PowerShell Weekly
PowerShell Weekly

Converting Visio to PNG and SVG

Matthew Dowst

When working in Visio, it is not uncommon that you need to export your diagram to a picture for sharing or placing in documentation. For example, when writing, I will often have multiple Visio diagrams that I continually tweak throughout the process. So, I wrote a function to take all the Visio diagrams in a folder and export them to SVG and PNG.

All you need to do is pass this function the path of the folder, and it will do the rest.


Function Export-VisioToImages {
    <#
.SYNOPSIS
Use to export Visio diagrams to PNG and SVG format

.PARAMETER Path
Specifies the path to the folder with the Visio diagrams

.PARAMETER Filter
Specifies a filter to qualify the Path parameter. Default value is "*.vsdx"

.PARAMETER Force
Forces the command to overwrite existing export files.

.EXAMPLE
Export-VisioToImages -Path $Path -Force

.NOTES
Requires that Visio is installed on the local machine
#>
    param(
        [string]$Path,
        [string]$Filter = "*.vsdx",
        [switch]$Force
    )

    # Create the Visio object
    $Visio = New-Object -comobject Visio.Application
    $Visio.Visible = $false

    # Get all the Visio files in the folder
    $FilesToExport = Get-ChildItem $Path -Filter $Filter

    foreach ($item in $FilesToExport) {
        # Open the Visio document
        $doc = $Visio.Documents.Open($item.FullName)

        # Set the paths for the svg and png files
        $ExportPaths = @(
            Join-Path $item.DirectoryName "$($item.BaseName).svg"
            Join-Path $item.DirectoryName "$($item.BaseName).png"
        )

        foreach ($export in $ExportPaths) {
            if (Test-Path $export) {
                # If file exists and force is true, the delete the existing file
                if ($Force) {
                    Remove-Item $export -Force
                }
                # else if the file exists and force is not true, go to the next file
                else {
                    Write-Warning "Skipping '$export' because it already exists. Use -force to overwrite it."
                    continue
                }
            }
            # Export the Visio document
            $doc.Pages | ForEach-Object {
                $_.Export($export)
            }
            Write-Output $export
        }
        # Close the document
        $doc.Close()
    }

    # Close Visio
    $Visio.Quit()
}

The this post of part of the series Automation Authoring. Refer the main article for more details on use cases and additional content in the series.

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