aboutsummaryrefslogtreecommitdiff
path: root/src/hyper/scrollbar.c
blob: ae0a92a899ad64416a2f76be057c745cee3e6606 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
/*
  Copyright (C) 1991-2002, The Numerical Algorithms Group Ltd.
  All rights reserved.
  Copyright (C) 2007-2008, Gabriel Dos Reis.
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:

      - Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

      - Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in
        the documentation and/or other materials provided with the
        distribution.

      - Neither the name of The Numerical Algorithms Group Ltd. nor the
        names of its contributors may be used to endorse or promote products
        derived from this software without specific prior written permission.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
  OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/******************************************************************************
 *
 * scrollbar.c:  HyperDoc Scrollbar routines
 *
 * Copyright The Numerical Algorithms Group Limited 1991, 1992, 1993.
 *
 ****************************************************************************/
#define _SCROLLBAR_C
#include "axiom-c-macros.h"

#include "debug.h"
#include "sockio.h"
#include "extent.h"
#include "display.h"
#include "group.h"
#include "initx.h"
#include "scrollbar.h"
#include "parse.h"

#include "all_hyper_proto.H1"

/*************************************************************************
  Scrollbar Comments                                    10/08/89

  The scrollbar is displayed on the side of the HyperDoc display, if needed.
  It is composed of four windows

  fScrollUpWindow --  the arrowed box at the top of the scrollbar. Scrolls the
  window up a line at a time.
  fScrollDownWindow --  Located at the bottom of the window, it is used to scroll
  down a single line at a time.
  scrollbar -- this is the window which does the variable scrolling. It
  houses the actual scroller.
  scroller -- This is the scroller inside the scroll bar.

  The procedure below, makes all these windows, and also makes three bitmaps,
  sup -- The up arrow for the fScrollUpWindow.
  sdown -- the down arrow for the fScrollDownWindow.
  scroller -- the scroller stipple.
  It then fills the window with the proper Pixmap background.

  The scrollbar and scroller works as follows. The size of the scroller is
  calculated as

  size of scroller            size of visible text
  -----------------  ===  ------------------------------  .
  size of scrollbar       size of whole scrolling region

  The top of the scroller shows the relative position in the page of
  the top of the scrolling region. This way the user knows how far
  down the page he or she has moved.
  When the user clicks in the scrollbar, the center of the
  scroller, if possible, is placed at the point of the click.

  See the routines
  showScrollBars --  to see how the scroll bars are actually realized.
  moveScroller --  to see how the scroller is moved when the user scrolls


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

#ifndef _NO_PROTO
static int  ch(int height);
static void changeWindowBackgroundPixmap(Window window, Pixmap pixmap);
#else
static int  ch();
static void changeWindowBackgroundPixmap();
#endif

static Pixmap sup = 0, sdown = 0, sup_pressed = 0, sdown_pressed = 0, scroller = 0, scrollbar_pix = 0;


/* #undef BITMAPS2D to get old style 2d effect */

#ifdef BITMAPS2D

#define CONTROLS_3D 0

#include "sdown.bitmap"
#include "sup.bitmap"

#define BACKCOLOR gBackgroundColor
#define FORECOLOR gActiveColor

#else

#define CONTROLS_3D 1

#include "sdown3d.bitmap"
#include "sdown3dpr.bitmap"

#include "sup3d.bitmap"
#include "sup3dpr.bitmap"

#define sup_width  sup3d_width
#define sup_height sup3d_height
#define sup_bits sup3d_bits

#define sdown_width  sdown3d_width
#define sdown_height sdown3d_height
#define sdown_bits   sdown3d_bits

#define BACKCOLOR gControlBackgroundColor
#define FORECOLOR gControlForegroundColor

#endif


#if 0
#define scroller_width 3
#define scroller_height 3
static char scroller_bits[] = {0x05, 0x07, 0x03};

#endif

#define scroller_width 2
#define scroller_height 2
static char scroller_bits[] = {
                               0x01, 0x02};



static int supheight = sup_height;
static int supwidth = sup_width;

#define scrollbar_pix_width 3
#define scrollbar_pix_height 3
static char scrollbar_pix_bits[] = {0x00, 0x03, 0x00};



int gScrollbarWidth = sup_width + 2;



void
makeScrollBarWindows(void)
{
    XSetWindowAttributes at;

    at.cursor = gActiveCursor;
    at.event_mask = ButtonPress;
    /** create the bitmaps **/
    if (supwidth != sdown_width || supheight != sdown_height) {
        fprintf(stderr,
                "Scrollbar error, up and down pointers must have the same dimensions\n");
        exit(-1);
    }

    if (sup == 0)
        sup = XCreatePixmapFromBitmapData(
                                          gXDisplay,
                                    RootWindow(gXDisplay, gXScreenNumber),
                                          sup_bits, supwidth, supheight,
                                          FORECOLOR, BACKCOLOR,
                                 DefaultDepth(gXDisplay, gXScreenNumber));

    if (sdown == 0)
        sdown = XCreatePixmapFromBitmapData(
                                            gXDisplay,
                                    RootWindow(gXDisplay, gXScreenNumber),
                                      sdown_bits, sdown_width, sdown_height,
                                            FORECOLOR, BACKCOLOR,
                                 DefaultDepth(gXDisplay, gXScreenNumber));

    if (CONTROLS_3D) {
        sup_pressed = XCreatePixmapFromBitmapData(
                                                  gXDisplay,
                                    RootWindow(gXDisplay, gXScreenNumber),
                                sup3dpr_bits, sup3dpr_width, sup3dpr_height,
                                                  FORECOLOR, BACKCOLOR,
                                 DefaultDepth(gXDisplay, gXScreenNumber));
        sdown_pressed = XCreatePixmapFromBitmapData(
                                                    gXDisplay,
                                    RootWindow(gXDisplay, gXScreenNumber),
                          sdown3dpr_bits, sdown3dpr_width, sdown3dpr_height,
                                                    FORECOLOR, BACKCOLOR,
                                 DefaultDepth(gXDisplay, gXScreenNumber));
    }

    gWindow->fScrollUpWindow = XCreateSimpleWindow(gXDisplay, gWindow->fMainWindow,
                                                1, 1, supwidth, supheight,
                                                gWindow->border_width,
                                                gBorderColor,
                                                BACKCOLOR);

    gWindow->fScrollDownWindow = XCreateSimpleWindow(gXDisplay, gWindow->fMainWindow,
                                            1, 1, sdown_width, sdown_height,
                                                  gWindow->border_width,
                                                  gBorderColor,
                                                  BACKCOLOR);

    gWindow->scrollbar = XCreateSimpleWindow(gXDisplay, gWindow->fMainWindow,
                                              1, 1, 1, 1,
                                              gWindow->border_width,
                                              gBorderColor,
                                              BACKCOLOR);
    gWindow->scroller = XCreateSimpleWindow(gXDisplay, gWindow->scrollbar,
                                             1, 1, 1, 1, 0,
                                             gBorderColor,
                                             BACKCOLOR);

#ifdef DEBUG
    fprintf(stderr, "Changing Window Attributes in scrollbar.c #2\n");
#endif

    at.background_pixmap = sup;
    XChangeWindowAttributes(gXDisplay, gWindow->fScrollUpWindow,
                            CWBackPixmap | CWEventMask | CWCursor, &at);

    at.background_pixmap = sdown;
    XChangeWindowAttributes(gXDisplay, gWindow->fScrollDownWindow,
                            CWBackPixmap | CWEventMask | CWCursor, &at);

    XChangeWindowAttributes(gXDisplay, gWindow->scrollbar,
                            CWEventMask | CWCursor, &at);


    if (scroller == 0)
        scroller = XCreatePixmapFromBitmapData(gXDisplay,
                                    RootWindow(gXDisplay, gXScreenNumber),
                                               scroller_bits, scroller_width,
                                               scroller_height,
                                               FORECOLOR,
                                               BACKCOLOR,
                                 DefaultDepth(gXDisplay, gXScreenNumber));
    if (scrollbar_pix == 0)
        scrollbar_pix = XCreatePixmapFromBitmapData(gXDisplay,
                                    RootWindow(gXDisplay, gXScreenNumber),
                                                    scrollbar_pix_bits,
                                                    scrollbar_pix_width,
                                                    scrollbar_pix_height,
                                                    FORECOLOR,
                                                    BACKCOLOR,
                                 DefaultDepth(gXDisplay, gXScreenNumber));

    at.background_pixmap = scroller;
    XChangeWindowAttributes(gXDisplay, gWindow->scroller,
                            CWBackPixmap | CWCursor, &at);
    at.background_pixmap = scrollbar_pix;
    XChangeWindowAttributes(gXDisplay, gWindow->scrollbar,
                            CWBackPixmap, &at);
}

static void
drawScroller3DEffects(HDWindow * hdWindow, int x1, int y1, int x2, int y2)
{
    XClearWindow(gXDisplay, hdWindow->scroller);

    /* draw right "black" line */

    XDrawLine(gXDisplay, hdWindow->scroller, hdWindow->fControlGC,
              x2 - 3, y1 + 2, x2 - 3, y2 - 3);

    /* draw bottom "black" line */

    XDrawLine(gXDisplay, hdWindow->scroller, hdWindow->fControlGC,
              x1 + 2, y2 - 3, x2 - 3, y2 - 3);

    /* flip foreground and background colors */

    XSetBackground(gXDisplay, hdWindow->fControlGC, gControlForegroundColor);
    XSetForeground(gXDisplay, hdWindow->fControlGC, gControlBackgroundColor);

    /* draw top "white" line */

    XDrawLine(gXDisplay, hdWindow->scroller, hdWindow->fControlGC,
              x1 + 2, y1 + 2, x2 - 3, y1 + 2);

    /* draw left "white" line */

    XDrawLine(gXDisplay, hdWindow->scroller, hdWindow->fControlGC,
              x1 + 2, y1 + 2, x1 + 2, y2 - 3);

    /* reset colors */

    XSetBackground(gXDisplay, hdWindow->fControlGC, gControlBackgroundColor);
    XSetForeground(gXDisplay, hdWindow->fControlGC, gControlForegroundColor);
}

void
showScrollBars(HDWindow * hdWindow)
{
    XWindowChanges wc;
    /*int src_x = 0, src_y = 0;*/
    /*unsigned int width = supwidth, height = supheight;*/
    /*int dest_x = 0, dest_y = 0;*/

    /* see if we even need scroll bars */

    if (hdWindow->page->scrolling->height <= hdWindow->scrollheight)
        return;

    wc.x = hdWindow->scrollx;
    wc.y = hdWindow->scrollupy;
    wc.height = supheight;
    wc.width = supwidth;
    XConfigureWindow(gXDisplay, hdWindow->fScrollUpWindow, CWX | CWY | CWHeight
                     | CWWidth, &wc);
    wc.y = hdWindow->scrolldowny;
    XConfigureWindow(gXDisplay, hdWindow->fScrollDownWindow,
                     CWX | CWY | CWHeight | CWWidth,
                     &wc);
    wc.height = hdWindow->fScrollBarHeight;
    wc.y = hdWindow->scrollbary;
    XConfigureWindow(gXDisplay, hdWindow->scrollbar,
                     CWX | CWY | CWHeight | CWWidth,
                     &wc);
    wc.x = 0;
    wc.y = hdWindow->fScrollerTopPos;
    wc.width = supwidth;
    wc.height = hdWindow->fScrollerHeight;
    XConfigureWindow(gXDisplay, hdWindow->scroller,
                     CWX | CWY | CWHeight | CWWidth,
                     &wc);

    /*
     * Now we map the windows, since the bitmaps are the backgrounds for the
     * windows, we need to worry about redrawing them.
     */

    XMapWindow(gXDisplay, hdWindow->fScrollUpWindow);
    XMapWindow(gXDisplay, hdWindow->fScrollDownWindow);
    XMapWindow(gXDisplay, hdWindow->scrollbar);
    XMapWindow(gXDisplay, hdWindow->scroller);

    drawScroller3DEffects(hdWindow, 0, 0, wc.width, wc.height);
}


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

  Moves the scroller to its proper place within the scrollbar. It
  calculates how far down the page we are, and then moves the scroller
  accordingly

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

void
moveScroller(HDWindow * hdWindow)
{
    XWindowChanges wc;

    /** moves the scroller to it's proper place **/

    int t = (int) (hdWindow->fScrollBarHeight * (-hdWindow->page->scroll_off));
    hdWindow->fScrollerTopPos = (int) (t / hdWindow->page->scrolling->height);
    wc.x = 0;
    wc.y = hdWindow->fScrollerTopPos;
    wc.width = supwidth;
    wc.height = hdWindow->fScrollerHeight;
    XConfigureWindow(gXDisplay, hdWindow->scroller,
                     CWX | CWY | CWHeight | CWWidth,
                     &wc);
    drawScroller3DEffects(hdWindow, 0, 0, wc.width, wc.height);
}

#define tophalf(y) ((y % 2 == 0)?(y/2):(y/2) + 1)
#define bothalf(y) (y/2)

void
drawScrollLines(void)
{
    /* Checks the page_flags to see if we need a top, or a bottom line.   */
    /* These are the horizontal lines framing a scrolling region when the */
    /* scrolling region is not the entire window.                         */

    if (!(gWindow->page->page_flags & NOLINES)) {
        line_top_group();
        if (gWindow->page->header->height) {
            XDrawLine(gXDisplay, gWindow->fMainWindow, gWindow->fStandardGC,
                      0,
                      gWindow->page->top_scroll_margin - tophalf(gWindow->border_width)
                      - 2 * scroll_top_margin,
                      gWindow->scrollwidth,
                      gWindow->page->top_scroll_margin - tophalf(gWindow->border_width)
                      - 2 * scroll_top_margin);
        }
        if (gWindow->page->footer->height) {
            XDrawLine(gXDisplay, gWindow->fMainWindow, gWindow->fStandardGC,
                      0,
                      gWindow->page->bot_scroll_margin + bothalf(gWindow->border_width) - 1,
                      gWindow->scrollwidth,
                      gWindow->page->bot_scroll_margin + bothalf(gWindow->border_width) - 1);
        }
        pop_group_stack();
    }
}


/*
 * Calculates all the measures for the scrollbars
 */

void
calculateScrollBarMeasures(void)
{
    int t;

    /*
     * The scrollhieght is the height of the scrolling region visible in the
     * HT window. Notice how it is a multiple of line height. This was needed
     * to make everything scroll nicely.
     */

    gWindow->scrollheight = gWindow->page->bot_scroll_margin -
        gWindow->page->top_scroll_margin - scroll_top_margin;
    gWindow->scrollheight = gWindow->scrollheight - gWindow->scrollheight % line_height;

    /*
     * Now do a quick check to see if I really need a scroll bar, and if not,
     * just return right away
     */

    if (gWindow->scrollheight >= gWindow->page->scrolling->height) {
        gWindow->page->scroll_off = 0;
        return;
    }

    /*
     * The height of the scrollbar region, extends form the top page margin
     * all the way to the bottom, excluding the room needed for the up and
     * down windows
     */

    gWindow->fScrollBarHeight = gWindow->page->bot_scroll_margin -
        gWindow->page->top_scroll_margin - 2 * supheight -
        2 * gWindow->border_width;

    gWindow->scrollupy = gWindow->page->top_scroll_margin - gWindow->border_width;
    gWindow->scrollupy -= 2 * scroll_top_margin;
    gWindow->scrolldowny = gWindow->page->bot_scroll_margin
        - supheight - gWindow->border_width;
    gWindow->scrollbary = gWindow->scrollupy + supheight + gWindow->border_width;
    gWindow->scrollx = gWindow->width - supwidth - gWindow->border_width;

    /*
     * the scroller height is calculated from the following formula
     *
     * fScrollerHeight                    scrollheight --------------       ==
     * --------- ------------- fScrollBarHeight
     * page->scrolling_height
     *
     */

    gWindow->fScrollerHeight = 1 + 2 * scroll_top_margin +        /** possible integer error correction **/
        (int) (gWindow->fScrollBarHeight * gWindow->scrollheight / gWindow->page->scrolling->height);

    /*
     * Check the scroll offset, to see if it is too Large
     */

    if (-(gWindow->page->scroll_off) >
        (gWindow->page->scrolling->height - gWindow->scrollheight))
        gWindow->page->scroll_off =
            -(gWindow->page->scrolling->height - gWindow->scrollheight);

    /*
     * Then move the top of the scroller to it's proper position
     */

    gWindow->fScrollBarHeight += 2 * scroll_top_margin;
    t = (int) (gWindow->fScrollBarHeight * (-gWindow->page->scroll_off));
    gWindow->fScrollerTopPos = (int) (t / (gWindow->page->scrolling->height));
}

void
linkScrollBars(void)
{
    HyperLink *uplink = (HyperLink *) halloc(sizeof(HyperLink), "HyperLink");
    HyperLink *downlink = (HyperLink *) halloc(sizeof(HyperLink), "HyperLink");
    HyperLink *barlink = (HyperLink *) halloc(sizeof(HyperLink), "HyperLink");

    uplink->win = gWindow->fScrollUpWindow;
    downlink->win = gWindow->fScrollDownWindow;
    barlink->win = gWindow->scrollbar;
    uplink->type = Scrollupbutton;
    downlink->type = Scrolldownbutton;
    barlink->type = Scrollbar;
    barlink->x = barlink->y = 0;
    uplink->x = uplink->y = 0;
    downlink->x = downlink->y = 0;
    uplink->reference.node = NULL;
    downlink->reference.node = NULL;
    hash_insert(gLinkHashTable, (char *)uplink,(char *) &uplink->win);
    hash_insert(gLinkHashTable, (char *)barlink,(char *) &barlink->win);
    hash_insert(gLinkHashTable, (char *)downlink,(char *) &downlink->win);
}

void
scrollUp(void)
{

    if (gWindow->page->scroll_off == 0);       /* BeepAtTheUser(); *//* The
                                                 * beeping annoyed me. RSS */
    else {
        changeWindowBackgroundPixmap(gWindow->fScrollUpWindow, sup_pressed);

        gWindow->page->scroll_off += line_height;      /* Scroll a line */
        if (gWindow->page->scroll_off > 0)
            gWindow->page->scroll_off = 0;
        XCopyArea(gXDisplay, gWindow->fScrollWindow, gWindow->fScrollWindow, gWindow->fStandardGC,
                  0, 0,
            gWindow->scrollwidth, gWindow->scrollheight - line_height + 1,
                  0, line_height);
        XClearArea(gXDisplay, gWindow->fScrollWindow, 0, 0,
                   gWindow->scrollwidth,
                   line_height, False);
        scroll_page(gWindow->page);

        changeWindowBackgroundPixmap(gWindow->fScrollUpWindow, sup);
    }

}

void
scrollUpPage(void)
{
    if (gWindow->page->scroll_off == 0);       /* BeepAtTheUser(); */
    else {
        /* Scroll a page */

        gWindow->page->scroll_off += ch(gWindow->scrollheight) - line_height;
        if (gWindow->page->scroll_off > 0)
            gWindow->page->scroll_off = 0;

        XClearWindow(gXDisplay, gWindow->fScrollWindow);
        scroll_page(gWindow->page);
    }
}

void
scrollToFirstPage(void)
{
    if (gWindow->page->scroll_off == 0);       /* BeepAtTheUser(); */
    else {
        gWindow->page->scroll_off = 0;
        XClearWindow(gXDisplay, gWindow->fScrollWindow);
        scroll_page(gWindow->page);
    }
}

void
scrollDown(void)
{

    if (-(gWindow->page->scroll_off) >=
        (gWindow->page->scrolling->height - gWindow->scrollheight)) {
        ;                       /* BeepAtTheUser(); */
    }
    else {
        changeWindowBackgroundPixmap(gWindow->fScrollDownWindow, sdown_pressed);

        gWindow->page->scroll_off -= line_height;      /* Scroll a line */

        XCopyArea(gXDisplay, gWindow->fScrollWindow, gWindow->fScrollWindow, gWindow->fStandardGC,
                  0, line_height,
            gWindow->scrollwidth, gWindow->scrollheight - line_height + 1,
                  0, 0);
        XClearArea(gXDisplay, gWindow->fScrollWindow, 0,
                   gWindow->scrollheight - line_height,
                   gWindow->scrollwidth,
                   line_height, False);
        scroll_page(gWindow->page);

        changeWindowBackgroundPixmap(gWindow->fScrollDownWindow, sdown);
    }
}


void
scrollDownPage(void)
{
    if (gWindow->page->scrolling == NULL || (-(gWindow->page->scroll_off) >=
            (gWindow->page->scrolling->height - gWindow->scrollheight))) {
        ;                       /* BeepAtTheUser(); */
    }
    else {
        gWindow->page->scroll_off -= ch(gWindow->scrollheight) - line_height;

        if (-(gWindow->page->scroll_off) >
            (gWindow->page->scrolling->height - gWindow->scrollheight))
            gWindow->page->scroll_off = -
                (gWindow->page->scrolling->height - gWindow->scrollheight);

        XClearWindow(gXDisplay, gWindow->fScrollWindow);

        scroll_page(gWindow->page);
    }
}

void
scrollScroller(XButtonEvent * event)
{

    /*
     * This routine checks to see where in the window the button press
     * occured. It then tries to move the scroller so that the top of the
     * scroller is at the spot of the event
     */

    int y = event->y;
    int top = y;

    if (top < 0) {
        top = 0;
        if (gWindow->fScrollerTopPos == 0)
            return;
        gWindow->page->scroll_off = 0;
    }
    else if ((top + gWindow->fScrollerHeight) > gWindow->fScrollBarHeight) {
        top = gWindow->fScrollBarHeight - gWindow->fScrollerHeight;
        if (top == gWindow->fScrollerTopPos)
            return;
        gWindow->page->scroll_off =
            -(gWindow->page->scrolling->height - gWindow->scrollheight);
        gWindow->page->scroll_off -= gWindow->page->scroll_off % line_height;
    }
    else {                      /** top is in an ok spot **/
        int t;

        t = -(gWindow->page->scrolling->height) * top;
        t = t / (gWindow->fScrollBarHeight);
        if (gWindow->page->scroll_off == (t -= t % line_height))
            return;
        gWindow->page->scroll_off = t;
        gWindow->fScrollerTopPos = top;
    }
    XClearWindow(gXDisplay, gWindow->fScrollWindow);
    scroll_page(gWindow->page);
}


void
hideScrollBars(HDWindow * hdWindow)
{
    XUnmapWindow(gXDisplay, hdWindow->fScrollDownWindow);
    XUnmapWindow(gXDisplay, hdWindow->fScrollUpWindow);
    XUnmapWindow(gXDisplay, hdWindow->scrollbar);
    XUnmapWindow(gXDisplay, hdWindow->scroller);
}

void
getScrollBarMinimumSize(int *width, int *height)
{
    (*width)  = sup_width + 4;
    (*height) = sup_height + sdown_height + 5;
}

static int
ch(int height)
{
    /*int rheight;*/
    int rem = height % line_height;

    if (rem == 0)
        return height;
    return height - rem + line_height;
}

static void
changeWindowBackgroundPixmap(Window window, Pixmap pixmap)
{
    if (pixmap) {
        XSetWindowAttributes at;

        at.background_pixmap = pixmap;
        XChangeWindowAttributes(gXDisplay, window, CWBackPixmap, &at);
        XClearWindow(gXDisplay, window);
    }
}