--- title: "Magnabanner" id: 54993 type: "computer_media" slug: "magnabanner" url: "http://localhost/computer_media/magnabanner/" markdown_url: "http://localhost/computer_media/magnabanner.md" published_at: "2024-06-10T01:44:45+00:00" modified_at: "2026-03-30T21:43:33+00:00" author: "David Anderson" featured_image: url: "http://localhost/wp-content/uploads/2019/02/20230809-041332.jpg" excerpt: "Print giant magnified banner text in four typographic styles using pixel-level font reading, machine code type rendering, and user-selectable fill characters." category: - name: "Archived Media" slug: "archived-media" taxonomy: "category" url: "http://localhost/category/archived-media/" post_tag: - name: "Downloadable" slug: "downloadable" taxonomy: "post_tag" url: "http://localhost/tag/downloadable/" - name: "TS 2068" slug: "ts2068" taxonomy: "post_tag" url: "http://localhost/tag/ts2068/" model: - name: "Timex/Sinclair 2068" slug: "ts-2068" taxonomy: "model" url: "http://localhost/model/ts-2068/" genre: - name: "Banner" slug: "banner" taxonomy: "genre" url: "http://localhost/type/banner/" media_contents: - id: 54964 title: "ISTUG Public Domain Library 6" type: "computer_media" url: "http://localhost/computer_media/istug-public-domain-library-6/" media_type: "Program" mediadate: "198x" images: - url: "http://localhost/wp-content/uploads/2024/06/SCR-20260329-nwfd.png" - url: "http://localhost/wp-content/uploads/2024/06/SCR-20260329-nvze.png" media_type_tags: "Banner" --- # Magnabanner This program generates large, magnified banner text for output to a printer (LPRINT) and screen, supporting four typographic styles: Bold, Modern, Italics, and Regular. It uses an embedded machine code routine, loaded via DATA statements into high memory at address 256*255, to handle the alternate type-style rendering. Characters are magnified by reading each pixel from the system font using the POINT command, then replacing each pixel with a user-selected print character or background character scaled to the chosen size (1–16). The program offers both a standalone “PROGRAMMED BANNER” mode with fixed block-graphic fill characters and an interactive “MAGNABANNER” mode where the user selects size, style, position (top/center/bottom), and fill characters. *** ## Program Analysis ### Program Structure The program is organized into distinct functional blocks, with REM comments acting as section labels: 1. **Lines 1–2:** Initialization — border, memory setup, machine code loading, and mode selection menu. 2. **Lines 3–5:** “Programmed Banner” path — fixed block-graphic characters, loops through a user-supplied message. 3. **Lines 6–9:** Demo loop — cycles through type styles (k=65–68) and sizes (a=1–16) with random fill characters. 4. **Lines 10–16:** Interactive “MAGNABANNER” input — size, style, message, position, print/background characters, plus input validation. 5. **Lines 17–18:** Subroutine — resolves style name to line number via `VAL z$`, computes vertical offset `e` for top/center/bottom positioning. 6. **Lines 19–55:** Core magnification subroutine — builds output strings and LPRINTs each enlarged row. 7. **Lines 60–68:** Helper subroutines — random character selection, type style POKEs. 8. **Lines 70–75:** Variable initialization for type-style line-number dispatch. 9. **Lines 80–90:** Machine code DATA (79 bytes total). 10. **Lines 95–120:** Subroutines for programmed banner initialization, demo C$ and z$ setup. 11. **Line 125:** Demo display helper. ### Machine Code Loader Line 1 clears memory above `256*t - 769` (where `t=255`, giving address 64511) and calls `GO SUB 70` to set `torg=255`. The 79-byte machine code is then POKEd into address `256*torg` (65280). The routine is invoked in line 68 via `RANDOMIZE USR (torg*256+2-typ)`, where `typ` is 0, 1, or 2 depending on style, effectively jumping to different entry points within the routine. Line 68 also sets `POKE 23607,torg-4` to move RAMTOP to protect the code. ### Type Style Dispatch The four type styles are mapped to BASIC line numbers using variables set in line 70: | Style | Variable | Value (line) | | --- | --- | --- | | Regular | `r` / `r1` | 65 | | Bold | `b` / `b1` | 66 | | Modern | `m` / `m1` | 67 | | Italics | `i` / `i1` | 68 | In line 17, `LET z=VAL z$` converts the style string (e.g., `"b1"`) to the numeric line number 66, then `GO SUB z` dispatches to that line. Lines 66–68 POKE system variables to set up the appropriate font transform before calling the machine code via `RANDOMIZE USR`. ### Character Magnification Technique The magnification subroutine (lines 20–55) works as follows: 1. Each character in the message is PRINTed at screen position AT 21,0 (line 21) to render it into display memory using the current font. 2. A double loop over `c=0 TO 7` and `r=0 TO 7` reads each pixel via `POINT (c,r)` (line 35). 3. Set pixels are replaced with the user’s print character string `p$`; clear pixels with background string `g$`, building the enlarged row in `x$`. 4. The resulting string is output via both `LPRINT` and `PRINT`, repeated `v2` times per row to achieve vertical scaling (line 55). The variable `v2` is computed in line 17 as `INT((a/4) + (1 AND a<>4 AND a<>8 AND a<>12 AND a<>16))`, giving the number of character repetitions per pixel row for sizes 1–16. ### Positioning Logic The variable `e` controls how many blank lines are prepended (via `c$`, built in line 19) to position output at the top, center, or bottom of the paper. For sizes below 13, `e` is set to `32 - (v2*8)` for top alignment, then halved for center. Bottom alignment leaves `e=0`. The string version `c$` used in line 100 exploits the Spectrum BASIC boolean string concatenation idiom: `("b" AND c=0)+("c" AND c=1)+("t" AND c=2)` returns the appropriate single-character string. ### Notable BASIC Idioms - **Boolean string selection:** Lines 100 and 115 use the `("string" AND condition)` idiom, where a false condition yields `""` and true yields the string, then concatenates the three results to select one value. - **VAL for computed GO SUB:**`LET z=VAL z$: GO SUB z` in line 17 computes the target line number at runtime from the style string, a recognized memory-saving dispatch technique. - **POKE 23692,0 / POKE 23693:** Line 21 saves and restores the ATTR P system variable around the temporary character print, preserving the screen attribute state. - **p$ and g$ string growth:** Lines 19 and later repeat the single print/background character `v2` times by concatenation in a loop, scaling the fill strings to match the magnification factor. ### Bugs and Anomalies - **Line 6 dead code:**`BEEP 1,-10: PAUSE 100` follows `GO TO 2` and is unreachable. - **Line 5 conflict:** Line 5 contains both `NEXT x: GO TO 2` (continuation of the programmed banner loop from lines 3–5) and the REM comment, but is also the target of the input-error `GO TO 5` in line 15. An invalid input will branch into the middle of the programmed banner loop rather than re-prompting — likely unintentional. - **DATA line 80 references `torg`:** The DATA statement at line 80 includes `torg-3` as the last value, which is a BASIC expression evaluated at READ time (not a literal), so it correctly resolves to 252 at runtime. - **Case inconsistency in validation:** Line 15 checks `C$<>"T"` (uppercase C$) while all other references use `c$`; since BASIC variables are case-sensitive on this platform, this effectively makes uppercase “T” always pass the check regardless of the actual value of `c$`. - **Line 23 incomplete REM:** The REM on line 23 is a truncated comment (`REM x$="THE VARIABLE CHARACTER IS STORED IN`) without a closing quote, which is syntactically valid as a REM but suggests editing truncation. ## Source Code ``` 1 BORDER 0: POKE 23624,6: LET t=255: CLEAR (256*t-769): GO SUB 70: FOR i=0 TO 79: READ h: POKE (i+256*torg),h: NEXT i: POKE 23296,0: REM MACHINE CODE LOADER 2 POKE 23658,8: POKE 23609,50: CLS : PRINT INK 2;AT 8,5;" S E L E C T T Y P E "''': PRINT TAB 5;"MAGNABANNER ......... M";''TAB 5;"PROGRAMMED BANNER ... P": INPUT "SELECT M / P :";i$: IF i$="P" THEN GO TO 10 3 GO SUB 95: GO SUB 17: INPUT "MESSAGE ";Z$: LET s=LEN Z$: FOR x=1 TO s: LET p$="\':": LET g$="\:.": LET a$=z$(x): GO SUB 19: LPRINT y$: IF x=s THEN GO TO 2: IF INKEY$<>"" THEN STOP 5 NEXT x: GO TO 2: REM LINES 3-5 PRINT PROGRAMMED TITLE BANNER 6 GO TO 2: BEEP 1,-10: PAUSE 100: FOR k=65 TO 68: FOR a=1 TO 16: GO SUB 125: LET a$=STR$ a: POKE 23692,0: GO SUB 60: IF INKEY$<>"" THEN GO TO 9: REM LINES 6-9 ARE THE DEMO 7 IF a>12 THEN LET c=0: LET c$="" 8 LET c=0: LET e=0: GO SUB 115: GO SUB 17: GO SUB 19: LPRINT a: PRINT a: PAUSE 200: NEXT a: NEXT k 9 IF INKEY$="" THEN GO TO 6: REM LINES 10-17 ARE THE MAIN PROGRAM 10 POKE 23607,60: INPUT "SIZE? (1-16) ";a 11 INPUT "ENTER TYPE THAT YOU WANT (BOLD,MODERN,ITALICS,REGULAR) ";z$: LET z$=z$+"1" 12 INPUT "ENTER YOUR MESSAGE ";a$ 13 INPUT "DO YOU WANT YOUR MESSAGE IN THE CENTER OF THE PAPER,IN THE TOP OF THE PAPER OR THE BOTTOM OF THE PAPER? ";c$ 14 INPUT "ENTER PRINT CHARACTER ";p$: INPUT "ENTER BACKGROUND CHARACTER ";G$ 15 IF a$="" OR g$="" OR p$="" OR a<1 OR a>16 OR (c$<>"c" AND c$<>"C" AND c$<>"t" AND C$<>"T" AND c$<>"b" AND c$<>"B") OR (z$<>"B1" AND z$<>"b1" AND z$<>"M1" AND z$<>"m1" AND z$<>"I1" AND z$<>"i1" AND z$<>"R1" AND z$<>"r1") THEN GO TO 5: REM CHECK FOR INPUT ERRORS 16 GO SUB 17: GO SUB 19: GO TO 10 17 LET z=VAL z$: GO SUB z: CLS : POKE 23692,0: LET v2=INT ((a/4)+(1 AND a<>4 AND a<>8 AND a<>12 AND a<>16)): IF (c$<>"b" AND c$<>"B") AND a<13 THEN LET e=32-(v2*8): IF (c$="c" OR c$="C") AND a<13 THEN LET e=e-(e/2) 18 RETURN 19 LET c$="": FOR d=1 TO e: LET c$=c$+" ": NEXT d: LET h$=g$(1): LET q$=p$(1): FOR v=1 TO v2-1: LET g$=g$+h$: LET p$=p$+q$: NEXT v 20 FOR j=1 TO LEN a$: REM LINES 19-45 ARE THE MAGNIFY SUB 21 LET co=PEEK 23693: POKE 23693,INT (co/8)*8: PRINT AT 21,0;a$(j): LET x$="": POKE 23693,co 23 REM x$="THE VARIABLE CHARACTER IS STORED IN 30 FOR c=0 TO 7: FOR r=0 TO 7 35 IF POINT (c,r)=1 THEN LET x$=x$+p$: GO TO 45 40 LET x$=x$+g$ 45 NEXT r: NEXT c: PRINT AT 0,0; 47 REM PRINT SUB 50 LET n2=v2*4+1: LET s=v2*8: LET g2=v2*64: LET g3=s-1: REM SETS VARIABLES FOR PRINTING 55 FOR g=1 TO g2 STEP s: FOR n=1 TO n2-a: LPRINT c$;x$(g TO g+g3): PRINT c$;x$(g TO g+g3): NEXT n: NEXT g: NEXT j: RETURN 57 REM RANDOM BACKGROUND & PRINT CHARACTERS FOR THE DEMO 60 RANDOMIZE 0: LET c=INT (RND*3): GO SUB 100: LET g=INT (RND*26): LET g$=CHR$ (g+32): LET p$=CHR$ (g+64): RETURN 63 REM EXTRA TYPE STYLE SUBS (FROM AUGUST ISSUE RAMTOP MODIFIED) 65 POKE 23607,60: RETURN 66 LET typ=2: POKE 23618,68: POKE 23619,0: POKE 23620,2 67 LET typ=1: POKE 23618,68: POKE 23619,0: POKE 23620,2 68 LET typ=0: RANDOMIZE USR (torg*256+2-typ): POKE 23607,torg-4: RETURN 70 LET torg=255: LET r=65: LET r1=r: LET b=66: LET b1=b: LET m=67: LET m1=m: LET i=68: LET i1=i: REM VARIABLES FOR TYPE STYLELINE NUMBERS 75 RETURN 80 DATA 0,0,121,203,39,203,39,50,21,255,33,0,61,17,0,torg-3 90 DATA 1,0,3,126,24,48,203,63,24,44,230,112,24,37,121,230,7,203,39,50,40,255,126,24,30,24,28,24,16,24,14,24,14,24,20,24,18,24,2,200,63,203,63,24,10,203,39,203,39,24,4,183,203,39,182,18,35,19,11,120,177,32,196,201 93 REM MACHINE CODE FOR EXTRA TYPE STYLES 95 LET c$="": LET e=0: LET z$="b1": LET j$="\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':\':": LET y$="\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.\:.": LET a=15: RETURN : REM INITIALIZE PRORAMMED BANNER VARIABLES 97 REM C$=WHETHER TO PRINT ON THE BOTTOM,THE TOP OR THE CENTER OF THE PAPER 100 LET C$=("b" AND c=0)+("c" AND c=1)+("t" AND c=2) 105 RETURN : REM SET C$ FOR THE DEMO 110 REM k=WHETHER TO HAVE BOLD,MODERN,ITALICS OR REGULAR PRINT FOR THE DEMO 115 LET z$=("r1" AND k=65)+("b1" AND k=66)+("m1" AND k=67)+("i1" AND k=68) 120 RETURN : REM SET K FOR THE DEMO 125 GO SUB b1: PRINT #1;AT 0,14;"DEMO": GO SUB r1: RETURN 9998 SAVE "MAGNABANER" LINE 1: REM VERIFY "" ```