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label: Add internal gtk_label_get_measuring_layout() and use it

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Avoids useless pango_layout_copy() calls and invalidations of an
existing layout when measuring sizes for a given label.
This commit is contained in:
Benjamin Otte 2011-03-29 02:27:26 +02:00
parent 5acd15d21b
commit d579166a63
1 changed files with 56 additions and 16 deletions
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72
gtk/gtklabel.c
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@ -3025,10 +3025,56 @@ get_font_metrics (PangoContext *context, GtkWidget *widget)
return retval;
}
/**
* gtk_label_get_measuring_layout:
* @label: the label
* @existing_layout: %NULL or an existing layout already in use.
* @width: the width to measure with in pango units, or -1 for infinite
*
* Gets a layout that can be used for measuring sizes. The returned
* layout will be identical to the label's layout except for the
* layout's width, which will be set to @width. Do not modify the returned
* layout.
*
* Returns: a new reference to a pango layout
**/
static PangoLayout *
gtk_label_get_measuring_layout (GtkLabel * label,
PangoLayout *existing_layout,
int width)
{
GtkLabelPrivate *priv = label->priv;
PangoLayout *copy;
if (existing_layout != NULL)
{
if (existing_layout != priv->layout)
{
pango_layout_set_width (existing_layout, width);
return existing_layout;
}
g_object_unref (existing_layout);
}
gtk_label_ensure_layout (label, FALSE);
if (pango_layout_get_width (priv->layout) == width)
{
g_object_ref (priv->layout);
return priv->layout;
}
copy = pango_layout_copy (priv->layout);
pango_layout_set_width (copy, width);
return copy;
}
static void
get_label_width (GtkLabel *label,
gint *minimum,
gint *natural)
get_label_width (GtkLabel *label,
PangoLayout *guess_layout,
gint *minimum,
gint *natural)
{
GtkLabelPrivate *priv;
PangoLayout *layout;
@ -3039,7 +3085,7 @@ get_label_width (GtkLabel *label,
priv = label->priv;
layout = pango_layout_copy (priv->layout);
layout = gtk_label_get_measuring_layout (label, NULL, -1);
context = pango_layout_get_context (layout);
metrics = get_font_metrics (context, GTK_WIDGET (label));
char_width = pango_font_metrics_get_approximate_char_width (metrics);
@ -3048,12 +3094,11 @@ get_label_width (GtkLabel *label,
pango_font_metrics_unref (metrics);
/* Fetch the length of the complete unwrapped text */
pango_layout_set_width (layout, -1);
pango_layout_get_extents (layout, NULL, &rect);
text_width = rect.width;
/* Fetch the width that was guessed by gtk_label_ensure_layout() */
pango_layout_get_extents (priv->layout, NULL, &rect);
/* Fetch the width that was guessed */
pango_layout_get_extents (guess_layout, NULL, &rect);
guess_width = rect.width;
/* enforce minimum width for ellipsized labels at ~3 chars */
@ -3158,7 +3203,7 @@ get_label_wrap_width (GtkLabel *label)
PangoRectangle rect;
gint char_width, digit_width, char_pixels, text_width;
layout = pango_layout_copy (priv->layout);
layout = gtk_label_get_measuring_layout (label, NULL, -1);
context = pango_layout_get_context (layout);
metrics = get_font_metrics (context, GTK_WIDGET (label));
char_width = pango_font_metrics_get_approximate_char_width (metrics);
@ -3166,7 +3211,6 @@ get_label_wrap_width (GtkLabel *label)
char_pixels = MAX (char_width, digit_width);
pango_font_metrics_unref (metrics);
pango_layout_set_width (layout, -1);
pango_layout_get_extents (layout, NULL, &rect);
g_object_unref (layout);
@ -3396,16 +3440,12 @@ get_size_for_allocation (GtkLabel *label,
gint *minimum_size,
gint *natural_size)
{
GtkLabelPrivate *priv = label->priv;
PangoLayout *layout;
GtkWidgetAuxInfo *aux_info =
_gtk_widget_get_aux_info (GTK_WIDGET (label), FALSE);
gint aux_size;
gint text_height;
gtk_label_ensure_layout (label, FALSE);
layout = pango_layout_copy (priv->layout);
if (aux_info)
{
if (orientation == GTK_ORIENTATION_HORIZONTAL)
@ -3417,9 +3457,9 @@ get_size_for_allocation (GtkLabel *label,
aux_size = 0;
if (aux_size > 0)
pango_layout_set_width (layout, aux_size * PANGO_SCALE);
layout = gtk_label_get_measuring_layout (label, NULL, aux_size * PANGO_SCALE);
else
pango_layout_set_width (layout, allocation * PANGO_SCALE);
layout = gtk_label_get_measuring_layout (label, NULL, allocation * PANGO_SCALE);
pango_layout_get_pixel_size (layout, NULL, &text_height);
@ -3470,7 +3510,7 @@ gtk_label_get_preferred_size (GtkWidget *widget,
natural_rect = required_rect;
/* Calculate text width itself based on GtkLabel property rules */
get_label_width (label, &required_rect.width, &natural_rect.width);
get_label_width (label, priv->layout, &required_rect.width, &natural_rect.width);
/* Now that we have minimum and natural sizes in pango extents, apply a possible transform */
if (priv->have_transform)