Fixed the depth values in the doc file, made some info more clear

core/image/netpbm/doc.odin

@@ -6,24 +6,25 @@ Formats:
 	PAM (P7    ): Portable Arbitrary Map, stores arbitrary channel images            (1 or 2 bytes per value)
 	PFM (Pf, PF): Portable Float Map,     stores floating-point images    (Pf: 1 channel, PF: 3 channel)
 
-Reading
+Reading:
 	All formats fill out header fields `format`, `width`, `height`, `channels`, `depth`
 	Specific formats use more fields
-		PGM, PPM, and PAM set `maxval`
-		PAM also sets `tupltype`, and is able to set `channels` to an arbitrary value
-		PFM sets `scale` and `little_endian`
+		PGM, PPM, and PAM set `maxval` (maximum of 65535)
+		PAM sets `tupltype` if there is one, and can set `channels` to any value (not just 1 or 3)
+		PFM sets `scale` (float equivalent of `maxval`) and `little_endian` (endianness of stored floats)
 	Currently doesn't support reading multiple images from one binary-format file
 
-Writing
+Writing:
+	You can use your own `Netpbm_Info` struct to control how images are written
 	All formats require the header field `format` to be specified
 	Additional header fields are required for specific formats
-		PGM, PPM, and PAM require `maxval`
+		PGM, PPM, and PAM require `maxval` (maximum of 65535)
 		PAM also uses `tupltype`, though it may be left as default (empty or nil string)
-		PFM requires `scale` and `little_endian`, though the latter may be left untouched (default is false)
+		PFM requires `scale`, and optionally `little_endian`
 
 Some syntax differences from the specifications:
-	`channels` stores what the PAM specification calls `depth`
-	`depth` instead stores how many bytes will fit `maxval` (should only be 1, 2, or 4)
+	`channels` stores the number of values per pixel, what the PAM specification calls `depth`
+	`depth` instead is the number of bits for a single value (32 for PFM, 16 or 8 otherwise)
 	`scale` and `little_endian` are separated, so the `header` will always store a positive `scale`
 	`little_endian` will only be true for a negative `scale` PFM, every other format will be false
 	`little_endian` only describes the netpbm data being read/written, the image buffer will be native

core/image/netpbm/netpbm.odin

@@ -109,7 +109,7 @@ save_to_buffer :: proc(img: ^Image, custom_info: Info = {}, allocator := context
 	// using info so we can just talk about the header
 	using info
 
-	//? validation
+	// validation
 	if header.format in (PBM + PGM + Formats{.Pf}) && img.channels != 1 \
 	|| header.format in (PPM + Formats{.PF}) && img.channels != 3 {
 		err = .Invalid_Number_Of_Channels