xref: /xsrc/external/mit/bitmap/dist/Graphics.c

/* $Xorg: Graphics.c,v 1.4 2001/02/09 02:05:28 xorgcvs Exp $ */
/*

Copyright 1989, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall
not be used in advertising or otherwise to promote the sale, use or
other dealings in this Software without prior written authorization
from The Open Group.

*/
/* $XFree86: xc/programs/bitmap/Graphics.c,v 1.5 2001/01/17 23:44:51 dawes Exp $ */

/*
 * Author:  Davor Matic, MIT X Consortium
 */

#include <X11/IntrinsicP.h>
#include <X11/StringDefs.h>
#include <X11/Xfuncs.h>
#include "BitmapP.h"
#include "Bitmap.h"
#include "Requests.h"

#include <stdio.h>
#include <math.h>

#ifndef abs
#define abs(x)                        (((x) > 0) ? (x) : -(x))
#endif
#define min(x, y)                     (((int)(x) < (int)(y)) ? (x) : (y))
#define max(x, y)                     (((int)(x) > (int)(y)) ? (x) : (y))
#ifndef rint
#define rint(x)                       floor(x + 0.5)
#endif

/*****************************************************************************\
 *                                   Graphics                                *
\*****************************************************************************/

#define GetBit(image, x, y)\
    ((bit)((*(image->data + (x) / 8 + (y) * image->bytes_per_line) &\
	    (1 << ((x) % 8))) ? 1 : 0))

#if 0
bit
BWGetBit(Widget w, Position x, Position y)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QueryInBitmap(BW, x, y))
	return GetBit(BW->bitmap.image, x, y);
    else
	return NotSet;
}
#endif

#define InvertBit(image, x, y)\
    (*(image->data + (x) / 8 + (y) * image->bytes_per_line) ^=\
     (bit) (1 << ((x) % 8)))


#define SetBit(image, x, y)\
    (*(image->data + (x) / 8 + (y) * image->bytes_per_line) |=\
     (bit) (1 << ((x) % 8)))

#define ClearBit(image, x, y)\
    (*(image->data + (x) / 8 + (y) * image->bytes_per_line) &=\
     (bit)~(1 << ((x) % 8)))


#define HighlightSquare(BW, x, y)\
    XFillRectangle(XtDisplay(BW), XtWindow(BW),\
                   BW->bitmap.highlighting_gc,\
		   InWindowX(BW, x), InWindowY(BW, y),\
                   BW->bitmap.squareW, BW->bitmap.squareH)
/*
void
HighlightSquare(BitmapWidget BW, Position x, Position y)
{
    XFillRectangle(XtDisplay(BW), XtWindow(BW),
                   BW->bitmap.highlighting_gc,
		   InWindowX(BW, x), InWindowY(BW, y),
                   BW->bitmap.squareW, BW->bitmap.squareH);
}
*/

#define DrawSquare(BW, x, y)\
    XFillRectangle(XtDisplay(BW), XtWindow(BW),\
                   BW->bitmap.drawing_gc,\
		   InWindowX(BW, x), InWindowY(BW, y),\
                   BW->bitmap.squareW, BW->bitmap.squareH)

/*
void
DrawSquare(BitmapWidget BW, Position x, Position y)
{
    XFillRectangle(XtDisplay(BW), XtWindow(BW),
                   BW->bitmap.drawing_gc,
		   InWindowX(BW, x), InWindowY(BW, y),
                   BW->bitmap.squareW, BW->bitmap.squareH);
}
*/

#define InvertPoint(BW, x, y)\
    {InvertBit(BW->bitmap.image, x, y); DrawSquare(BW, x, y);}

#define DrawPoint(BW, x, y, value)\
    if (GetBit(BW->bitmap.image, x, y) != value)\
       InvertPoint(BW, x, y)

void
BWDrawPoint(Widget w, Position x, Position y, bit value)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QueryInBitmap(BW, x, y)) {
	if (value == Highlight)
	    HighlightSquare(BW, x, y);
	else
	    DrawPoint(BW, x, y, value);
    }
}

static XPoint *
HotSpotShape(BitmapWidget BW, Position x, Position y)
{
    static XPoint points[5];

    points[0].x = InWindowX(BW, x);
    points[0].y = InWindowY(BW, y + 1.0/2);
    points[1].x = InWindowX(BW, x + 1.0/2);
    points[1].y = InWindowY(BW, y + 1);
    points[2].x = InWindowX(BW, x + 1);
    points[2].y = InWindowY(BW, y + 1.0/2);
    points[3].x = InWindowX(BW, x + 1.0/2);
    points[3].y = InWindowY(BW, y);
    points[4].x = InWindowX(BW, x);
    points[4].y = InWindowY(BW, y + 1.0/2);

    return points;
}

#define DrawHotSpot(BW, x, y)\
  XFillPolygon(XtDisplay(BW), XtWindow(BW), BW->bitmap.drawing_gc,\
	       HotSpotShape(BW, x, y), 5, Convex, CoordModeOrigin)

#define HighlightHotSpot(BW, x, y)\
  XFillPolygon(XtDisplay(BW), XtWindow(BW), BW->bitmap.highlighting_gc,\
	       HotSpotShape(BW, x, y), 5, Convex, CoordModeOrigin)

/*
XImage *CreateBitmapImage();
void DestroyBitmapImage();
*/

void
BWRedrawHotSpot(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y))
	DrawHotSpot(BW, BW->bitmap.hot.x, BW->bitmap.hot.y);
}

void
BWClearHotSpot(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)) {
      DrawHotSpot(BW, BW->bitmap.hot.x, BW->bitmap.hot.y);
      BW->bitmap.hot.x = BW->bitmap.hot.y = NotSet;
    }
}

void
BWDrawHotSpot(Widget w, Position x, Position y, int value)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QueryInBitmap(BW, x, y)) {
	if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y) &&
	    ((BW->bitmap.hot.x == x) && (BW->bitmap.hot.y == y))) {
	    if ((value == Clear) || (value == Invert)) {
		BWClearHotSpot(w);
	    }
	}
	else
	    if ((value == Set) || (value == Invert)) {
		BWClearHotSpot(w);
		DrawHotSpot(BW, x, y);
		BW->bitmap.hot.x = x;
		BW->bitmap.hot.y = y;
	    }

	if (value == Highlight)
	    HighlightHotSpot(BW, x, y);
    }
}

void
BWSetHotSpot(Widget w, Position x, Position y)
{
    if (QuerySet(x, y))
	BWDrawHotSpot(w, x, y, Set);
    else
	BWClearHotSpot(w);
}

/* high level procedures */

void
BWRedrawSquares(Widget w,
		Position x, Position y,
		Dimension width, Dimension height)
{
    BitmapWidget BW = (BitmapWidget) w;
    Position from_x = InBitmapX(BW, x);
    Position from_y = InBitmapY(BW, y);
    Position to_x = InBitmapX(BW, x + width);
    Position to_y = InBitmapY(BW, y + height);

    QuerySwap(from_x, to_x);
    QuerySwap(from_y, to_y);
    from_x = max(0, from_x);
    from_y = max(0, from_y);
    to_x = min(BW->bitmap.image->width - 1, to_x);
    to_y = min(BW->bitmap.image->height - 1, to_y);

    for (x = from_x; x <= to_x; x++)
	for (y = from_y; y <= to_y; y++)
	    if (GetBit(BW->bitmap.image, x, y)) DrawSquare(BW, x, y);
}

void
BWDrawGrid(Widget w,
	   Position from_x, Position from_y,
	   Position to_x, Position to_y)
{
    BitmapWidget BW = (BitmapWidget) w;
    int i;

    QuerySwap(from_x, to_x);
    QuerySwap(from_y, to_y);
    from_x = max(0, from_x);
    from_y = max(0, from_y);
    to_x = min(BW->bitmap.image->width - 1, to_x);
    to_y = min(BW->bitmap.image->height - 1, to_y);

    for(i = from_x + (from_x == 0); i <= to_x; i++)
	XDrawLine(XtDisplay(BW), XtWindow(BW),
		  BW->bitmap.frame_gc,
		  InWindowX(BW, i), InWindowY(BW, from_y),
		  InWindowX(BW, i), InWindowY(BW, to_y + 1));

    for(i = from_y + (from_y == 0); i <= to_y; i++)
	XDrawLine(XtDisplay(BW), XtWindow(BW),
		  BW->bitmap.frame_gc,
		  InWindowX(BW, from_x), InWindowY(BW, i),
		  InWindowX(BW, to_x + 1), InWindowY(BW, i));
}


void
BWRedrawGrid(Widget w,
	     Position x, Position y,
	     Dimension width, Dimension height)
{
    BitmapWidget BW = (BitmapWidget) w;
    Position from_x = InBitmapX(BW, x);
    Position from_y = InBitmapY(BW, y);
    Position to_x = InBitmapX(BW, x + width);
    Position to_y = InBitmapY(BW, y + height);

    if (BW->bitmap.grid)
	BWDrawGrid(w, from_x, from_y, to_x, to_y);
}

void
BWDrawLine(Widget w,
	   Position from_x, Position from_y,
	   Position to_x, Position to_y, int value)
{
    Position i;
    register double x, y;
    double dx, dy, delta;

    dx = to_x - from_x;
    dy = to_y - from_y;
    x = from_x + 0.5;
    y = from_y + 0.5;
    delta = max(abs(dx), abs(dy));
    if (delta > 0) {
	dx /= delta;
	dy /= delta;
	for(i = 0; i <= delta; i++) {
	    BWDrawPoint(w, (Position) x, (Position) y, value);
	    x += dx;
	    y += dy;
	}
    }
    else
	BWDrawPoint(w, from_x, from_y, value);
}

void
BWBlindLine(Widget w,
	    Position from_x, Position from_y,
	    Position to_x, Position to_y, int value)
{
    Position i;
    register double x, y;
    double dx, dy, delta;

    dx = to_x - from_x;
    dy = to_y - from_y;
    x = from_x + 0.5;
    y = from_y + 0.5;
    delta = max(abs(dx), abs(dy));
    if (delta > 0) {
	dx /= delta;
	dy /= delta;
	x += dx;
	y += dy;
	for(i = 1; i <= delta; i++) {
	    BWDrawPoint(w, (Position) x, (Position) y, value);
	    x += dx;
	    y += dy;
	}
    }
    else
	BWDrawPoint(w, from_x, from_y, value);
}

void
BWDrawRectangle(Widget w,
		Position from_x, Position from_y,
		Position to_x, Position to_y, int value)
{
    register Position i;
    Dimension delta, width, height;

    QuerySwap(from_x, to_x);
    QuerySwap(from_y, to_y);

    width = to_x - from_x;
    height = to_y - from_y;

    delta = max(width, height);

    if (!QueryZero(width, height)) {
	for (i = 0; (int)i < (int)delta; i++) {
	    if ((int)i < (int)width) {
		BWDrawPoint(w, from_x + i, from_y, value);
		BWDrawPoint(w, to_x - i, to_y, value);
	    }
	    if ((int)i < (int)height) {
		BWDrawPoint(w, from_x, to_y - i, value);
		BWDrawPoint(w, to_x, from_y + i, value);
	    }
	}
    }
    else
	BWDrawLine(w,
		   from_x, from_y,
		   to_x, to_y, value);
}

void
BWDrawFilledRectangle(Widget w,
		      Position from_x, Position from_y,
		      Position to_x, Position to_y, int value)
{
    register Position x, y;

    QuerySwap(from_x, to_x);
    QuerySwap(from_y, to_y);

    for (x = from_x; x <= to_x; x++)
	for (y = from_y; y <= to_y; y++)
	    BWDrawPoint(w, x, y, value);
}

void
BWDrawCircle(Widget w,
	     Position origin_x, Position origin_y,
	     Position point_x, Position point_y, int value)
{
    register Position i, delta;
    Dimension dx, dy, half;
    double radius;

    dx = abs(point_x - origin_x);
    dy = abs(point_y - origin_y);
    radius = sqrt((double) ((int)dx * (int)dx + (int)dy * (int)dy));
    if (radius < 1.0) {
	BWDrawPoint(w, origin_x, origin_y, value);
    }
    else {
	BWDrawPoint(w, origin_x - (Position) floor(radius), origin_y, value);
	BWDrawPoint(w, origin_x + (Position) floor(radius), origin_y, value);
	BWDrawPoint(w, origin_x, origin_y - (Position) floor(radius), value);
	BWDrawPoint(w, origin_x, origin_y + (Position) floor(radius), value);
    }
    half = radius / sqrt(2.0);
    for(i = 1; (int)i <= (int)half; i++) {
	delta = sqrt(radius * radius - i * i);
	BWDrawPoint(w, origin_x - delta, origin_y - i, value);
	BWDrawPoint(w, origin_x - delta, origin_y + i, value);
	BWDrawPoint(w, origin_x + delta, origin_y - i, value);
	BWDrawPoint(w, origin_x + delta, origin_y + i, value);
	if (i != delta) {
	    BWDrawPoint(w, origin_x - i, origin_y - delta, value);
	    BWDrawPoint(w, origin_x - i, origin_y + delta, value);
	    BWDrawPoint(w, origin_x + i, origin_y - delta, value);
	    BWDrawPoint(w, origin_x + i, origin_y + delta, value);
	}
    }
}

void
BWDrawFilledCircle(Widget w,
		   Position origin_x, Position origin_y,
		   Position point_x, Position point_y, int value)
{
    register Position i, j, delta;
    Dimension dx, dy;
    double radius;

    dx = abs(point_x - origin_x);
    dy = abs(point_y - origin_y);
    radius = sqrt((double) ((int)dx * (int)dx + (int)dy * (int)dy));
    for(j = origin_x - (Position) floor(radius);
	j <= origin_x + (Position) floor(radius); j++)
	BWDrawPoint(w, j, origin_y, value);
    for(i = 1; i <= (Position) floor(radius); i++) {
	delta = sqrt(radius * radius - i * i);
	for(j = origin_x - delta; j <= origin_x + delta; j++) {
	    BWDrawPoint(w, j, origin_y - i, value);
	    BWDrawPoint(w, j, origin_y + i, value);
	}
    }
}

#define QueryFlood(BW, x, y, value)\
    ((GetBit(BW->bitmap.image, x, y) !=\
      (value & 1)) && QueryInBitmap(BW, x, y))

#define Flood(BW, x, y, value)\
    {if (value == Highlight) HighlightSquare(BW, x, y);\
     else InvertPoint(BW, x, y);}

/*
static void
FloodLoop(BitmapWidget BW, Position x, Position y, int value)
{
    if (QueryFlood(BW, x, y, value)) {
	Flood(BW, x, y, value);
	FloodLoop(BW, x, y - 1, value);
	FloodLoop(BW, x - 1, y, value);
	FloodLoop(BW, x, y + 1, value);
	FloodLoop(BW, x + 1, y, value);
    }
}
*/

static void
FloodLoop(BitmapWidget BW, Position x, Position y, int value)
{
    Position save_x, save_y, x_left, x_right;

    if (QueryFlood(BW, x, y, value))
	Flood(BW, x, y, value)


    save_x = x;
    save_y = y;

    x++;
    while (QueryFlood(BW, x, y, value)) {
	Flood(BW, x, y, value);
	x++;
    }
    x_right = --x;

    x = save_x;
    x--;
    while (QueryFlood(BW, x, y, value)) {
	Flood(BW, x, y, value);
	x--;
    }
    x_left = ++x;


    x = x_left;
    y = save_y;
    y++;

    while (x <= x_right) {
	Boolean flag = False;
	Position x_enter;

	while (QueryFlood(BW, x, y, value) && (x <= x_right)) {
	    flag = True;
	    x++;
	}

	if (flag) {
	    if ((x == x_right) && QueryFlood(BW, x, y, value))
		FloodLoop(BW, x, y, value);
	    else
		FloodLoop(BW, x - 1, y, value);
	}

	x_enter = x;

	while (!QueryFlood(BW, x, y, value) && (x < x_right))
	    x++;

	if (x == x_enter) x++;
    }

    x = x_left;
    y = save_y;
    y--;

    while (x <= x_right) {
	Boolean flag = False;
	Position x_enter;

	while (QueryFlood(BW, x, y, value) && (x <= x_right)) {
	    flag = True;
	    x++;
	}

	if (flag) {
	    if ((x == x_right) && QueryFlood(BW, x, y, value))
		FloodLoop(BW, x, y, value);
	    else
		FloodLoop(BW, x - 1, y, value);
	}

	x_enter = x;

	while (!QueryFlood(BW, x, y, value) && (x < x_right))
	    x++;

	if (x == x_enter) x++;
    }
}

void
BWFloodFill(Widget w, Position x, Position y, int value)
{
    BitmapWidget BW = (BitmapWidget) w;
    int pixel;

    pixel = GetBit(BW->bitmap.image, x, y);

    if (value == Invert)
	FloodLoop(BW, x, y, (pixel ? Clear : Set));
    else if (value != pixel)
	FloodLoop(BW, x, y, value);
}

#define QueryHotInMark(BW)\
    ((BW->bitmap.hot.x == max(BW->bitmap.mark.from_x,\
			      min(BW->bitmap.hot.x, BW->bitmap.mark.to_x)))\
     &&\
     (BW->bitmap.hot.y == max(BW->bitmap.mark.from_y,\
			      min(BW->bitmap.hot.y, BW->bitmap.mark.to_y))))

void
BWUp(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    bit first, up, down=0;
    Position from_x, from_y, to_x, to_y;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }

    if ((to_y - from_y) == 0)
	return;

    for(x = from_x; x <= to_x; x++) {
	first = up = GetBit(BW->bitmap.image, x, to_y);
	for(y = to_y - 1; y >= from_y; y--) {
	    down = GetBit(BW->bitmap.image, x, y);
	    if (up != down)
		InvertPoint(BW, x, y);
	    up =down;
	}
	if(first != down)
	    InvertPoint(BW, x, to_y);
    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w))
	BWSetHotSpot(w,
		     BW->bitmap.hot.x,
		     (BW->bitmap.hot.y - 1 + BW->bitmap.image->height) %
		     BW->bitmap.image->height);

}

void
BWDown(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    bit first, down, up=0;
    Position from_x, from_y, to_x, to_y;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }

    if ((to_y - from_y) == 0)
	return;

    for(x = from_x; x <= to_x; x++) {
	first = down = GetBit(BW->bitmap.image, x, from_y);
	for(y = from_y + 1; y <= to_y; y++) {
	    up = GetBit(BW->bitmap.image, x, y);
	    if (down != up)
		InvertPoint(BW, x, y);
	    down = up;
	}
	if(first != up)
	    InvertPoint(BW, x, from_y);
    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w))
	BWSetHotSpot(w,
		     BW->bitmap.hot.x,
		     (BW->bitmap.hot.y + 1) % BW->bitmap.image->height);
}

void
BWLeft(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    bit first, left, right=0;
    Position from_x, from_y, to_x, to_y;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }

    if ((to_x - from_x) == 0)
	return;

    for(y = from_y; y <= to_y; y++) {
	first = left = GetBit(BW->bitmap.image, to_x, y);
	for(x = to_x - 1; x >= from_x; x--) {
	    right = GetBit(BW->bitmap.image, x, y);
	    if (left != right)
		InvertPoint(BW, x, y);
	    left = right;
	}
	if(first != right)
	    InvertPoint(BW, to_x, y);
    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w))
	BWSetHotSpot(w,
		     (BW->bitmap.hot.x - 1 + BW->bitmap.image->width) %
		     BW->bitmap.image->width,
		     BW->bitmap.hot.y);
}

void
BWRight(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    bit first, right, left=0;
    Position from_x, from_y, to_x, to_y;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }

    if ((to_x - from_x) == 0)
	return;

    for(y = from_y; y <= to_y; y++) {
	first = right = GetBit(BW->bitmap.image, from_x, y);
	for(x = from_x + 1; x <= to_x; x++) {
	    left = GetBit(BW->bitmap.image, x, y);
	    if (right != left)
		InvertPoint(BW, x, y);
	    right = left;
	}
	if(first != left)
	    InvertPoint(BW, from_x, y);
    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w))
	BWSetHotSpot(w,
		     (BW->bitmap.hot.x + 1) % BW->bitmap.image->width,
		     BW->bitmap.hot.y);
}

/* void TransferImageData(); */

void
BWFold(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    Position x, y, new_x, new_y;
    Dimension horiz, vert;
    char *storage_data;
    XImage *storage;

    storage_data = CreateCleanData(Length(BW->bitmap.image->width,
					  BW->bitmap.image->height));

    storage = CreateBitmapImage(BW, storage_data,
				(Dimension) BW->bitmap.image->width,
				(Dimension) BW->bitmap.image->height);

    TransferImageData(BW->bitmap.image, storage);

    BW->bitmap.fold ^= True;
    horiz = (BW->bitmap.image->width + BW->bitmap.fold) / 2;
    vert = (BW->bitmap.image->height + BW->bitmap.fold) / 2;

    for (x = 0; x < BW->bitmap.image->width; x++)
	for (y = 0; y < BW->bitmap.image->height; y++) {
	    new_x = (int)(x + horiz) % (int)BW->bitmap.image->width;
	    new_y = (int)(y + vert) % (int)BW->bitmap.image->height;
	    if(GetBit(BW->bitmap.image, new_x, new_y) !=
	       GetBit(storage, x, y))
		InvertPoint(BW, new_x, new_y);
	}

    DestroyBitmapImage(&storage);

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y))
      BWSetHotSpot(w,
		   (Position)
		   ((int)(BW->bitmap.hot.x+horiz)
		    %(int)BW->bitmap.image->width),
		   (Position)
		   ((int)(BW->bitmap.hot.y+vert)
		    %(int)BW->bitmap.image->height)
		   );
}


void
BWClear(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    int i, length;

    length = Length(BW->bitmap.image->width, BW->bitmap.image->height);

    for (x = 0; x < BW->bitmap.image->width; x++)
	for (y = 0; y < BW->bitmap.image->height; y++)
	    if (GetBit(BW->bitmap.image, x, y))
		DrawSquare(BW, x, y);

    for (i = 0; i < length; i++)
	BW->bitmap.image->data[i] = 0;

}

void
BWSet(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    int i, length;

    length = Length(BW->bitmap.image->width, BW->bitmap.image->height);

    for (x = 0; x < BW->bitmap.image->width; x++)
	for (y = 0; y < BW->bitmap.image->height; y++)
	    if (!GetBit(BW->bitmap.image, x, y))
		DrawSquare(BW, x, y);

    for (i = 0; i < length; i++)
	BW->bitmap.image->data[i] = (char)255;

}

void
BWRedraw(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    XClearArea(XtDisplay(BW), XtWindow(BW),
	       0, 0, BW->core.width, BW->core.height,
	       True);
}

void
BWInvert(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    int i, length;

    length = Length(BW->bitmap.image->width, BW->bitmap.image->height);

    XFillRectangle(XtDisplay(BW), XtWindow(BW),
		   BW->bitmap.drawing_gc,
		   InWindowX(BW, 0), InWindowY(BW, 0),
		   InWindowX(BW, BW->bitmap.image->width) - InWindowX(BW, 0),
		   InWindowY(BW, BW->bitmap.image->height) - InWindowY(BW, 0));

    for (i = 0; i < length; i++)
	BW->bitmap.image->data[i] ^= 255;
}

void
BWFlipHoriz(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    Position from_x, from_y, to_x, to_y;
    float half;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }
    half = (float) (to_y - from_y) / 2.0 + 0.5;

    if (half == 0.0)
	return;

    for (x = from_x; x <= to_x; x++)
	for (y = 0; y <  half; y++)
	    if (GetBit(BW->bitmap.image, x, from_y + y) !=
		GetBit(BW->bitmap.image, x, to_y - y)) {
		InvertPoint(BW, x, from_y + y);
		InvertPoint(BW, x, to_y - y);
	    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w))
	BWSetHotSpot(w,
		     BW->bitmap.hot.x,
		     BW->bitmap.image->height - 1 - BW->bitmap.hot.y);
}

void
BWFlipVert(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    register Position x, y;
    Position from_x, from_y, to_x, to_y;
    float half;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }
    half = (float) (to_x - from_x) / 2.0 + 0.5;

    if (half == 0)
	return;

    for (y = from_y; y <= to_y; y++)
	for (x = 0; x < half; x++)
	    if (GetBit(BW->bitmap.image, from_x + x, y) !=
		GetBit(BW->bitmap.image, to_x - x, y)) {
		InvertPoint(BW, from_x + x, y);
		InvertPoint(BW, to_x - x, y);
	    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w))
	BWSetHotSpot(w,
		     BW->bitmap.image->width - 1 - BW->bitmap.hot.x,
		     BW->bitmap.hot.y);
}


void
BWRotateRight(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    Position x, y, delta, shift, tmp;
    Position half_width, half_height;
    XPoint hot;
    bit quad1, quad2, quad3, quad4;
    Position from_x, from_y, to_x, to_y;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }

    half_width = floor((to_x - from_x) / 2.0 + 0.5);
    half_height = floor((to_y - from_y ) / 2.0 + 0.5);
    shift = min((Position)(to_x - from_x), (Position)(to_y - from_y )) % 2;
    delta = min((Position) half_width, (Position) half_height) - shift;

    for (x = 0; x <= delta; x++) {
	for (y = 1 - shift; y <= delta; y++) {
	    quad1 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width + x,
			   from_y + (Position)half_height + y);
	    quad2 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width + y,
			   from_y + (Position)half_height - shift - x);
	    quad3 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width - shift - x,
			   from_y + (Position)half_height - shift - y);
	    quad4 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width - shift - y,
			   from_y + (Position)half_height + x);

	    if (quad1 != quad2)
		InvertPoint(BW,
			    from_x + (Position)half_width + x,
			    from_y + (Position)half_height + y);
	    if (quad2 != quad3)
		InvertPoint(BW,
			    from_x + (Position)half_width + y,
			    from_y + (Position)half_height - shift - x);
	    if (quad3 != quad4)
		InvertPoint(BW,
			    from_x + (Position)half_width - shift - x,
			    from_y + (Position)half_height - shift - y);
	    if (quad4 != quad1)
		InvertPoint(BW,
			    from_x + (Position)half_width - shift - y,
			    from_y + (Position)half_height + x);
	}
    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w)) {
	hot.x = BW->bitmap.hot.x - half_width;
	hot.y = BW->bitmap.hot.y - half_height;
	if (hot.x >= 0) hot.x += shift;
	if (hot.y >= 0) hot.y += shift;
	tmp = hot.x;
	hot.x = - hot.y;
	hot.y = tmp;
	if (hot.x > 0) hot.x -= shift;
	if (hot.y > 0) hot.y -= shift;
	hot.x += half_width;
	hot.y += half_height;
	if (QueryInBitmap(BW, hot.x, hot.y))
	    BWSetHotSpot(w, hot.x, hot.y);
    }

}

void
BWRotateLeft(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    Position x, y,delta, shift, tmp;
    Position half_width, half_height;
    XPoint hot;
    bit quad1, quad2, quad3, quad4;
    Position from_x, from_y, to_x, to_y;

    if (BWQueryMarked(w)) {
	from_x = BW->bitmap.mark.from_x;
	from_y = BW->bitmap.mark.from_y;
	to_x = BW->bitmap.mark.to_x;
	to_y = BW->bitmap.mark.to_y;
    }
    else {
	from_x = 0;
	from_y = 0;
	to_x = BW->bitmap.width - 1;
	to_y = BW->bitmap.height - 1;
    }

    half_width = floor((to_x - from_x) / 2.0 + 0.5);
    half_height = floor((to_y - from_y ) / 2.0 + 0.5);
    shift = min((Position)(to_x - from_x), (Position)(to_y - from_y )) % 2;
    delta = min((Position) half_width, (Position) half_height) - shift;

    for (x = 0; x <= delta; x++) {
	for (y = 1 - shift; y <= delta; y++) {
	    quad1 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width + x,
			   from_y + (Position)half_height + y);
	    quad2 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width + y,
			   from_y + (Position)half_height - shift - x);
	    quad3 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width - shift - x,
			   from_y + (Position)half_height - shift - y);
	    quad4 = GetBit(BW->bitmap.image,
			   from_x + (Position)half_width - shift - y,
			   from_y + (Position)half_height + x);

	    if (quad1 != quad4)
		InvertPoint(BW,
			    from_x + (Position)half_width + x,
			    from_y + (Position)half_height + y);
	    if (quad2 != quad1)
		InvertPoint(BW,
			    from_x + (Position)half_width + y,
			    from_y + (Position)half_height - shift - x);
	    if (quad3 != quad2)
		InvertPoint(BW,
			    from_x + (Position)half_width - shift - x,
			    from_y + (Position)half_height - shift - y);
	    if (quad4 != quad3)
		InvertPoint(BW,
			    from_x + (Position)half_width - shift - y,
			    from_y + (Position)half_height + x);
	}
    }

    if (QuerySet(BW->bitmap.hot.x, BW->bitmap.hot.y)
	&&
	!BWQueryMarked(w)) {
	hot.x = BW->bitmap.hot.x - half_width;
	hot.y = BW->bitmap.hot.y - half_height;
	if (hot.x >= 0) hot.x += shift;
	if (hot.y >= 0) hot.y += shift;
	tmp = hot.x;
	hot.x = hot.y;
	hot.y = - tmp;
	if (hot.x > 0) hot.x -= shift;
	if (hot.y > 0) hot.y -= shift;
	hot.x += half_width;
	hot.y += half_height;
	if (QueryInBitmap(BW, hot.x, hot.y))
	    BWSetHotSpot(w, hot.x, hot.y);
    }
}


void
CopyImageData(XImage *source, XImage *destination,
	      Position from_x, Position from_y,
	      Position to_x, Position to_y,
	      Position at_x, Position at_y)
{
    Position x, y, delta_x, delta_y;

    delta_x = to_x - from_x + 1;
    delta_y = to_y - from_y + 1;

    for (x = 0; x < delta_x; x++)
	for (y = 0; y < delta_y; y++)
	    if (GetBit(source, from_x + x, from_y + y))
		SetBit(destination, at_x + x, at_y + y);
	    else
		ClearBit(destination, at_x + x, at_y + y);
}

XImage *
ConvertToBitmapImage(BitmapWidget BW, XImage *image)
{
    XImage *bitmap_image;
    char   *data;
    Position x, y;

    data = CreateCleanData(Length(image->width, image->height));
    bitmap_image = CreateBitmapImage(BW, data,
				     (Dimension) image->width,
				     (Dimension) image->height);

    for (x = 0; x < min(image->width, bitmap_image->width); x++)
	for (y = 0; y < min(image->height, bitmap_image->height); y++)
	    if ((XGetPixel(image, x, y) != 0) != GetBit(bitmap_image, x, y))
		InvertBit(bitmap_image, x, y);

    return bitmap_image;
}

void
TransferImageData(XImage *source, XImage *destination)
{
    Position x, y;

    for (x = 0; x < min(source->width, destination->width); x++)
	for (y = 0; y < min(source->height, destination->height); y++)
	    if (GetBit(source, x, y) != GetBit(destination, x, y))
		InvertBit(destination, x, y);
}

void
BWStore(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    Dimension width, height;
    char *storage_data;

    if (QuerySet(BW->bitmap.mark.from_x, BW->bitmap.mark.from_y)) {

	DestroyBitmapImage(&BW->bitmap.storage);

	width = BW->bitmap.mark.to_x - BW->bitmap.mark.from_x + 1;
	height = BW->bitmap.mark.to_y - BW->bitmap.mark.from_y + 1;

	storage_data = CreateCleanData(Length(width, height));

	BW->bitmap.storage = CreateBitmapImage(BW,
					       storage_data,
					       width, height);

	CopyImageData(BW->bitmap.image, BW->bitmap.storage,
		      BW->bitmap.mark.from_x,  BW->bitmap.mark.from_y,
		      BW->bitmap.mark.to_x,  BW->bitmap.mark.to_y,
		      0, 0);
    }
}

void
BWClearMarked(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QuerySet(BW->bitmap.mark.from_x, BW->bitmap.mark.from_y))
	BWDrawFilledRectangle(w,
			      BW->bitmap.mark.from_x,
			      BW->bitmap.mark.from_y,
			      BW->bitmap.mark.to_x,
			      BW->bitmap.mark.to_y,
			      Clear);
}


void
BWDragMarked(Widget w, Position at_x, Position at_y)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QuerySet(BW->bitmap.mark.from_x, BW->bitmap.mark.from_y))
	BWDrawRectangle(w,
			at_x, at_y,
			at_x + BW->bitmap.mark.to_x - BW->bitmap.mark.from_x,
			at_y + BW->bitmap.mark.to_y - BW->bitmap.mark.from_y,
			Highlight);
}

void
BWDragStored(Widget w, Position at_x, Position at_y)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (BW->bitmap.storage)
	BWDrawRectangle(w,
			at_x, at_y,
			at_x + BW->bitmap.storage->width - 1,
			at_y + BW->bitmap.storage->height - 1,
			Highlight);
}

static void
DrawImageData(BitmapWidget BW, XImage *image,
	      Position at_x, Position at_y, int value)
{
    Position x, y;
    Boolean  C, S, I, H;
    bit      A, B;

    C = value == Clear;
    S = value == Set;
    I = value == Invert;
    H = value == Highlight;

    for (x = 0; x < image->width; x++)
	for (y = 0; y < image->height; y++) {
	    A = GetBit(image, x, y);
	    B = GetBit(BW->bitmap.image, at_x + x, at_y + y);
	    if ((A & C) | ((A | B) & S) | ((A ^ B) & I) | ((A | B) & H))
		value = (A & H) ? Highlight : Set;
	    else
		value = Clear;
	    BWDrawPoint((Widget) BW,
			 at_x + x, at_y + y,
			 value);
	}
}

void
BWRestore(Widget w, Position at_x, Position at_y, int value)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (BW->bitmap.storage) {
      DrawImageData(BW, BW->bitmap.storage, at_x, at_y, value);
      /*DestroyBitmapImage(&BW->bitmap.storage);*/
    }
}

void
BWCopy(Widget w, Position at_x, Position at_y, int value)
{
    BitmapWidget BW = (BitmapWidget) w;
    XImage *storage;
    char *storage_data;
    Dimension width, height;

    if (QuerySet(BW->bitmap.mark.from_x, BW->bitmap.mark.from_y)) {

	width = BW->bitmap.mark.to_x - BW->bitmap.mark.from_x + 1;
	height = BW->bitmap.mark.to_y - BW->bitmap.mark.from_y + 1;

	storage_data = CreateCleanData(Length(width, height));

	storage = CreateBitmapImage(BW, storage_data, width, height);

	CopyImageData(BW->bitmap.image, storage,
		      BW->bitmap.mark.from_x,  BW->bitmap.mark.from_y,
		      BW->bitmap.mark.to_x,  BW->bitmap.mark.to_y,
		      0, 0);

	DrawImageData(BW, storage, at_x, at_y, value);

	DestroyBitmapImage(&storage);
    }
}

/* void BWMark(); */

void
BWMove(Widget w, Position at_x, Position at_y, int value)
{
    BitmapWidget BW = (BitmapWidget) w;
    XImage *storage;
    char *storage_data;
    Dimension width, height;

    if (QuerySet(BW->bitmap.mark.from_x, BW->bitmap.mark.from_y)) {

	width = BW->bitmap.mark.to_x - BW->bitmap.mark.from_x + 1;
	height = BW->bitmap.mark.to_y - BW->bitmap.mark.from_y + 1;

	storage_data = CreateCleanData(Length(width, height));

	storage = CreateBitmapImage(BW, storage_data, width, height);

	CopyImageData(BW->bitmap.image, storage,
		      BW->bitmap.mark.from_x,  BW->bitmap.mark.from_y,
		      BW->bitmap.mark.to_x,  BW->bitmap.mark.to_y,
		      0, 0);

	BWDrawFilledRectangle(w,
			      BW->bitmap.mark.from_x, BW->bitmap.mark.from_y,
			      BW->bitmap.mark.to_x, BW->bitmap.mark.to_y,
			      Clear);

	DrawImageData(BW, storage, at_x, at_y, value);

	BWMark(w, at_x, at_y,
	     at_x + BW->bitmap.mark.to_x - BW->bitmap.mark.from_x,
	     at_y + BW->bitmap.mark.to_y - BW->bitmap.mark.from_y);

	DestroyBitmapImage(&storage);
    }
}

void
BWRedrawMark(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    if (QuerySet(BW->bitmap.mark.from_x, BW->bitmap.mark.from_y))
	XFillRectangle(XtDisplay(BW), XtWindow(BW), BW->bitmap.highlighting_gc,
		       InWindowX(BW, BW->bitmap.mark.from_x),
		       InWindowY(BW, BW->bitmap.mark.from_y),
		       InWindowX(BW, BW->bitmap.mark.to_x + 1) -
		       InWindowX(BW, BW->bitmap.mark.from_x),
		       InWindowY(BW, BW->bitmap.mark.to_y + 1) -
		       InWindowY(BW, BW->bitmap.mark.from_y));
}

void
BWStoreToBuffer(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    memmove( BW->bitmap.buffer->data, BW->bitmap.image->data,
	  Length(BW->bitmap.image->width, BW->bitmap.image->height));

    BW->bitmap.buffer_hot = BW->bitmap.hot;
    BW->bitmap.buffer_mark = BW->bitmap.mark;
}

void
BWUnmark(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    BW->bitmap.buffer_mark = BW->bitmap.mark;

    if (QuerySet(BW->bitmap.mark.from_x, BW->bitmap.mark.from_y)) {
	XFillRectangle(XtDisplay(BW), XtWindow(BW), BW->bitmap.highlighting_gc,
		       InWindowX(BW, BW->bitmap.mark.from_x),
		       InWindowY(BW, BW->bitmap.mark.from_y),
		       InWindowX(BW, BW->bitmap.mark.to_x + 1) -
		       InWindowX(BW, BW->bitmap.mark.from_x),
		       InWindowY(BW, BW->bitmap.mark.to_y + 1) -
		       InWindowY(BW, BW->bitmap.mark.from_y));

	BW->bitmap.mark.from_x = BW->bitmap.mark.from_y = NotSet;
	BW->bitmap.mark.to_x = BW->bitmap.mark.to_y = NotSet;
    }
}

void
BWMark(Widget w, Position from_x, Position from_y,
       Position to_x, Position to_y)
{
    BitmapWidget BW = (BitmapWidget) w;

    BWUnmark(w);

    if (QuerySet(from_x, from_y)) {
	if ((from_x == to_x) && (from_y == to_y)) {
	    /*
	      BW->bitmap.mark.from_x = 0;
	      BW->bitmap.mark.from_y = 0;
	      BW->bitmap.mark.to_x = BW->bitmap.image->width - 1;
	      BW->bitmap.mark.to_y = BW->bitmap.image->height - 1;
	      */
	    return;
	}
	else {
	    QuerySwap(from_x, to_x);
	    QuerySwap(from_y, to_y);
	    from_x = max(0, from_x);
	    from_y = max(0, from_y);
	    to_x = min(BW->bitmap.image->width - 1, to_x);
	    to_y = min(BW->bitmap.image->height - 1, to_y);

	    BW->bitmap.mark.from_x = from_x;
	    BW->bitmap.mark.from_y = from_y;
	    BW->bitmap.mark.to_x = to_x;
	    BW->bitmap.mark.to_y = to_y;
	}

	XFillRectangle(XtDisplay(BW), XtWindow(BW), BW->bitmap.highlighting_gc,
		       InWindowX(BW, BW->bitmap.mark.from_x),
		       InWindowY(BW, BW->bitmap.mark.from_y),
		       InWindowX(BW, BW->bitmap.mark.to_x + 1) -
		       InWindowX(BW, BW->bitmap.mark.from_x),
		       InWindowY(BW, BW->bitmap.mark.to_y +1) -
		       InWindowY(BW, BW->bitmap.mark.from_y));
    }
}

void
BWMarkAll(Widget w)
{
  BitmapWidget BW = (BitmapWidget) w;

  BWMark(w, 0, 0, BW->bitmap.image->width - 1, BW->bitmap.image->height - 1);
}

void
BWUndo(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;
    Position x, y;
    char *tmp_data;
    XPoint tmp_hot;
    BWArea tmp_mark;

    tmp_data = BW->bitmap.image->data;
    BW->bitmap.image->data = BW->bitmap.buffer->data;
    BW->bitmap.buffer->data = tmp_data;

    tmp_hot = BW->bitmap.hot;
    tmp_mark = BW->bitmap.mark;

    for (x = 0; x < BW->bitmap.image->width; x++)
	for (y = 0; y < BW->bitmap.image->height; y++)
	 if (GetBit(BW->bitmap.image, x, y) != GetBit(BW->bitmap.buffer, x, y))
	     DrawSquare(BW, x, y);

    BWSetHotSpot(w, BW->bitmap.buffer_hot.x, BW->bitmap.buffer_hot.y);
/*
    BWMark(w, BW->bitmap.buffer_mark.from_x, BW->bitmap.buffer_mark.from_y,
	   BW->bitmap.buffer_mark.to_x, BW->bitmap.buffer_mark.to_y);
*/
    BW->bitmap.buffer_hot = tmp_hot;
    BW->bitmap.buffer_mark= tmp_mark;

}

void
BWHighlightAxes(Widget w)
{
    BitmapWidget BW = (BitmapWidget) w;

    XDrawLine(XtDisplay(BW), XtWindow(BW),
	      BW->bitmap.axes_gc,
	      InWindowX(BW, 0),
	      InWindowY(BW, 0),
	      InWindowX(BW, BW->bitmap.width),
	      InWindowY(BW, BW->bitmap.height));
    XDrawLine(XtDisplay(BW), XtWindow(BW),
	      BW->bitmap.axes_gc,
	      InWindowX(BW, BW->bitmap.width),
	      InWindowY(BW, 0),
	      InWindowX(BW, 0),
	      InWindowY(BW, BW->bitmap.height));
    XDrawLine(XtDisplay(BW), XtWindow(BW),
	      BW->bitmap.axes_gc,
	      InWindowX(BW, 0),
	      InWindowY(BW, (float)BW->bitmap.height / 2.0),
	      InWindowX(BW, BW->bitmap.width),
	      InWindowY(BW, (float)BW->bitmap.height / 2.0));
    XDrawLine(XtDisplay(BW), XtWindow(BW),
	      BW->bitmap.axes_gc,
	      InWindowX(BW, (float)BW->bitmap.width / 2.0),
	      InWindowY(BW, 0),
	      InWindowX(BW, (float)BW->bitmap.width / 2.0),
	      InWindowY(BW, BW->bitmap.height));
}

typedef struct {
    Position *x, *y;
    Dimension *width, *height;
} Table;

XImage *
ScaleBitmapImage(BitmapWidget BW, XImage *src,
		 double scale_x, double scale_y)
{
    char *data;
    XImage *dst;
    Table table;
    Position x, y, w, h;
    Dimension width, height;
    bit pixel;

    width = max(rint(scale_x * src->width), 1);
    height = max(rint(scale_y * src->height), 1);

    data = CreateCleanData(Length(width, height));
    dst = CreateBitmapImage(BW, data, width, height);

    /*
     * It would be nice to check if width or height < 1.0 and
     * average the skipped pixels. But, it is slow as it is now.
     */
    if (scale_x == 1.0 && scale_y == 1.0)
	memmove( dst->data, src->data, Length(width, height));
    else {
	table.x = (Position *) XtMalloc(sizeof(Position) * src->width);
	table.y = (Position *) XtMalloc(sizeof(Position) * src->height);
	table.width = (Dimension *) XtMalloc(sizeof(Dimension) * src->width);
	table.height = (Dimension *) XtMalloc(sizeof(Dimension) * src->height);

	for (x = 0; x < src->width; x++) {
	    table.x[x] = rint(scale_x * x);
	    table.width[x] = rint(scale_x * (x + 1)) - rint(scale_x * x);
	}
	for (y = 0; y < src->height; y++) {
	    table.y[y] = rint(scale_y * y);
	    table.height[y] = rint(scale_y * (y + 1)) - rint(scale_y * y);
	}

	for (x = 0; x < src->width; x++)
	    for (y = 0; y < src->height; y++) {
	        pixel = GetBit(src, x, y);
		for (w = 0; (int)w < (int)table.width[x]; w++)
		    for (h = 0; (int)h < (int)table.height[y]; h++)
			if (pixel) SetBit(dst,
					table.x[x] + w,
					table.y[y] + h);
	    }

	XtFree((char *)table.x);
	XtFree((char *)table.y);
	XtFree((char *)table.width);
	XtFree((char *)table.height);
    }

    return (dst);
}

/*****************************************************************************/