//#version 3.7;
//#version 3.8;

// povray v37_vs_v38_ImageFileReadTests.pov -fn +kfi<frame_number>

// The file name is v38grey16.png

// OK v3.7 & v3.8
#declare Pig00 = pigment {image_map {"v38grey16.png"} }

#if (frame_number=1)
// OK v3.7 & v3.8 When the output file format/type is png.
// (output can be off, -fn, and still be OK so long as
// the file type is correct - which is perhaps confusing)
#declare Pig01 = pigment {image_map {"v38grey16"} }
#end

#if (frame_number=2)
// This Christoph fixed in v3.8. It doesn't work in v3.7
// without an explicit leading file type token.
//    Parse Error: Expected 'map file spec'
#declare Str02 = "v38grey16.png";
#declare Pig02 =pigment {image_map {Str02} }
#end

#if (frame_number=3)
// This Christoph fixed in v3.8 so long as the output
// file type leads to the right extension - or you can set
// the file type explicitly.
// It doesn't work in v3.7 without an explcit file type.
#declare Str03 = "v38grey16";
#declare Pig03 =pigment {image_map {Str03} }
#end

#if (frame_number=4)
// If the image file name has no extension, v3.7 and v3.8
// will try read the file depending upon the output file
// type. If this is different than the actual file type,
// both v3.7 and v3.8 require the file type be specified
// for the image read to work. Otherwise parsing fails.
#declare Pig04 =pigment {image_map {"NoFileExtension"} }
#end

#if (frame_number=5)
// For a string ID, v3.7 forces the file type without
// trying to read the file as being in the ouput format.
// v3.8 attempts to read the file as being in the
// output format. If this not valid, the file type
// is required in v3.8 for parsing to work.
#declare Str05 = "NoFileExtension";
#declare Pig05 =pigment {image_map {Str05} }
#end

// So long as your file type and/or extension is set correctly, it
// never hurts to specify it. Once in a while that might save you
// should you have multiple file formats of an image and you really
// want to use a particular format which is different than the
// output file type.

#error "OK. Stopping early at parse end"