geanywraplabel.c

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/*
 *      geanywraplabel.c - this file is part of Geany, a fast and lightweight IDE
 *
 *      Copyright 2009 The Geany contributors
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 2 of the License, or
 *      (at your option) any later version.
 *
 *      This program 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 General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License along
 *      with this program; if not, write to the Free Software Foundation, Inc.,
 *      51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
/*
 * A GtkLabel subclass that can wrap to any width, unlike GtkLabel which has a fixed wrap point.
 * (inspired by libview's WrapLabel, http://view.sourceforge.net)
 */
 
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
 
#include "geanywraplabel.h"
 
 
struct _GeanyWrapLabelClass
{
    GtkLabelClass parent_class;
};
 
typedef struct
{
    gint wrap_width;
    gint wrap_height;
} GeanyWrapLabelPrivate;
 
struct _GeanyWrapLabel
{
    GtkLabel parent;
    GeanyWrapLabelPrivate *priv;
};
 
 
static gboolean geany_wrap_label_draw(GtkWidget *widget, cairo_t *cr);
static void geany_wrap_label_get_preferred_width (GtkWidget *widget,
        gint *minimal_width, gint *natural_width);
static void geany_wrap_label_get_preferred_height (GtkWidget *widget,
        gint *minimal_height, gint *natural_height);
static void geany_wrap_label_get_preferred_width_for_height (GtkWidget *widget,
        gint height, gint *minimal_width, gint *natural_width);
static void geany_wrap_label_get_preferred_height_for_width (GtkWidget *widget,
        gint width, gint *minimal_height, gint *natural_height);
static GtkSizeRequestMode geany_wrap_label_get_request_mode(GtkWidget *widget);
static void geany_wrap_label_size_allocate  (GtkWidget *widget, GtkAllocation *alloc);
static void geany_wrap_label_set_wrap_width (GtkWidget *widget, gint width);
static void geany_wrap_label_label_notify   (GObject *object, GParamSpec *pspec, gpointer data);
 
G_DEFINE_TYPE(GeanyWrapLabel, geany_wrap_label, GTK_TYPE_LABEL)
 
 
static void geany_wrap_label_class_init(GeanyWrapLabelClass *klass)
{
    GtkWidgetClass *widget_class = GTK_WIDGET_CLASS(klass);
 
    widget_class->size_allocate = geany_wrap_label_size_allocate;
    widget_class->draw = geany_wrap_label_draw;
    widget_class->get_preferred_width = geany_wrap_label_get_preferred_width;
    widget_class->get_preferred_width_for_height = geany_wrap_label_get_preferred_width_for_height;
    widget_class->get_preferred_height = geany_wrap_label_get_preferred_height;
    widget_class->get_preferred_height_for_width = geany_wrap_label_get_preferred_height_for_width;
    widget_class->get_request_mode = geany_wrap_label_get_request_mode;
 
    g_type_class_add_private(klass, sizeof (GeanyWrapLabelPrivate));
}
 
 
static void geany_wrap_label_init(GeanyWrapLabel *self)
{
    self->priv = G_TYPE_INSTANCE_GET_PRIVATE(self,
        GEANY_WRAP_LABEL_TYPE, GeanyWrapLabelPrivate);
 
    self->priv->wrap_width = 0;
    self->priv->wrap_height = 0;
 
    g_signal_connect(self, "notify::label", G_CALLBACK(geany_wrap_label_label_notify), NULL);
    gtk_misc_set_alignment(GTK_MISC(self), 0.0, 0.0);
}
 
 
/* Sets the point at which the text should wrap. */
static void geany_wrap_label_set_wrap_width(GtkWidget *widget, gint width)
{
    GeanyWrapLabel *self = GEANY_WRAP_LABEL(widget);
    PangoLayout *layout;
 
    if (width <= 0)
        return;
 
    layout = gtk_label_get_layout(GTK_LABEL(widget));
 
    /*
    * We may need to reset the wrap width, so do this regardless of whether
    * or not we've changed the width.
    */
    pango_layout_set_width(layout, width * PANGO_SCALE);
    pango_layout_set_wrap(layout, PANGO_WRAP_WORD_CHAR);
    pango_layout_get_pixel_size(layout, NULL, &self->priv->wrap_height);
 
    if (self->priv->wrap_width != width)
    {
        self->priv->wrap_width = width;
        gtk_widget_queue_resize(widget);
    }
}
 
 
/* updates the wrap width when the label text changes */
static void geany_wrap_label_label_notify(GObject *object, GParamSpec *pspec, gpointer data)
{
    GeanyWrapLabel *self = GEANY_WRAP_LABEL(object);
 
    geany_wrap_label_set_wrap_width(GTK_WIDGET(object), self->priv->wrap_width);
}
 
 
/* makes sure the layout is setup for rendering and chains to parent renderer */
static gboolean geany_wrap_label_draw(GtkWidget *widget, cairo_t *cr)
{
    GeanyWrapLabel *self = GEANY_WRAP_LABEL(widget);
    PangoLayout *layout = gtk_label_get_layout(GTK_LABEL(widget));
 
    pango_layout_set_width(layout, self->priv->wrap_width * PANGO_SCALE);
    pango_layout_set_wrap(layout, PANGO_WRAP_WORD_CHAR);
 
    return (* GTK_WIDGET_CLASS(geany_wrap_label_parent_class)->draw)(widget, cr);
}
 
 
static void geany_wrap_label_get_preferred_width (GtkWidget *widget,
        gint *minimal_width, gint *natural_width)
{
    *minimal_width = *natural_width = 0;
}
 
 
static void geany_wrap_label_get_preferred_width_for_height (GtkWidget *widget,
        gint height, gint *minimal_width, gint *natural_width)
{
    PangoLayout *layout = gtk_label_get_layout(GTK_LABEL(widget));;
 
    pango_layout_set_height(layout, height * PANGO_SCALE);
    pango_layout_set_wrap(layout, PANGO_WRAP_WORD_CHAR);
    pango_layout_get_pixel_size(layout, natural_width, NULL);
 
    *minimal_width = 0;
}
 
 
static void geany_wrap_label_get_preferred_height (GtkWidget *widget,
        gint *minimal_height, gint *natural_height)
{
    *minimal_height = *natural_height = GEANY_WRAP_LABEL(widget)->priv->wrap_height;
}
 
 
static void geany_wrap_label_get_preferred_height_for_width (GtkWidget *widget,
        gint width, gint *minimal_height, gint *natural_height)
{
    PangoLayout *layout = gtk_label_get_layout(GTK_LABEL(widget));
 
    pango_layout_set_width(layout, width * PANGO_SCALE);
    pango_layout_set_wrap(layout, PANGO_WRAP_WORD_CHAR);
    pango_layout_get_pixel_size(layout, NULL, natural_height);
 
    *minimal_height = *natural_height;
}
 
 
static GtkSizeRequestMode geany_wrap_label_get_request_mode(GtkWidget *widget)
{
    return GTK_SIZE_REQUEST_WIDTH_FOR_HEIGHT;
}
 
 
/* Sets the wrap width to the width allocated to us. */
static void geany_wrap_label_size_allocate(GtkWidget *widget, GtkAllocation *alloc)
{
    GtkWidget *parent;
 
    (* GTK_WIDGET_CLASS(geany_wrap_label_parent_class)->size_allocate)(widget, alloc);
 
    geany_wrap_label_set_wrap_width(widget, alloc->width);
 
    /* ask the parent to recompute our size, because it seems GTK size
     * caching is too aggressive */
    parent = gtk_widget_get_parent(widget);
    if (GTK_IS_CONTAINER(parent))
        gtk_container_check_resize(GTK_CONTAINER(parent));
}
 
 
GtkWidget *geany_wrap_label_new(const gchar *text)
{
    return g_object_new(GEANY_WRAP_LABEL_TYPE, "label", text, NULL);
}