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<#
.SYNOPSIS
Resize an image
.DESCRIPTION
Resize an image based on a new given height or width or a single dimension and a maintain ratio flag.
The execution of this CmdLet creates a new file named "OriginalName_resized" and maintains the original
file extension
.PARAMETER Width
The new width of the image. Can be given alone with the MaintainRatio flag
.PARAMETER Height
The new height of the image. Can be given alone with the MaintainRatio flag
.PARAMETER ImagePath
The path to the image being resized
.PARAMETER MaintainRatio
Maintain the ratio of the image by setting either width or height. Setting both width and height and also this parameter
results in an error
.PARAMETER Percentage
Resize the image *to* the size given in this parameter. It's imperative to know that this does not resize by the percentage but to the percentage of
the image.
.EXAMPLE
Resize-Image -Height 45 -Width 45 -ImagePath "Path/to/image.jpg"
.EXAMPLE
Resize-Image -Height 45 -MaintainRatio -ImagePath "Path/to/image.jpg"
.EXAMPLE
#Resize to 50% of the given image
Resize-Image -Percentage 50 -ImagePath "Path/to/image.jpg"
.NOTES
Written By:
Christopher Walker
#>
Function Resize-Image() {
[CmdLetBinding(
SupportsShouldProcess=$true,
PositionalBinding=$false,
ConfirmImpact="Medium",
DefaultParameterSetName="Absolute"
)]
Param (
[Parameter(Mandatory=$True)]
[ValidateScript({
$_ | ForEach-Object {
Test-Path $_
}
})][String[]]$ImagePath,
[Parameter(Mandatory=$False)][Switch]$MaintainRatio,
[Parameter(Mandatory=$False, ParameterSetName="Absolute")][Int]$Height,
[Parameter(Mandatory=$False, ParameterSetName="Absolute")][Int]$Width,
[Parameter(Mandatory=$False, ParameterSetName="Percent")][Double]$Percentage
)
Begin {
If ($Width -and $Height -and $MaintainRatio) {
Throw "Absolute Width and Height cannot be given with the MaintainRatio parameter."
}
If (($Width -xor $Height) -and (-not $MaintainRatio)) {
Throw "MaintainRatio must be set with incomplete size parameters (Missing height or width without MaintainRatio)"
}
If ($Percentage -and $MaintainRatio) {
Write-Warning "The MaintainRatio flag while using the Percentage parameter does nothing"
}
}
Process {
ForEach ($Image in $ImagePath) {
$Path = (Resolve-Path $Image).Path
$Dot = $Path.LastIndexOf(".")
#Add name modifier (OriginalName_resized.jpg)
$OutputPath = $Path.Substring(0,$Dot) + "_resized" + $Path.Substring($Dot,$Path.Length - $Dot)
$OldImage = New-Object -TypeName System.Drawing.Bitmap -ArgumentList $Path
$OldHeight = $OldImage.Height
$OldWidth = $OldImage.Width
If ($MaintainRatio) {
$OldHeight = $OldImage.Height
$OldWidth = $OldImage.Width
If ($Height) {
$Width = $OldWidth / $OldHeight * $Height
}
If ($Width) {
$Height = $OldHeight / $OldWidth * $Width
}
}
If ($Percentage) {
$Percentage = ($Percentage / 100)
$Height = $OldHeight * $Percentage
$Width = $OldWidth * $Percentage
}
$Bitmap = New-Object -TypeName System.Drawing.Bitmap -ArgumentList $Width, $Height
$NewImage = [System.Drawing.Graphics]::FromImage($Bitmap)
#Retrieving the best quality possible
$NewImage.SmoothingMode = [System.Drawing.Drawing2D.SmoothingMode]::HighQuality
$NewImage.InterpolationMode = [System.Drawing.Drawing2D.InterpolationMode]::HighQualityBicubic
$NewImage.PixelOffsetMode = [System.Drawing.Drawing2D.PixelOffsetMode]::HighQuality
$NewImage.DrawImage($OldImage, $(New-Object -TypeName System.Drawing.Rectangle -ArgumentList 0, 0, $Width, $Height))
If ($PSCmdlet.ShouldProcess("Resized image based on $Path", "saved to $OutputPath")) {
$Bitmap.Save($OutputPath)
}
$Bitmap.Dispose()
$NewImage.Dispose()
}
}
}
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