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PDFapp.project.item(index).replaceWithSolid(color,name,width,height,pixelAspect).
Description
Changes the source of this FootageItem to the specified solid. Creates a new SolidSource object, sets its values from theparameters, andsets mainSource to that object.
Parameters
color The color of the solid, an array of three floating-point values, [R, G, B], in the range [0.0..1.0].
name A string containing the name of the solid.
width The width of the solid in pixels, an integer in the range [4..30000].
height The height of the solid in pixels, an integer in the range [4..30000].
pixelAspect The pixel aspect ratio of the solid, a floating-point value in the range [0.01..100.0].