+ <li class="title"><a name="mousecursor">Messing with the mouse cursor</a>
+ <p>
+ It it possible to modify the shape of the mouse pointer (also
+ called the X pointer) when in certain states, as we otfen see in
+ programs. For example, a busy application would often display
+ the sand clock over its main window, to give the user a visual
+ hint that he should wait. Let's see how we can change the mouse
+ cursor of our windows.
+ </p>
+ <ol>
+ <li class="subtitle"><a name="mousecursorcreate">Creating and destroying a mouse cursor</a>
+ <p>
+ There are two methods for creating cursors. One of them is by
+ using a set of predefined cursors, that are supplied by the X
+ server, the other is by using a user-supplied bitmap.
+ </p>
+ <p>
+ In the first method, we use a special font named "cursor", and
+ the function <span class="code">xcb_create_glyph_cursor</span>:
+ </p>
+ <pre class="code">
+xcb_void_cookie_t xcb_create_glyph_cursor_checked (xcb_connection_t *c,
+ xcb_cursor_t cid,
+ xcb_font_t source_font, /* font for the source glyph */
+ xcb_font_t mask_font, /* font for the mask glyph or XCB_NONE */
+ uint16_t source_char, /* character glyph for the source */
+ uint16_t mask_char, /* character glyph for the mask */
+ uint16_t fore_red, /* red value for the foreground of the source */
+ uint16_t fore_green, /* green value for the foreground of the source */
+ uint16_t fore_blue, /* blue value for the foreground of the source */
+ uint16_t back_red, /* red value for the background of the source */
+ uint16_t back_green, /* green value for the background of the source */
+ uint16_t back_blue) /* blue value for the background of the source */
+</pre>
+ <p>
+ <b>TODO</b>: Describe <span class="code">source_char</span>
+ and <span class="code">mask_char</span>, for example by giving
+ an example on how to get the values. There is a list there:
+ <a href="http://tronche.com/gui/x/xlib/appendix/b/">X Font Cursors</a>
+ </p>
+ <p>
+ So we first open that font (see <a href="#loadfont">Loading a Font</a>)
+ and create the new cursor. As for every X ressource, we have to
+ ask for an X id with <span class="code">xcb_cursor_new</span>
+ first:
+ </p>
+ <pre class="code">
+xcb_font_t font;
+xcb_cursor_t cursor;
+
+/* The connection is set */
+
+font = xcb_font_new (conn);
+xcb_open_font (conn, font, strlen ("cursor"), "cursor");
+
+cursor = xcb_cursor_new (conn);
+xcb_create_glyph_cursor (conn, cursor, font, font,
+ 58, 58 + 1,
+ 0, 0, 0,
+ 0, 0, 0);
+</pre>
+ <p>
+ We have created the cursor "right hand" by specifying 58 to
+ the <span class="code">source_fon</span>t argument and 58 + 1
+ to the <span class="code">mask_font</span>.
+ </p>
+ <p>
+ The cursor is destroyed by using the function
+ </p>
+ <pre class="code">
+xcb_void_cookie_t xcb_free_cursor (xcb_connection_t *c,
+ xcb_cursor_t cursor);
+</pre>
+ <p>
+ In the second method, we create a new cursor by using a pair
+ of pixmaps, with depth of one (that is, two colors
+ pixmaps). One pixmap defines the shape of the cursor, while
+ the other works as a mask, specifying which pixels of the
+ cursor will be actually drawn. The rest of the pixels will be
+ transparent.
+ </p>
+ <p>
+ <b>TODO</b>: give an example.
+ </p>
+ <li class="subtitle"><a name="mousecursorset">Setting a window's mouse cursor</a>
+ <p>
+ Once the cursor is created, we can modify the cursor of our
+ window by using <span class="code">xcb_change_window_attributes</span>
+ and using the <span class="code">XCB_CWCURSOR</span> attribute:
+ </p>
+ <pre class="code">
+uint32_t mask;
+uint32_t value_list;
+
+/* The connection and window are set */
+/* The cursor is already created */
+
+mask = XCB_CWCURSOR;
+value_list = cursor.xid;
+xcb_change_window_attributes (conn, window, mask, &value_list);
+</pre>
+ <p>
+ Of course, the cursor and the font must be freed.
+ </p>
+ <li class="subtitle"><a name="mousecursorexample">Complete example</a>
+ <p>
+ <b>TODO</b>: to do...
+ </p>
+ </ol>