No this is not correct.So the XX byte that follows each JCV2 offset are:
0x060634 XX=0000 0001
0x0658dd XX=1000 0000 <- bit8 is 1 so mean end-of-list
0x00992f XX=0000 0001
0x00992f XX=1000 0000 <- bit8 is 1 so mean end-of-list
Does this means bit1 is for day/night (day=1 and night=0)? If so, any idea of what the 6 middle bits are for?
The 8 bits that follow a jcv2offset do not mean "end-of-list".
It is false to say "day=1 and night=0"
In all JCV4 records (Asian or not), each jcv2 offset bitstream is followed by a list of 8 bits: the first bit (lsb) is set when the layer is used for day, the last bit is set when the layer is used for night
10000000 means that the picture (the layer) is used for day
00000001 means the picture is used for night
10000001 means the picture is used for day and night.
All combinations are possible and can be found in various JCV files
No, this is wrong: it is false to say that only one bit represents it; as I said before , there are two bits: lsb for day and msb for night. And so it is possible to have a jcv2 picture for both night and day (and this is the most common case!!!!! )So it's not possible to have a JCV2 belonging to BOTH day and night. It's either day or night, since only one bit is used to represent it?
Last edited by sherco40; 24th August 2015 at 10:13 AM.
I don't know what the 6 other bits are for but sometimes they are used (for example in the JCVs of City Navigator HongKong-Macau)I have no idea about the other 6 bits which seem to be 0 and not used so far.
There is no "end of list" bit.
There is no "real" set and no "fake" set.
For example, in the Asian JCV, each junction view has 4 "pictures": first picture (I mean next jcv2 offset bitstream) is followed by 10000000 (so it is only for day), next picture is followed by 00000001 ( so it is only for night), next picture is followed by 10000000 (so it is only for day and so it is a second layer for day which will be displayed over the previous day layer) , next picture is followed by 000000001 so it is the second layer for night.
But I think we should continue in another thread.... See your pm please.
Of course I have read this and of course I have understood your questiion.Ok, looks like you didn't read my original question/comment about a kludge to prevent Asian JCV from showing on non-asian unit. The "fake set" followed the "real set" and since its layer is higher its override the "real set." syzygy tool copy the "real set" over to the "fake set", making a duplicate of the JCV's. That is how you are able to see it on a non-asian unit.
But please, read my answer!!!!
I repeat, there is no end-of-list" bit in JCV4. Of course I know what Syzygy patch does!!! ImgTool clearly shows this. The Asian JCV have 4 pictures (in fact 4 jcv2 offset bitstream ) in each JCV4 record.
The first JCV2 offset bitstream is followed by 10000000 (so it is for only for day) , the second is followed by 00000001 (so it is only for night), the third is followed by 10000000 (so it is only for day) and the fourth is followed by 00000001 (so it is only for night).Now we have reached the end of the pointers bitstream (because we now the length of this bitstream: look at your pm)
So there are 2 layers for day and 2 layers for night.
Of course , as these layers are not transparent, only the second layer is visible on the unit.
In original ASIAN JCV, the second layer is always the copyright picture and if you use an ASIAN unit , it will be able to display the first layer instead of the second layer.
Syzygy pathch replaces the pointers to the second layers by the same pointers as for the firs layer. So the JCV4 record always has four pictures: 2 layers for day and 2 layers for night but the second layers are identical to the first layer and so the non-ASIaN unit can also display the wanted picture.
Layer0 - day background
Layer1 - day arrow
Layer2 - day sign
where Layer0,Layer1 and Layer2 formed the day set
Layer0 - night background
Layer1 - night arrow
where Layer0 and Layer1 formed the night set
Note that the number of bitmap in day set is not same as night set.
Now if all you found "so far" is always:
Layer0 - day bitmap/set
Layer1 - night bitmap/set
that is fine; but it doesn't mean that it will always be.
When the number of bitmaps are not same across a set, then the only way to know where the real ones end and the fake ones start is some sort of indication. If there is none, then you can "assumed" that they are evenly distributed: first half is real and second half is fake. But again, it doesn't have to be. Because it's possible to have JCV2 records (in order of storage/display)
bitmap1 - day background
bitmap2 - day arrow
bitmap3 - day sign
bitmap4 - night background
bitmap5 - night arrow
bitmap6 - day copyright <- last day bitmap displayed so it will hide all bitmaps below (iff it doesn't have transparency)
bitmap7 - night copyright <- last night bitmap displayed so it will hide all bitmaps below (iff it doesn't have transparency)
So using the "halves" rule to kludge the display won't be correct.
Osiris4isis: please read what I wrote and don't make me say what I have not said.
Point by point:
I had written "The Asian JCV have 4 pictures" and it is exact (of course other JCV have various combinations of pictures and layers): all the JCV4 records of an Asian JCV contain 4 pictures!!!Why do you assumed that there are always 4 pictures
A layer is stratum in a view: generally (but not always) a junction view is made with several layers.Your used of "layer" terminology is confusing
No, it is not as simple as this: ImgTool builds the junction views using the 8 bits following each JCV2 pointer to determine if the bitmap must be embedded in the view or not. Moreover a layer can be a bitmap (png, jpeg) or a vector layer inside a vector SVG fileImgTool showed each bitmap as a layer (ie: Layer0, Layer1, etc...)
No, I have never said thatBut you referred a layer as a set of bitmaps
????? Why are you writing this???? Have you seen an example? I have never seen this and I would be very surprised that a JCV file should have a number of layers different for night than for day.When the number of bitmaps are not same across a set
Please, read what I wrote: in the pointers bitstream, all the pointers are sequentially read from start to end. Each pointer is followed by 8 bits indicating if the pointed picture is used for day or night or day&night and each following picture is displayed over the previous. There is no fake (maybe we are not using the term "fake" with the same meaning) in the meaning that all the pointers in JCV4 are real and they point to real pictures in JCV2If there is none, then you can "assumed" that they are evenly distributed: first half is real and second half is fake. But again, it doesn't have to be. Because it's possible to have JCV2 records (in order of storage/display)
???????????????? It's Chinese for me (and I don't understand Chinese....)So using the "halves" rule to kludge the display won't be correct.