Code To Create PNG File in the Z-Graphics Buffer

Here is the code I am using to produce a line plot as a PNG file.

    ; Plot in the Z-graphics buffer
    thisDevice = !D.Name
    Set_Plot, 'Z'
    Device, Set_Resolution=[500,500]
    
    ; Load drawing colors.
    LoadCT, 0
    TVLCT, cgColor('blue', /Triple), 1
    TVLCT, cgColor('red', /Triple), 2
    TVLCT, cgColor('white', /Triple), !P.Background
    TVLCT, cgColor('black', /Triple), !P.Color
    
    ; Draw graphics.
    Plot, Indgen(10), Color=1
    OPlot, Indgen(10)+1, Color=2
    
    ; Add a legend.
    Al_Legend, ['al_legend','plot','oplot'], LineStyle=[-99,0,0], $
        Color=[255,1,2], /Right, /Bottom
        
    ; Save the image for output to a PNG file.
    image = TVRD()
    TVLCT, r, g, b, /Get
    Write_PNG, 'test.png', image, r, g, b
    Set_Plot, thisDevice
    END

Version of IDL used to prepare this article: IDL 7.1.