[Xcb-commit] doc
Vincent Torri
doursse at kemper.freedesktop.org
Wed Feb 7 11:04:21 PST 2007
doc/tutorial/index.html | 311 ++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 303 insertions(+), 8 deletions(-)
New commits:
diff-tree acefe83bea9b2b17a956d68f5be504866d34196f (from 8a8c1fa184939ef23f96421990c171b49d16ee33)
Author: TORRI Vincent <torri at alf94-3-82-66-248-160.fbx.proxad.net>
Date: Wed Feb 7 20:04:10 2007 +0100
font part
diff --git a/doc/tutorial/index.html b/doc/tutorial/index.html
index de7849a..ac173a0 100644
--- a/doc/tutorial/index.html
+++ b/doc/tutorial/index.html
@@ -59,9 +59,10 @@
<li><a class="section" href="#font">Handling text and fonts</a>
<ol>
<li><a class="subsection" href="#fontstruct">The Font structure</a>
- <li>Loading a Font
- <li>Assigning a Font to a Graphic Context
- <li>Drawing text in a window
+ <li><a class="subsection" href="#openingfont">Opening a Font</a>
+ <li><a class="subsection" href="#assigningfont">Assigning a Font to a Graphic Context</a>
+ <li><a class="subsection" href="#drawingtext">Drawing text in a drawable</a>
+ <li><a class="subsection" href="#fontcompleteexample">Complete example</a>
</ol>
<li>Windows hierarchy
<ol>
@@ -977,8 +978,9 @@ main ()
change its attributes (for example, changing the foreground
color we use to draw a line, or changing the attributes of the
font we use to display strings. See Subsections Drawing with a
- color and Assigning a Font to a Graphic Context). This is done
- by using this function:
+ color and
+ <a href="#assigningfont">Assigning a Font to a Graphic Context</a>).
+ This is done by using this function:
</p>
<pre class="code">
xcb_void_cookie_t xcb_change_gc (xcb_connection_t *c, /* The XCB Connection */
@@ -2046,7 +2048,7 @@ main ()
<ol>
<li class="subtitle"><a name="fontstruct">The Font structure</a>
<p>
- In order to support flexible fonts, a font structure is
+ In order to support flexible fonts, a font type is
defined. You know what ? It's an Id:
</p>
<pre class="code">
@@ -2055,11 +2057,304 @@ typedef uint32_t xcb_font_t;
<p>
It is used to contain information about a font, and is passed
to several functions that handle fonts selection and text drawing.
+ We ask the X server to attribute an Id to our font with the
+ function:
+ </p>
+ <pre class="code">
+xcb_font_t xcb_generate_id (xcb_connection_t *c);
+</pre>
+ <p>
+ <li class="subtitle"><a name="openingfont">Opening a Font</a>
+ <p>
+ To open a font, we use the following function:
+ </p>
+ <pre class="code">
+xcb_void_cookie_t xcb_open_font (xcb_connection_t *c,
+ xcb_font_t fid,
+ uint16_t name_len,
+ const char *name);
+</pre>
+ <p>
+ The <span class="code">fid</span> parameter is the font Id
+ defined by <span class="code">xcb_generate_id()</span> (see
+ above). The <span class="code">name</span> parameter is the
+ name of the font you want to open. Use the command
+ <span class="code">xlsfonts</span> in a terminal to know which
+ are the fonts available on your computer. The parameter
+ <span class="code">name_len</span> is the length of the name
+ of the font (given by <span class="code">strlen()</span>).
+ </p>
+ <li class="subtitle"><a name="assigningfont">Assigning a Font to a Graphic Context</a>
+ <p>
+ Once a font is opened, you have to create a Graphic Context
+ that will contain the informations about the color of the
+ foreground and the background used when you draw a text in a
+ Drawable. Here is an exemple of a Graphic Context that will
+ allow us to draw an opened font with a black foreground and a
+ white background:
+ </p>
+ <pre class="code">
+ /*
+ * c is the connection
+ * screen is the screen where the window is displayed
+ * window is the window in which we will draw the text
+ * font is the opened font
+ */
+
+ uint32_t value_list[3];
+ xcb_gcontext_t gc;
+ uint32_t mask;
+
+ gc = xcb_generate_id (c);
+ mask = XCB_GC_FOREGROUND | XCB_GC_BACKGROUND | XCB_GC_FONT;
+ value_list[0] = screen->black_pixel;
+ value_list[1] = screen->white_pixel;
+ value_list[2] = font;
+ xcb_create_gc (c, gc, window, mask, value_list);
+
+ /* The font is not needed anymore, so we close it */
+ xcb_close_font (c, font);
+</pre>
+ <li class="subtitle"><a name="drawingtext">Drawing text in a drawable</a>
+ <p>
+ To draw a text in a drawable, we use the following function:
+ </p>
+ <pre class="code">
+xcb_void_cookie_t xcb_image_text_8 (xcb_connection_t *c,
+ uint8_t string_len,
+ xcb_drawable_t drawable,
+ xcb_gcontext_t gc,
+ int16_t x,
+ int16_t y,
+ const char *string);
+</pre>
+ <p>
+ The <span class="code">string</span> parameter is the text to
+ draw. The location of the drawing is given by the parameters
+ <span class="code">x</span> and <span class="code">y</span>.
+ The base line of the text is exactly the parameter
+ <span class="code">y</span>.
</p>
+ <li class="subtitle"><a name="fontcompleteexample">Complete example</a>
<p>
- <b>TODO:</b> example for picking a font and displaying some text.
- Even better, also demonstrate translating keypresses to text.
+ This example draw a text at 10 pixels (for the base line) of
+ the bottom of a window. Pressing the Esc key exits the program.
</p>
+ <pre class="code">#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <xcb/xcb.h>
+
+#define WIDTH 300
+#define HEIGHT 100
+
+
+
+static xcb_gc_t gc_font_get (xcb_connection_t *c,
+ xcb_screen_t *screen,
+ xcb_window_t window,
+ const char *font_name);
+
+static void text_draw (xcb_connection_t *c,
+ xcb_screen_t *screen,
+ xcb_window_t window,
+ int16_t x1,
+ int16_t y1,
+ const char *label);
+
+static void
+text_draw (xcb_connection_t *c,
+ xcb_screen_t *screen,
+ xcb_window_t window,
+ int16_t x1,
+ int16_t y1,
+ const char *label)
+{
+ xcb_void_cookie_t cookie_gc;
+ xcb_void_cookie_t cookie_text;
+ xcb_generic_error_t *error;
+ xcb_gcontext_t gc;
+ uint8_t length;
+
+ length = strlen (label);
+
+ gc = gc_font_get(c, screen, window, "7x13");
+
+ cookie_text = xcb_image_text_8_checked (c, length, window, gc,
+ x1,
+ y1, label);
+ error = xcb_request_check (c, cookie_text);
+ if (error) {
+ fprintf (stderr, "ERROR: can't paste text : %d\n", error->error_code);
+ xcb_disconnect (c);
+ exit (-1);
+ }
+
+ cookie_gc = xcb_free_gc (c, gc);
+ error = xcb_request_check (c, cookie_gc);
+ if (error) {
+ fprintf (stderr, "ERROR: can't free gc : %d\n", error->error_code);
+ xcb_disconnect (c);
+ exit (-1);
+ }
+}
+
+static xcb_gc_t
+gc_font_get (xcb_connection_t *c,
+ xcb_screen_t *screen,
+ xcb_window_t window,
+ const char *font_name)
+{
+ uint32_t value_list[3];
+ xcb_void_cookie_t cookie_font;
+ xcb_void_cookie_t cookie_gc;
+ xcb_generic_error_t *error;
+ xcb_font_t font;
+ xcb_gcontext_t gc;
+ uint32_t mask;
+
+ font = xcb_generate_id (c);
+ cookie_font = xcb_open_font_checked (c, font,
+ strlen (font_name),
+ font_name);
+
+ error = xcb_request_check (c, cookie_font);
+ if (error) {
+ fprintf (stderr, "ERROR: can't open font : %d\n", error->error_code);
+ xcb_disconnect (c);
+ return -1;
+ }
+
+ gc = xcb_generate_id (c);
+ mask = XCB_GC_FOREGROUND | XCB_GC_BACKGROUND | XCB_GC_FONT;
+ value_list[0] = screen->black_pixel;
+ value_list[1] = screen->white_pixel;
+ value_list[2] = font;
+ cookie_gc = xcb_create_gc_checked (c, gc, window, mask, value_list);
+ error = xcb_request_check (c, cookie_gc);
+ if (error) {
+ fprintf (stderr, "ERROR: can't create gc : %d\n", error->error_code);
+ xcb_disconnect (c);
+ exit (-1);
+ }
+
+ cookie_font = xcb_close_font_checked (c, font);
+ error = xcb_request_check (c, cookie_font);
+ if (error) {
+ fprintf (stderr, "ERROR: can't close font : %d\n", error->error_code);
+ xcb_disconnect (c);
+ exit (-1);
+ }
+
+ return gc;
+}
+
+int main ()
+{
+ xcb_screen_iterator_t screen_iter;
+ xcb_connection_t *c;
+ const xcb_setup_t *setup;
+ xcb_screen_t *screen;
+ xcb_generic_event_t *e;
+ xcb_generic_error_t *error;
+ xcb_void_cookie_t cookie_window;
+ xcb_void_cookie_t cookie_map;
+ xcb_window_t window;
+ uint32_t mask;
+ uint32_t values[2];
+ int screen_number;
+
+ /* getting the connection */
+ c = xcb_connect (NULL, &screen_number);
+ if (!c) {
+ fprintf (stderr, "ERROR: can't connect to an X server\n");
+ return -1;
+ }
+
+ /* getting the current screen */
+ setup = xcb_get_setup (c);
+
+ screen = NULL;
+ screen_iter = xcb_setup_roots_iterator (setup);
+ for (; screen_iter.rem != 0; --screen_number, xcb_screen_next (&screen_iter))
+ if (screen_number == 0)
+ {
+ screen = screen_iter.data;
+ break;
+ }
+ if (!screen) {
+ fprintf (stderr, "ERROR: can't get the current screen\n");
+ xcb_disconnect (c);
+ return -1;
+ }
+
+ /* creating the window */
+ window = xcb_generate_id (c);
+ mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
+ values[0] = screen->white_pixel;
+ values[1] =
+ XCB_EVENT_MASK_KEY_RELEASE |
+ XCB_EVENT_MASK_BUTTON_PRESS |
+ XCB_EVENT_MASK_EXPOSURE |
+ XCB_EVENT_MASK_POINTER_MOTION;
+ cookie_window = xcb_create_window_checked (c,
+ screen->root_depth,
+ window, screen->root,
+ 20, 200, WIDTH, HEIGHT,
+ 0, XCB_WINDOW_CLASS_INPUT_OUTPUT,
+ screen->root_visual,
+ mask, values);
+ cookie_map = xcb_map_window_checked (c, window);
+
+ /* error managing */
+ error = xcb_request_check (c, cookie_window);
+ if (error) {
+ fprintf (stderr, "ERROR: can't create window : %d\n", error->error_code);
+ xcb_disconnect (c);
+ return -1;
+ }
+ error = xcb_request_check (c, cookie_map);
+ if (error) {
+ fprintf (stderr, "ERROR: can't map window : %d\n", error->error_code);
+ xcb_disconnect (c);
+ return -1;
+ }
+
+ xcb_flush(c);
+
+ while (1) {
+ e = xcb_poll_for_event(c);
+ if (e) {
+ switch (e->response_type) {
+ case XCB_EXPOSE: {
+ char *text;
+
+ text = "Press ESC key to exit...";
+ text_draw (c, screen, window, 10, HEIGHT - 10, text);
+ break;
+ }
+ case XCB_KEY_RELEASE: {
+ xcb_key_release_event_t *ev;
+
+ ev = (xcb_key_release_event_t *)e;
+
+ switch (ev->detail) {
+ /* ESC */
+ case 9:
+ free (e);
+ xcb_disconnect (c);
+ return 0;
+ }
+ }
+ }
+ free (e);
+ }
+ }
+
+ return 0;
+}
+</pre>
</ol>
<li class="title"><a name="wm">Interacting with the window manager</a>
<p>
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