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label: Don't recreate the layout just for measuring

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Instead, create a custom one.
This commit is contained in:
Benjamin Otte 2011-03-29 02:49:19 +02:00
parent d579166a63
commit db474e82c4
1 changed files with 85 additions and 23 deletions
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108
gtk/gtklabel.c
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@ -3232,12 +3232,79 @@ get_label_wrap_width (GtkLabel *label)
return priv->wrap_width;
}
static PangoLayout *
gtk_label_get_layout_with_guessed_wrap_width (GtkLabel *label)
{
GdkScreen *screen;
PangoRectangle logical_rect;
gint wrap_width, width, height, longest_paragraph;
PangoLayout *layout;
if (!label->priv->wrap)
return gtk_label_get_measuring_layout (label, NULL, -1);
screen = gtk_widget_get_screen (GTK_WIDGET (label));
layout = gtk_label_get_measuring_layout (label, NULL, -1);
pango_layout_get_extents (layout, NULL, &logical_rect);
width = logical_rect.width;
/* Try to guess a reasonable maximum width */
longest_paragraph = width;
wrap_width = get_label_wrap_width (label);
width = MIN (width, wrap_width);
width = MIN (width,
PANGO_SCALE * (gdk_screen_get_width (screen) + 1) / 2);
layout = gtk_label_get_measuring_layout (label, layout, width);
pango_layout_get_extents (layout, NULL, &logical_rect);
width = logical_rect.width;
height = logical_rect.height;
/* Unfortunately, the above may leave us with a very unbalanced looking paragraph,
* so we try short search for a narrower width that leaves us with the same height
*/
if (longest_paragraph > 0)
{
gint nlines, perfect_width;
nlines = pango_layout_get_line_count (layout);
perfect_width = (longest_paragraph + nlines - 1) / nlines;
if (perfect_width < width)
{
layout = gtk_label_get_measuring_layout (label, layout, perfect_width);
pango_layout_get_extents (layout, NULL, &logical_rect);
if (logical_rect.height <= height)
width = logical_rect.width;
else
{
gint mid_width = (perfect_width + width) / 2;
if (mid_width > perfect_width)
{
layout = gtk_label_get_measuring_layout (label, layout, mid_width);
pango_layout_get_extents (layout, NULL, &logical_rect);
if (logical_rect.height <= height)
width = logical_rect.width;
}
}
}
}
return gtk_label_get_measuring_layout (label, layout, width);
}
static void
gtk_label_ensure_layout (GtkLabel *label, gboolean guess_wrap_width)
{
GtkLabelPrivate *priv = label->priv;
GtkWidget *widget;
PangoRectangle logical_rect;
GtkWidget *widget;
gboolean rtl;
widget = GTK_WIDGET (label);
@ -3483,6 +3550,7 @@ gtk_label_get_preferred_size (GtkWidget *widget,
PangoRectangle required_rect;
PangoRectangle natural_rect;
gint xpad, ypad;
PangoLayout *layout;
/* "width-chars" Hard-coded minimum width:
* - minimum size should be MAX (width-chars, strlen ("..."));
@ -3496,34 +3564,36 @@ gtk_label_get_preferred_size (GtkWidget *widget,
/* When calculating ->wrap sometimes we need to invent a size; Ideally we should be doing
* that stuff here instead of inside gtk_label_ensure_layout() */
if (priv->wrap)
gtk_label_clear_layout (label);
gtk_label_ensure_layout (label, TRUE);
layout = gtk_label_get_layout_with_guessed_wrap_width (label);
/* Start off with the pixel extents of the rendered layout */
pango_layout_get_extents (priv->layout, NULL, &required_rect);
pango_layout_get_extents (layout, NULL, &required_rect);
required_rect.x = required_rect.y = 0;
if (priv->single_line_mode || priv->wrap)
required_rect.height = get_single_line_height (GTK_WIDGET (label), priv->layout);
required_rect.height = get_single_line_height (GTK_WIDGET (label), layout);
natural_rect = required_rect;
/* Calculate text width itself based on GtkLabel property rules */
get_label_width (label, priv->layout, &required_rect.width, &natural_rect.width);
get_label_width (label, 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)
{
PangoLayout *layout = pango_layout_copy (priv->layout);
PangoContext *context = pango_layout_get_context (priv->layout);
const PangoMatrix *matrix = pango_context_get_matrix (context);
PangoLayout *copy;
PangoContext *context;
const PangoMatrix *matrix;
pango_layout_set_width (layout, -1);
pango_layout_set_ellipsize (layout, PANGO_ELLIPSIZE_NONE);
copy = pango_layout_copy (priv->layout);
context = pango_layout_get_context (copy);
matrix = pango_context_get_matrix (context);
pango_layout_get_extents (layout, NULL, &natural_rect);
g_object_unref (layout);
pango_layout_set_width (copy, -1);
pango_layout_set_ellipsize (copy, PANGO_ELLIPSIZE_NONE);
pango_layout_get_extents (copy, NULL, &natural_rect);
g_object_unref (copy);
pango_matrix_transform_rectangle (matrix, &required_rect);
pango_matrix_transform_rectangle (matrix, &natural_rect);
@ -3608,15 +3678,7 @@ gtk_label_get_preferred_size (GtkWidget *widget,
*natural_size += ypad * 2;
}
/* Restore real allocated size of layout; sometimes size-requests
* are randomly called without a following allocation; for this case
* we need to make sure we dont have a mucked up layout because we
* went and guessed the wrap-size.
*/
if (priv->wrap)
gtk_label_clear_layout (label);
gtk_label_ensure_layout (label, FALSE);
g_object_unref (layout);
}