gri3-wm/libi3/font.c

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/*
* vim:ts=4:sw=4:expandtab
*
* i3 - an improved dynamic tiling window manager
* © 2009-2011 Michael Stapelberg and contributors (see also: LICENSE)
*
*/
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <err.h>
#include "libi3.h"
extern xcb_connection_t *conn;
static const i3Font *savedFont = NULL;
/*
* Loads a font for usage, also getting its metrics. If fallback is true,
* the fonts 'fixed' or '-misc-*' will be loaded instead of exiting.
*
*/
i3Font load_font(const char *pattern, const bool fallback) {
i3Font font;
font.type = FONT_TYPE_NONE;
/* Send all our requests first */
font.specific.xcb.id = xcb_generate_id(conn);
xcb_void_cookie_t font_cookie = xcb_open_font_checked(conn, font.specific.xcb.id,
strlen(pattern), pattern);
xcb_query_font_cookie_t info_cookie = xcb_query_font(conn, font.specific.xcb.id);
/* Check for errors. If errors, fall back to default font. */
xcb_generic_error_t *error;
error = xcb_request_check(conn, font_cookie);
/* If we fail to open font, fall back to 'fixed' */
if (fallback && error != NULL) {
ELOG("Could not open font %s (X error %d). Trying fallback to 'fixed'.\n",
pattern, error->error_code);
pattern = "fixed";
font_cookie = xcb_open_font_checked(conn, font.specific.xcb.id,
strlen(pattern), pattern);
info_cookie = xcb_query_font(conn, font.specific.xcb.id);
/* Check if we managed to open 'fixed' */
error = xcb_request_check(conn, font_cookie);
/* Fall back to '-misc-*' if opening 'fixed' fails. */
if (error != NULL) {
ELOG("Could not open fallback font 'fixed', trying with '-misc-*'.\n");
pattern = "-misc-*";
font_cookie = xcb_open_font_checked(conn, font.specific.xcb.id,
strlen(pattern), pattern);
info_cookie = xcb_query_font(conn, font.specific.xcb.id);
if ((error = xcb_request_check(conn, font_cookie)) != NULL)
errx(EXIT_FAILURE, "Could open neither requested font nor fallbacks "
"(fixed or -misc-*): X11 error %d", error->error_code);
}
}
/* Get information (height/name) for this font */
if (!(font.specific.xcb.info = xcb_query_font_reply(conn, info_cookie, NULL)))
errx(EXIT_FAILURE, "Could not load font \"%s\"", pattern);
/* Get the font table, if possible */
if (xcb_query_font_char_infos_length(font.specific.xcb.info) == 0)
font.specific.xcb.table = NULL;
else
font.specific.xcb.table = xcb_query_font_char_infos(font.specific.xcb.info);
/* Calculate the font height */
font.height = font.specific.xcb.info->font_ascent + font.specific.xcb.info->font_descent;
/* Set the font type and return successfully */
font.type = FONT_TYPE_XCB;
return font;
}
/*
* Defines the font to be used for the forthcoming calls.
*
*/
void set_font(i3Font *font) {
savedFont = font;
}
/*
* Frees the resources taken by the current font.
*
*/
void free_font(void) {
switch (savedFont->type) {
case FONT_TYPE_NONE:
/* Nothing to do */
break;
case FONT_TYPE_XCB: {
/* Close the font and free the info */
xcb_close_font(conn, savedFont->specific.xcb.id);
if (savedFont->specific.xcb.info)
free(savedFont->specific.xcb.info);
break;
}
default:
assert(false);
break;
}
}
/*
* Defines the colors to be used for the forthcoming draw_text calls.
*
*/
void set_font_colors(xcb_gcontext_t gc, uint32_t foreground, uint32_t background) {
assert(savedFont != NULL);
switch (savedFont->type) {
case FONT_TYPE_NONE:
/* Nothing to do */
break;
case FONT_TYPE_XCB: {
/* Change the font and colors in the GC */
uint32_t mask = XCB_GC_FOREGROUND | XCB_GC_BACKGROUND | XCB_GC_FONT;
uint32_t values[] = { foreground, background, savedFont->specific.xcb.id };
xcb_change_gc(conn, gc, mask, values);
break;
}
default:
assert(false);
break;
}
}
static int predict_text_width_xcb(const xcb_char2b_t *text, size_t text_len);
static void draw_text_xcb(const xcb_char2b_t *text, size_t text_len, xcb_drawable_t drawable,
xcb_gcontext_t gc, int x, int y, int max_width) {
/* X11 coordinates for fonts start at the baseline */
int pos_y = y + savedFont->specific.xcb.info->font_ascent;
/* The X11 protocol limits text drawing to 255 chars, so we may need
* multiple calls */
int offset = 0;
for (;;) {
/* Calculate the size of this chunk */
int chunk_size = (text_len > 255 ? 255 : text_len);
const xcb_char2b_t *chunk = text + offset;
/* Draw it */
xcb_image_text_16(conn, chunk_size, drawable, gc, x, pos_y, chunk);
/* Advance the offset and length of the text to draw */
offset += chunk_size;
text_len -= chunk_size;
/* Check if we're done */
if (text_len == 0)
break;
/* Advance pos_x based on the predicted text width */
x += predict_text_width_xcb(chunk, chunk_size);
}
}
/*
* Draws text onto the specified X drawable (normally a pixmap) at the
* specified coordinates (from the top left corner of the leftmost, uppermost
* glyph) and using the provided gc.
*
* Text must be specified as an i3String.
*
*/
void draw_text(i3String *text, xcb_drawable_t drawable,
xcb_gcontext_t gc, int x, int y, int max_width) {
assert(savedFont != NULL);
switch (savedFont->type) {
case FONT_TYPE_NONE:
/* Nothing to do */
return;
case FONT_TYPE_XCB:
draw_text_xcb(i3string_as_ucs2(text), i3string_get_num_glyphs(text),
drawable, gc, x, y, max_width);
break;
default:
assert(false);
}
}
/*
* ASCII version of draw_text to print static strings.
*
*/
void draw_text_ascii(const char *text, xcb_drawable_t drawable,
xcb_gcontext_t gc, int x, int y, int max_width) {
assert(savedFont != NULL);
switch (savedFont->type) {
case FONT_TYPE_NONE:
/* Nothing to do */
return;
case FONT_TYPE_XCB:
{
size_t text_len = strlen(text);
if (text_len > 255) {
/* The text is too long to draw it directly to X */
i3String *str = i3string_from_utf8(text);
draw_text(str, drawable, gc, x, y, max_width);
i3string_free(str);
} else {
/* X11 coordinates for fonts start at the baseline */
int pos_y = y + savedFont->specific.xcb.info->font_ascent;
xcb_image_text_8(conn, text_len, drawable, gc, x, pos_y, text);
}
break;
}
default:
assert(false);
}
}
static int xcb_query_text_width(const xcb_char2b_t *text, size_t text_len) {
/* Make the user know were using the slow path, but only once. */
static bool first_invocation = true;
if (first_invocation) {
fprintf(stderr, "Using slow code path for text extents\n");
first_invocation = false;
}
/* Query the text width */
xcb_generic_error_t *error;
xcb_query_text_extents_cookie_t cookie = xcb_query_text_extents(conn,
savedFont->specific.xcb.id, text_len, (xcb_char2b_t*)text);
xcb_query_text_extents_reply_t *reply = xcb_query_text_extents_reply(conn,
cookie, &error);
if (reply == NULL) {
/* We return a safe estimate because a rendering error is better than
* a crash. Plus, the user will see the error in his log. */
fprintf(stderr, "Could not get text extents (X error code %d)\n",
error->error_code);
return savedFont->specific.xcb.info->max_bounds.character_width * text_len;
}
int width = reply->overall_width;
free(reply);
return width;
}
static int predict_text_width_xcb(const xcb_char2b_t *input, size_t text_len) {
if (text_len == 0)
return 0;
int width;
if (savedFont->specific.xcb.table == NULL) {
/* If we don't have a font table, fall back to querying the server */
width = xcb_query_text_width(input, text_len);
} else {
/* Save some pointers for convenience */
xcb_query_font_reply_t *font_info = savedFont->specific.xcb.info;
xcb_charinfo_t *font_table = savedFont->specific.xcb.table;
/* Calculate the width using the font table */
width = 0;
for (size_t i = 0; i < text_len; i++) {
xcb_charinfo_t *info;
int row = input[i].byte1;
int col = input[i].byte2;
if (row < font_info->min_byte1 ||
row > font_info->max_byte1 ||
col < font_info->min_char_or_byte2 ||
col > font_info->max_char_or_byte2)
continue;
/* Don't you ask me, how this one works… (Merovius) */
info = &font_table[((row - font_info->min_byte1) *
(font_info->max_char_or_byte2 - font_info->min_char_or_byte2 + 1)) +
(col - font_info->min_char_or_byte2)];
if (info->character_width != 0 ||
(info->right_side_bearing |
info->left_side_bearing |
info->ascent |
info->descent) != 0) {
width += info->character_width;
}
}
}
return width;
}
/*
* Predict the text width in pixels for the given text. Text must be
* specified as an i3String.
*
*/
int predict_text_width(i3String *text) {
assert(savedFont != NULL);
switch (savedFont->type) {
case FONT_TYPE_NONE:
/* Nothing to do */
return 0;
case FONT_TYPE_XCB:
return predict_text_width_xcb(i3string_as_ucs2(text), i3string_get_num_glyphs(text));
default:
assert(false);
return 0;
}
}