netsurf/gtk/font_pango.c

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/*
* This file is part of NetSurf, http://netsurf.sourceforge.net/
* Licensed under the GNU General Public License,
* http://www.opensource.org/licenses/gpl-license
* Copyright 2005 James Bursa <bursa@users.sourceforge.net>
*/
/** \file
* Font handling (GTK implementation).
*
* Pango is used handle and render fonts.
*/
#include <assert.h>
#include <stdio.h>
#include <gtk/gtk.h>
#include "netsurf/css/css.h"
#include "netsurf/gtk/font_pango.h"
#include "netsurf/gtk/gtk_window.h"
#include "netsurf/render/font.h"
#include "netsurf/utils/utils.h"
#include "netsurf/utils/log.h"
#include "netsurf/desktop/options.h"
/* Until we can consider the descenders etc, we need to not render using cairo */
#undef CAIRO_VERSION
static PangoFontDescription *nsfont_style_to_description(
const struct css_style *style);
/**
* Measure the width of a string.
*
* \param style css_style for this text, with style->font_size.size ==
* CSS_FONT_SIZE_LENGTH
* \param string UTF-8 string to measure
* \param length length of string
* \param width updated to width of string[0..length)
* \return true on success, false on error and error reported
*/
bool nsfont_width(const struct css_style *style,
const char *string, size_t length,
int *width)
{
PangoFontDescription *desc;
PangoContext *context;
PangoLayout *layout;
if (length == 0) {
*width = 0;
return true;
}
desc = nsfont_style_to_description(style);
context = gdk_pango_context_get();
layout = pango_layout_new(context);
pango_layout_set_font_description(layout, desc);
pango_layout_set_text(layout, string, length);
pango_layout_get_pixel_size(layout, width, 0);
g_object_unref(layout);
g_object_unref(context);
pango_font_description_free(desc);
return true;
}
/**
* Find the position in a string where an x coordinate falls.
*
* \param style css_style for this text, with style->font_size.size ==
* CSS_FONT_SIZE_LENGTH
* \param string UTF-8 string to measure
* \param length length of string
* \param x x coordinate to search for
* \param char_offset updated to offset in string of actual_x, [0..length]
* \param actual_x updated to x coordinate of character closest to x
* \return true on success, false on error and error reported
*/
bool nsfont_position_in_string(const struct css_style *style,
const char *string, size_t length,
int x, size_t *char_offset, int *actual_x)
{
int index;
PangoFontDescription *desc;
PangoContext *context;
PangoLayout *layout;
PangoRectangle pos;
desc = nsfont_style_to_description(style);
context = gdk_pango_context_get();
layout = pango_layout_new(context);
pango_layout_set_font_description(layout, desc);
pango_layout_set_text(layout, string, length);
pango_layout_xy_to_index(layout, x * PANGO_SCALE, 0, &index, 0);
pango_layout_index_to_pos(layout, index, &pos);
g_object_unref(layout);
g_object_unref(context);
pango_font_description_free(desc);
*char_offset = index?index+1:0;
*actual_x = PANGO_PIXELS(pos.x);
return true;
}
/**
* Find where to split a string to make it fit a width.
*
* \param style css_style for this text, with style->font_size.size ==
* CSS_FONT_SIZE_LENGTH
* \param string UTF-8 string to measure
* \param length length of string
* \param x width available
* \param char_offset updated to offset in string of actual_x, [0..length]
* \param actual_x updated to x coordinate of character closest to x
* \return true on success, false on error and error reported
*
* On exit, [char_offset == 0 ||
* string[char_offset] == ' ' ||
* char_offset == length]
*/
bool nsfont_split(const struct css_style *style,
const char *string, size_t length,
int x, size_t *char_offset, int *actual_x)
{
int index = length;
int x_pos;
PangoFontDescription *desc;
PangoContext *context;
PangoLayout *layout;
PangoLayoutLine *line;
desc = nsfont_style_to_description(style);
context = gdk_pango_context_get();
layout = pango_layout_new(context);
pango_layout_set_font_description(layout, desc);
pango_layout_set_text(layout, string, length);
pango_layout_set_width(layout, x * PANGO_SCALE);
pango_layout_set_wrap(layout, PANGO_WRAP_WORD);
line = pango_layout_get_line(layout, 1);
if (line)
index = line->start_index - 1;
pango_layout_line_index_to_x(pango_layout_get_line(layout, 0),
index, 0, &x_pos);
g_object_unref(layout);
g_object_unref(context);
pango_font_description_free(desc);
*char_offset = index;
*actual_x = PANGO_PIXELS(x_pos);
return true;
}
/**
* Render a string.
*
* \param style css_style for this text, with style->font_size.size ==
* CSS_FONT_SIZE_LENGTH
* \param string UTF-8 string to measure
* \param length length of string
* \param x x coordinate
* \param y y coordinate
* \param c colour for text
* \return true on success, false on error and error reported
*/
bool nsfont_paint(const struct css_style *style,
const char *string, size_t length,
int x, int y, colour c)
{
PangoFontDescription *desc;
PangoLayout *layout;
gint size;
#ifdef CAIRO_VERSION
int width, height;
#else
PangoLayoutLine *line;
PangoContext *context;
GdkColor colour = { 0,
((c & 0xff) << 8) | (c & 0xff),
(c & 0xff00) | (c & 0xff00 >> 8),
((c & 0xff0000) >> 8) | (c & 0xff0000 >> 16) };
#endif
if (length == 0)
return true;
desc = nsfont_style_to_description(style);
size = (gint)((double)pango_font_description_get_size(desc) * nsgtk_plot_get_scale());
if (pango_font_description_get_size_is_absolute(desc))
pango_font_description_set_absolute_size(desc, size);
else
pango_font_description_set_size(desc, size);
#ifdef CAIRO_VERSION
layout = pango_cairo_create_layout(current_cr);
#else
context = gdk_pango_context_get();
layout = pango_layout_new(context);
#endif
pango_layout_set_font_description(layout, desc);
pango_layout_set_text(layout, string, length);
#ifdef CAIRO_VERSION
pango_layout_get_pixel_size(layout, &width, &height);
cairo_move_to(current_cr, x, y - height);
nsgtk_set_colour(c);
pango_cairo_show_layout(current_cr, layout);
#else
line = pango_layout_get_line(layout, 0);
gdk_draw_layout_line_with_colors(current_drawable, current_gc,
x, y, line, &colour, 0);
g_object_unref(context);
#endif
g_object_unref(layout);
pango_font_description_free(desc);
return true;
}
/**
* Convert a css_style to a PangoFontDescription.
*
* \param style css_style for this text, with style->font_size.size ==
* CSS_FONT_SIZE_LENGTH
* \return a new Pango font description
*/
PangoFontDescription *nsfont_style_to_description(
const struct css_style *style)
{
unsigned int size;
PangoFontDescription *desc;
PangoWeight weight = PANGO_WEIGHT_NORMAL;
PangoStyle styl = PANGO_STYLE_NORMAL;
assert(style->font_size.size == CSS_FONT_SIZE_LENGTH);
switch (style->font_family) {
case CSS_FONT_FAMILY_SERIF:
desc = pango_font_description_from_string(option_font_serif);
break;
case CSS_FONT_FAMILY_MONOSPACE:
desc = pango_font_description_from_string(option_font_mono);
break;
case CSS_FONT_FAMILY_CURSIVE:
desc = pango_font_description_from_string(option_font_cursive);
break;
case CSS_FONT_FAMILY_FANTASY:
desc = pango_font_description_from_string(option_font_fantasy);
break;
case CSS_FONT_FAMILY_SANS_SERIF:
default:
desc = pango_font_description_from_string(option_font_sans);
break;
}
if (style->font_size.value.length.unit == CSS_UNIT_PX)
size = style->font_size.value.length.value;
else
size = css_len2pt(&style->font_size.value.length, style);
if (size < abs(option_font_min_size / 10))
size = option_font_min_size / 10;
size *= PANGO_SCALE;
switch (style->font_style) {
case CSS_FONT_STYLE_ITALIC:
styl = PANGO_STYLE_ITALIC;
break;
case CSS_FONT_STYLE_OBLIQUE:
styl = PANGO_STYLE_OBLIQUE;
break;
default:
break;
}
pango_font_description_set_style(desc, styl);
switch (style->font_weight) {
case CSS_FONT_WEIGHT_NORMAL:
weight = PANGO_WEIGHT_NORMAL; break;
case CSS_FONT_WEIGHT_BOLD:
weight = PANGO_WEIGHT_BOLD; break;
case CSS_FONT_WEIGHT_100: weight = 100; break;
case CSS_FONT_WEIGHT_200: weight = 200; break;
case CSS_FONT_WEIGHT_300: weight = 300; break;
case CSS_FONT_WEIGHT_400: weight = 400; break;
case CSS_FONT_WEIGHT_500: weight = 500; break;
case CSS_FONT_WEIGHT_600: weight = 600; break;
case CSS_FONT_WEIGHT_700: weight = 700; break;
case CSS_FONT_WEIGHT_800: weight = 800; break;
case CSS_FONT_WEIGHT_900: weight = 900; break;
default: break;
}
pango_font_description_set_weight(desc, weight);
if (style->font_size.value.length.unit == CSS_UNIT_PX)
pango_font_description_set_absolute_size(desc, size);
else
pango_font_description_set_size(desc, size);
switch (style->font_variant) {
case CSS_FONT_VARIANT_SMALL_CAPS:
pango_font_description_set_variant(desc, PANGO_VARIANT_SMALL_CAPS);
break;
case CSS_FONT_VARIANT_NORMAL:
default:
pango_font_description_set_variant(desc, PANGO_VARIANT_NORMAL);
}
return desc;
}