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https://github.com/PDP-10/its.git
synced 2026-04-19 01:18:29 +00:00
C library for TV raster graphics.
This commit is contained in:
Lars Brinkhoff
@@ -1353,6 +1353,11 @@ expect ":KILL"
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respond "*" ":testc\r"
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expect "Done."
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# C library for drawing on a TV display.
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respond "*" ":cwd clib\r"
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respond "*" ":cc tv.>\r"
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expect ":KILL"
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# TJ6
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respond "*" ":midas sysbin;_tj6;tj6\r"
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expect ":KILL"
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436
src/clib/tv.128
Normal file
436
src/clib/tv.128
Normal file
@@ -0,0 +1,436 @@
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/*
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TV Package for doing graphics on Knight TV's
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tvopen() Map PDP-10 memory onto PDP-11 memory.
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A pointer to the beginning of the TV array is
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returned, but this pointer may be ignored by
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the caller, since the package uses its own copy
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of the TV array pointer. A return code of 0
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indicates failure.
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tvclose() Undo the mapping and release the memory used
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by the TV array. No value is returned and no
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action is taken if the TV is not open.
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tvmode(mode) Change the mode by which updates to the TV
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buffer are affected. Useful modes are defined
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as macro variables below. The previous mode is
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returned.
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tvclear() Clear the screen. The cursor is moved to the
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lower left corner of the screen. The request is
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ignored if the TV is not open and no value is
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returned.
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tvbase() Return the value of the TV pointer. The TV pointer
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is always 0 if the TV memory is not mapped into
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the program address space.
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tvsetup() Open TV, clear the screen, and set the TV mode
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to inclusive-OR mode. A pointer to the TV buffer
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is returned or 0 if the TV could not be opened.
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tvwrite(line, word, data)
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Write the 32 rightmost bits of the supplied data
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to the indicated line and word of the TV buffer.
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If necessary, the TV is opened and the mode is
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changed to SET mode. The routine checks for out
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of bounds line and word arguments. Returns 1,
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unless the write could not be performed.
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point(x, y) Draw dot at the raster point (x, y). Returns
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0 if the point was not on the screen or the TV
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could not be opened, otherwise returns 1.
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testp(x, y) Returns 1, if the indicated point is set,
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0, if the indicated point is clear, and
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-1, if the indicated point is off the screen or
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if the TV could not be opened.
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line(x0, 01, y1, y1)
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Draw a line from (x0, y0) to (x1, y1). Returns
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0 is either point is off the screen or if the TV
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mapping could not be established, otherwise
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returns 1.
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connect(x, y) Draws a line from the last point drawn to the
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indicated point. Returns 1, if the new point lies
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on the screen and the line could be drawn, 0 otherwise.
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move(x, y) Move to (x, y) without drawing anything. It
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does not open the TV if it is closed. Move
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returns 0 if the point is off of the screen, and
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returns 1 otherwise.
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circle(x, y, r) Draw a circle of radius r, centered at (x, y).
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Returns 1, if the circle is inside the screen and
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was successfully drawn, otherwise returns 0.
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Note that in all cases, the specified operation will not be performed if
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it would result in movement off of the screen. All of the drawing
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functions test to see if the TV has been opened and if it has not been
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opened, open it by calling tvsetup(). So if the user starts drawing on
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the TV display, then the TV will be opened, the screen will be cleared,
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and the TV display will be in inclusive-OR mode so that overlapping
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lines will not erase one another. The routine testp is the only
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plotting function that does not return 0 if the point is off of the
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screen or the TV could not be opened. The routine tvwrite uses a
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default mode of SET, since that is advantageous for dumping images on
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the screen.
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For information on the algorithms used in this graphics package,
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consult
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B. K. P. Horn, "Circle Generators for Display Devices",
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Computer Graphics and Image Processing 5, 280-288 (1976).
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*/
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/*Useful TV modes. */
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#define TVAND 013 /* AND mode */
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#define TVXOR 006 /* Exclusive OR mode */
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#define TVIOR 016 /* Inclusive OR mode */
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#define TVEQV 011 /* Equivalence mode */
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#define TVSET 017 /* Set bits regardless of previous value */
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#define TVANDC 002 /* AND the complement of the new value
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with the old value */
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#define TVSETZ 003 /* Set the TV word to zero */
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#define TVCOMP 005 /* Complement the TV word */
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#define TVSAME 012 /* Do nothing */
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#define TVSETO 014 /* Set the TV word to all one's */
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#define NP 9 /* Number of pages in PDP-11 address space */
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#define RW 0600000 /* Read/write access to mapped pages */
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#define MAXLINE 453 /* Number of the highest usable raster line */
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#define MAXBIT 575 /* Number of highest raster bit */
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#define MAXWORD 17 /* Number of the highest 36 bit word
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in a TV line */
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/* Macro for consing up an AOBJN pointer for use in the CORBLK call */
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#define AOBJNPTR(cnt,addr) (-(cnt)<<18 | ((addr) & 0777777))
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/* Macro to test for point inside raster */
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#define ONSCREEN(x, y) (x >= 0 && x <= MAXBIT && y >= 0 && y <= MAXLINE)
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#macro PUTDOT(tvline, bit) /* Macro for setting a bit in the TV raster */
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((*tv)[tvline][(bit)/32] = 1 << (35 - ((bit) % 32)))
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#end
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#macro TESTDOT(tvline, bit) /* Macro for testing a bit in the TV raster */
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((*tv)[tvline][(bit)/32] & ~(1 << (35 - ((bit) % 32))))
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#end
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/* Macro for outputting a 32 bit word */
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#macro PUTWORD(tvline, word, mask, offset)
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((*tv)[tvline][word] = mask << (4 + offset))
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#end
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#macro SWAP(x, y) /* Swap two variables */
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{int temporary;
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temporary = x;
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x = y;
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y = temporary; }
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#end
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extern int cerr; /* All error messages to standard error output */
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typedef int TVBUFFER[455][18]; /* Structure of TV buffer memory */
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static TVBUFFER *tv 0; /* Pointer to beginning of TV buffer */
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tvopen() {
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int tvpage, rc;
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if(tv != 0) return(tv);
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if((tvpage = pg_get(NP)) <= 0) {
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cprint(cerr, "TVOPEN: Cannot get enough pages\n");
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return(0);
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};
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if((rc = corblk(RW,-1,AOBJNPTR(NP,tvpage),-2,0)) < 0) {
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cprint(cerr, "TVOPEN: Corblk failure code %o\n", -rc);
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return(0);
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};
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return(tv = tvpage << 10);
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}
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tvclose() {
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int temp;
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if(tv) {
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pg_ret((temp = tv) >> 10, NP);
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tv = 0;
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};
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}
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tvmode(mode)
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int mode; {
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int newmode;
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static int oldmode TVSET;
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if(tv == 0) return(oldmode);
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(*tv)[455][2] = (mode << 28) | (newmode = (*tv)[455][2] & (07777777 << 4));
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mode = oldmode;
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oldmode = (newmode >> 28) & 0377;
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return(mode);
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}
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#define TVBUFFERSIZE (453 * 18) /* Number of writeable words in the TV buffer */
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tvclear() {
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int oldmode, *ptr, word;
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if(tv == 0) return;
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oldmode = tvmode(TVSET);
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for(ptr = tv, word = 0; word < TVBUFFERSIZE; word++)
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*(ptr++) = 0;
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spctty('Z'); /* Move to lower left corner */
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tvmode(oldmode); /* Restore old TV mode */
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}
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tvbase() { return(tv); }
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tvsetup() {
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if(tv == 0)
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if(tvopen() == 0) return(0);
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tvclear();
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tvmode(TVIOR);
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return(tv);
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}
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tvwrite(line, word, bits)
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int line, word, bits; {
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if(tv == 0)
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if(tvopen() == 0) return(0);
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if(line < 0 || line > MAXLINE || word < 0 || word > MAXWORD)
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return(0);
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PUTWORD(line, word, bits, 0);
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}
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static int oldx, oldy; /* Endpoints of last line drawn */
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point(x, y)
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int x, y; {
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if(tv == 0)
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if(tvsetup() == 0) return(0);
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if(ONSCREEN(x, y)) {
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PUTDOT(MAXLINE - y, x);
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return(1);
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}
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else return(0);
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}
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testp(x, y)
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int x,y; {
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if(tv == 0)
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if(tvsetup() == 0) return(-1);
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if(ONSCREEN(x, y)) return(TESTDOT(MAXLINE - y, x));
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else return(-1);
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}
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static int swapxy, negatex, negatey; /* Flags for line and circle drawing */
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static int xcenter, ycenter;
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line(x0, y0, x1, y1)
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int x0, y0, x1, y1; {
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int a, b, s, x, y;
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if(tv == 0)
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if(tvsetup() == 0) return(0);
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if(!(ONSCREEN(x0, y0) && ONSCREEN(x1, y1))) return(0);
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oldx = x1; /* Save endpoints for use by connect */
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oldy = y1;
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negatex = negatey = swapxy = 0;
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a = x1 - x0; /* Compute slope parameters */
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b = y1 - y0;
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if(a == 0) {vertline(x0,y0,y1); return(1);} /* Look for easy cases */
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if(b == 0) {hortline(x0,y0,x1); return(1);}
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if(a < 0) {a = -a; negatex = 1;} /* Reduce problem to first quadrant */
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if(b < 0) {b = -b; negatey = 1;}
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if(a < b) {SWAP(a,b); swapxy = 1;} /* Reduce problem to first octant */
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xcenter = x0;
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ycenter = y0;
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for(x = y = 0, s = -a/2; x <= a; x++) {
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plotdot(x,y);
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if((s =+ b) > 0) {s =- a; y++;}
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}
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return(1);
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}
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static int mask[] { /* Table of masks */
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01, 03, 07, 017, 037, 077, 0177, 0377, 0777,
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01777, 03777, 07777, 017777, 037777, 077777,
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0177777, 0377777, 0777777, 01777777, 03777777, 07777777,
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017777777, 037777777, 077777777,
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0177777777, 0377777777, 0777777777,
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01777777777, 03777777777, 07777777777,
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017777777777, 037777777777 };
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hortline(x, y, x2) /* Draw horizontal line from x to x2 */
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int x, x2, y; {
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int first, last, tvline;
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if(tv == 0)
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if(tvsetup() == 0) return(0);
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if(x > x2) SWAP(x, x2);
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tvline = MAXLINE - y; /* Compute line number */
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first = x/32; /* Compute range of words affected */
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last = x2/32;
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if(first == last) {
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PUTWORD(tvline, first, mask[x2 - x], 31 - (x2 % 32));
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}
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else {
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PUTWORD(tvline, first, mask[31 - (x % 32)], 0);
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PUTWORD(tvline, last, mask[x2 % 32], 31 - (x2 % 32));
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for(first++; first < last; first++)
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PUTWORD(tvline, first, mask[31], 0);
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};
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return(1);
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}
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vertline(x, y, y2) /* Draw vertical line from y to y2 */
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int x, y, y2; {
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int bitmask, word;
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if(tv == 0)
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if(tvsetup() == 0) return(0);
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if(y > y2) SWAP(y, y2);
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bitmask = 1 << (35 - (x % 32));
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word = x/32;
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for(; y <= y2; y++)
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(*tv)[MAXLINE - y][word] = bitmask;
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return(1);
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}
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connect(x, y)
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int x, y; {
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return(line(oldx, oldy, x, y));
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}
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move(x, y)
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int x, y; {
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if(!ONSCREEN(x, y)) return(0);
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oldx = x;
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oldy = y;
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return(1);
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}
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circle(x, y, r)
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int x, y, r; {
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if(tv == 0)
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if(tvsetup() == 0) return(0);
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if(x + r > MAXBIT || x - r < 0 || y + r > MAXLINE || y - r < 0)
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return(0);
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xcenter = x;
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ycenter = y;
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for(negatex = 0; negatex < 2; negatex++)
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for(negatey = 0; negatey < 2; negatey++)
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for(swapxy = 0; swapxy < 2; swapxy++)
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sector(r);
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return(1);
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}
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sector(r) /* Draw one octant of circle */
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int r; {
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int x, y, s;
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x = r;
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y = 0;
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s = -r;
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while(y <= x) {
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plotdot(x, y);
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s =+ 2 * (y++) + 1;
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if(s > 0) s =- 2 * (x--);
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};
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}
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plotdot(x, y)
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int x, y; {
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if(swapxy) SWAP(x, y);
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if(negatex) x = -x;
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if(negatey) y = -y;
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PUTDOT(MAXLINE - ycenter - y, xcenter + x);
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}
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#ifdef DEBUG
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main() { /* For testing the graphics routines */
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int x0, y0, offset, radius;
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x0 = y0 = 250;
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tvopen();
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tvclear();
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tvmode(TVIOR);
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for(radius = 200; radius > 20; radius =- 50)
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circle(x0, y0, radius);
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for(offset = -200; offset < 200; offset =+ 20) {
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if(line(x0 - offset, y0 + 200, x0 + offset, y0 - 200) == 0)
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cprint("First line write failed, offset %d\n", offset);
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if(line(x0 - 200, y0 - offset, x0 + 200, y0 + offset) == 0)
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cprint("Second line write failed, offset %d\n", offset);
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};
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valret(""); /* Avoid :KILL */
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}
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#endif
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