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#Apple ]\[ HGR Font Tutorial
#Apple ]\[ //e HGR Font 6502 Assembly Language Tutorial
Revision: 34, Jan 14, 2016.
Revision: 35, Jan 14, 2016.
# Table of Contents
@ -31,11 +31,13 @@ Revision: 34, Jan 14, 2016.
* Y Cursor Position
* Natural Params SetCursorColRow()
* DrawString()
* Recap
* Copy text screen to HGR
* Exercises
* Exercise 1: ScrollHgrUpLine()
* Exercise 2: ScrollHgrUpPixel()
* Recap
* Conclusion
* Solutions
* Solution 1: ScrollHgrUpLine()
* Solution 2: ScrollHgrUpPixel()
* References
@ -1872,46 +1874,6 @@ Note: An easy way to get the hex bytes for a string is to use this tiny JavaScri
```
# Recap
Here are all the routines we've entered in so far:
0301: 48 6A 6A 6A 6A 20 0A
0308:03 68 29 0F AA BD 90 03
0310:4C 3A 03 BD A0 03 85 F5
0318:BD B8 03 18 65 E6 85 F6
0320:60 86 F5 B9 A0 03 18 65
0328:F5 85 F5 B9 B8 03 18 65
0330:E6 85 F6 60 EA 48 20 13
0338:03 68 2A 2A 2A AA 29 F8
0340:8D 53 03 8A 29 03 2A 69
0348:60 8D 54 03 A6 F6 86 FD
0350:A2 00 BD 00 00 91 F5 18
0358:A5 F6 69 04 85 F6 E8 E0
0360:08 D0 EF C8 A6 FD 86 F6
0368:60
0390:30 31 32 33 34 35 36 37
0398:38 39 41 42 43 44 45 46
03A0:00 80 00 80 00 80 00 80
03A8:28 A8 28 A8 28 A8 28 A8
03B0:50 D0 50 D0 50 D0 50 D0
03B8:00 00 01 01 02 02 03 03
03C0:00 00 01 01 02 02 03 03
03C8:00 00 01 01 02 02 03 03
(To save this: `BSAVE CODE_0300.BIN,A$300,L$D0`)
What's left? Quite a few things actually:
* Copy the 40-Column text screen to HGR
* Scroll the HGR screen up by 1 pixel
* Copy the 80-Column text screen to DHGR (Double High Resolution)
* Hook into the COUT so all text appears onto the HGR or DHGR screen
Let's implement those first two.
## Copy text screen to HGR
For our final trick we are going to copy the characters off the text screen onto the HGR screen. More magic? Nah, just bit-shuffling.
@ -2097,6 +2059,8 @@ And to restore the bottom 4 text rows
C053
# Exercises
## Exercise 1: ScrollHgrUpPixel()
Hey! Homework? Yes, the only (true) way to demonstrate you understand the theory is with implementation:
@ -2125,21 +2089,60 @@ Hey! Homework? Yes, the only (true) way to demonstrate you understand the theo
very bottom scanline should be "blank."
# Recap
Here are all the (core) routines we've entered in so far:
0301: 48 6A 6A 6A 6A 20 0A
0308:03 68 29 0F AA BD 90 03
0310:4C 3A 03 BD A0 03 85 F5
0318:BD B8 03 18 65 E6 85 F6
0320:60 86 F5 B9 A0 03 18 65
0328:F5 85 F5 B9 B8 03 18 65
0330:E6 85 F6 60 EA 48 20 13
0338:03 68 2A 2A 2A AA 29 F8
0340:8D 53 03 8A 29 03 2A 69
0348:60 8D 54 03 A6 F6 86 FD
0350:A2 00 BD 00 00 91 F5 18
0358:A5 F6 69 04 85 F6 E8 E0
0360:08 D0 EF C8 A6 FD 86 F6
0368:60
0390:30 31 32 33 34 35 36 37
0398:38 39 41 42 43 44 45 46
03A0:00 80 00 80 00 80 00 80
03A8:28 A8 28 A8 28 A8 28 A8
03B0:50 D0 50 D0 50 D0 50 D0
03B8:00 00 01 01 02 02 03 03
03C0:00 00 01 01 02 02 03 03
03C8:00 00 01 01 02 02 03 03
(To save this: `BSAVE CODE_0300.BIN,A$300,L$D0`)
What's left? Quite a few things actually:
* Copy the 80-Column text screen to DHGR (Double High Resolution)
* Hook into the COUT so all text appears onto the HGR or DHGR screen
* Other 7x8 fonts
* Other non-7x8 fonts
## Conclusion
Hope this HGR font tutorial helped you understand the inner workings of a font blitter!
Happy (Apple ]\[ //e //c) Hacking!
Michael "AppleWin Debug Dev"
# Solutions
## Solution 1: ScrollHgrUpLine()
Figure it out ! You have all the tools and knowledge.
## Solution 2: ScrollHgrUpPixel()
There are many different ways to solve this depending if we want to prioritize space or speed.