xcb_query_text_extents

Section: XCB Requests (3)
Updated: libxcb 1.12
Index Return to Main Contents

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NAME

xcb_query_text_extents - get text extents  

SYNOPSIS

#include <xcb/xproto.h>  

Request function

xcb_query_text_extents_cookie_t xcb_query_text_extents(xcb_connection_t *conn, xcb_fontable_t font, uint32_t string_len, const xcb_char2b_t *string);

 

Reply datastructure

typedef struct xcb_query_text_extents_reply_t {
    uint8_t  response_type;
    uint8_t  draw_direction;
    uint16_t sequence;
    uint32_t length;
    int16_t  font_ascent;
    int16_t  font_descent;
    int16_t  overall_ascent;
    int16_t  overall_descent;
    int32_t  overall_width;
    int32_t  overall_left;
    int32_t  overall_right;
} xcb_query_text_extents_reply_t;

 

Reply function

xcb_query_text_extents_reply_t *xcb_query_text_extents_reply(xcb_connection_t *conn, xcb_query_text_extents_cookie_t cookie, xcb_generic_error_t **e);

 

REQUEST ARGUMENTS

conn

The XCB connection to X11.

font

The font to calculate text extents in. You can also pass a graphics context.

string_len

The number of characters in string.

string

The text to get text extents for.

 

REPLY FIELDS

response_type

The type of this reply, in this case XCB_QUERY_TEXT_EXTENTS. This field is also present in the xcb_generic_reply_t and can be used to tell replies apart from each other.

sequence

The sequence number of the last request processed by the X11 server.

length

The length of the reply, in words (a word is 4 bytes).

draw_direction

One of the following values:

XCB_FONT_DRAW_LEFT_TO_RIGHT

TODO: NOT YET DOCUMENTED.

XCB_FONT_DRAW_RIGHT_TO_LEFT

TODO: NOT YET DOCUMENTED.

TODO: NOT YET DOCUMENTED.

font_ascent

TODO: NOT YET DOCUMENTED.

font_descent

TODO: NOT YET DOCUMENTED.

overall_ascent

TODO: NOT YET DOCUMENTED.

overall_descent

TODO: NOT YET DOCUMENTED.

overall_width

TODO: NOT YET DOCUMENTED.

overall_left

TODO: NOT YET DOCUMENTED.

overall_right

TODO: NOT YET DOCUMENTED.

 

DESCRIPTION

Query text extents from the X11 server. This request returns the bounding box of the specified 16-bit character string in the specified font or the font contained in the specified graphics context.

font_ascent is set to the maximum of the ascent metrics of all characters in the string. font_descent is set to the maximum of the descent metrics. overall_width is set to the sum of the character-width metrics of all characters in the string. For each character in the string, let W be the sum of the character-width metrics of all characters preceding it in the string. Let L be the left-side-bearing metric of the character plus W. Let R be the right-side-bearing metric of the character plus W. The lbearing member is set to the minimum L of all characters in the string. The rbearing member is set to the maximum R.

For fonts defined with linear indexing rather than 2-byte matrix indexing, each xcb_char2b_t structure is interpreted as a 16-bit number with byte1 as the most significant byte. If the font has no defined default character, undefined characters in the string are taken to have all zero metrics.

Characters with all zero metrics are ignored. If the font has no defined default_char, the undefined characters in the string are also ignored.  

RETURN VALUE

Returns an xcb_query_text_extents_cookie_t. Errors have to be handled when calling the reply function xcb_query_text_extents_reply.

If you want to handle errors in the event loop instead, use xcb_query_text_extents_unchecked. See xcb-requests(3) for details.  

ERRORS

xcb_font_error_t

The specified font does not exist.

xcb_g_context_error_t

The specified graphics context does not exist.

 

SEE ALSO

xcb-requests(3)  

AUTHOR

Generated from xproto.xml. Contact xcb@lists.freedesktop.org for corrections and improvements.

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Index

NAME

SYNOPSIS

Request function

Reply datastructure

Reply function

REQUEST ARGUMENTS

REPLY FIELDS

DESCRIPTION

RETURN VALUE

ERRORS

SEE ALSO

AUTHOR