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1.1     ! root        1: .bp
        !             2: .SH
        !             3: Appendix A - Example X Programs
        !             4: .XS
        !             5: Appendix A - Example X Programs
        !             6: .XE
        !             7: .SH
        !             8: Xrefresh - Refresh the Entire Screen.
        !             9: .PP
        !            10: .IN "Example Programs" "xrefresh"
        !            11: The following program (\fIxrefresh\fP) is the simplest X application to date.
        !            12: It is useful if your screen has gotten trashed,
        !            13: either by a program error
        !            14: (for example, using the \fIRootWindow\fP when you didn't mean to),
        !            15: or by the system putting messages out underneath you.
        !            16: .IN "Examples of Use" "XOpenDisplay"
        !            17: .IN "Examples of Use" "XCreateWindow"
        !            18: .IN "Examples of Use" "XMapWindow"
        !            19: .IN "Examples of Use" "XDestroyWindow"
        !            20: .IN "Examples of Use" "XFlush"
        !            21: .nf
        !            22: .DS
        !            23: .TA .5i 3i
        !            24: .ta .5i 3i
        !            25: .cs R36
        !            26: #include <X/Xlib.h>
        !            27: #include <stdio.h>
        !            28: /*
        !            29:  * Copyright 1985, Massachusetts Institute of Technology.
        !            30:  * This program just throws up a window over the whole screen, causing
        !            31:  * exposure events to be generated on all windows.  This may be useful
        !            32:  * to cause the whole screen to be repainted when it has somehow gotten
        !            33:  * trashed.
        !            34:  */
        !            35: 
        !            36: main(argc, argv)
        !            37: int argc;
        !            38: char **argv;
        !            39: {
        !            40:        Window w;
        !            41: 
        !            42:        if (XOpenDisplay(argc ? argv[1] : "\\0") == NULL) 
        !            43:                fprintf (stderr, "Could not open Display!\\n");
        !            44: 
        !            45: .IN "Examples of Use" "DisplayWidth"
        !            46: .IN "Examples of Use" "DisplayHeight"
        !            47: .IN "Examples of Use" "BlackPixmap" 
        !            48:        w = XCreateWindow(RootWindow, 0, 0, DisplayWidth(), DisplayHeight(),
        !            49:                0, (Pixmap) 0, (Pixmap) 0);
        !            50:        XMapWindow(w);                  /* put it up on the screen      */
        !            51:        XDestroyWindow(w);              /* throw it away                */
        !            52: 
        !            53:        XFlush();                       /* and make sure the server sees it*/
        !            54: }
        !            55: .cs R
        !            56: .DE
        !            57: .fi
        !            58: .PP
        !            59: In short, \fIxrefresh\fP connects to the display, creates a window with a black
        !            60: background and zero width border over the root window, maps it to
        !            61: the screen, and destroys the window.
        !            62: The side effects of this will be to send exposure events to the client programs
        !            63: who have selected exposure events on all mapped unobscured windows.
        !            64: This causes most clients to repaint their windows.
        !            65: The call to \fIXFlush\fP is necessary since no input call occurs after the
        !            66: \fIXDestroyWindow\fP call to flush the output buffer.
        !            67: Since the background pixmap is 0, the window will be covered with the
        !            68: background pixmap, for a pleasing effect.
        !            69: The most common X programming mistake is to forget to flush the
        !            70: output buffer when first experimenting with X.
        !            71: .SH
        !            72: Xfd - Display a Font in a Window
        !            73: .IN "Example Programs" "xrefresh"
        !            74: .PP
        !            75: The following program is more ambitious, as it parses many
        !            76: arguments and defaults before creating a simple window to paint text in.
        !            77: .nf
        !            78: .DS
        !            79: .TA .5i 1i 1.5i 2i 2.5i 3i 3.5i 4i 4.5i 5i 5.5i 6i 6.5i 7i 7.5i 8i
        !            80: .ta .5i 1i 1.5i 2i 2.5i 3i 3.5i 4i 4.5i 5i 5.5i 6i 6.5i 7i 7.5i 8i
        !            81: .cs R36
        !            82: /* Copyright 1985, Massachusetts Institute of Technology */
        !            83: #include <Xlib/Xlib.h>
        !            84: #include <stdio.h>
        !            85: #include <strings.h>
        !            86: 
        !            87: short gray_bits[16] = {
        !            88:     0xaaaa, 0x5555, 0xaaaa, 0x5555,
        !            89:     0xaaaa, 0x5555, 0xaaaa, 0x5555,
        !            90:     0xaaaa, 0x5555, 0xaaaa, 0x5555,
        !            91:     0xaaaa, 0x5555, 0xaaaa, 0x5555};
        !            92: 
        !            93: 
        !            94: char chars[9];
        !            95: int last_line;
        !            96: 
        !            97: main(argc, argv) 
        !            98:     int argc;
        !            99:     char **argv;
        !           100:     {
        !           101:     Window w;                          /* window id of the window */
        !           102:     FontInfo *fontInfo;                /* font to be displayed */
        !           103:     int width;
        !           104:     char *fontname = "vtsingle";
        !           105:     register char *option;
        !           106:     char *border_color, *back_color, *fore_color;      /* strings */
        !           107:     int border_width;
        !           108:     int reverse = 0;
        !           109:     char *geometry;                    /* user supplied geometry spec */
        !           110:     char def[32];                      /* default size */
        !           111:     int defwidth, defheight;
        !           112:     char display[128];
        !           113:     register int i;
        !           114:     OpaqueFrame window;                /* frame for the window */
        !           115:     Pixmap border_pixmap;
        !           116:     int background;                    /* color of background */
        !           117:     int foreground;                    /* color of graph */
        !           118:     int highlight;                     /* color of text, scale */
        !           119:     Color cdef;                                /* color structure */
        !           120: .IN "Examples of Use" "Color"
        !           121: 
        !           122: .IN "Examples of Use" "XGetDefault"
        !           123:     if ((option = XGetDefault(argv[0],"ReverseVideo")) != NULL )
        !           124:                if (strcmp (option, "on") == 0)
        !           125:                        reverse = 1;
        !           126:     if ((option = XGetDefault(argv[0],"BorderWidth")) != NULL)
        !           127:        border_width = atoi(option);
        !           128:     if ((border_color = XGetDefault(argv[0],"Border")) == NULL)
        !           129:        border_color = XGetDefault(argv[0],"BorderColor");
        !           130:     back_color = XGetDefault(argv[0],"Background");
        !           131:     fore_color = XGetDefault(argv[0],"Foreground");
        !           132:     display[0] = '\\0';
        !           133: 
        !           134:     for (i = 1; i < argc; i++) {               /* Parse line */
        !           135:        if (argv[i][0] == '=') {
        !           136:            geometry = argv[i];
        !           137:            continue;
        !           138:        }
        !           139:        if (index(argv[i], ':') != NULL) {              /* host:display */
        !           140:            (void)strncpy(display, argv[i], sizeof(display));
        !           141:            continue;
        !           142:        }
        !           143:        if (strcmp(argv[i], "-rv") == 0) {              /* black on white */
        !           144:            reverse = 1;
        !           145:            continue;
        !           146:        }
        !           147:        if (strcmp(argv[i], "-bw") == 0) {              /* border width */
        !           148:            if (++i >= argc) usage(argv[0]);
        !           149:            border_width = atoi(argv[i]);
        !           150:            continue;
        !           151:        }
        !           152:        if (strcmp(argv[i], "-bd") == 0) {              /* border color */
        !           153:           if (++i >= argc) usage(argv[0]);
        !           154:           border_color = argv[i];
        !           155:           continue;
        !           156:        }
        !           157:        if (strcmp(argv[i], "-fg") == 0) {              /* foreground color */
        !           158:           if (++i >= argc) usage(argv[0]);
        !           159:           fore_color = argv[i];
        !           160:           continue;
        !           161:        }
        !           162:        if (strcmp(argv[i], "-bg") == 0) {              /* background color */
        !           163:           if (++i >= argc) usage(argv[0]);
        !           164:           back_color = argv[i];
        !           165:           continue;
        !           166:        }
        !           167:        if (argv[i][0] == '-') usage (argv[0]);
        !           168:        fontname = argv[i];
        !           169:     }
        !           170: .IN "Examples of Use" "XOpenDisplay"
        !           171:     if (!XOpenDisplay(display)) {
        !           172:                fprintf (stderr, "%s: Could not open display %s!\\n", argv[0], display);
        !           173:        exit(1);
        !           174:     }
        !           175: .IN "Examples of Use" "XOpenFont"
        !           176:     if (!(fontInfo = XOpenFont (fontname))) {
        !           177:                fprintf (stderr, "%s: Could not open font %s!\\n", argv[0], fontname);
        !           178:        exit(1);
        !           179:     }
        !           180:     last_line = (unsigned char)(fontInfo->lastchar)/8;
        !           181:     width = ComputeWidth (fontInfo);
        !           182: 
        !           183:     /* if DisplayCells are greater than 2, then on color display */
        !           184: .IN "Examples of Use" "XParseColor"
        !           185: .IN "Examples of Use" "XGetHardwareColor"
        !           186: .IN "Examples of Use" "DisplayCells"
        !           187:     if (border_color && DisplayCells() > 2 &&
        !           188:        XParseColor(border_color, &cdef) && XGetHardwareColor(&cdef))
        !           189: .IN "Examples of Use" "XMakeTile"
        !           190:        border_pixmap = XMakeTile(cdef.pixel);
        !           191:     else if (border_color && strcmp(border_color, "black") == 0)
        !           192: .IN "Examples of Use" "BlackPixmap"
        !           193:        border_pixmap = BlackPixmap;
        !           194:     else if (border_color && strcmp(border_color, "white") == 0)
        !           195: .IN "Examples of Use" "WhitePixmap"
        !           196:        border_pixmap = WhitePixmap;
        !           197:     else
        !           198: .IN "Examples of Use" "XStorePixmap"
        !           199:        border_pixmap = XMakePixmap (XStoreBitmap (16, 16, gray_bits),
        !           200:                                        BlackPixel, WhitePixel);
        !           201: .IN "Examples of Use" "WhitePixel"
        !           202: .IN "Examples of Use" "BlackPixel"
        !           203:     if (back_color && DisplayCells() > 2 &&
        !           204:        XParseColor(back_color, &cdef) && XGetHardwareColor(&cdef)) {
        !           205:        background = cdef.pixel;
        !           206:     } else if (back_color && strcmp(back_color, "white") == 0) {
        !           207:        background = WhitePixel;
        !           208:        reverse = 0;
        !           209:     } else if (back_color && strcmp(back_color, "black") == 0) {
        !           210:        background = BlackPixel;
        !           211:        reverse = 0;
        !           212:     } else
        !           213:        background = BlackPixel;
        !           214: 
        !           215:     if (fore_color && DisplayCells() > 2 &&
        !           216:        XParseColor(fore_color, &cdef) && XGetHardwareColor(&cdef)) {
        !           217:        foreground = cdef.pixel;
        !           218:     } else if (fore_color && strcmp(fore_color, "black") == 0) {
        !           219:        foreground = BlackPixel;
        !           220:        reverse = 0;
        !           221:     } else if (fore_color && strcmp(fore_color, "white") == 0) {
        !           222:        foreground = WhitePixel;
        !           223:        reverse = 0;
        !           224:     } else
        !           225:        foreground = WhitePixel;
        !           226: 
        !           227:     if (reverse) {
        !           228:        highlight = background;
        !           229:        background = foreground;
        !           230:        foreground = highlight;
        !           231:     }
        !           232: 
        !           233: .IN "Examples of Use" "XMakeTile"
        !           234: .IN "Examples of Use" "OpaqueFrame"
        !           235:     window.bdrwidth = border_width;
        !           236:     window.border = border_pixmap;
        !           237:     window.background = XMakeTile(background);
        !           238: 
        !           239:     defwidth = width + 10;
        !           240:     defheight = fontInfo->height * (last_line + 1) + 10;
        !           241:     (void) sprintf(def, "=%dx%d+300+300", defwidth, defheight);
        !           242: .IN "Examples of Use" "XCreate"
        !           243:     w = XCreate ("Font Display", argv[0], geometry, def, &window,
        !           244:                defwidth, defheight);
        !           245: 
        !           246:     if (!w) {
        !           247:        fprintf (stderr, "XCreateWindow failed\\n");
        !           248:        exit(1);
        !           249:     }
        !           250: .IN "Examples of Use" "XSelectInput"
        !           251:     XSelectInput (w, ExposeWindow | ButtonPressed);
        !           252: .IN "Examples of Use" "XMapWindow"
        !           253:     XMapWindow (w);
        !           254:     while (1) {
        !           255:        XEvent event;
        !           256:        int i, j;
        !           257: .IN "Examples of Use" "XWindowEvent"
        !           258:        XWindowEvent (w, ExposeWindow | ButtonPressed, &event);
        !           259:        if(event.type == ButtonPressed) exit(0);
        !           260:        for (i=0;i<=last_line;i++) {
        !           261:                    for (j=0;j<8;j++)
        !           262:                chars[j] = (char)((8*i)+j);
        !           263: .IN "Examples of Use" "XText"
        !           264:                    XText (w, 5, 5+(i*fontInfo->height), chars, 8,
        !           265:              fontInfo->id, foreground, background);
        !           266:                    }
        !           267:        }
        !           268:     }    
        !           269: 
        !           270: usage (program)
        !           271:        char *program;
        !           272:     {
        !           273:        fprintf(stderr,
        !           274:                "usage: %s [host:display] [=geom]
        !           275:                 [-fw] [-rv] [-bw] [-bd] [-fg] [-bg] fontname\\n", program);
        !           276:        exit(1);
        !           277:     }
        !           278: 
        !           279: ComputeWidth (fontInfo)
        !           280:     FontInfo *fontInfo;
        !           281:     {
        !           282:     int maxwidth, i, j;
        !           283: 
        !           284:     /* Horrible hack needed for first line because line starts
        !           285:        with \\0, and XStringWidth considers \\0 to terminate string */
        !           286:     for (j=1;j<8;j++)
        !           287:        chars[j] = j;
        !           288: .IN "Examples of Use" "XStringWidth"
        !           289:     maxwidth = XStringWidth (&chars[1], fontInfo, 0, 0);
        !           290:     /* add the width of the '\\0' character, if it has one */
        !           291:     if (fontInfo->firstchar == '\\0')
        !           292:        maxwidth += (fontInfo->fixedwidth ? 
        !           293:            fontInfo->width : fontInfo->widths[0]);
        !           294:     
        !           295:     /* now measure the width of remaining lines */
        !           296:     for (i=1;i<=last_line;i++) {
        !           297:        int this_width;
        !           298:        for (j=0;j<8;j++)
        !           299:            chars[j] = (char)((8*i)+j);
        !           300:        this_width = XStringWidth (chars, fontInfo, 0, 0);
        !           301:        if (this_width > maxwidth)
        !           302:            maxwidth = this_width;
        !           303:        }
        !           304:     return (maxwidth);
        !           305:     }
        !           306: .cs R
        !           307: .DE
        !           308: .fi
        !           309: .PP
        !           310: After parsing all the arguments,
        !           311: the program allocates colors if on a color display for the foreground
        !           312: and background text colors, and the background and border pixmaps.
        !           313: It then creates the window, making sure that it is the right size,
        !           314: and then maps it to the screen.
        !           315: The fact the window was mapped to the screen generates an expose
        !           316: window event.
        !           317: The program repaints the window on each expose window event,
        !           318: and exits if any mouse button event is detected on the window.
        !           319: .EH ''\fB- ii -\fP''
        !           320: .OH ''\fB- ii -\fP''
        !           321: .bp 
        !           322: .XS
        !           323: Index
        !           324: .XE
        !           325: .PX

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