = 1,
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[int]$Padding = 0
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)
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if (!(Test-Path -LiteralPath $InputPath)) {
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throw "Input file not found: $InputPath"
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}
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if ($BackupPath -ne "") {
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Copy-Item -LiteralPath $InputPath -Destination $BackupPath -Force
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}
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Add-Type -AssemblyName System.Drawing
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# Load from stream to avoid locking
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$fs = [System.IO.File]::Open($InputPath, [System.IO.FileMode]::Open, [System.IO.FileAccess]::Read, [System.IO.FileShare]::ReadWrite)
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try {
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$bmp = New-Object System.Drawing.Bitmap($fs)
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} finally {
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$fs.Dispose()
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}
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$minX = $bmp.Width
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$minY = $bmp.Height
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$maxX = -1
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$maxY = -1
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for ($y = 0; $y -lt $bmp.Height; $y++) {
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for ($x = 0; $x -lt $bmp.Width; $x++) {
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$c = $bmp.GetPixel($x, $y)
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if ($c.A -ge $AlphaThreshold) {
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if ($x -lt $minX) { $minX = $x }
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if ($y -lt $minY) { $minY = $y }
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if ($x -gt $maxX) { $maxX = $x }
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if ($y -gt $maxY) { $maxY = $y }
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}
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}
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}
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if ($maxX -lt 0 -or $maxY -lt 0) {
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# No non-transparent pixels, just copy input
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$bmp.Dispose()
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Copy-Item -LiteralPath $InputPath -Destination $OutputPath -Force
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exit 0
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}
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$minX = [math]::Max(0, $minX - $Padding)
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$minY = [math]::Max(0, $minY - $Padding)
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$maxX = [math]::Min($bmp.Width - 1, $maxX + $Padding)
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$maxY = [math]::Min($bmp.Height - 1, $maxY + $Padding)
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$newW = $maxX - $minX + 1
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$newH = $maxY - $minY + 1
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$rect = New-Object System.Drawing.Rectangle($minX, $minY, $newW, $newH)
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$cropped = $bmp.Clone($rect, [System.Drawing.Imaging.PixelFormat]::Format32bppArgb)
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$tmp = "$OutputPath.tmp"
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try {
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$cropped.Save($tmp, [System.Drawing.Imaging.ImageFormat]::Png)
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} finally {
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$cropped.Dispose()
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$bmp.Dispose()
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}
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Move-Item -LiteralPath $tmp -Destination $OutputPath -Force
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