UDG designer

[Moggy]

This is the part that's throwing me...

"NOTE for 128 char mode.
To obtain 128 unique characters on a ZX81 the inverted characters are replaced with a second set of 64 characters HOWEVER.... the ZX81 hardware will still invert these characters so what is stored in the character maps is actually the inverse of what will be displayed. "

In reality the UDG's remain unique and the zx81 doesn't automatically invert anything at all from a program perspective, what I design is what I get not its inverse as the text suggests.





So if I read this right ...

I choose the first chr in the 64 range , a blank square. I change this into say a letter p with a funny shape so I know what's what.
If I ask my program to print that letter p using graphics key the zeddy will print my funny shaped p inverted?

But it doesn't stop me from creating 128 unique UDG's that wont be inverted automatically?
In other words if I make the second set into 64 letter "X"'s black on white that's what I'll get but if I use only the FIRST 64 UDG's they are the ones that get inverted in the second set.

The impression I was getting was that no matter what I created in the second set it would be inverted by default because that's how the zeddy works.


Explaining's not my strong point either.


Cracking designer though Andy by the way.

[Andy Rea]

I'm confused now...

Make a completely blank char say character number 0.... the 8 bytes are all 0 to represent an all blank char...

Now make anothrt completely blank char say character 128... the 8 bytes are all 255 which would normally be an all black char but because the zeddy hardware inverts in it will display as we want all white...

Anyway the editor is WYSIWYG so it matters not how it works as long as you get the characters you expect...

Regards andy

[Moggy]

Understood Andy and I have grasped what you're saying but the text does suggest that the replacement 64 UDG's in the second set will still be inverted in use, at least that's how it reads to me.

"NOTE for 128 char mode.
To obtain 128 unique characters on a ZX81 the inverted characters are replaced with a second set of 64 characters HOWEVER.... the ZX81 will still invert these characters so what is stored in the character maps is actually the inverse of what will be displayed."

I do get it that I can have 128 UDG's of what ever shade I want with no automatic inversion whatsoever.

The byte values are meaningless to a dolt like me only the end result.

If I make the first 64 UDG's letter "X" s black on white then in the second set 64 letter "Y" s black on white then that is what I'll get not 64 inverted letter "Y" s as the text implies about this replaced set.

[1024MAK]

From a user perspective, what the hardware does after the user has designed the new characters using the USB Designer program does not matter at all.

However, there should be a note to say that the hardware inverts the data bytes used to form character patterns for characters 65 to 128. The USB Designer program automatically adjusts the data for these characters, but that if you use other programs or copy data between character sets in your own program, you should be aware of this hardware limitation.

Incidentally, what do we mean by invert? Well first let's explain that each horizontal character line is eight pixels long, which is eight binary digits (bits), which makes one byte. For characters 65 to 128, the hardware changes any white pixels to black, and any black pixels to white. Because this is stored as a binary pattern in one byte, the logical operation in digital logic to change a binary number in this way is called inverting the number.

Mark

[Moggy]

From a user perspective, what the hardware does after the user has designed the new characters using the USB Designer program does not matter at all.

However, there should be a note to say that the hardware inverts the data bytes used to form character patterns for characters 65 to 128. The USB Designer program automatically adjusts the data for these characters, but that if you use other programs or copy data between character sets in your own program, you should be aware of this hardware limitation.

Incidentally, what do we mean by invert? Well first let's explain that each horizontal character line is eight pixels long, which is eight binary digits (bits), which makes one byte. For characters 65 to 128, the hardware changes any white pixels to black, and any black pixels to white. Because this is stored as a binary pattern in one byte, the logical operation in digital logic to change a binary number in this way is called inverting the number.

Mark

You'll have to bare with me because as I've explained many times before I'm not the brightest one here.

When you say "The hardware changes any white pixel to black etc" What hardware the zeddy or the UDG board?

I grasp that in 64 mode the second set of UDG's are the inverse of the first 64 so what you are saying can only apply to this mode, but in 128 mode I can make the UDG's 65-128 any thing I want and they stay that way and do not get inverted by any hardware.

In other words this "inversion" "white to black or black to white" call it what you will doesn't occur in 128 mode.

Sorry for being dense but as I'm reading it what ever I create in the set 65-128 it will be inverted because...

QUOTE
"However, there should be a note to say that the hardware inverts the data bytes used to form character patterns for characters 65 to 128. The USB Designer program automatically adjusts the data for these characters, but that if you use other programs or copy data between character sets in your own program, you should be aware of this hardware limitation."


All I know is at the end of the day I can create 128 unique UDG's that stay as they are un-inverted by any hardware and can use as I see fit so cannot see any limitation.

Again apologies for my lack of understanding

[Andy Rea]

You'll have to bare with me because as I've explained many times before I'm not the brightest one here.

When you say "The hardware changes any white pixel to black etc" What hardware the zeddy or the UDG board?

The ZEDDY does the inversion in the same way as it does for an unexpanded zeddy.

I grasp that in 64 mode the second set of UDG's are the inverse of the first 64 so what you are saying can only apply to this mode, but in 128 mode I can make the UDG's 65-128 128-191 any thing I want and they stay that way and do not get inverted by any hardware.

In other words this "inversion" "white to black or black to white" call it what you will doesn't occur in 128 mode.

yes it does BUT the editor i wrote deliberatly shows you the end result in an effort to make this inversion transparent.

each single row of a character is represented by 8 binary bits or a decimal number 0 to 255, normally 0 is all white and 255 is all black, for characters 128-191 all white is stored as 255 and all black stored as 0, the edit window should also have the word "inverted" above it to remind you that what you are actually seeing is what the resulting character will look like, and is the inverse of the values stored.

Sorry for being dense but as I'm reading it what ever I create in the set 65-128 128-191 it will be inverted because...

QUOTE
"However, there should be a note to say that the hardware inverts the data bytes used to form character patterns for characters 65 to 128. The USB Designer program automatically adjusts the data for these characters, but that if you use other programs or copy data between character sets in your own program, you should be aware of this hardware limitation."


All I know is at the end of the day I can create 128 unique UDG's that stay as they are un-inverted by any hardware and can use as I see fit so cannot see any limitation.

Because i wrote the editor in such a way as the end user wouldn't have to worry about the technicalities.

Again apologies for my lack of understanding

Regards Andy

[Moggy]

AAAGGGHHHHHH the penny finally drops!!

I've got the count wrong (128-191 not 65-128) I've been looking at the wrong UDG's!
What a sodding plonker I am.

Thanks for baring with me Andy,this what happens when your a bit thick like I is.

Also I'm liking version 2 of the designer with the SHIFT-R jobby.When I've made a cock up of a UDG or a set I can now just go back to default and start again, top marks for that one.

Thanks again Andy it is certainly appreciated by this end user.

Moggy.

[mrtinb]

Word Sinc II.3 which has support for printing lower case chars on Alphacom 32, can with UDG show lower case on the screen as well. Even control chars are shown with UDG.


P.S. Just tried ZxPand support in EightyOne. That is great hardware.

[Andy Rea]

Hi Martin.... where in the world internet can i get a copy of this word sinc ?

regards Andy

[mrtinb]

Word Sinc II.3 Can be found in this thread.

The UDG-font is one I made tonight. I can't upload it from my phone, so you'll have to wait for that for tomorrow.

Unfortunately I can't find anyone who has uploaded the manual for Word Sinc, so I've learned a bit with trial and error.