moving from https://github.com/perberos/mate-desktop-environment

1 files changed, 615 insertions, 0 deletions

diff --git a/eel/eel-pango-extensions.c b/eel/eel-pango-extensions.c
new file mode 100644
index 00000000..ec34c9c9
--- /dev/null
+++ b/eel/eel-pango-extensions.c
@@ -0,0 +1,615 @@
+/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
+
+/* eel-pango-extensions.h - interface for new functions that conceptually
+                            belong in pango. Perhaps some of these will be
+                            actually rolled into pango someday.
+
+   Copyright (C) 2001 Anders Carlsson
+
+   The Eel Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The Eel Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the Eel Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+
+   Authors: Anders Carlsson <[email protected]>
+*/
+
+#include <config.h>
+#include "eel-pango-extensions.h"
+
+#if !defined (EEL_OMIT_SELF_CHECK)
+#include "eel-lib-self-check-functions.h"
+#endif
+
+#include <gtk/gtk.h>
+#include <pango/pango.h>
+#include <string.h>
+
+PangoAttrList *
+eel_pango_attr_list_copy_or_create (PangoAttrList *attr_list)
+{
+    if (attr_list != NULL)
+    {
+        return pango_attr_list_copy (attr_list);
+    }
+    return pango_attr_list_new ();
+}
+
+PangoAttrList *
+eel_pango_attr_list_apply_global_attribute (PangoAttrList *attr_list,
+        PangoAttribute *attr)
+{
+    PangoAttrList *new_attr_list;
+
+    g_return_val_if_fail (attr != NULL, NULL);
+
+    attr->start_index = 0;
+    attr->end_index = G_MAXINT;
+
+    new_attr_list = eel_pango_attr_list_copy_or_create (attr_list);
+    pango_attr_list_change (new_attr_list, attr);
+    return new_attr_list;
+}
+
+#define ELLIPSIS "..."
+
+/* Caution: this is an _expensive_ function */
+static int
+measure_string_width (const char  *string,
+                      PangoLayout *layout)
+{
+    int width;
+
+    pango_layout_set_text (layout, string, -1);
+    pango_layout_get_pixel_size (layout, &width, NULL);
+
+    return width;
+}
+
+/* this is also plenty slow */
+static void
+compute_character_widths (const char    *string,
+                          PangoLayout   *layout,
+                          int           *char_len_return,
+                          int          **widths_return,
+                          int          **cuts_return)
+{
+    int *widths;
+    int *offsets;
+    int *cuts;
+    int char_len;
+    int byte_len;
+    const char *p;
+    int i;
+    PangoLayoutIter *iter;
+    PangoLogAttr *attrs;
+
+#define BEGINS_UTF8_CHAR(x) (((x) & 0xc0) != 0x80)
+
+    char_len = g_utf8_strlen (string, -1);
+    byte_len = strlen (string);
+
+    widths = g_new (int, char_len);
+    offsets = g_new (int, byte_len);
+
+    /* Create a translation table from byte index to char offset */
+    p = string;
+    i = 0;
+    while (*p)
+    {
+        int byte_index = p - string;
+
+        if (BEGINS_UTF8_CHAR (*p))
+        {
+            offsets[byte_index] = i;
+            ++i;
+        }
+        else
+        {
+            offsets[byte_index] = G_MAXINT; /* segv if we try to use this */
+        }
+
+        ++p;
+    }
+
+    /* Now fill in the widths array */
+    pango_layout_set_text (layout, string, -1);
+
+    iter = pango_layout_get_iter (layout);
+
+    do
+    {
+        PangoRectangle extents;
+        int byte_index;
+
+        byte_index = pango_layout_iter_get_index (iter);
+
+        if (byte_index < byte_len)
+        {
+            pango_layout_iter_get_char_extents (iter, &extents);
+
+            g_assert (BEGINS_UTF8_CHAR (string[byte_index]));
+            g_assert (offsets[byte_index] < char_len);
+
+            widths[offsets[byte_index]] = PANGO_PIXELS (extents.width);
+        }
+
+    }
+    while (pango_layout_iter_next_char (iter));
+
+    pango_layout_iter_free (iter);
+
+    g_free (offsets);
+
+    *widths_return = widths;
+
+    /* Now compute character offsets that are legitimate places to
+     * chop the string
+     */
+    attrs = g_new (PangoLogAttr, char_len + 1);
+
+    pango_get_log_attrs (string, byte_len, -1,
+                         pango_context_get_language (
+                             pango_layout_get_context (layout)),
+                         attrs,
+                         char_len + 1);
+
+    cuts = g_new (int, char_len);
+    i = 0;
+    while (i < char_len)
+    {
+        cuts[i] = attrs[i].is_cursor_position;
+
+        ++i;
+    }
+
+    g_free (attrs);
+
+    *cuts_return = cuts;
+
+    *char_len_return = char_len;
+}
+
+
+static char *
+eel_string_ellipsize_start (const char *string, PangoLayout *layout, int width)
+{
+    int resulting_width;
+    int *cuts;
+    int *widths;
+    int char_len;
+    const char *p;
+    int truncate_offset;
+
+    /* Zero-length string can't get shorter - catch this here to
+     * avoid expensive calculations
+     */
+    if (*string == '\0')
+        return g_strdup ("");
+
+    /* I'm not sure if this short-circuit is a net win; it might be better
+     * to just dump this, and always do the compute_character_widths() etc.
+     * down below.
+     */
+    resulting_width = measure_string_width (string, layout);
+
+    if (resulting_width <= width)
+    {
+        /* String is already short enough. */
+        return g_strdup (string);
+    }
+
+    /* Remove width of an ellipsis */
+    width -= measure_string_width (ELLIPSIS, layout);
+
+    if (width < 0)
+    {
+        /* No room even for an ellipsis. */
+        return g_strdup ("");
+    }
+
+    /* Our algorithm involves removing enough chars from the string to bring
+     * the width to the required small size. However, due to ligatures,
+     * combining characters, etc., it's not guaranteed that the algorithm
+     * always works 100%. It's sort of a heuristic thing. It should work
+     * nearly all the time... but I wouldn't put in
+     * g_assert (width of resulting string < width).
+     *
+     * Hmm, another thing that this breaks with is explicit line breaks
+     * in "string"
+     */
+
+    compute_character_widths (string, layout, &char_len, &widths, &cuts);
+
+    for (truncate_offset = 1; truncate_offset < char_len; truncate_offset++)
+    {
+
+        resulting_width -= widths[truncate_offset];
+
+        if (resulting_width <= width &&
+                cuts[truncate_offset])
+        {
+            break;
+        }
+    }
+
+    g_free (cuts);
+    g_free (widths);
+
+    p = g_utf8_offset_to_pointer (string, truncate_offset);
+
+    return g_strconcat (ELLIPSIS, p, NULL);
+}
+
+static char *
+eel_string_ellipsize_end (const char *string, PangoLayout *layout, int width)
+{
+    int resulting_width;
+    int *cuts;
+    int *widths;
+    int char_len;
+    const char *p;
+    int truncate_offset;
+    char *result;
+
+    /* See explanatory comments in ellipsize_start */
+
+    if (*string == '\0')
+        return g_strdup ("");
+
+    resulting_width = measure_string_width (string, layout);
+
+    if (resulting_width <= width)
+    {
+        return g_strdup (string);
+    }
+
+    width -= measure_string_width (ELLIPSIS, layout);
+
+    if (width < 0)
+    {
+        return g_strdup ("");
+    }
+
+    compute_character_widths (string, layout, &char_len, &widths, &cuts);
+
+    for (truncate_offset = char_len - 1; truncate_offset > 0; truncate_offset--)
+    {
+        resulting_width -= widths[truncate_offset];
+        if (resulting_width <= width &&
+                cuts[truncate_offset])
+        {
+            break;
+        }
+    }
+
+    g_free (cuts);
+    g_free (widths);
+
+    p = g_utf8_offset_to_pointer (string, truncate_offset);
+
+    result = g_malloc ((p - string) + strlen (ELLIPSIS) + 1);
+    memcpy (result, string, (p - string));
+    strcpy (result + (p - string), ELLIPSIS);
+
+    return result;
+}
+
+static char *
+eel_string_ellipsize_middle (const char *string, PangoLayout *layout, int width)
+{
+    int resulting_width;
+    int *cuts;
+    int *widths;
+    int char_len;
+    int starting_fragment_byte_len;
+    int ending_fragment_byte_index;
+    int starting_fragment_length;
+    int ending_fragment_offset;
+    char *result;
+
+    /* See explanatory comments in ellipsize_start */
+
+    if (*string == '\0')
+        return g_strdup ("");
+
+    resulting_width = measure_string_width (string, layout);
+
+    if (resulting_width <= width)
+    {
+        return g_strdup (string);
+    }
+
+    width -= measure_string_width (ELLIPSIS, layout);
+
+    if (width < 0)
+    {
+        return g_strdup ("");
+    }
+
+    compute_character_widths (string, layout, &char_len, &widths, &cuts);
+
+    starting_fragment_length = char_len / 2;
+    ending_fragment_offset = starting_fragment_length + 1;
+
+    /* Shave off a character at a time from the first and the second half
+     * until we can fit
+     */
+    resulting_width -= widths[ending_fragment_offset - 1];
+
+    /* depending on whether the original string length is odd or even, start by
+     * shaving off the characters from the starting or ending fragment
+     */
+    if (char_len % 2)
+    {
+        goto shave_end;
+    }
+
+    while (starting_fragment_length > 0 || ending_fragment_offset < char_len)
+    {
+        if (resulting_width <= width &&
+                cuts[ending_fragment_offset] &&
+                cuts[starting_fragment_length])
+        {
+            break;
+        }
+
+        if (starting_fragment_length > 0)
+        {
+            resulting_width -= widths[starting_fragment_length];
+            starting_fragment_length--;
+        }
+
+shave_end:
+        if (resulting_width <= width &&
+                cuts[ending_fragment_offset] &&
+                cuts[starting_fragment_length])
+        {
+            break;
+        }
+
+        if (ending_fragment_offset < char_len)
+        {
+            resulting_width -= widths[ending_fragment_offset];
+            ending_fragment_offset++;
+        }
+    }
+
+    g_free (cuts);
+    g_free (widths);
+
+    /* patch the two fragments together with an ellipsis */
+    result = g_malloc (strlen (string) + strlen (ELLIPSIS) + 1); /* a bit wasteful, no biggie */
+
+    starting_fragment_byte_len = g_utf8_offset_to_pointer (string, starting_fragment_length) - string;
+    ending_fragment_byte_index = g_utf8_offset_to_pointer (string, ending_fragment_offset) - string;
+
+    memcpy (result, string, starting_fragment_byte_len);
+    strcpy (result + starting_fragment_byte_len, ELLIPSIS);
+    strcpy (result + starting_fragment_byte_len + strlen (ELLIPSIS), string + ending_fragment_byte_index);
+
+    return result;
+}
+
+
+/**
+ * eel_pango_layout_set_text_ellipsized
+ *
+ * @layout: a pango layout
+ * @string: A a string to be ellipsized.
+ * @width: Desired maximum width in points.
+ * @mode: The desired ellipsizing mode.
+ *
+ * Truncates a string if required to fit in @width and sets it on the
+ * layout. Truncation involves removing characters from the start, middle or end
+ * respectively and replacing them with "...". Algorithm is a bit
+ * fuzzy, won't work 100%.
+ *
+ */
+void
+eel_pango_layout_set_text_ellipsized (PangoLayout  *layout,
+                                      const char   *string,
+                                      int           width,
+                                      EelEllipsizeMode mode)
+{
+    char *s;
+
+    g_return_if_fail (PANGO_IS_LAYOUT (layout));
+    g_return_if_fail (string != NULL);
+    g_return_if_fail (width >= 0);
+
+    switch (mode)
+    {
+    case EEL_ELLIPSIZE_START:
+        s = eel_string_ellipsize_start (string, layout, width);
+        break;
+    case EEL_ELLIPSIZE_MIDDLE:
+        s = eel_string_ellipsize_middle (string, layout, width);
+        break;
+    case EEL_ELLIPSIZE_END:
+        s = eel_string_ellipsize_end (string, layout, width);
+        break;
+    default:
+        g_return_if_reached ();
+    }
+
+    pango_layout_set_text (layout, s, -1);
+
+    g_free (s);
+}
+
+
+int
+eel_pango_font_description_get_largest_fitting_font_size (const PangoFontDescription *font_desc,
+        PangoContext *context,
+        const char   *text,
+        int           available_width,
+        int           minimum_acceptable_font_size,
+        int           maximum_acceptable_font_size)
+{
+    int i;
+    int width;
+    PangoLayout *layout;
+    PangoFontDescription *font;
+
+    g_return_val_if_fail (text != NULL, 0);
+    g_return_val_if_fail (text[0] != '\0', 0);
+    g_return_val_if_fail (available_width > 0, 0);
+    g_return_val_if_fail (minimum_acceptable_font_size > 0, 0);
+    g_return_val_if_fail (maximum_acceptable_font_size > 0, 0);
+    g_return_val_if_fail (maximum_acceptable_font_size > minimum_acceptable_font_size, 0);
+
+    layout = pango_layout_new (context);
+    pango_layout_set_text (layout, text, -1);
+    pango_layout_set_font_description (layout, font_desc);
+
+    font = pango_font_description_new ();
+
+    for (i = maximum_acceptable_font_size; i >= minimum_acceptable_font_size; i--)
+    {
+
+        pango_font_description_set_size (font, i * PANGO_SCALE);
+        pango_layout_set_font_description (layout, font);
+        pango_layout_get_pixel_size (layout, &width, NULL);
+
+        if (width <= available_width)
+        {
+            pango_font_description_free (font);
+            g_object_unref (layout);
+            return i;
+        }
+    }
+
+    pango_font_description_free (font);
+    g_object_unref (layout);
+    return i;
+}
+
+
+#if !defined (EEL_OMIT_SELF_CHECK)
+
+static PangoContext *
+eel_create_bogus_test_pango_context (void)
+{
+    PangoContext *context;
+
+    context = gdk_pango_context_get ();
+    pango_context_set_language (context, gtk_get_default_language ());
+
+    return context;
+}
+
+/* Testing string truncation is tough because we do not know what font/
+ * font metrics to expect on a given system. To work around this we use
+ * a substring of the original, measure it's length using the given font,
+ * add the length of the "..." string and use that for truncation.
+ * The result should then be the substring prepended with a "..."
+ */
+static char *
+eel_self_check_ellipsize (const char *string, const char *truncate_to_length_string, EelEllipsizeMode mode)
+{
+    PangoContext *context;
+    int truncation_length;
+    char *result;
+    PangoLayout *layout;
+
+    context = eel_create_bogus_test_pango_context ();
+    layout = pango_layout_new (context);
+
+    /* measure the length we want to truncate to */
+    truncation_length = measure_string_width (truncate_to_length_string, layout);
+
+    eel_pango_layout_set_text_ellipsized (layout, string, truncation_length, mode);
+
+    result = g_strdup (pango_layout_get_text (layout));
+
+    g_object_unref (G_OBJECT (context));
+    g_object_unref (G_OBJECT (layout));
+
+    return result;
+}
+
+static char *
+eel_self_check_ellipsize_start (const char *string, const char *truncate_to_length_string)
+{
+    return eel_self_check_ellipsize (string, truncate_to_length_string, EEL_ELLIPSIZE_START);
+}
+
+static char *
+eel_self_check_ellipsize_middle (const char *string, const char *truncate_to_length_string)
+{
+    return eel_self_check_ellipsize (string, truncate_to_length_string, EEL_ELLIPSIZE_MIDDLE);
+}
+
+static char *
+eel_self_check_ellipsize_end (const char *string, const char *truncate_to_length_string)
+{
+    return eel_self_check_ellipsize (string, truncate_to_length_string, EEL_ELLIPSIZE_END);
+}
+
+void
+eel_self_check_pango_extensions (void)
+{
+    PangoContext *context;
+
+    /* used to test ellipsize routines */
+    context = eel_create_bogus_test_pango_context ();
+
+    /* Turned off these tests because they are failing for me and I
+     * want the release to be able to pass "make check". We'll have
+     * to revisit this at some point. The failures started because
+     * I changed my default font and enabled Xft support. I presume
+     * this is simply the "fuzziness" Havoc mentions in his comments
+     * above.
+     *                                                - Darin
+     */
+
+    if (0)
+    {
+        /* eel_string_ellipsize_start */
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_start ("012345678", "0012345678"), "012345678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_start ("012345678", "012345678"), "012345678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_start ("012345678", "...45678"), "...45678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_start ("012345678", "...5678"), "...5678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_start ("012345678", "...678"), "...678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_start ("012345678", "...78"), "...78");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_start ("012345678", "...8"), "...8");
+
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("012345678", "0123456789"), "012345678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("012345678", "012345678"), "012345678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("012345678", "012...78"), "012...78");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("012345678", "01...78"), "01...78");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("012345678", "01...8"), "01...8");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("012345678", "0...8"), "0...8");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("012345678", "0..."), "0...");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("0123456789", "0123456789"), "0123456789");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("0123456789", "012...789"), "012...789");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("0123456789", "012...89"), "012...89");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("0123456789", "01...89"), "01...89");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("0123456789", "01...9"), "01...9");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("0123456789", "0...9"), "0...9");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_middle ("0123456789", "0..."), "0...");
+
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_end ("012345678", "0123456789"), "012345678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_end ("012345678", "012345678"), "012345678");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_end ("012345678", "01234..."), "01234...");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_end ("012345678", "0123..."), "0123...");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_end ("012345678", "012..."), "012...");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_end ("012345678", "01..."), "01...");
+        EEL_CHECK_STRING_RESULT (eel_self_check_ellipsize_end ("012345678", "0..."), "0...");
+    }
+
+    g_object_unref (context);
+}
+
+#endif /* !EEL_OMIT_SELF_CHECK */