/* Copyright (C) 2001-2018 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/


/* X Windows driver for Ghostscript library */
#include "gx.h"			/* for gx_bitmap; includes std.h */
#include "math_.h"
#include "memory_.h"
#include "x_.h"
#include "gserrors.h"
#include "gsmatrix.h"		/* for gscoord.h */
#include "gscoord.h"		/* for gs_currentmatrix */
#include "gsdevice.h"		/* for gs_currentdevice */
#include "gsparam.h"
#include "gxdevice.h"
#include "gxpath.h"
#include "gxgetbit.h"
#include "gxiparam.h"
#include "gsiparm2.h"
#include "gxdevmem.h"
#include "gdevx.h"
#include "gdevkrnlsclass.h" /* 'standard' built in subclasses, currently First/Last Page and obejct filter */

/* Define whether to try to read back exposure events after XGetImage. */
/****** THIS IS USELESS.  XGetImage DOES NOT GENERATE EXPOSURE EVENTS. ******/
#define GET_IMAGE_EXPOSURES 0

/* GC descriptors */
private_st_device_X();

/* Forward references */
static int x_copy_image(gx_device_X * xdev, const byte * base, int sourcex,
                         int raster, int x, int y, int w, int h);
static int set_tile(gx_device *, const gx_strip_bitmap *);
static void free_cp(gx_device *);

/* Screen updating machinery */
static void update_init(gx_device_X *);
static void update_do_flush(gx_device_X *);

#define flush_text(xdev)\
  if (IN_TEXT(xdev)) do_flush_text(xdev)
static void do_flush_text(gx_device_X *);

/* Driver procedures */
/* (External procedures are declared in gdevx.h.) */
/*extern int gdev_x_open(gx_device_X *);*/
static dev_proc_open_device(x_open);
static dev_proc_get_initial_matrix(x_get_initial_matrix);
static dev_proc_sync_output(x_sync);
static dev_proc_output_page(x_output_page);
/*extern int gdev_x_close(gx_device_X *);*/
static dev_proc_close_device(x_close);
/*extern dev_proc_map_rgb_color(gdev_x_map_rgb_color);*/
/*extern dev_proc_map_color_rgb(gdev_x_map_color_rgb);*/
static dev_proc_fill_rectangle(x_fill_rectangle);
static dev_proc_copy_mono(x_copy_mono);
static dev_proc_copy_color(x_copy_color);
/*extern dev_proc_get_params(gdev_x_get_params);*/
/*extern dev_proc_put_params(gdev_x_put_params);*/
static dev_proc_get_page_device(x_get_page_device);
static dev_proc_strip_tile_rectangle(x_strip_tile_rectangle);
static dev_proc_begin_typed_image(x_begin_typed_image);
static dev_proc_get_bits_rectangle(x_get_bits_rectangle);
/*extern dev_proc_get_xfont_procs(gdev_x_finish_copydevice);*/
static dev_proc_fillpage(x_fillpage);

/* The device descriptor */
#define x_device(this_device, dev_body) \
const gx_device_X this_device = { \
    dev_body, \
    {				/* std_procs */ \
        x_open, \
        x_get_initial_matrix, \
        x_sync, \
        x_output_page, \
        x_close, \
        gdev_x_map_rgb_color, \
        gdev_x_map_color_rgb, \
        x_fill_rectangle, \
        NULL,			/* tile_rectangle */ \
        x_copy_mono, \
        x_copy_color, \
        NULL,			/* draw_line */ \
        NULL,			/* get_bits */ \
        gdev_x_get_params, \
        gdev_x_put_params, \
        NULL,			/* map_cmyk_color */ \
        NULL, \
        NULL,			/* get_xfont_device */ \
        NULL,			/* map_rgb_alpha_color */ \
        x_get_page_device, \
        NULL,			/* get_alpha_bits */ \
        NULL,			/* copy_alpha */ \
        NULL,			/* get_band */ \
        NULL,			/* copy_rop */ \
        NULL,			/* fill_path */ \
        NULL,			/* stroke_path */ \
        NULL,			/* fill_mask */ \
        NULL,			/* fill_trapezoid */ \
        NULL,			/* fill_parallelogram */ \
        NULL,			/* fill_triangle */ \
        NULL,			/* draw_thin_line */ \
        NULL,			/* begin_image */ \
        NULL,			/* image_data */ \
        NULL,			/* end_image */ \
        x_strip_tile_rectangle, \
        NULL,			/* strip_copy_rop */ \
        NULL,			/* get_clipping_box */ \
        x_begin_typed_image, \
        x_get_bits_rectangle, \
        NULL,			/* map_color_rgb_alpha */ \
        NULL,			/* create_compositor */ \
        NULL,			/* get_hardware_params */ \
        NULL,			/* text_begin */ \
        gdev_x_finish_copydevice, \
        NULL,			/* begin_transparency_group */ \
        NULL,                   /* end_transparency_group */ \
        NULL,                  /* begin_transparency_mask */ \
        NULL,                    /* end_transparency_mask */ \
        NULL,                       /* discard_transparency_layer */ \
        NULL,                  /* get_color_mapping_procs */ \
        NULL,                     /* get_color_comp_index */ \
        NULL,                     /* encode_color */ \
        NULL,                     /* decode_color */ \
        NULL,                   /* pattern_manage */ \
        NULL,                       /* fill_rectangle_hl_color */ \
        NULL,                      /* include_color_space */ \
        NULL,                    /* fill_linear_color_scanline */ \
        NULL,                   /* fill_linear_color_trapezoid */ \
        NULL,                    /* fill_linear_color_triangle */ \
        NULL,                    /* update_spot_equivalent_colors */ \
        NULL,                  /* ret_devn_params */ \
        x_fillpage,              /* fillpage */ \
        NULL,                      /* push_transparency_state */ \
        NULL,                      /* pop_transparency_state */ \
        NULL,                      /* put_image */ \
        NULL,                      /* dev_spec_op */ \
        NULL,                      /* copy_planes */ \
        NULL,                      /* get_profile */ \
        NULL,        /* set_graphics_type_tag */ \
        NULL, \
        NULL, \
        NULL, \
        NULL  \
    }, \
    gx_device_bbox_common_initial(0 /*false*/, 1 /*true*/, 1 /*true*/), \
    0 /*false*/,		/* is_buffered */ \
    1 /*true*/,			/* IsPageDevice */ \
    NULL,			/* buffer */ \
    0,				/* buffer_size */ \
    {0},                        /* orig_color_info */ \
    {				/* image */ \
        0, 0,			/* width, height */ \
        0, XYBitmap, NULL,	/* xoffset, format, data */ \
        MSBFirst, 8,		/* byte-order, bitmap-unit */ \
        MSBFirst, 8, 1,		/* bitmap-bit-order, bitmap-pad, depth */ \
        0, 1,			/* bytes_per_line, bits_per_pixel */ \
        0, 0, 0,		/* red_mask, green_mask, blue_mask */ \
        NULL,			/* *obdata */ \
        {NULL,			/* *(*create_image)() */ \
         NULL,			/* (*destroy_image)() */ \
         NULL,			/* (*get_pixel)() */ \
         NULL,			/* (*put_pixel)() */ \
         NULL,			/* *(*sub_image)() */ \
         NULL			/* (*add_pixel)() */ \
        }, \
    }, \
    NULL, NULL,			/* dpy, scr */ \
                                /* (connection not initialized) */ \
    NULL,			/* vinfo */ \
    (Colormap) None,		/* cmap */ \
    (Window) None,		/* win */ \
    NULL,			/* gc */ \
    (Window) None,		/* pwin */ \
    (Pixmap) 0,			/* bpixmap */ \
    0,				/* ghostview */ \
    (Window) None,		/* mwin */ \
    {identity_matrix_body},	/* initial matrix (filled in) */ \
    (Atom) 0, (Atom) 0, (Atom) 0,	/* Atoms: NEXT, PAGE, DONE */ \
    {				/* update */ \
        {			/* box */ \
            {max_int_in_fixed, max_int_in_fixed}, \
            {min_int_in_fixed, min_int_in_fixed} \
        }, \
        0,			/* area */ \
        0,			/* total */ \
        0			/* count */ \
    }, \
    (Pixmap) 0,			/* dest */ \
    0L, (ulong)~0L,		/* colors_or, colors_and */ \
    {				/* cp */ \
        (Pixmap) 0,		/* pixmap */ \
        NULL,			/* gc */ \
        -1, -1			/* raster, height */ \
    }, \
    {				/* ht */ \
        (Pixmap) None,		/* pixmap */ \
        (Pixmap) None,		/* no_pixmap */ \
        gx_no_bitmap_id,	/* id */ \
        0, 0, 0,		/* width, height, raster */ \
        0, 0			/* fore_c, back_c */ \
    }, \
    GXcopy,			/* function */ \
    FillSolid,			/* fill_style */ \
    0,				/* font */ \
    0, 0,			/* back_color, fore_color */ \
    0, 0,			/* background, foreground */ \
    { 0 },			/* cman */ \
    0, 0,			/* borderColor, borderWidth */ \
    NULL,			/* geometry */ \
    128, 5,			/* maxGrayRamp, maxRGBRamp */ \
    NULL,			/* palette */ \
    0.0, 0.0,			/* xResolution, yResolution */ \
    1,				/* useBackingPixmap */ \
    1, 1,			/* useXPutImage, useXSetTile */ \
 \
    0 /*false*/,		/* AlwaysUpdate */ \
    20000,			/* MaxTempPixmap */ \
    5000,			/* MaxTempImage */ \
 \
    {				/* text */ \
        0,			/* item_count */ \
        0,			/* char_count */ \
        {0, 0},			/* origin */ \
        0,			/* x */ \
        { \
            {0}},		/* items */ \
        {0}			/* chars */ \
    } \
};

x_device(gs_x11_device,
         std_device_color_stype_body(gx_device_X, 0, "x11", &st_device_X,
                                     FAKE_RES * DEFAULT_WIDTH_10THS / 10,
                                     FAKE_RES * DEFAULT_HEIGHT_10THS / 10,	/* x and y extent (nominal) */
                                     FAKE_RES, FAKE_RES,	/* x and y density (nominal) */
                                     24, 255, 256 ))

x_device(gs_x11alpha_device,
         std_device_dci_alpha_type_body(gx_device_X, 0, "x11alpha", &st_device_X,
                                        FAKE_RES * DEFAULT_WIDTH_10THS / 10,
                                        FAKE_RES * DEFAULT_HEIGHT_10THS / 10,	/* x and y extent (nominal) */
                                        FAKE_RES, FAKE_RES,	/* x and y density (nominal) */
                                        3, 24, 255, 255, 256, 256, 4, 4 ))

/* If XPutImage doesn't work, do it ourselves. */
static int alt_put_image(gx_device * dev, Display * dpy, Drawable win,
GC gc, XImage * pi, int sx, int sy, int dx, int dy, unsigned w, unsigned h);

#define put_image(dpy,win,gc,im,sx,sy,x,y,w,h)\
  BEGIN\
    if ( xdev->useXPutImage && !(XInitImage(im) == 0) ) {\
      XPutImage(dpy,win,gc,im,sx,sy,x,y,w,h);\
    } else {\
      int code_ = alt_put_image(dev,dpy,win,gc,im,sx,sy,x,y,w,h);\
      if ( code_ < 0 ) return code_;\
    }\
  END

/* Open the device.  Most of the code is in gdevxini.c. */
static int
x_open(gx_device * dev)
{
    gx_device_X *xdev = (gx_device_X *) dev;
    int code;

    if (xdev->color_info.anti_alias.text_bits > 1 ||
        xdev->color_info.anti_alias.graphics_bits > 1)
        xdev->space_params.MaxBitmap = 50000000;		/* default MaxBitmap when using AA */
    xdev->orig_color_info = xdev->color_info;
    code = gdev_x_open(xdev);

    if (code < 0)
        return code;
    update_init(xdev);
    code = install_internal_subclass_devices((gx_device **)&xdev, NULL);
    if (code < 0)
        return code;

    if (xdev->is_buffered)
        xdev->box_proc_data = xdev;

    return 0;
}

/* Close the device. */
static int
x_close(gx_device * dev)
{
    gx_device_X *xdev = (gx_device_X *) dev;

    return gdev_x_close(xdev);
}

/* Get initial matrix for X device. */
/* This conflicts seriously with the code for page devices; */
/* we only do it if Ghostview is active. */
static void
x_get_initial_matrix(gx_device * dev, gs_matrix * pmat)
{
    gx_device_X *xdev = (gx_device_X *) dev;

    if (!xdev->ghostview) {
        gx_default_get_initial_matrix(dev, pmat);
        return;
    }
    pmat->xx = xdev->initial_matrix.xx;
    pmat->xy = xdev->initial_matrix.xy;
    pmat->yx = xdev->initial_matrix.yx;
    pmat->yy = xdev->initial_matrix.yy;
    pmat->tx = xdev->initial_matrix.tx;
    pmat->ty = xdev->initial_matrix.ty;
}

/* Synchronize the display with the commands already given. */
static int
x_sync(gx_device * dev)
{
    gx_device_X *xdev = (gx_device_X *) dev;

    update_do_flush(xdev);
    XSync(xdev->dpy, False);
    return 0;
}

/* Send event to ghostview process */
void
gdev_x_send_event(gx_device_X *xdev, Atom msg)
{
    XEvent event;

    event.xclient.type = ClientMessage;
    event.xclient.display = xdev->dpy;
    event.xclient.window = xdev->win;
    event.xclient.message_type = msg;
    event.xclient.format = 32;
    event.xclient.data.l[0] = xdev->mwin;
    event.xclient.data.l[1] = xdev->dest;
    XSendEvent(xdev->dpy, xdev->win, False, 0, &event);
}

/* Output "page" */
static int
x_output_page(gx_device * dev, int num_copies, int flush)
{
    gx_device_X *xdev = (gx_device_X *) dev;

    x_sync(dev);

    /* Send ghostview a "page" client event */
    /* Wait for a "next" client event */
    if (xdev->ghostview) {
        XEvent event;

        gdev_x_send_event(xdev, xdev->PAGE);
        XNextEvent(xdev->dpy, &event);
        while (event.type != ClientMessage ||
               event.xclient.message_type != xdev->NEXT) {
            XNextEvent(xdev->dpy, &event);
        }
    }
    return gx_finish_output_page(dev, num_copies, flush);
}

/* Fill a rectangle with a color. */
static int
x_fill_rectangle(gx_device * dev,
                 int x, int y, int w, int h, gx_color_index gscolor)
{
    gx_device_X *xdev = (gx_device_X *) dev;
    unsigned long color = (unsigned long) gscolor;

    fit_fill(dev, x, y, w, h);
    flush_text(xdev);
    X_SET_FILL_STYLE(xdev, FillSolid);
    X_SET_FORE_COLOR(xdev, color);
    X_SET_FUNCTION(xdev, GXcopy);
    XFillRectangle(xdev->dpy, xdev->dest, xdev->gc, x, y, w, h);
    /* If we are filling the entire screen, reset */
    /* colors_or and colors_and.  It's wasteful to test this */
    /* on every operation, but there's no separate driver routine */
    /* for erasepage (yet). */
    if (x == 0 && y == 0 && w == xdev->width && h == xdev->height) {
        if (color == xdev->foreground || color == xdev->background)
            gdev_x_free_dynamic_colors(xdev);
        xdev->colors_or = xdev->colors_and = color;
    }
    if (xdev->bpixmap != (Pixmap) 0) {
        x_update_add(xdev, x, y, w, h);
    }
    if_debug5m('F', dev->memory, "[F] fill (%d,%d):(%d,%d) %ld\n",
               x, y, w, h, (long)color);
    return 0;
}

/* Copy a monochrome bitmap. */
static int
x_copy_mono(gx_device * dev,
            const byte * base, int sourcex, int raster, gx_bitmap_id id,
            int x, int y, int w, int h,
            gx_color_index zero, gx_color_index one)
/*
 * X doesn't directly support the simple operation of writing a color
 * through a mask specified by an image.  The plot is the following:
 *  If neither color is gx_no_color_index ("transparent"),
 *      use XPutImage with the "copy" function as usual.
 *  If the color either bitwise-includes or is bitwise-included-in
 *      every color written to date
 *      (a special optimization for writing black/white on color displays),
 *      use XPutImage with an appropriate Boolean function.
 *  Otherwise, do the following complicated stuff:
 *      Create pixmap of depth 1 if necessary.
 *      If foreground color is "transparent" then
 *        invert the raster data.
 *      Use XPutImage to copy the raster image to the newly
 *        created Pixmap.
 *      Install the Pixmap as the clip_mask in the X GC and
 *        tweak the clip origin.
 *      Do an XFillRectangle, fill style=solid, specifying a
 *        rectangle the same size as the original raster data.
 *      De-install the clip_mask.
 */
{
    gx_device_X *xdev = (gx_device_X *) dev;
    int function = GXcopy;
    unsigned long
        lzero = zero,
        lone = one;
    x_pixel
        bc = lzero,
        fc = lone;

    fit_copy(dev, base, sourcex, raster, id, x, y, w, h);
    flush_text(xdev);

    xdev->image.width = sourcex + w;
    xdev->image.height = h;
    xdev->image.data = (char *)base;
    xdev->image.bytes_per_line = raster;
    X_SET_FILL_STYLE(xdev, FillSolid);

    /* Check for null, easy 1-color, hard 1-color, and 2-color cases. */
    if (zero != gx_no_color_index) {
        if (one != gx_no_color_index) {
            /* 2-color case. */
            /* Simply replace existing bits with what's in the image. */
        } else if (!(~xdev->colors_and & bc)) {
            function = GXand;
            fc = ~(x_pixel) 0;
        } else if (!(~bc & xdev->colors_or)) {
            function = GXor;
            fc = 0;
        } else {
            goto hard;
        }
    } else {
        if (one == gx_no_color_index) {		/* no-op */
            return 0;
        } else if (!(~xdev->colors_and & fc)) {
            function = GXand;
            bc = ~(x_pixel) 0;
        } else if (!(~fc & xdev->colors_or)) {
            function = GXor;
            bc = 0;
        } else {
            goto hard;
        }
    }
    xdev->image.format = XYBitmap;
    X_SET_FUNCTION(xdev, function);
    if (bc != xdev->back_color) {
        XSetBackground(xdev->dpy, xdev->gc, (xdev->back_color = bc));
    }
    if (fc != xdev->fore_color) {
        XSetForeground(xdev->dpy, xdev->gc, (xdev->fore_color = fc));
    }
    if (zero != gx_no_color_index)
        NOTE_COLOR(xdev, lzero);
    if (one != gx_no_color_index)
        NOTE_COLOR(xdev, lone);
    put_image(xdev->dpy, xdev->dest, xdev->gc, &xdev->image,
              sourcex, 0, x, y, w, h);

    goto out;

  hard:			/* Handle the hard 1-color case. */
    if (raster > xdev->cp.raster || h > xdev->cp.height) {
        /* Must allocate a new pixmap and GC. */
        /* Release the old ones first. */
        free_cp(dev);

        /* Create the clipping pixmap, depth must be 1. */
        xdev->cp.pixmap =
            XCreatePixmap(xdev->dpy, xdev->win, raster << 3, h, 1);
        if (xdev->cp.pixmap == (Pixmap) 0) {
            lprintf("x_copy_mono: can't allocate pixmap\n");
            return_error(gs_error_VMerror);
        }
        xdev->cp.gc = XCreateGC(xdev->dpy, xdev->cp.pixmap, 0, 0);
        if (xdev->cp.gc == (GC) 0) {
            lprintf("x_copy_mono: can't allocate GC\n");
            return_error(gs_error_VMerror);
        }
        xdev->cp.raster = raster;
        xdev->cp.height = h;
    }
    /* Initialize static mask image params */
    xdev->image.format = XYBitmap;
    X_SET_FUNCTION(xdev, GXcopy);

    /* Select polarity based on fg/bg transparency. */
    if (one == gx_no_color_index) {	/* invert */
        XSetBackground(xdev->dpy, xdev->cp.gc, (x_pixel) 1);
        XSetForeground(xdev->dpy, xdev->cp.gc, (x_pixel) 0);
        X_SET_FORE_COLOR(xdev, lzero);
    } else {
        XSetBackground(xdev->dpy, xdev->cp.gc, (x_pixel) 0);
        XSetForeground(xdev->dpy, xdev->cp.gc, (x_pixel) 1);
        X_SET_FORE_COLOR(xdev, lone);
    }
    put_image(xdev->dpy, xdev->cp.pixmap, xdev->cp.gc,
              &xdev->image, sourcex, 0, 0, 0, w, h);

    /* Install as clipmask. */
    XSetClipMask(xdev->dpy, xdev->gc, xdev->cp.pixmap);
    XSetClipOrigin(xdev->dpy, xdev->gc, x, y);

    /*
     * Draw a solid rectangle through the raster clip mask.
     * Note fill style is guaranteed to be solid from above.
     */
    XFillRectangle(xdev->dpy, xdev->dest, xdev->gc, x, y, w, h);

    /* Tidy up.  Free the pixmap if it's big. */
    XSetClipMask(xdev->dpy, xdev->gc, None);
    if (raster * h > xdev->MaxTempPixmap)
        free_cp(dev);

  out:if (xdev->bpixmap != (Pixmap) 0) {
        /* We wrote to the pixmap, so update the display now. */
        x_update_add(xdev, x, y, w, h);
    }
    return 0;
}

/* Internal routine to free the GC and pixmap used for copying. */
static void
free_cp(gx_device * dev)
{
    gx_device_X *xdev = (gx_device_X *) dev;

    if (xdev->cp.gc != NULL) {
        XFreeGC(xdev->dpy, xdev->cp.gc);
        xdev->cp.gc = NULL;
    }
    if (xdev->cp.pixmap != (Pixmap) 0) {
        XFreePixmap(xdev->dpy, xdev->cp.pixmap);
        xdev->cp.pixmap = (Pixmap) 0;
    }
    xdev->cp.raster = -1;	/* mark as unallocated */
}

/* Copy a color bitmap. */
static int
x_copy_image(gx_device_X * xdev, const byte * base, int sourcex, int raster,
             int x, int y, int w, int h)
{
    int depth = xdev->color_info.depth;

    X_SET_FILL_STYLE(xdev, FillSolid);
    X_SET_FUNCTION(xdev, GXcopy);

    /* Filling with a colored halftone often gives rise to */
    /* copy_color calls for a single pixel.  Check for this now. */

    if (h == 1 && w == 1) {
        uint sbit = sourcex * depth;
        const byte *ptr = base + (sbit >> 3);
        x_pixel pixel;

        if (depth < 8)
            pixel = (byte) (*ptr << (sbit & 7)) >> (8 - depth);
        else {
            pixel = *ptr++;
            while ((depth -= 8) > 0)
                pixel = (pixel << 8) + *ptr++;
        }
        X_SET_FORE_COLOR(xdev, pixel);
        XDrawPoint(xdev->dpy, xdev->dest, xdev->gc, x, y);
    } else {
        /* Reduce base, sourcex  */
        int width = sourcex + w;
        int vdepth = xdev->vinfo->depth;
        xdev->image.width = width;
        xdev->image.height = h;
        xdev->image.format = ZPixmap;
        xdev->image.data = (char *)base;
        xdev->image.depth = vdepth;
        xdev->image.bitmap_pad = 8;
        if (width * vdepth < raster * 8)
            xdev->image.bytes_per_line = raster;
        else
            xdev->image.bytes_per_line = 0;
        xdev->image.bits_per_pixel = depth;
        if (XInitImage(&xdev->image) == 0){
            errprintf(xdev->memory, "XInitImage failed in x_copy_image.\n");
            return_error(gs_error_unknownerror);
        }
        XPutImage(xdev->dpy, xdev->dest, xdev->gc, &xdev->image,
                  sourcex, 0, x, y, w, h);
        xdev->image.depth = xdev->image.bits_per_pixel = 1;

        /* give up on optimization */
        xdev->colors_or = (x_pixel)(-1);
        xdev->colors_and = 0;
    }
    return 0;
}
static int
x_copy_color(gx_device * dev,
             const byte * base, int sourcex, int raster, gx_bitmap_id id,
             int x, int y, int w, int h)
{
    gx_device_X *xdev = (gx_device_X *) dev;
    int code;

    fit_copy(dev, base, sourcex, raster, id, x, y, w, h);
    flush_text(xdev);
    code = x_copy_image(xdev, base, sourcex, raster, x, y, w, h);
    if (xdev->bpixmap != (Pixmap) 0)
        x_update_add(xdev, x, y, w, h);
    if_debug4m('F', dev->memory, "[F] copy_color (%d,%d):(%d,%d)\n",
               x, y, w, h);
    return code;
}

/* Get the page device.  We reimplement this so that we can make this */
/* device be a page device conditionally. */
static gx_device *
x_get_page_device(gx_device * dev)
{
    return (((gx_device_X *) dev)->IsPageDevice ? dev : (gx_device *) 0);
}

/* Tile a rectangle. */
static int
x_strip_tile_rectangle(gx_device * dev, const gx_strip_bitmap * tiles,
                       int x, int y, int w, int h,
                       gx_color_index zero, gx_color_index one,
                       int px, int py)
{
    gx_device_X *xdev = (gx_device_X *) dev;
    unsigned long lzero = (unsigned long) zero;
    unsigned long lone = (unsigned long) one;

    /* Give up if one color is transparent, or if the tile is colored. */
    /* We should implement the latter someday, since X can handle it. */

    if (one == gx_no_color_index || zero == gx_no_color_index)
        return gx_default_strip_tile_rectangle(dev, tiles, x, y, w, h,
                                               zero, one, px, py);

    /* For the moment, give up if the phase or shift is non-zero. */
    if (tiles->shift | px | py)
        return gx_default_strip_tile_rectangle(dev, tiles, x, y, w, h,
                                               zero, one, px, py);

    fit_fill(dev, x, y, w, h);
    flush_text(xdev);

    /* Imaging with a halftone often gives rise to very small */
    /* tile_rectangle calls.  Check for this now. */

    if (h <= 2 && w <= 2) {
        int j;

        X_SET_FILL_STYLE(xdev, FillSolid);
        X_SET_FUNCTION(xdev, GXcopy);
        for (j = y + h; --j >= y;) {
            const byte *ptr =
            tiles->data + (j % tiles->rep_height) * tiles->raster;
            int i;

            for (i = x + w; --i >= x;) {
                uint tx = i % tiles->rep_width;
                byte mask = 0x80 >> (tx & 7);
                x_pixel pixel = (ptr[tx >> 3] & mask ? lone : lzero);

                X_SET_FORE_COLOR(xdev, pixel);
                XDrawPoint(xdev->dpy, xdev->dest, xdev->gc, i, j);
            }
        }
        if (xdev->bpixmap != (Pixmap) 0) {
            x_update_add(xdev, x, y, w, h);
        }
        return 0;
    }
    /*
     * Remember, an X tile is already filled with particular
     * pixel values (i.e., colors).  Therefore if we are changing
     * fore/background color, we must invalidate the tile (using
     * the same technique as in set_tile).  This problem only
     * bites when using grayscale -- you may want to change
     * fg/bg but use the same halftone screen.
     */
    if ((lzero != xdev->ht.back_c) || (lone != xdev->ht.fore_c))
        xdev->ht.id = ~tiles->id;	/* force reload */

    X_SET_BACK_COLOR(xdev, lzero);
    X_SET_FORE_COLOR(xdev, lone);
    if (!set_tile(dev, tiles)) {	/* Bad news.  Fall back to the default algorithm. */
        return gx_default_strip_tile_rectangle(dev, tiles, x, y, w, h,
                                               zero, one, px, py);
    }
    /* Use the tile to fill the rectangle */
    X_SET_FILL_STYLE(xdev, FillTiled);
    X_SET_FUNCTION(xdev, GXcopy);
    XFillRectangle(xdev->dpy, xdev->dest, xdev->gc, x, y, w, h);
    if (xdev->bpixmap != (Pixmap) 0) {
        x_update_add(xdev, x, y, w, h);
    }
    if_debug6m('F', dev->memory, "[F] tile (%d,%d):(%d,%d) %ld,%ld\n",
               x, y, w, h, lzero, lone);
    return 0;
}

/* Implement ImageType 2 using CopyArea if possible. */
/* Note that since ImageType 2 images don't have any source data, */
/* this procedure does all the work. */
static int
x_begin_typed_image(gx_device * dev,
                    const gs_gstate * pgs1, const gs_matrix * pmat,
                    const gs_image_common_t * pic, const gs_int_rect * prect,
              const gx_drawing_color * pdcolor, const gx_clip_path * pcpath,
                    gs_memory_t * mem, gx_image_enum_common_t ** pinfo)
{
    gx_device_X *xdev = (gx_device_X *) dev;
    const gs_image2_t *pim;
    gs_gstate *pgs = (gs_gstate *)pgs1;
    gx_device *sdev;
    gs_matrix smat, dmat;

    if (pic->type->index != 2)
        goto punt;
    pim = (const gs_image2_t *)pic;
    if (!pim->PixelCopy)
        goto punt;
    pgs = pim->DataSource;
    if (pgs == 0)
        goto punt;
    sdev = gs_currentdevice(pgs);
    if (dev->dname != sdev->dname ||
        memcmp(&dev->color_info, &sdev->color_info,
               sizeof(dev->color_info))
        )
        goto punt;
    flush_text(xdev);
    gs_currentmatrix(pgs, &smat);
    /*
     * Figure 7.2 of the Adobe 3010 Supplement says that we should
     * compute CTM x ImageMatrix here, but I'm almost certain it
     * should be the other way around.  Also see gximage2.c.
     */
    gs_matrix_multiply(&pim->ImageMatrix, &smat, &smat);
    gs_currentmatrix(pgs, &dmat);
    if (!((is_xxyy(&dmat) || is_xyyx(&dmat)) &&
#define eqe(e) smat.e == dmat.e
          eqe(xx) && eqe(xy) && eqe(yx) && eqe(yy))
#undef eqe
        )
        goto punt;
    {
        gs_rect rect, src, dest;
        gs_int_point size;
        int srcx, srcy, destx, desty;

        rect.p.x = rect.p.y = 0;
        rect.q.x = pim->Width, rect.q.y = pim->Height;
        gs_bbox_transform(&rect, &dmat, &dest);
        if (pcpath != NULL &&
            !gx_cpath_includes_rectangle(pcpath,
                               float2fixed(dest.p.x), float2fixed(dest.p.y),
                               float2fixed(dest.q.x), float2fixed(dest.q.y))
            )
            goto punt;
        rect.q.x += (rect.p.x = pim->XOrigin);
        rect.q.y += (rect.p.y = pim->YOrigin);
        gs_bbox_transform(&rect, &smat, &src);
        (*pic->type->source_size) (pgs, pic, &size);
        X_SET_FILL_STYLE(xdev, FillSolid);
        X_SET_FUNCTION(xdev, GXcopy);
        srcx = (int)(src.p.x + 0.5);
        srcy = (int)(src.p.y + 0.5);
        destx = (int)(dest.p.x + 0.5);
        desty = (int)(dest.p.y + 0.5);
        XCopyArea(xdev->dpy, xdev->bpixmap, xdev->bpixmap, xdev->gc,
                  srcx, srcy, size.x, size.y, destx, desty);
        x_update_add(xdev, destx, desty, size.x, size.y);
    }
    return 0;
  punt:return gx_default_begin_typed_image(dev, pgs, pmat, pic, prect,
                                        pdcolor, pcpath, mem, pinfo);
}

/* Read bits back from the screen. */
static int
x_get_bits_rectangle(gx_device * dev, const gs_int_rect * prect,
                     gs_get_bits_params_t * params, gs_int_rect ** unread)
{
    gx_device_X *xdev = (gx_device_X *) dev;
    int depth = dev->color_info.depth;
    int x0 = prect->p.x, y0 = prect->p.y, x1 = prect->q.x, y1 = prect->q.y;
    uint width_bytes = ((x1 - x0) * depth + 7) >> 3;
    uint band = xdev->MaxTempImage / width_bytes;
    uint default_raster = bitmap_raster((x1 - x0) * depth);
    gs_get_bits_options_t options = params->options;
    uint raster =
    (options & GB_RASTER_SPECIFIED ? params->raster :
     (params->raster = default_raster));
    long plane_mask = (1L << depth) - 1;
    int y, h;
    XImage *image;
    int code = 0;
#if GET_IMAGE_EXPOSURES
    XWindowAttributes attributes;
#endif /* GET_IMAGE_EXPOSURES */

    if (x0 < 0 || y0 < 0 || x1 > dev->width || y1 > dev->height)
        return_error(gs_error_rangecheck);
    /* XGetImage can only handle x_offset = 0. */
    if ((options & GB_OFFSET_SPECIFIED) && params->x_offset == 0)
        options = (options & ~GB_OFFSET_SPECIFIED) | GB_OFFSET_0;
    if (~options &
        (GB_RETURN_COPY | GB_OFFSET_0 | GB_PACKING_CHUNKY |
         GB_COLORS_NATIVE) ||
        !(options & GB_ALIGN_ALL) ||
        !(options & GB_RASTER_ALL)
        )
        return
            gx_default_get_bits_rectangle(dev, prect, params, unread);
    params->options =
        GB_COLORS_NATIVE | GB_ALPHA_NONE | GB_PACKING_CHUNKY |
        GB_RETURN_COPY | GB_OFFSET_0 |
        (options & GB_ALIGN_ALL) |
        (options & GB_RASTER_SPECIFIED ? GB_RASTER_SPECIFIED :
         GB_RASTER_STANDARD);
    if (x0 >= x1 || y0 >= y1)
        return 0;
    if (x1 <= xdev->update.box.p.x || x0 >= xdev->update.box.q.x ||
        y1 <= xdev->update.box.p.y || y0 >= xdev->update.box.q.y
        ) {
        /*
         * The area being read back doesn't overlap the pending update:
         * just flush text.
         */
        flush_text(xdev);
    } else
        update_do_flush(xdev);
    /*
     * If we want a list of unread rectangles, turn on graphics
     * exposures, and accept exposure events.
     */
        /******
         ****** FOLLOWING IS WRONG.  XGetImage DOES NOT GENERATE
         ****** EXPOSURE EVENTS.
         ******/
#if GET_IMAGE_EXPOSURES
    if (unread) {
        XSetGraphicsExposures(xdev->dpy, xdev->gc, True);
        XGetWindowAttributes(xdev->dpy, xdev->win, &attributes);
        XSelectInput(xdev->dpy, xdev->win,
                     attributes.your_event_mask | ExposureMask);
    }
#endif /* GET_IMAGE_EXPOSURES */
    /*
     * The X library doesn't provide any way to specify the desired
     * bit or byte ordering for the result, so we may have to swap the
     * bit or byte order.
     */
    if (band == 0)
        band = 1;
    for (y = y0; y < y1; y += h) {
        int cy;

        h = min(band, y1 - y);
        image = XGetImage(xdev->dpy, xdev->dest, x0, y, x1 - x0, h,
                          plane_mask, ZPixmap);
        for (cy = y; cy < y + h; ++cy) {
            const byte *source =
                (const byte *)image->data + (cy - y) * image->bytes_per_line;
            byte *dest = params->data[0] + (cy - y0) * raster;

            /*
             * XGetImage can return an image with any bit order, byte order,
             * unit size (for bitmaps), and bits_per_pixel it wants: it's up
             * to us to convert the results.  (It's a major botch in the X
             * design that even though the server has to have the ability to
             * convert images from any format to any format, there's no way
             * to specify a requested format for XGetImage.)
             */
            if (image->bits_per_pixel == image->depth &&
                (image->depth > 1 || image->bitmap_bit_order == MSBFirst) &&
                (image->byte_order == MSBFirst || image->depth <= 8)
                ) {
                /*
                 * The server has been nice enough to return an image in the
                 * format we use.
                 */
                memcpy(dest, source, width_bytes);
            } else {
                /*
                 * We need to swap byte order and/or bit order.  What a
                 * totally unnecessary nuisance!  For the moment, the only
                 * cases we deal with are 15-, 16- and 24-bit images with padding
                 * and/or byte swapping.
                 * If we ever need to support other color depths, consider rewriting
                 * all these byte swaps with XGetPixel() .
                 */
                if (image->depth == 24) {
                    int cx;
                    const byte *p = source;
                    byte *q = dest;
                    int step = image->bits_per_pixel >> 3;

                    if (image->byte_order == MSBFirst) {
                        p += step - 3;
                        for (cx = x0; cx < x1; p += step, q += 3, ++cx)
                            q[0] = p[0], q[1] = p[1], q[2] = p[2];
                    } else {
                        for (cx = x0; cx < x1; p += step, q += 3, ++cx)
                            q[0] = p[2], q[1] = p[1], q[2] = p[0];
                    }
                } else if (image->depth == 16 || image->depth == 15) {
                    int cx;
                    const byte *p = source;
                    byte *q = dest;
                    int step = image->bits_per_pixel >> 3;

                    if (image->byte_order == MSBFirst) {
                        p += step - 2;
                        for (cx = x0; cx < x1; p += step, q += 2, ++cx)
                            q[0] = p[0], q[1] = p[1];
                    } else {
                        for (cx = x0; cx < x1; p += step, q += 2, ++cx)
                            q[0] = p[1], q[1] = p[0];
                    }
                } else
                    code = gs_note_error(gs_error_rangecheck);
            }
        }
        XDestroyImage(image);
    }
    if (unread) {
#if GET_IMAGE_EXPOSURES
        XEvent event;
#endif /* GET_IMAGE_EXPOSURES */

        *unread = 0;
#if GET_IMAGE_EXPOSURES
        /* Read any exposure events. */
        XWindowEvent(xdev->dpy, xdev->win, ExposureMask, &event);
        if (event.type == GraphicsExpose) {
            gs_int_rect *rects = (gs_int_rect *)
                gs_alloc_bytes(dev->memory, sizeof(gs_int_rect),
                               "x_get_bits_rectangle");
            int num_rects = 0;

            for (;;) {
                if (rects == 0) {
                    code = gs_note_error(gs_error_VMerror);
                    break;
                }
#define xevent (*(XGraphicsExposeEvent *)&event)
                rects[num_rects].q.x = xevent.width +
                    (rects[num_rects].p.x = xevent.x);
                rects[num_rects].q.y = xevent.height +
                    (rects[num_rects].p.y = xevent.y);
                ++num_rects;
                if (!xevent.count)
                    break;
#undef xevent
                rects = gs_resize_object(dev->memory, rects,
                                         (num_rects + 1) * sizeof(gs_int_rect),
                                         "x_get_bits_rectangle");
            }
            if (code >= 0) {
                *unread = rects;
                code = num_rects;
            }
        }
        /* Restore the window state. */
        XSetGraphicsExposures(xdev->dpy, xdev->gc, False);
        XSelectInput(xdev->dpy, xdev->win, attributes.your_event_mask);
#endif /* GET_IMAGE_EXPOSURES */
    }
    return code;
}

/* Supplying a fillpage prevents the erasepage optimisation
   device being installed.
 */
static int
x_fillpage(gx_device *dev, gs_gstate * pgs, gx_device_color *pdevc)
{
    return gx_default_fillpage(dev, pgs, pdevc);
}

/* Set up with a specified tile. */
/* Return false if we can't do it for some reason. */
static int
set_tile(gx_device * dev, const gx_strip_bitmap * tile)
{
    gx_device_X *xdev = (gx_device_X *) dev;

#ifdef DEBUG
    if (gs_debug['T'])
        return 0;
#endif
    if (tile->id == xdev->ht.id && tile->id != gx_no_bitmap_id)
        return xdev->useXSetTile;
    /* Set up the tile Pixmap */
    if (tile->size.x != xdev->ht.width ||
        tile->size.y != xdev->ht.height ||
        xdev->ht.pixmap == (Pixmap) 0) {
        if (xdev->ht.pixmap != (Pixmap) 0)
            XFreePixmap(xdev->dpy, xdev->ht.pixmap);
        xdev->ht.pixmap = XCreatePixmap(xdev->dpy, xdev->win,
                                        tile->size.x, tile->size.y,
                                        xdev->vinfo->depth);
        if (xdev->ht.pixmap == (Pixmap) 0)
            return 0;
        xdev->ht.width = tile->size.x, xdev->ht.height = tile->size.y;
        xdev->ht.raster = tile->raster;
    }
    xdev->ht.fore_c = xdev->fore_color;
    xdev->ht.back_c = xdev->back_color;
    /* Copy the tile into the Pixmap */
    xdev->image.data = (char *)tile->data;
    xdev->image.width = tile->size.x;
    xdev->image.height = tile->size.y;
    xdev->image.bytes_per_line = tile->raster;
    xdev->image.format = XYBitmap;
    X_SET_FILL_STYLE(xdev, FillSolid);
#ifdef DEBUG
    if (gs_debug['H']) {
        int i;

        dmlprintf4(xdev->memory, "[H] 0x%lx: width=%d height=%d raster=%d\n",
              (ulong) tile->data, tile->size.x, tile->size.y, tile->raster);
        dmlputs(xdev->memory, "");
        for (i = 0; i < tile->raster * tile->size.y; i++)
            dmprintf1(xdev->memory, " %02x", tile->data[i]);
        dmputc(xdev->memory, '\n');
    }
#endif
    XSetTile(xdev->dpy, xdev->gc, xdev->ht.no_pixmap);	/* *** X bug *** */
    X_SET_FUNCTION(xdev, GXcopy);
    put_image(xdev->dpy, xdev->ht.pixmap, xdev->gc, &xdev->image,
              0, 0, 0, 0, tile->size.x, tile->size.y);
    XSetTile(xdev->dpy, xdev->gc, xdev->ht.pixmap);
    xdev->ht.id = tile->id;
    return xdev->useXSetTile;
}

/* ------ Screen update procedures ------ */

/* Initialize the update machinery. */
static void
update_init(gx_device_X *xdev)
{
    xdev->update.box.p.x = xdev->update.box.p.y = max_int_in_fixed;
    xdev->update.box.q.x = xdev->update.box.q.y = min_int_in_fixed;
    xdev->update.area = xdev->update.total = xdev->update.count = 0;
}

/* Flush updates to the screen if needed. */
static void
update_do_flush(gx_device_X * xdev)
{
    flush_text(xdev);
    if (xdev->update.box.q.x == min_int_in_fixed || xdev->update.box.q.y == min_int_in_fixed)
        return;
    if (xdev->update.box.p.x == max_int_in_fixed || xdev->update.box.p.y == max_int_in_fixed)
        return;
    if (xdev->update.count != 0) {
        int x = xdev->update.box.p.x, y = xdev->update.box.p.y;
        int w = xdev->update.box.q.x - x, h = xdev->update.box.q.y - y;
        const gx_device_memory *mdev = NULL;

        /*
         * Copy from memory image to X server if any.
         */
        if (xdev->is_buffered) {
            /*
             * The bbox device may have set the target to NULL
             * temporarily.  If this is the case, defer the screen
             * update.
             */
            if (!(mdev = (const gx_device_memory *)xdev->target))
                return;
        }

        /*
         * mdev->width and mdev->height arn't the same as
         * xdev->width and xdev->height ... at least for gv
         */
        if (mdev)
            fit_fill_xywh(mdev, x, y, w, h);
        else
            fit_fill_xywh(xdev, x, y, w, h);

        if (w > 0 && h > 0) {
            if (mdev)
                x_copy_image(xdev, mdev->line_ptrs[y], x, mdev->raster,
                             x, y, w, h);
            if (xdev->bpixmap) {
                /* Copy from X backing pixmap to screen. */

                X_SET_FUNCTION(xdev, GXcopy);
                XCopyArea(xdev->dpy, xdev->bpixmap, xdev->win, xdev->gc,
                          x, y, w, h, x, y);
            }
        }
        update_init(xdev);
    }
}

/* Add a region to be updated, after writing to that region. */
void
x_update_add(gx_device_X * xdev, int xo, int yo, int w, int h)
{
    int xe = xo + w, ye = yo + h;
    long added = (long)w * h;
    long old_area = xdev->update.area;
    gs_int_rect u;
    int nw, nh;
    long new_up_area;

    u.p.x = min(xo, xdev->update.box.p.x);
    u.p.y = min(yo, xdev->update.box.p.y);
    u.q.x = max(xe, xdev->update.box.q.x);
    u.q.y = max(ye, xdev->update.box.q.y);
    nw = u.q.x - u.p.x;
    nh = u.q.y - u.p.y;
    new_up_area = (long)nw * nh;
    xdev->update.count++;
    xdev->update.area = new_up_area;
    xdev->update.total += added;
    if (!xdev->AlwaysUpdate) {
        /*
         * Test whether adding this rectangle would result in too much being
         * copied unnecessarily.  The fraction of new_up_area used in the
         * following test is not particularly critical; using a denominator
         * that is a power of 2 eliminates a divide.
         */
        if (nw + nh >= 70 && (nw | nh) >= 16 &&
            old_area + added < new_up_area - (new_up_area >> 2)
            )
            DO_NOTHING;
        else {
            xdev->update.box = u;
            return;
        }
    }
    if (xdev->is_buffered && (xdev->target == NULL))
        xdev->update.box = u;	/* update deferred since bbox has target disabled */
    else {
        update_do_flush(xdev);
        xdev->update.box.p.x = xo, xdev->update.box.p.y = yo;
        xdev->update.box.q.x = xe, xdev->update.box.q.y = ye;
        xdev->update.count = 1;
        xdev->update.area = xdev->update.total = added;
    }
}

/* Flush buffered text to the screen. */
static void
do_flush_text(gx_device_X * xdev)
{
    if (!IN_TEXT(xdev))
        return;
    DRAW_TEXT(xdev);
    xdev->text.item_count = xdev->text.char_count = 0;
}

/* Bounding box device procedures (only used when buffering) */
static bool
x_bbox_init_box(void *pdata)
{
    gx_device_X *const xdev = pdata;

    update_init(xdev);
    return true;
}
static void
x_bbox_get_box(const void *pdata, gs_fixed_rect *pbox)
{
    const gx_device_X *const xdev = pdata;

    pbox->p.x = int2fixed(xdev->update.box.p.x);
    pbox->p.y = int2fixed(xdev->update.box.p.y);
    pbox->q.x = int2fixed(xdev->update.box.q.x);
    pbox->q.y = int2fixed(xdev->update.box.q.y);
}
static void
x_bbox_add_rect(void *pdata, fixed x0, fixed y0, fixed x1, fixed y1)
{
    gx_device_X *const xdev = pdata;
    int x = fixed2int(x0), y = fixed2int(y0);

    x_update_add(xdev, x, y, fixed2int_ceiling(x1) - x,
                 fixed2int_ceiling(y1) - y);
}
static bool
x_bbox_in_rect(const void *pdata, const gs_fixed_rect *pbox)
{
    gs_fixed_rect box;

    x_bbox_get_box(pdata, &box);
    return rect_within(*pbox, box);
}
const gx_device_bbox_procs_t gdev_x_box_procs = {
    x_bbox_init_box, x_bbox_get_box, x_bbox_add_rect, x_bbox_in_rect
};

/* ------ Internal procedures ------ */

/*
 * Substitute for XPutImage using XFillRectangle.  This is a hack to get
 * around an apparent bug in some X servers.  It only works with the
 * specific parameters (bit/byte order, padding) used above.
 */
static int
alt_put_image(gx_device *dev, Display *dpy, Drawable win, GC gc, XImage *pi,
              int sx, int sy, int dx, int dy, unsigned w, unsigned h)
{
    int raster = pi->bytes_per_line;
    byte *data = (byte *) pi->data + sy * raster + (sx >> 3);
    int init_mask = 0x80 >> (sx & 7);
    int invert = 0;
    int yi;
#define NUM_RECTS 40
    XRectangle rects[NUM_RECTS];
    XRectangle *rp = rects;
    XGCValues gcv;

#ifdef DEBUG
    if (pi->format != XYBitmap || pi->byte_order != MSBFirst ||
        pi->bitmap_bit_order != MSBFirst || pi->depth != 1
        ) {
        lprintf("alt_put_image: unimplemented parameter values!\n");
        return_error(gs_error_rangecheck);
    }
#endif

    XGetGCValues(dpy, gc, (GCFunction | GCForeground | GCBackground), &gcv);

    if (gcv.function == GXcopy) {
        XSetForeground(dpy, gc, gcv.background);
        XFillRectangle(dpy, win, gc, dx, dy, w, h);
        XSetForeground(dpy, gc, gcv.foreground);
    } else if (gcv.function == GXand) {
        /* The only cases used above are fc = ~0 or bc = ~0. */
#ifdef DEBUG
        if (gcv.foreground != ~(x_pixel)0 && gcv.background != ~(x_pixel)0) {
            lprintf("alt_put_image: unimplemented GXand case!\n");
            return_error(gs_error_rangecheck);
        }
#endif
        if (gcv.background != ~(x_pixel) 0) {
            XSetForeground(dpy, gc, gcv.background);
            invert = 0xff;
        }
    } else if (gcv.function == GXor) {
        /* The only cases used above are fc = 0 or bc = 0. */
#ifdef DEBUG
        if (gcv.foreground != 0 && gcv.background != 0) {
            lprintf("alt_put_image: unimplemented GXor case!\n");
            return_error(gs_error_rangecheck);
        }
#endif
        if (gcv.background != 0) {
            XSetForeground(dpy, gc, gcv.background);
            invert = 0xff;
        }
    } else {
        lprintf("alt_put_image: unimplemented function.\n");
        return_error(gs_error_rangecheck);
    }

    for (yi = 0; yi < h; yi++, data += raster) {
        int mask = init_mask;
        byte *dp = data;
        int xi = 0;

        while (xi < w) {
            if ((*dp ^ invert) & mask) {
                int xleft = xi;

                if (rp == &rects[NUM_RECTS]) {
                    XFillRectangles(dpy, win, gc, rects, NUM_RECTS);
                    rp = rects;
                }
                /* Scan over a run of 1-bits */
                rp->x = dx + xi, rp->y = dy + yi;
                do {
                    if (!(mask >>= 1))
                        mask = 0x80, dp++;
                    xi++;
                } while (xi < w && ((*dp ^ invert) & mask));
                rp->width = xi - xleft, rp->height = 1;
                rp++;
            } else {
                if (!(mask >>= 1))
                    mask = 0x80, dp++;
                xi++;
            }
        }
    }
    XFillRectangles(dpy, win, gc, rects, rp - rects);
    if (invert)
        XSetForeground(dpy, gc, gcv.foreground);
    return 0;
#undef NUM_RECTS
}
