glut_cursor.c revision c041511d 
1
2/* Copyright (c) Mark J. Kilgard, 1995, 1998. */
3
4/* This program is freely distributable without licensing fees
5   and is provided without guarantee or warrantee expressed or
6   implied. This program is -not- in the public domain. */
7
8#include "glutint.h"
9
10#if !defined(_WIN32)
11#include <X11/Xatom.h>  /* For XA_CURSOR */
12#include <X11/cursorfont.h>
13#endif
14
15typedef struct _CursorTable {
16#if defined(_WIN32)
17  char* glyph;
18#else
19  int glyph;
20#endif
21  Cursor cursor;
22} CursorTable;
23/* *INDENT-OFF* */
24
25static CursorTable cursorTable[] = {
26  {XC_arrow, None},		  /* GLUT_CURSOR_RIGHT_ARROW */
27  {XC_top_left_arrow, None},	  /* GLUT_CURSOR_LEFT_ARROW */
28  {XC_hand1, None},		  /* GLUT_CURSOR_INFO */
29  {XC_pirate, None},		  /* GLUT_CURSOR_DESTROY */
30  {XC_question_arrow, None},	  /* GLUT_CURSOR_HELP */
31  {XC_exchange, None},		  /* GLUT_CURSOR_CYCLE */
32  {XC_spraycan, None},		  /* GLUT_CURSOR_SPRAY */
33  {XC_watch, None},		  /* GLUT_CURSOR_WAIT */
34  {XC_xterm, None},		  /* GLUT_CURSOR_TEXT */
35  {XC_crosshair, None},		  /* GLUT_CURSOR_CROSSHAIR */
36  {XC_sb_v_double_arrow, None},	  /* GLUT_CURSOR_UP_DOWN */
37  {XC_sb_h_double_arrow, None},	  /* GLUT_CURSOR_LEFT_RIGHT */
38  {XC_top_side, None},		  /* GLUT_CURSOR_TOP_SIDE */
39  {XC_bottom_side, None},	  /* GLUT_CURSOR_BOTTOM_SIDE */
40  {XC_left_side, None},		  /* GLUT_CURSOR_LEFT_SIDE */
41  {XC_right_side, None},	  /* GLUT_CURSOR_RIGHT_SIDE */
42  {XC_top_left_corner, None},	  /* GLUT_CURSOR_TOP_LEFT_CORNER */
43  {XC_top_right_corner, None},	  /* GLUT_CURSOR_TOP_RIGHT_CORNER */
44  {XC_bottom_right_corner, None}, /* GLUT_CURSOR_BOTTOM_RIGHT_CORNER */
45  {XC_bottom_left_corner, None},  /* GLUT_CURSOR_BOTTOM_LEFT_CORNER */
46};
47/* *INDENT-ON* */
48
49#if !defined(_WIN32)
50static Cursor blankCursor = None;
51static Cursor fullCrosshairCusor = None;
52
53/* SGI X server's support a special property called the
54   _SGI_CROSSHAIR_CURSOR that when installed as a window's
55   cursor, becomes a full screen crosshair cursor.  SGI
56   has special cursor generation hardware for this case. */
57static Cursor
58getFullCrosshairCursor(void)
59{
60  Cursor cursor;
61  Atom crosshairAtom, actualType;
62  int rc, actualFormat;
63  unsigned long n, left;
64  unsigned char *value;
65
66  if (fullCrosshairCusor == None) {
67    crosshairAtom = XInternAtom(__glutDisplay,
68      "_SGI_CROSSHAIR_CURSOR", True);
69    if (crosshairAtom != None) {
70      value = 0;        /* Make compiler happy. */
71      rc = XGetWindowProperty(__glutDisplay, __glutRoot,
72        crosshairAtom, 0, 1, False, XA_CURSOR, &actualType,
73        &actualFormat, &n, &left, &value);
74      if (rc == Success && actualFormat == 32 && n >= 1) {
75        cursor = ((unsigned long *)value)[0];
76        XFree(value);
77        return cursor;
78      }
79    }
80  }
81  return XCreateFontCursor(__glutDisplay, XC_crosshair);
82}
83
84/* X11 forces you to create a blank cursor if you want
85   to disable the cursor. */
86static Cursor
87makeBlankCursor(void)
88{
89  static char data[1] =
90  {0};
91  Cursor cursor;
92  Pixmap blank;
93  XColor dummy;
94
95  blank = XCreateBitmapFromData(__glutDisplay, __glutRoot,
96    data, 1, 1);
97  if (blank == None)
98    __glutFatalError("out of memory.");
99  cursor = XCreatePixmapCursor(__glutDisplay, blank, blank,
100    &dummy, &dummy, 0, 0);
101  XFreePixmap(__glutDisplay, blank);
102
103  return cursor;
104}
105#endif /* !_WIN32 */
106
107/* Win32 and X11 use this same function to accomplish
108   fairly different tasks.  X11 lets you just define the
109   cursor for a window and the window system takes care
110   of making sure that the window's cursor is installed
111   when the mouse is in the window.  Win32 requires the
112   application to handle a WM_SETCURSOR message to install
113   the right cursor when windows are entered.  Think of
114   the Win32 __glutSetCursor (called from __glutWindowProc)
115   as "install cursor".  Think of the X11 __glutSetCursor
116   (called from glutSetCursor) as "define cursor". */
117void
118__glutSetCursor(GLUTwindow *window)
119{
120  int cursor = window->cursor;
121  Cursor xcursor = 0;
122
123  if (cursor >= 0 &&
124    cursor < sizeof(cursorTable) / sizeof(cursorTable[0])) {
125    if (cursorTable[cursor].cursor == None) {
126      cursorTable[cursor].cursor = XCreateFontCursor(__glutDisplay,
127        cursorTable[cursor].glyph);
128    }
129    xcursor = cursorTable[cursor].cursor;
130  } else {
131    /* Special cases. */
132    switch (cursor) {
133    case GLUT_CURSOR_INHERIT:
134#if defined(_WIN32)
135      while (window->parent) {
136        window = window->parent;
137        if (window->cursor != GLUT_CURSOR_INHERIT) {
138          __glutSetCursor(window);
139          return;
140        }
141      }
142      /* XXX Default to an arrow cursor.  Is this
143         right or should we be letting the default
144         window proc be installing some system cursor? */
145      xcursor = cursorTable[0].cursor;
146      if (xcursor == NULL) {
147        xcursor =
148          cursorTable[0].cursor =
149          LoadCursor(NULL, cursorTable[0].glyph);
150      }
151#else
152      xcursor = None;
153#endif
154      break;
155    case GLUT_CURSOR_NONE:
156#if defined(_WIN32)
157      xcursor = NULL;
158#else
159      if (blankCursor == None) {
160        blankCursor = makeBlankCursor();
161      }
162      xcursor = blankCursor;
163#endif
164      break;
165    case GLUT_CURSOR_FULL_CROSSHAIR:
166#if defined(_WIN32)
167      xcursor = (HICON) IDC_CROSS;
168#else
169      if (fullCrosshairCusor == None) {
170        fullCrosshairCusor = getFullCrosshairCursor();
171      }
172      xcursor = fullCrosshairCusor;
173#endif
174      break;
175    }
176  }
177  XDefineCursor(__glutDisplay,
178    window->win, xcursor);
179  XFlush(__glutDisplay);
180}
181
182/* CENTRY */
183void GLUTAPIENTRY
184glutSetCursor(int cursor)
185{
186#ifdef _WIN32
187  POINT point;
188
189  __glutCurrentWindow->cursor = cursor;
190  /* Are we in the window right now?  If so,
191     install the cursor. */
192  GetCursorPos(&point);
193  if (__glutCurrentWindow->win == WindowFromPoint(point)) {
194    __glutSetCursor(__glutCurrentWindow);
195  }
196#else
197  __glutCurrentWindow->cursor = cursor;
198  __glutSetCursor(__glutCurrentWindow);
199#endif
200}
201/* ENDCENTRY */
202