【PowerShell】Dwebpで伸長したPNGをiTextSharpでPDFにまとめる

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function Optimize-ImagesWithDecompressing() {
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  <#
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  .SYNOPSIS
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    Converts multiple WebP images to JPEG format with specified quality.
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  .DESCRIPTION
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    This function converts WebP images to JPEG format. It first decompresses each WebP to PNG using dwebp, then compresses the PNG to JPEG using the specified quality.
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  .PARAMETER pathList
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    An array of full file paths to the WebP images to be converted.
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  .PARAMETER suffix
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    A string suffix to append to the filename before the .png extension during the decompression stage. This suffix is not used in final jpeg filename.
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  .PARAMETER quality
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    An integer representing the JPEG compression quality (0-100). 100 is highest quality.
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  .EXAMPLE
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    $images = Get-ChildItem -Path "C:\path\to\images" -Filter "*.webp"
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    Optimize-ImagesWithDecompressing -pathList $images.FullName -suffix "decompressed" -quality 85
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  .INPUTS
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    System.Array, System.String, System.Int32
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  .OUTPUTS
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    None.  Output files are written to disk.
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  .NOTES
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      Requires the dwebp tool and System.Drawing assembly.
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  .LINK
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    dwebp, [System.Drawing.Image]
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  #>
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  [CmdletBinding()]
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  param (
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    [array]$pathList,
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    [string]$suffix,
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    [int]$quality
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  )
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  # Add-Type -AssemblyName System.Drawing
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  foreach ($file in $pathList) {
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    $extension = (Get-Item $file.FullName).Extension;
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    $outputImg1 = "{0}_{1:D2}{2}" -f $file.FullName.Substring(0, $file.FullName.Length - $extension.Length), $suffix, ".png";
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    Write-Output "<1st Source File Name: $file>";
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    Optimize-ImageWithDecompressing -ImagePath $file -OutputPath $outputImg1;
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    $extension = (Get-Item $outputImg1).Extension;
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    $outputImg2 = "{0}{1}" -f $outputImg1.Substring(0, $outputImg1.Length - $extension.Length), ".jpg";
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    Write-Output "<2nd Source File Name: $outputImg>";
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    Optimize-ImageWithCompressing -ImagePath $outputImg1 -OutputPath $outputImg2 -Quality $quality;
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    $updatedCount++;
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    Write-Output "----------------";
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  };
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  Write-Output("{0} .jpg images converted." -f $updatedCount);
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  Write-Output "----------------";
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}
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$targetFolder = (Get-Location).Path;
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$imgPathList = Get-ChildItem -Path $targetFolder | Where-Object { $_.Extension -in @(".webp") };
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$suffix = "compressed";
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$quality = [int]($Args[0]); # 0-100
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Optimize-ImagesWithDecompressing $imgPathList $suffix $quality;
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$tmp = Read-Host "Input 'y' if you wanna move original images......";
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If ($tmp -eq "y") {
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  Move-Item -Path $imgPathList -Destination .\5_original_files;
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  $imgPathList = Get-ChildItem -Path $targetFolder | Where-Object { $_.Extension -in @(".png") };
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  Move-Item -Path $imgPathList -Destination .\5_original_files;
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}

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function Optimize-ImageWithDecompressing {
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  # Load System.Drawing assembly
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  Add-Type -AssemblyName System.Drawing
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  try {
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    dwebp $ImagePath -o $OutputPath;
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    Write-Host "Image decompressed and saved to: $OutputPath";
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  }
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  catch {
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    Write-Error "An error occurred: $_"
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  }
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  finally {
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    if ($image) {
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      $image.Dispose()
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    }
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  }
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}

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function Optimize-ImageWithCompressing {
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  param (
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    [string]$ImagePath,
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    [string]$OutputPath,
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    [int]$Quality  # 0-100, 100 is highest quality (least compression)
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  )
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  # Load System.Drawing assembly
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  Add-Type -AssemblyName System.Drawing
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  try {
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    # Load the image
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    $image = [System.Drawing.Image]::FromFile($ImagePath)
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    # Create an EncoderParameter object for quality
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    $qualityParam = New-Object System.Drawing.Imaging.EncoderParameter(
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      [System.Drawing.Imaging.Encoder]::Quality, $Quality
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    )
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    # Get the JPEG codec
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    $jpegCodec = [System.Drawing.Imaging.ImageCodecInfo]::GetImageDecoders() | Where-Object { $_.FormatID -eq [System.Drawing.Imaging.ImageFormat]::Jpeg.Guid }
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    # Create an EncoderParameters object
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    $encoderParams = New-Object System.Drawing.Imaging.EncoderParameters(1)
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    $encoderParams.Param[0] = $qualityParam
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    # Save the image with the specified quality
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    $image.Save($OutputPath, $jpegCodec[0], $encoderParams)
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    Write-Host "Image compressed and saved to: $OutputPath"
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  }
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  catch {
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    Write-Error "An error occurred: $_"
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  }
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  finally {
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    if ($image) {
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      $image.Dispose()
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    }
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  }
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}

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function Merge-ImagesIntoPdfWithITextSharp([array]$imgPathList, [string]$iTextSharpPath) {
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  Unblock-File -Path $iTextSharpPath;
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  # [System.Reflection.Assembly]::LoadFrom($iTextSharpPath);
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  # Add-Type -Path $iTextSharpPath
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  Add-Type -LiteralPath $iTextSharpPath
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  # $error[0].Exception.GetBaseException().LoaderExceptions
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  $ext = ".pdf";
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  $pdfName = "{0}\{1}{2}" -f $imgPathList[0].DirectoryName, $imgPathList[0].BaseName, $ext;
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  Write-Output $imgPathList;
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  Write-Host ("{0}: decided PDF file name`n" -f $MyInvocation.MyCommand.Name);
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  Write-Output $pdfName;
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  $doc = New-Object iTextSharp.text.Document;
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  $pdfWriter = [iTextSharp.text.pdf.PdfWriter]::GetInstance($doc, [System.IO.File]::Create($pdfName))
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  $doc.Open()
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  # Get image files to add into PDF.
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  foreach ($path in $imgPathList) {
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    Write-Output $path;
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    Write-Output $path.GetType().FullName;
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    Write-Output $path.FullName.GetType().FullName;
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    Write-Host ("{0}: adding an image into a PDF...`n" -f $MyInvocation.MyCommand.Name);
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    $image = [iTextSharp.text.Image]::GetInstance($path.FullName);
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    # Scale images to each page size.
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    $doc.SetPageSize($image);
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    $doc.NewPage();
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    $image.SetAbsolutePosition(0, 0);
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    # $image.ScaleToFit($doc.PageSize.Width, $doc.PageSize.Height);
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    $image.Alignment = [iTextSharp.text.Image]::ALIGN_CENTER;
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    $doc.Add($image);
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  }
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  $doc.Close();
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  $pdfWriter.Close();
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  Write-Host ("{0}: completed adding images into a PDF`n" -f $MyInvocation.MyCommand.Name);
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}