Imported from libpng-1.0.5.tarv1.0.5

1 files changed, 1241 insertions, 0 deletions

diff --git a/contrib/gregbook/rpng2-x.c b/contrib/gregbook/rpng2-x.c
new file mode 100644
index 000000000..bfa83e609
--- /dev/null
+++ b/contrib/gregbook/rpng2-x.c
@@ -0,0 +1,1241 @@
+/*---------------------------------------------------------------------------
+
+   rpng2 - progressive-model PNG display program                  rpng2-x.c 
+
+   This program decodes and displays PNG files progressively, as if it were
+   a web browser (though the front end is only set up to read from files).
+   It supports gamma correction, user-specified background colors, and user-
+   specified background patterns (for transparent images).  This version is
+   for the X Window System (tested under Unix, but may work under VMS or OS/2
+   with a little tweaking).  Thanks to Adam Costello and Pieter S. van der
+   Meulen for the "diamond" and "radial waves" patterns, respectively.
+
+   to do:
+    - 8-bit support
+    - finish resizable checkerboard-gradient (sizes 4-128?)
+    - use %.1023s to simplify truncation of title-bar string?
+
+  ---------------------------------------------------------------------------
+
+      Copyright (c) 1998-1999 Greg Roelofs.  All rights reserved.
+
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+
+  ---------------------------------------------------------------------------*/
+
+#define PROGNAME  "rpng2-x"
+#define LONGNAME  "Progressive PNG Viewer for X"
+#define VERSION   "1.01 of 31 March 1999"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>	/* for jmpbuf declaration in readpng2.h */
+#include <time.h>
+#include <math.h>	/* only for PvdM background code */
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>	/* defines XK_* macros */
+
+/* all for PvdM background code: */
+#ifndef PI
+#  define PI             3.141592653589793238
+#endif
+#define PI_2             (PI*0.5)
+#define INV_PI_360       (360.0 / PI)
+#define MAX(a,b)         (a>b?a:b)
+#define MIN(a,b)         (a<b?a:b)
+#define CLIP(a,min,max)  MAX(min,MIN((a),max))
+#define ABS(a)           ((a)<0?-(a):(a))
+#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
+#define ROUNDF(f)        ((int)(f + 0.5))
+
+#define rgb1_max   bg_freq
+#define rgb1_min   bg_gray
+#define rgb2_max   bg_bsat
+#define rgb2_min   bg_brot
+
+/* #define DEBUG */	/* this enables the Trace() macros */
+
+#include "readpng2.h"	/* typedefs, common macros, readpng2 prototypes */
+
+
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+
+#define alpha_composite(composite, fg, alpha, bg) {			\
+    ush temp = ((ush)(fg)*(ush)(alpha) +				\
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);	\
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);			\
+}
+
+
+#define INBUFSIZE 4096	/* with pseudo-timing on (1 sec delay/block), this
+			 *  block size corresponds roughly to a download
+			 *  speed 10% faster than theoretical 33.6K maximum
+			 *  (assuming 8 data bits, 1 stop bit and no other
+			 *  overhead) */
+
+/* local prototypes */
+static void rpng2_x_init(void);
+static int  rpng2_x_create_window(void);
+static int  rpng2_x_load_bg_image(void);
+static void rpng2_x_display_row(ulg row);
+static void rpng2_x_finish_display(void);
+static void rpng2_x_cleanup(void);
+static int  rpng2_x_msb(ulg u32val);
+
+
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *filename;
+static FILE *infile;
+
+static mainprog_info rpng2_info;
+
+static uch inbuf[INBUFSIZE];
+static int incount;
+
+static int pat = 6;		/* must be less than num_bgpat */
+static int bg_image = 0;
+static int bgscale = 16;
+static ulg bg_rowbytes;
+static uch *bg_data;
+
+static struct rgb_color {
+    uch r, g, b;
+} rgb[] = {
+    {  0,   0,   0},	/*  0:  black */
+    {255, 255, 255},	/*  1:  white */
+    {173, 132,  57},	/*  2:  tan */
+    { 64, 132,   0},	/*  3:  medium green */
+    {189, 117,   1},	/*  4:  gold */
+    {253, 249,   1},	/*  5:  yellow */
+    {  0,   0, 255},	/*  6:  blue */
+    {  0,   0, 120},	/*  7:  medium blue */
+    {255,   0, 255},	/*  8:  magenta */
+    { 64,   0,  64},	/*  9:  dark magenta */
+    {255,   0,   0},	/* 10:  red */
+    { 64,   0,   0},	/* 11:  dark red */
+    {255, 127,   0},	/* 12:  orange */
+    {192,  96,   0},	/* 13:  darker orange */
+    { 24,  60,   0},	/* 14:  dark green-yellow */
+    { 85, 125, 200} 	/* 15:  ice blue */
+};
+/* not used for now, but should be for error-checking:
+static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
+ */
+
+/*
+    This whole struct is a fairly cheesy way to keep the number of
+    command-line options to a minimum.  The radial-waves background
+    type is a particularly poor fit to the integer elements of the
+    struct...but a few macros and a little fixed-point math will do
+    wonders for ya.
+
+    type bits:
+       F E D C B A 9 8 7 6 5 4 3 2 1 0
+                             | | | | |
+                             | | +-+-+-- 0 = sharp-edged checkerboard
+                             | |         1 = soft diamonds
+                             | |         2 = radial waves
+                             | |       3-7 = undefined
+                             | +-- gradient #2 inverted?
+                             +-- alternating columns inverted?
+ */
+static struct background_pattern {
+    ush type;
+    int rgb1_max, rgb1_min;	/* or bg_freq, bg_gray */
+    int rgb2_max, rgb2_min;	/* or bg_bsat, bg_brot (both scaled by 10)*/
+} bg[] = {
+    {0+8,   2,0,  1,15},  	/* checkered:  tan/black vs. white/ice blue */
+    {0+24,  2,0,  1,0},  	/* checkered:  tan/black vs. white/black */
+    {0+8,   4,5,  0,2},  	/* checkered:  gold/yellow vs. black/tan */
+    {0+8,   4,5,  0,6},  	/* checkered:  gold/yellow vs. black/blue */
+    {0,     7,0,  8,9},  	/* checkered:  deep blue/black vs. magenta */
+    {0+8,  13,0,  5,14},  	/* checkered:  orange/black vs. yellow */
+    {0+8,  12,0, 10,11},  	/* checkered:  orange/black vs. red */
+    {1,     7,0,  8,0},  	/* diamonds:  deep blue/black vs. magenta */
+    {1,    12,0, 11,0},  	/* diamonds:  orange vs. dark red */
+    {1,    10,0,  7,0},  	/* diamonds:  red vs. medium blue */
+    {1,     4,0,  5,0},  	/* diamonds:  gold vs. yellow */
+    {1,     3,0,  0,0},  	/* diamonds:  medium green vs. black */
+    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
+    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
+    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
+    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
+};
+static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
+
+
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static int RPixelShift, GPixelShift, BPixelShift;
+static ulg RedMask, GreenMask, BlueMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+
+
+
+
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p, *bgstr = NULL;
+    int rc, alen, flen;
+    int error = 0;
+    int timing = FALSE;
+    int have_bg = FALSE;
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    XEvent e;
+    KeySym k;
+
+
+    /* First initialize a few things, just to be sure--memset takes care of
+     * default background color (black), booleans (FALSE), pointers (NULL),
+     * etc. */
+
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+    memset(&rpng2_info, 0, sizeof(mainprog_info));
+
+
+    /* Set the default value for our display-system exponent, i.e., the
+     * product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+
+
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        rpng2_info.display_exponent = atof(p);
+    else
+        rpng2_info.display_exponent = default_display_exponent;
+
+
+    /* Now parse the command line for options and the PNG filename. */
+
+    while (*++argv && !error) {
+        if (!strcmp(*argv, "-display")) {
+            if (!*++argv)
+                ++error;
+            displayname = *argv;
+        } else if (!strcmp(*argv, "-gamma")) {
+            if (!*++argv)
+                ++error;
+            rpng2_info.display_exponent = atof(*argv);
+            if (rpng2_info.display_exponent <= 0.0)
+                ++error;
+        } else if (!strcmp(*argv, "-bgcolor")) {
+            if (!*++argv)
+                ++error;
+            bgstr = *argv;
+            if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                ++error;
+            else {
+                have_bg = TRUE;
+                bg_image = FALSE;
+            }
+        } else if (!strcmp(*argv, "-bgpat")) {
+            if (!*++argv)
+                ++error;
+            pat = atoi(*argv) - 1;
+            if (pat < 0 || pat >= num_bgpat)
+                ++error;
+            else {
+                bg_image = TRUE;
+                have_bg = FALSE;
+            }
+        } else if (!strcmp(*argv, "-timing")) {
+            timing = TRUE;
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+
+    if (!filename) {
+        ++error;
+    } else if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
+            fprintf(stderr, PROGNAME
+              ":  [%s] is not a PNG file: incorrect signature\n",
+              filename);
+            ++error;
+        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
+            switch (rc) {
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n",
+                      filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng2_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng2_cleanup(&rpng2_info);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+        readpng2_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+          "        %*s [-timing] file.png\n\n"
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7f00'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images; overrides -bgpat\n"
+          "    pat \tdesired background pattern number (1-%d); used with\n"
+          "\t\t  transparent images; overrides -bgcolor\n"
+          "    -timing\tenables delay for every block read, to simulate modem\n"
+          "\t\t  download of image (~36 Kbps)\n"
+          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+          "\n", PROGNAME, strlen(PROGNAME), " ", default_display_exponent,
+          num_bgpat);
+        exit(1);
+    }
+
+
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+
+
+    /* set some final rpng2_info variables before entering main data loop */
+
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        rpng2_info.bg_red   = (uch)r;
+        rpng2_info.bg_green = (uch)g;
+        rpng2_info.bg_blue  = (uch)b;
+    } else
+        rpng2_info.need_bgcolor = TRUE;
+
+    rpng2_info.done = FALSE;
+    rpng2_info.mainprog_init = rpng2_x_init;
+    rpng2_info.mainprog_display_row = rpng2_x_display_row;
+    rpng2_info.mainprog_finish_display = rpng2_x_finish_display;
+
+
+    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
+     * the loop to deal with our first buffer of data (read in above to verify
+     * that the file is a PNG image), then loop through the file and continue
+     * calling the same routine to handle each chunk of data.  It in turn
+     * passes the data to libpng, which will invoke one or more of our call-
+     * backs as decoded data become available.  We optionally call sleep() for
+     * one second per iteration to simulate downloading the image via an analog
+     * modem. */
+
+    for (;;) {
+        Trace((stderr, "about to call readpng2_decode_data()\n"))
+        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
+            ++error;
+        Trace((stderr, "done with readpng2_decode_data()\n"))
+        if (error || feof(infile) || rpng2_info.done)
+            break;
+        if (timing)
+            sleep(1);
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+    }
+
+
+    /* clean up PNG stuff and report any decoding errors */
+
+    fclose(infile);
+    Trace((stderr, "about to call readpng2_cleanup()\n"))
+    readpng2_cleanup(&rpng2_info);
+
+    if (error) {
+        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
+        exit(3);
+    }
+
+
+    /* wait for the user to tell us when to quit */
+
+    do
+        XNextEvent(display, &e);
+    while (!(e.type == ButtonPress && e.xbutton.button == Button1) &&
+           !(e.type == KeyPress &&    /*  v--- or 1 for shifted keys */
+             ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape) ));
+
+
+    /* we're done:  clean up all image and X resources and go away */
+
+    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
+    rpng2_x_cleanup();
+
+    return 0;
+}
+
+
+
+
+
+/* this function is called by readpng2_info_callback() in readpng2.c, which
+ * in turn is called by libpng after all of the pre-IDAT chunks have been
+ * read and processed--i.e., we now have enough info to finish initializing */
+
+static void rpng2_x_init()
+{
+    ulg i;
+    ulg rowbytes = rpng2_info.rowbytes;
+
+    Trace((stderr, "beginning rpng2_x_init()\n"))
+    Trace((stderr, "  rowbytes = %ld\n", rpng2_info.rowbytes))
+    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
+    Trace((stderr, "  height = %ld\n", rpng2_info.height))
+
+    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
+    if (!rpng2_info.image_data) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
+    if (!rpng2_info.row_pointers) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+
+    for (i = 0;  i < rpng2_info.height;  ++i)
+        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
+
+
+    /* do the basic X initialization stuff, make the window, and fill it with
+     * the user-specified, file-specified or default background color or
+     * pattern */
+
+    if (rpng2_x_create_window()) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+}
+
+
+
+
+
+static int rpng2_x_create_window()
+{
+    ulg bg_red   = rpng2_info.bg_red;
+    ulg bg_green = rpng2_info.bg_green;
+    ulg bg_blue  = rpng2_info.bg_blue;
+    ulg bg_pixel = 0L;
+    int screen, pad;
+    uch *xdata;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XSizeHints *size_hints;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XWMHints *wm_hints;
+
+
+    Trace((stderr, "beginning rpng2_x_create_window()\n"))
+
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+
+/* GRR:  add 8-bit support */
+    if (/* depth != 8 && */ depth != 16 && depth != 24 && depth != 32) {
+        fprintf(stderr,
+          "screen depth %d not supported (only 16-, 24- or 32-bit TrueColor)\n",
+          depth);
+        return 2;
+    }
+
+    XMatchVisualInfo(display, screen, depth,
+      (depth == 8)? PseudoColor : TrueColor, &visual_info);
+    visual = visual_info.visual;
+
+    RedMask   = visual->red_mask;
+    GreenMask = visual->green_mask;
+    BlueMask  = visual->blue_mask;
+
+/* GRR:  add/check 8-bit support */
+    if (depth == 8) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+        bg_image = FALSE;	/* gradient just wastes palette entries */
+    } else if (depth == 16) {
+        RPixelShift = 15 - rpng2_x_msb(RedMask);   /* these are right-shifts */
+        GPixelShift = 15 - rpng2_x_msb(GreenMask);
+        BPixelShift = 15 - rpng2_x_msb(BlueMask);
+    } else /* if (depth > 16) */ {
+        RPixelShift = rpng2_x_msb(RedMask) - 7;    /* these are left-shifts */
+        GPixelShift = rpng2_x_msb(GreenMask) - 7;
+        BPixelShift = rpng2_x_msb(BlueMask) - 7;
+    }
+
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+
+    window = XCreateWindow(display, root, 0, 0, rpng2_info.width,
+      rpng2_info.height, 0, depth, InputOutput, visual,
+      CWBackingStore | CWEventMask, &attr);
+
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+
+    /* OK if either hints allocation fails; XSetWMProperties() allows NULLs */
+
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = rpng2_info.width;
+        size_hints->min_height = size_hints->max_height = rpng2_info.height;
+    }
+
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, NULL);
+
+    XMapWindow(display, window);
+
+    gc = XCreateGC(display, window, 0, &gcvalues);
+
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*rpng2_info.width*rpng2_info.height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*rpng2_info.width*rpng2_info.height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(rpng2_info.width*rpng2_info.height);
+        pad = 8;
+    }
+
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, rpng2_info.width, rpng2_info.height, pad, 0);
+
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+
+    /* to avoid testing the bitmap order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (e.g., Linux/x86, old VAXen, etc.)--this is not the
+     * most efficient approach (the giant if-test would be better), but in
+     * the interest of clarity, we'll take the easy way out... */
+
+    ximage->byte_order = MSBFirst;
+
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color (default is black) or
+    faked "background image" (but latter is disabled if 8-bit; gradients
+    just waste palette entries).
+  ---------------------------------------------------------------------------*/
+
+    if (bg_image)
+        rpng2_x_load_bg_image();	/* resets bg_image if fails */
+
+    if (!bg_image) {
+        if (depth == 24 || depth == 32) {
+            bg_pixel = (bg_red   << RPixelShift) |
+                       (bg_green << GPixelShift) |
+                       (bg_blue  << BPixelShift);
+        } else if (depth == 16) {
+            bg_pixel = (((bg_red   << 8) >> RPixelShift) & RedMask)   |
+                       (((bg_green << 8) >> GPixelShift) & GreenMask) |
+                       (((bg_blue  << 8) >> BPixelShift) & BlueMask);
+        } else /* depth == 8 */ {
+
+            /* GRR:  add 8-bit support */
+
+        }
+        XSetForeground(display, gc, bg_pixel);
+        XFillRectangle(display, window, gc, 0, 0, rpng2_info.width,
+          rpng2_info.height);
+    }
+
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush and return.
+  ---------------------------------------------------------------------------*/
+
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+
+    XFlush(display);
+
+    return 0;
+
+} /* end function rpng2_x_create_window() */
+
+
+
+
+
+static int rpng2_x_load_bg_image()
+{
+    uch *src, *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max = (bgscale-1);
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, row;
+    ulg pixel;
+
+/*---------------------------------------------------------------------------
+    Allocate buffer for fake background image to be used with transparent
+    images; if this fails, revert to plain background color.
+  ---------------------------------------------------------------------------*/
+
+    bg_rowbytes = 3 * rpng2_info.width;
+    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
+    if (!bg_data) {
+        fprintf(stderr, PROGNAME
+          ":  unable to allocate memory for background image\n");
+        bg_image = 0;
+        return 1;
+    }
+
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            even_odd_vert = (row / bgscale) & 1;
+
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (i / bgscale) & 1;
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {		/* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {			/* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;      /* not inverted or */
+                        *dest++ = g2;      /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;  /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 1) {
+
+        hmax = (bgscale-1)/2;	/* half the max weight of a color */
+        max = 2*hmax;		/* the max weight of a color */
+
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = i % bgscale;
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+
+        fprintf(stderr, "%s:  computing radial background...",
+          PROGNAME);
+        fflush(stderr);
+
+        hh = rpng2_info.height / 2;
+        hw = rpng2_info.width / 2;
+
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = row - hh;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = i - hw;
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+        fprintf(stderr, "done.\n");
+        fflush(stderr);
+    }
+
+/*---------------------------------------------------------------------------
+    Blast background image to display buffer before beginning PNG decode.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = *src++;
+                green = *src++;
+                blue  = *src++;
+                pixel = (red   << RPixelShift) |
+                        (green << GPixelShift) |
+                        (blue  << BPixelShift);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = ((uch *)&pixel)[3];
+                *dest++ = ((uch *)&pixel)[2];
+                *dest++ = ((uch *)&pixel)[1];
+                *dest++ = ((uch *)&pixel)[0];
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);
+                ++src;
+                green = ((ush)(*src) << 8);
+                ++src;
+                blue  = ((ush)(*src) << 8);
+                ++src;
+                pixel = ((red   >> RPixelShift) & RedMask)   |
+                        ((green >> GPixelShift) & GreenMask) |
+                        ((blue  >> BPixelShift) & BlueMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = ((uch *)&pixel)[1];
+                *dest++ = ((uch *)&pixel)[0];
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+    XPutImage(display, window, gc, ximage, 0, 0, 0, 0, rpng2_info.width,
+      rpng2_info.height);
+
+    return 0;
+
+} /* end function rpng2_x_load_bg_image() */
+
+
+
+
+
+static void rpng2_x_display_row(ulg row)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL, *dest;
+    uch r, g, b, a;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, pixel;
+    static int rows=0;
+    static ulg firstrow;
+
+/*---------------------------------------------------------------------------
+    rows and firstrow simply track how many rows (and which ones) have not
+    yet been displayed; alternatively, we could call XPutImage() for every
+    row and not bother with the records-keeping.
+  ---------------------------------------------------------------------------*/
+
+    Trace((stderr, "beginning rpng2_x_display_row()\n"))
+
+    if (rows == 0)
+        firstrow = row;   /* first row not yet displayed */
+
+    ++rows;   /* count of rows received but not yet displayed */
+
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct, the lack of an outer loop
+    (over rows) and moving the XPutImage() call outside the "if (depth)"
+    tests, this routine is identical to rpng_x_display_image() in the non-
+    progressive version of the program.
+  ---------------------------------------------------------------------------*/
+
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+
+        src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = *src++;
+                green = *src++;
+                blue  = *src++;
+                pixel = (red   << RPixelShift) |
+                        (green << GPixelShift) |
+                        (blue  << BPixelShift);
+                /* recall that we set ximage->byte_order = MSBFirst */
+                *dest++ = ((uch *)&pixel)[3];
+                *dest++ = ((uch *)&pixel)[2];
+                *dest++ = ((uch *)&pixel)[1];
+                *dest++ = ((uch *)&pixel)[0];
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = r;
+                    green = g;
+                    blue  = b;
+                } else if (a == 0) {
+                    red   = bg_red;
+                    green = bg_green;
+                    blue  = bg_blue;
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result into the
+                     * first argument */
+                    alpha_composite(red,   r, a, bg_red);
+                    alpha_composite(green, g, a, bg_green);
+                    alpha_composite(blue,  b, a, bg_blue);
+                }
+                pixel = (red   << RPixelShift) |
+                        (green << GPixelShift) |
+                        (blue  << BPixelShift);
+                /* recall that we set ximage->byte_order = MSBFirst */
+                *dest++ = ((uch *)&pixel)[3];
+                *dest++ = ((uch *)&pixel)[2];
+                *dest++ = ((uch *)&pixel)[1];
+                *dest++ = ((uch *)&pixel)[0];
+            }
+        }
+
+    } else if (depth == 16) {
+        ush red, green, blue;
+
+        src = rpng2_info.row_pointers[row];
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);
+                ++src;
+                green = ((ush)(*src) << 8);
+                ++src;
+                blue  = ((ush)(*src) << 8);
+                ++src;
+                pixel = ((red   >> RPixelShift) & RedMask)   |
+                        ((green >> GPixelShift) & GreenMask) |
+                        ((blue  >> BPixelShift) & BlueMask);
+                /* recall that we set ximage->byte_order = MSBFirst */
+                *dest++ = ((uch *)&pixel)[1];
+                *dest++ = ((uch *)&pixel)[0];
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                } else if (a == 0) {
+                    red   = ((ush)bg_red   << 8);
+                    green = ((ush)bg_green << 8);
+                    blue  = ((ush)bg_blue  << 8);
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result back into
+                     * the first argument (== fg byte here:  safe) */
+                    alpha_composite(r, r, a, bg_red);
+                    alpha_composite(g, g, a, bg_green);
+                    alpha_composite(b, b, a, bg_blue);
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                }
+                pixel = ((red   >> RPixelShift) & RedMask)   |
+                        ((green >> GPixelShift) & GreenMask) |
+                        ((blue  >> BPixelShift) & BlueMask);
+                /* recall that we set ximage->byte_order = MSBFirst */
+                *dest++ = ((uch *)&pixel)[1];
+                *dest++ = ((uch *)&pixel)[0];
+            }
+        }
+
+    } else /* depth == 8 */ {
+
+        /* GRR:  add 8-bit support */
+
+    }
+
+
+/*---------------------------------------------------------------------------
+    Display after every 16 rows or when on last row.  (Region may include
+    previously displayed lines due to interlacing--i.e., not contiguous.)
+  ---------------------------------------------------------------------------*/
+
+    if ((rows & 0xf) == 0 || row == rpng2_info.height-1) {
+        XPutImage(display, window, gc, ximage, 0, firstrow, 0, firstrow,
+          rpng2_info.width, row - firstrow + 1);
+        XFlush(display);
+        rows = 0;
+    }
+
+}
+
+
+
+
+
+static void rpng2_x_finish_display()
+{
+    Trace((stderr, "beginning rpng2_x_finish_display()\n"))
+
+    /* last row has already been displayed by rpng2_x_display_row(), so we
+     * have nothing to do here except set a flag and let the user know that
+     * the image is done */
+
+    rpng2_info.done = TRUE;
+    printf("Done.  Press Q, Esc or mouse button 1 to quit.\n");
+}
+
+
+
+
+
+static void rpng2_x_cleanup()
+{
+    if (bg_image && bg_data) {
+        free(bg_data);
+        bg_data = NULL;
+    }
+
+    if (rpng2_info.image_data) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+    }
+
+    if (rpng2_info.row_pointers) {
+        free(rpng2_info.row_pointers);
+        rpng2_info.row_pointers = NULL;
+    }
+
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+
+    XFreeGC(display, gc);
+
+    if (have_window)
+        XDestroyWindow(display, window);
+
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+}
+
+
+
+
+
+static int rpng2_x_msb(ulg u32val)
+{
+    int i;
+
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}