electron/browser/ui/gtk/gtk_util.cc
2014-03-12 20:38:52 +08:00

89 lines
2.8 KiB
C++

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "browser/ui/gtk/gtk_util.h"
#include <cairo/cairo.h>
#include "base/logging.h"
namespace gtk_util {
namespace {
const char kBoldLabelMarkup[] = "<span weight='bold'>%s</span>";
// Returns the approximate number of characters that can horizontally fit in
// |pixel_width| pixels.
int GetCharacterWidthForPixels(GtkWidget* widget, int pixel_width) {
DCHECK(gtk_widget_get_realized(widget))
<< " widget must be realized to compute font metrics correctly";
PangoContext* context = gtk_widget_create_pango_context(widget);
GtkStyle* style = gtk_widget_get_style(widget);
PangoFontMetrics* metrics = pango_context_get_metrics(context,
style->font_desc, pango_context_get_language(context));
// This technique (max of char and digit widths) matches the code in
// gtklabel.c.
int char_width = pixel_width * PANGO_SCALE /
std::max(pango_font_metrics_get_approximate_char_width(metrics),
pango_font_metrics_get_approximate_digit_width(metrics));
pango_font_metrics_unref(metrics);
g_object_unref(context);
return char_width;
}
void OnLabelRealize(GtkWidget* label, gpointer pixel_width) {
gtk_label_set_width_chars(
GTK_LABEL(label),
GetCharacterWidthForPixels(label, GPOINTER_TO_INT(pixel_width)));
}
} // namespace
GtkWidget* LeftAlignMisc(GtkWidget* misc) {
gtk_misc_set_alignment(GTK_MISC(misc), 0, 0.5);
return misc;
}
GtkWidget* CreateBoldLabel(const std::string& text) {
GtkWidget* label = gtk_label_new(NULL);
char* markup = g_markup_printf_escaped(kBoldLabelMarkup, text.c_str());
gtk_label_set_markup(GTK_LABEL(label), markup);
g_free(markup);
return LeftAlignMisc(label);
}
bool IsWidgetAncestryVisible(GtkWidget* widget) {
GtkWidget* parent = widget;
while (parent && gtk_widget_get_visible(parent))
parent = gtk_widget_get_parent(parent);
return !parent;
}
void SetLabelWidth(GtkWidget* label, int pixel_width) {
gtk_label_set_line_wrap(GTK_LABEL(label), TRUE);
gtk_misc_set_alignment(GTK_MISC(label), 0, 0.5);
// Do the simple thing in LTR because the bug only affects right-aligned
// text. Also, when using the workaround, the label tries to maintain
// uniform line-length, which we don't really want.
if (gtk_widget_get_direction(label) == GTK_TEXT_DIR_LTR) {
gtk_widget_set_size_request(label, pixel_width, -1);
} else {
// The label has to be realized before we can adjust its width.
if (gtk_widget_get_realized(label)) {
OnLabelRealize(label, GINT_TO_POINTER(pixel_width));
} else {
g_signal_connect(label, "realize", G_CALLBACK(OnLabelRealize),
GINT_TO_POINTER(pixel_width));
}
}
}
} // namespace gtk_util