[Xcb-commit] tutorial.mdwn
XCB site
xcb at freedesktop.org
Sun Nov 11 20:31:29 PST 2007
tutorial.mdwn | 356 ++++++++++++++++++++++++++++------------------------------
1 file changed, 175 insertions(+), 181 deletions(-)
New commits:
commit bad86aded890740044b199c9a4c0db71a68fa8e6
Author: brian.thomas.will <brian.thomas.will at gmail.com>
Date: Sun Nov 11 20:31:29 2007 -0800
refactored section 9.3 ("drawing primitives")
diff --git a/tutorial.mdwn b/tutorial.mdwn
index 0c04b87..d83d4c8 100644
--- a/tutorial.mdwn
+++ b/tutorial.mdwn
@@ -568,97 +568,96 @@ TODO: give an example which sets several attributes.
### 9.3 Drawing primitives: point, line, box, circle,...
-
After we have created a Graphic Context, we can draw on a window using this Graphic Context, with a set of XCB functions, collectively called "drawing primitives". Let see how they are used.
To draw a point, or several points, we use:
- xcb_void_cookie_t xcb_poly_point (xcb_connection_t *c, /* The connection to the X server */
- uint8_t coordinate_mode, /* Coordinate mode, usually set to XCB_COORD_MODE_ORIGIN */
- xcb_drawable_t drawable, /* The drawable on which we want to draw the point(s) */
- xcb_gcontext_t gc, /* The Graphic Context we use to draw the point(s) */
- uint32_t points_len, /* The number of points */
- const xcb_point_t *points); /* An array of points */
+ xcb_void_cookie_t xcb_poly_point (xcb_connection_t *c, /* The connection to the X server */
+ uint8_t coordinate_mode, /* Coordinate mode, usually set to XCB_COORD_MODE_ORIGIN */
+ xcb_drawable_t drawable, /* The drawable on which we want to draw the point(s) */
+ xcb_gcontext_t gc, /* The Graphic Context we use to draw the point(s) */
+ uint32_t points_len, /* The number of points */
+ const xcb_point_t *points ); /* An array of points */
The coordinate_mode parameter specifies the coordinate mode. Available values are:
-* XCB_COORD_MODE_ORIGIN
-* XCB_COORD_MODE_PREVIOUS
+ XCB_COORD_MODE_ORIGIN
+ XCB_COORD_MODE_PREVIOUS
-If XCB_COORD_MODE_PREVIOUS is used, then all points but the first one are relative to the immediately previous point.
+If XCB\_COORD\_MODE\_PREVIOUS is used, then all points but the first one are relative to the immediately previous point.
-The xcb_point_t type is just a structure with two fields (the coordinates of the point):
+The xcb\_point\_t type is just a structure with two fields (the coordinates of the point):
- typedef struct {
- int16_t x;
- int16_t y;
- } xcb_point_t;
+ typedef struct {
+ int16_t x;
+ int16_t y;
+ } xcb_point_t;
You could see an example in xpoints.c. TODO Set the link.
To draw a line, or a polygonal line, we use:
- xcb_void_cookie_t xcb_poly_line (xcb_connection_t *c, /* The connection to the X server */
- uint8_t coordinate_mode, /* Coordinate mode, usually set to XCB_COORD_MODE_ORIGIN */
- xcb_drawable_t drawable, /* The drawable on which we want to draw the line(s) */
- xcb_gcontext_t gc, /* The Graphic Context we use to draw the line(s) */
- uint32_t points_len, /* The number of points in the polygonal line */
- const xcb_point_t *points); /* An array of points */
+ xcb_void_cookie_t xcb_poly_line (xcb_connection_t *c, /* The connection to the X server */
+ uint8_t coordinate_mode, /* Coordinate mode, usually set to XCB_COORD_MODE_ORIGIN */
+ xcb_drawable_t drawable, /* The drawable on which we want to draw the line(s) */
+ xcb_gcontext_t gc, /* The Graphic Context we use to draw the line(s) */
+ uint32_t points_len, /* The number of points in the polygonal line */
+ const xcb_point_t *points ); /* An array of points */
This function will draw the line between the first and the second points, then the line between the second and the third points, and so on.
-To draw a segment, or several segments, we use
+To draw a segment, or several segments, we use:
- xcb_void_cookie_t xcb_poly_segment (xcb_connection_t *c, /* The connection to the X server */
- xcb_drawable_t drawable, /* The drawable on which we want to draw the segment(s) */
- xcb_gcontext_t gc, /* The Graphic Context we use to draw the segment(s) */
- uint32_t segments_len, /* The number of segments */
- const xcb_segment_t *segments); /* An array of segments */
-
-The xcb_segment_t type is just a structure with four fields (the coordinates of the two points that define the segment):
-
- typedef struct {
- int16_t x1;
- int16_t y1;
- int16_t x2;
- int16_t y2;
- } xcb_segment_t;
+ xcb_void_cookie_t xcb_poly_segment (xcb_connection_t *c, /* The connection to the X server */
+ xcb_drawable_t drawable, /* The drawable on which we want to draw the segment(s) */
+ xcb_gcontext_t gc, /* The Graphic Context we use to draw the segment(s) */
+ uint32_t segments_len, /* The number of segments */
+ const xcb_segment_t *segments ); /* An array of segments */
-To draw a rectangle, or several rectangles, we use
+The xcb\_segment\_t type is just a structure with four fields (the coordinates of the two points that define the segment):
- xcb_void_cookie_t xcb_poly_rectangle (xcb_connection_t *c, /* The connection to the X server */
- xcb_drawable_t drawable, /* The drawable on which we want to draw the rectangle(s) */
- xcb_gcontext_t gc, /* The Graphic Context we use to draw the rectangle(s) */
- uint32_t rectangles_len, /* The number of rectangles */
- const xcb_rectangle_t *rectangles); /* An array of rectangles */
-
-The xcb_rectangle_t type is just a structure with four fields (the coordinates of the top-left corner of the rectangle, and its width and height):
-
- typedef struct {
- int16_t x;
- int16_t y;
- uint16_t width;
- uint16_t height;
- } xcb_rectangle_t;
+ typedef struct {
+ int16_t x1;
+ int16_t y1;
+ int16_t x2;
+ int16_t y2;
+ } xcb_segment_t;
-To draw an elliptical arc, or several elliptical arcs, we use
+To draw a rectangle, or several rectangles, we use:
- xcb_void_cookie_t xcb_poly_arc (xcb_connection_t *c, /* The connection to the X server */
- xcb_drawable_t drawable, /* The drawable on which we want to draw the arc(s) */
- xcb_gcontext_t gc, /* The Graphic Context we use to draw the arc(s) */
- uint32_t arcs_len, /* The number of arcs */
- const xcb_arc_t *arcs); /* An array of arcs */
+ xcb_void_cookie_t xcb_poly_rectangle (xcb_connection_t *c, /* The connection to the X server */
+ xcb_drawable_t drawable, /* The drawable on which we want to draw the rectangle(s) */
+ xcb_gcontext_t gc, /* The Graphic Context we use to draw the rectangle(s) */
+ uint32_t rectangles_len, /* The number of rectangles */
+ const xcb_rectangle_t *rectangles ); /* An array of rectangles */
-The xcb_arc_t type is a structure with six fields:
+The xcb\_rectangle\_t type is just a structure with four fields (the coordinates of the top-left corner of the rectangle, and its width and height):
- typedef struct {
- int16_t x; /* Top left x coordinate of the rectangle surrounding the ellipse */
- int16_t y; /* Top left y coordinate of the rectangle surrounding the ellipse */
- uint16_t width; /* Width of the rectangle surrounding the ellipse */
- uint16_t height; /* Height of the rectangle surrounding the ellipse */
- int16_t angle1; /* Angle at which the arc begins */
- int16_t angle2; /* Angle at which the arc ends */
- } xcb_arc_t;
+ typedef struct {
+ int16_t x;
+ int16_t y;
+ uint16_t width;
+ uint16_t height;
+ } xcb_rectangle_t;
+
+To draw an elliptical arc, or several elliptical arcs, we use:
+
+ xcb_void_cookie_t xcb_poly_arc (xcb_connection_t *c, /* The connection to the X server */
+ xcb_drawable_t drawable, /* The drawable on which we want to draw the arc(s) */
+ xcb_gcontext_t gc, /* The Graphic Context we use to draw the arc(s) */
+ uint32_t arcs_len, /* The number of arcs */
+ const xcb_arc_t *arcs ); /* An array of arcs */
+
+The xcb\_arc\_t type is a structure with six fields:
+
+ typedef struct {
+ int16_t x; /* Top left x coordinate of the rectangle surrounding the ellipse */
+ int16_t y; /* Top left y coordinate of the rectangle surrounding the ellipse */
+ uint16_t width; /* Width of the rectangle surrounding the ellipse */
+ uint16_t height; /* Height of the rectangle surrounding the ellipse */
+ int16_t angle1; /* Angle at which the arc begins */
+ int16_t angle2; /* Angle at which the arc ends */
+ } xcb_arc_t;
Note: the angles are expressed in units of 1/64 of a degree, so to have an angle of 90 degrees, starting at 0, angle1 = 0 and angle2 = 90 << 6. Positive angles indicate counterclockwise motion, while negative angles indicate clockwise motion.
@@ -666,156 +665,151 @@ The corresponding function which fill inside the geometrical object are listed b
To Fill a polygon defined by the points given as arguments , we use
- xcb_void_cookie_t xcb_fill_poly (xcb_connection_t *c,
- xcb_drawable_t drawable,
- xcb_gcontext_t gc,
- uint8_t shape,
- uint8_t coordinate_mode,
- uint32_t points_len,
- const xcb_point_t *points);
-
-The shape parameter specifies a shape that helps the server to improve performance. Available values are
+ xcb_void_cookie_t xcb_fill_poly (xcb_connection_t *c,
+ xcb_drawable_t drawable,
+ xcb_gcontext_t gc,
+ uint8_t shape,
+ uint8_t coordinate_mode,
+ uint32_t points_len,
+ const xcb_point_t *points );
-* XCB_POLY_SHAPE_COMPLEX
-* XCB_POLY_SHAPE_NONCONVEX
-* XCB_POLY_SHAPE_CONVEX
+The shape parameter specifies a shape that helps the server to improve performance. Available values are:
-To fill one or several rectangles, we use
+ XCB_POLY_SHAPE_COMPLEX
+ XCB_POLY_SHAPE_NONCONVEX
+ XCB_POLY_SHAPE_CONVEX
- xcb_void_cookie_t xcb_poly_fill_rectangle (xcb_connection_t *c,
- xcb_drawable_t drawable,
- xcb_gcontext_t gc,
- uint32_t rectangles_len,
- const xcb_rectangle_t *rectangles);
+To fill one or several rectangles, we use:
-To fill one or several arcs, we use
+ xcb_void_cookie_t xcb_poly_fill_rectangle (xcb_connection_t *c,
+ xcb_drawable_t drawable,
+ xcb_gcontext_t gc,
+ uint32_t rectangles_len,
+ const xcb_rectangle_t *rectangles );
- xcb_void_cookie_t xcb_poly_fill_arc (xcb_connection_t *c,
- xcb_drawable_t drawable,
- xcb_gcontext_t gc,
- uint32_t arcs_len,
- const xcb_arc_t *arcs);
+To fill one or several arcs, we use:
+ xcb_void_cookie_t xcb_poly_fill_arc (xcb_connection_t *c,
+ xcb_drawable_t drawable,
+ xcb_gcontext_t gc,
+ uint32_t arcs_len,
+ const xcb_arc_t *arcs );
To illustrate these functions, here is an example that draws four points, a polygonal line, two segments, two rectangles and two arcs. Remark that we use events for the first time, as an introduction to the next section.
TODO: Use screen->root_depth for depth parameter.
- #include <stdlib.h>
- #include <stdio.h>
+ #include <stdlib.h>
+ #include <stdio.h>
- #include <xcb/xcb.h>
+ #include <xcb/xcb.h>
- int
- main ()
- {
- xcb_connection_t *c;
- xcb_screen_t *screen;
- xcb_drawable_t win;
- xcb_gcontext_t foreground;
- xcb_generic_event_t *e;
- uint32_t mask = 0;
- uint32_t values[2];
+ int
+ main ()
+ {
+ /* geometric objects */
+ xcb_point_t points[] = {
+ {10, 10},
+ {10, 20},
+ {20, 10},
+ {20, 20}};
- /* geometric objects */
- xcb_point_t points[] = {
- {10, 10},
- {10, 20},
- {20, 10},
- {20, 20}};
+ xcb_point_t polyline[] = {
+ {50, 10},
+ { 5, 20}, /* rest of points are relative */
+ {25,-20},
+ {10, 10}};
- xcb_point_t polyline[] = {
- {50, 10},
- { 5, 20}, /* rest of points are relative */
- {25,-20},
- {10, 10}};
+ xcb_segment_t segments[] = {
+ {100, 10, 140, 30},
+ {110, 25, 130, 60}};
- xcb_segment_t segments[] = {
- {100, 10, 140, 30},
- {110, 25, 130, 60}};
+ xcb_rectangle_t rectangles[] = {
+ { 10, 50, 40, 20},
+ { 80, 50, 10, 40}};
- xcb_rectangle_t rectangles[] = {
- { 10, 50, 40, 20},
- { 80, 50, 10, 40}};
+ xcb_arc_t arcs[] = {
+ {10, 100, 60, 40, 0, 90 << 6},
+ {90, 100, 55, 40, 0, 270 << 6}};
- xcb_arc_t arcs[] = {
- {10, 100, 60, 40, 0, 90 << 6},
- {90, 100, 55, 40, 0, 270 << 6}};
- /* Open the connection to the X server */
- c = xcb_connect (NULL, NULL);
+ /* Open the connection to the X server */
+ xcb_connection_t *connection = xcb_connect (NULL, NULL);
- /* Get the first screen */
- screen = xcb_setup_roots_iterator (xcb_get_setup (c)).data;
+ /* Get the first screen */
+ xcb_screen_t *screen = xcb_setup_roots_iterator (xcb_get_setup (connection)).data;
- /* Create black (foreground) graphic context */
- win = screen->root;
+ /* Create black (foreground) graphic context */
+ xcb_drawable_t window = screen->root;
+ xcb_gcontext_t foreground = xcb_generate_id (connection);
+ uint32_t mask = XCB_GC_FOREGROUND | XCB_GC_GRAPHICS_EXPOSURES;
+ uint32_t values[2] = {screen->black_pixel, 0};
- foreground = xcb_generate_id (c);
- mask = XCB_GC_FOREGROUND | XCB_GC_GRAPHICS_EXPOSURES;
- values[0] = screen->black_pixel;
- values[1] = 0;
- xcb_create_gc (c, foreground, win, mask, values);
+ xcb_create_gc (connection, foreground, window, mask, values);
- /* Ask for our window's Id */
- win = xcb_generate_id(c);
- /* Create the window */
- mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
- values[0] = screen->white_pixel;
- values[1] = XCB_EVENT_MASK_EXPOSURE;
- xcb_create_window (c, /* Connection */
- XCB_COPY_FROM_PARENT, /* depth */
- win, /* window Id */
- screen->root, /* parent window */
- 0, 0, /* x, y */
- 150, 150, /* width, height */
- 10, /* border_width */
- XCB_WINDOW_CLASS_INPUT_OUTPUT, /* class */
- screen->root_visual, /* visual */
- mask, values); /* masks */
+ /* Create a window */
- /* Map the window on the screen */
- xcb_map_window (c, win);
+ window = xcb_generate_id (connection);
+ mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
+ values[0] = screen->white_pixel;
+ values[1] = XCB_EVENT_MASK_EXPOSURE;
- /* We flush the request */
- xcb_flush (c);
+ xcb_create_window (connection, /* connection */
+ XCB_COPY_FROM_PARENT, /* depth */
+ window, /* window Id */
+ screen->root, /* parent window */
+ 0, 0, /* x, y */
+ 150, 150, /* width, height */
+ 10, /* border_width */
+ XCB_WINDOW_CLASS_INPUT_OUTPUT, /* class */
+ screen->root_visual, /* visual */
+ mask, values ); /* masks */
- while ((e = xcb_wait_for_event (c))) {
- switch (e->response_type & ~0x80) {
- case XCB_EXPOSE: {
- /* We draw the points */
- xcb_poly_point (c, XCB_COORD_MODE_ORIGIN, win, foreground, 4, points);
- /* We draw the polygonal line */
- xcb_poly_line (c, XCB_COORD_MODE_PREVIOUS, win, foreground, 4, polyline);
+ /* Map the window on the screen and flush*/
+ xcb_map_window (connection, window);
+ xcb_flush (connection);
+
+
+ /* draw primitives */
- /* We draw the segements */
- xcb_poly_segment (c, win, foreground, 2, segments);
+ xcb_generic_event_t *event;
+ while (event = xcb_wait_for_event (connection)) {
+ switch (event->response_type & ~0x80) {
+ case XCB_EXPOSE:
+ /* We draw the points */
+ xcb_poly_point (connection, XCB_COORD_MODE_ORIGIN, window, foreground, 4, points);
- /* We draw the rectangles */
- xcb_poly_rectangle (c, win, foreground, 2, rectangles);
+ /* We draw the polygonal line */
+ xcb_poly_line (connection, XCB_COORD_MODE_PREVIOUS, window, foreground, 4, polyline);
- /* We draw the arcs */
- xcb_poly_arc (c, win, foreground, 2, arcs);
+ /* We draw the segements */
+ xcb_poly_segment (connection, window, foreground, 2, segments);
- /* We flush the request */
- xcb_flush (c);
+ /* draw the rectangles */
+ xcb_poly_rectangle (connection, window, foreground, 2, rectangles);
- break;
- }
- default: {
- /* Unknown event type, ignore it */
- break;
- }
- }
- /* Free the Generic Event */
- free (e);
- }
+ /* draw the arcs */
+ xcb_poly_arc (connection, window, foreground, 2, arcs);
+
+ /* flush the request */
+ xcb_flush (connection);
+
+ break;
+ default:
+ /* Unknown event type, ignore it */
+ break;
+ }
+
+ /* Free the Generic Event */
+ free (event);
+ }
+
+ return 0;
+ }
- return 0;
- }
# 10. X Events
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