sway/common/pango.c
Kenny Levinsen 8c5b23e592 common/pango: Disable glyph position rounding
Pango rounds glyph position and widths to nearest integer, which leads
to font dimensions jumping around when rendering with a scale, causing
text geometry to jump around when changing scale. This is disturbing
when text buffers change scale, and also mean that the text geometry
calculations in sway_text_node are incorrect.

Disable this rounding to make the geometry stable.
2024-07-10 18:49:42 -04:00

142 lines
3.6 KiB
C

#include <cairo.h>
#include <pango/pangocairo.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cairo_util.h"
#include "log.h"
#include "stringop.h"
size_t escape_markup_text(const char *src, char *dest) {
size_t length = 0;
if (dest) {
dest[0] = '\0';
}
while (src[0]) {
switch (src[0]) {
case '&':
length += 5;
lenient_strcat(dest, "&amp;");
break;
case '<':
length += 4;
lenient_strcat(dest, "&lt;");
break;
case '>':
length += 4;
lenient_strcat(dest, "&gt;");
break;
case '\'':
length += 6;
lenient_strcat(dest, "&apos;");
break;
case '"':
length += 6;
lenient_strcat(dest, "&quot;");
break;
default:
if (dest) {
dest[length] = *src;
dest[length + 1] = '\0';
}
length += 1;
}
src++;
}
return length;
}
PangoLayout *get_pango_layout(cairo_t *cairo, const PangoFontDescription *desc,
const char *text, double scale, bool markup) {
PangoLayout *layout = pango_cairo_create_layout(cairo);
pango_context_set_round_glyph_positions(pango_layout_get_context(layout), false);
PangoAttrList *attrs;
if (markup) {
char *buf;
GError *error = NULL;
if (pango_parse_markup(text, -1, 0, &attrs, &buf, NULL, &error)) {
pango_layout_set_text(layout, buf, -1);
free(buf);
} else {
sway_log(SWAY_ERROR, "pango_parse_markup '%s' -> error %s", text,
error->message);
g_error_free(error);
markup = false; // fallback to plain text
}
}
if (!markup) {
attrs = pango_attr_list_new();
pango_layout_set_text(layout, text, -1);
}
pango_attr_list_insert(attrs, pango_attr_scale_new(scale));
pango_layout_set_font_description(layout, desc);
pango_layout_set_single_paragraph_mode(layout, 1);
pango_layout_set_attributes(layout, attrs);
pango_attr_list_unref(attrs);
return layout;
}
void get_text_size(cairo_t *cairo, const PangoFontDescription *desc, int *width, int *height,
int *baseline, double scale, bool markup, const char *fmt, ...) {
va_list args;
va_start(args, fmt);
char *buf = vformat_str(fmt, args);
va_end(args);
if (buf == NULL) {
return;
}
PangoLayout *layout = get_pango_layout(cairo, desc, buf, scale, markup);
pango_cairo_update_layout(cairo, layout);
pango_layout_get_pixel_size(layout, width, height);
if (baseline) {
*baseline = pango_layout_get_baseline(layout) / PANGO_SCALE;
}
g_object_unref(layout);
free(buf);
}
void get_text_metrics(const PangoFontDescription *description, int *height, int *baseline) {
cairo_t *cairo = cairo_create(NULL);
PangoContext *pango = pango_cairo_create_context(cairo);
pango_context_set_round_glyph_positions(pango, false);
// When passing NULL as a language, pango uses the current locale.
PangoFontMetrics *metrics = pango_context_get_metrics(pango, description, NULL);
*baseline = pango_font_metrics_get_ascent(metrics) / PANGO_SCALE;
*height = *baseline + pango_font_metrics_get_descent(metrics) / PANGO_SCALE;
pango_font_metrics_unref(metrics);
g_object_unref(pango);
cairo_destroy(cairo);
}
void render_text(cairo_t *cairo, const PangoFontDescription *desc,
double scale, bool markup, const char *fmt, ...) {
va_list args;
va_start(args, fmt);
char *buf = vformat_str(fmt, args);
va_end(args);
if (buf == NULL) {
return;
}
PangoLayout *layout = get_pango_layout(cairo, desc, buf, scale, markup);
cairo_font_options_t *fo = cairo_font_options_create();
cairo_get_font_options(cairo, fo);
pango_cairo_context_set_font_options(pango_layout_get_context(layout), fo);
cairo_font_options_destroy(fo);
pango_cairo_update_layout(cairo, layout);
pango_cairo_show_layout(cairo, layout);
g_object_unref(layout);
free(buf);
}