Public/Tools/Resize-Image.ps1
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function Resize-Image { <# .SYNOPSIS Resizes a [System.Drawing.Image] object to the given height with the same aspect ratio. .DESCRIPTION Resizes a [System.Drawing.Image] object to the given height with the same aspect ratio and outputs a new Image object which uses the same codec as the original image unless otherwise specified. .EXAMPLE PS C:\> $image = $camera | Get-Snapshot -Live | ConvertFrom-Snapshot | Resize-Image -Height 200 -DisposeSource Get's a live snapshot from $camera and converts it to a System.Drawing.Image object, resizes it to 200 pixels tall and disposes the original image. .OUTPUTS [System.Drawing.Image] .NOTES Don't forget to call Dispose() when you're done with the image! #> [CmdletBinding()] [OutputType([System.Drawing.Image])] param( [Parameter(Mandatory, ValueFromPipeline)] [System.Drawing.Image] $Image, [Parameter(Mandatory)] [int] $Height, [Parameter()] [long] $Quality = 95, [Parameter()] [ValidateSet('BMP', 'JPEG', 'GIF', 'TIFF', 'PNG')] [string] $OutputFormat, [Parameter()] [switch] $DisposeSource ) process { if ($null -eq $Image -or $Image.Width -le 0 -or $Image.Height -le 0) { Write-Error 'Cannot resize an invalid image object.' return } [int]$width = $image.Width / $image.Height * $Height $bmp = [system.drawing.bitmap]::new($width, $Height) $graphics = [system.drawing.graphics]::FromImage($bmp) $graphics.InterpolationMode = [system.drawing.drawing2d.interpolationmode]::HighQualityBicubic $graphics.DrawImage($Image, 0, 0, $width, $Height) $graphics.Dispose() try { $formatId = if ([string]::IsNullOrWhiteSpace($OutputFormat)) { $Image.RawFormat.Guid } else { ([system.drawing.imaging.imagecodecinfo]::GetImageEncoders() | Where-Object FormatDescription -eq $OutputFormat).FormatID } $encoder = [system.drawing.imaging.imagecodecinfo]::GetImageEncoders() | Where-Object FormatID -eq $formatId $encoderParameters = [system.drawing.imaging.encoderparameters]::new(1) $qualityParameter = [system.drawing.imaging.encoderparameter]::new([system.drawing.imaging.encoder]::Quality, $Quality) $encoderParameters.Param[0] = $qualityParameter Write-Verbose "Saving resized image as $($encoder.FormatDescription) with $Quality% quality" $ms = [io.memorystream]::new() $bmp.Save($ms, $encoder, $encoderParameters) $resizedImage = [system.drawing.image]::FromStream($ms) Write-Output ($resizedImage) } finally { $qualityParameter.Dispose() $encoderParameters.Dispose() $bmp.Dispose() if ($DisposeSource) { $Image.Dispose() } } } } |