PowerShell を使って画像ファイルをリサイズ&回転する

PowerShell を使って画像ファイルをリサイズ&回転するサンプル スクリプトです。

やりたい事

• jpgやpngなど画像ファイルをリサイズしたい
• 画像の回転もさせたい
• 複数画像に対し処理させたい
• 別フォルダへ画像を出力 or 上書きしたい

PowerShell スクリプト

	function Set-Image{
	<#
	.SYNOPSIS
	Resize and Rotate image file.
	.DESCRIPTION
	Image resizing and rotating cmdlets.
	.PARAMETER Source
	Specifies an source image file.
	.PARAMETER Destination
	Specifies a destination folder.
	.PARAMETER AspectRatio
	Specifies a AspectRatio(ValidateSet).
	WidthFixed : Fixed width pixel and Height pixel is auto caluculate.
	HeightFixed : Fixed height pixel and Width pixel is auto caluculate.
	Free : No AspectRatio.
	.PARAMETER WidthPx
	Specifies a width of image in pixel.
	.PARAMETER HeightPx
	Specifies a height of image in pixel.
	.PARAMETER Rotate
	Specifies a Rotate.
	RotateNoneFlipNone : 0.
	Rotate90FlipNone : 90.
	Rotate180FlipNone : 180.
	Rotate270FlipNone : 270.
	.PARAMETER Overwrite
	Specifies a destination exist then overwrite it without prompt.
	.EXAMPLE
	Convert-ImageResize -Source "C:\temp2\aaa.jpg", "C:\temp2\bbb.jpg" -Verbose
	.EXAMPLE
	Convert-ImageResize -Source C:\temp2\aaa.jpg -Destination c:\temp -AspectRatio WidthFixed -WidthPx 800 -ImageFormat Jpeg -Rotate RotateNoneFlipNone -Verbose
	.EXAMPLE
	$source = "C:\source"
	$destination = "C:\destination"
	$width = 1600
	$height = 600
	gci "$source\*.jpg" | foreach{
	$img = New-Object System.Drawing.Bitmap($_.FullName)
	if($img.Width -gt $width){
	$img.Dispose()
	Convert-ImageResize -Source $_.fullName `
	-Destination $destination `
	-AspectRatio WidthFixed -WidthPx $width -HeightPx $height `
	-Rotate Rotate90FlipNone `
	-Overwrite `
	-Verbose
	}
	else{
	$img.Dispose()
	}
	}
	.NOTES
	Author: Satoru Nasu
	Blog : http://nasunoblogb.blogspot.com/
	#>
	[CmdletBinding()]
	param(
	[Parameter(Mandatory=$True,Position=1)]
	[string[]]$Source,
	[string]$Destination = $("$env:USERPROFILE\Documents"),
	[ValidateSet("WidthFixed", "HeightFixed", "Free")]
	[string]$AspectRatio = "WidthFixed",
	[Int]$WidthPx = "1600",
	[Int]$HeightPx,
	[ValidateSet("RotateNoneFlipNone","Rotate90FlipNone","Rotate180FlipNone","Rotate270FlipNone")]
	[string]$Rotate = "RotateNoneFlipNone",
	[switch]$Overwrite
	)
	Begin{
	# アセンブリの読み込み
	Add-Type -AssemblyName System.Drawing
	# or
	#[Reflection.Assembly]::LoadWithPartialName("System.Drawing")
	}
	process{
	# 出力先フォルダーをチェック
	if((Test-Path($Destination)) -eq $false){
	New-Item $Destination -ItemType Directory | Out-Null
	}
	$Source | foreach{
	# ファイル名を取得
	$name = (Get-Item -Path $_).Name
	# 拡張子を取得
	$ext = ((Get-Item -Path $_).Extension).ToLower()
	# 画像ファイルの読み込み
	$image = New-Object System.Drawing.Bitmap($_)
	# アスペクト比の指定から画像の高さ(px)と幅(px)を指定
	$oldWidth = $image.Width
	$oldHeight = $image.Height
	if($AspectRatio -eq "WidthFixed"){
	$w = $WidthPx
	$h = $image.Height/($oldWidth / $w)
	}
	elseif($AspectRatio -eq "HeightFixed"){
	$h = $HeightPx
	$w = $image.Width/($oldHeight / $h)
	}
	else{
	if([int]$Width -and [int]$Height){
	$w = $WidthPx
	$h = $HeightPx
	}
	else{
	Write-Host "no value Width or Height." -ForegroundColor Yellow
	throw
	}
	}
	# 縮小先のオブジェクトを生成
	$canvas = New-Object System.Drawing.Bitmap([int]$w, [int]$h)
	# 縮小先へ描画
	$graphics = [System.Drawing.Graphics]::FromImage($canvas)
	$graphics.DrawImage($image, (New-Object System.Drawing.Rectangle(0, 0, $canvas.Width, $canvas.Height)))
	# 回転
	$canvas.RotateFlip($Rotate)
	# 拡張子
	# https://msdn.microsoft.com/ja-jp/library/system.drawing.imaging.imageformat(v=vs.110).aspx
	$hash = @{".bmp"="Bmp"; ".jpg"="Jpeg"; ".jpeg"="Jpeg"; ".png"="Png" ;".gif"="Gif"}
	$ImageFormat = $hash[$ext]
	# 保存
	$canvas.Save("$Destination\$Name", [System.Drawing.Imaging.ImageFormat]::$ImageFormat)
	Write-Verbose "Save $Name file from $($oldWidth)x$($oldHeight) to $($w)x$($h)."
	# オブジェクトの破棄
	$graphics.Dispose()
	$canvas.Dispose()
	$image.Dispose()
	# 上書き
	if($Overwrite){
	$path = (Get-Item -Path $_).DirectoryName
	Remove-Item -Path $_ -Force
	Move-Item -Path "$Destination\$Name" -Destination $path -Force
	Write-Verbose "Overwrite $Name."
	}
	}
	}
	End{}
	}

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