gtk2/gtk/gtkthemingbackground.c

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/* GTK - The GIMP Toolkit
* Copyright (C) 2010 Carlos Garnacho <carlosg@gnome.org>
* Copyright (C) 2011 Red Hat, Inc.
*
* Authors: Carlos Garnacho <carlosg@gnome.org>
* Cosimo Cecchi <cosimoc@gnome.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gtkthemingbackgroundprivate.h"
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#include "gtkcssarrayvalueprivate.h"
#include "gtkcssbgsizevalueprivate.h"
#include "gtkcssenumvalueprivate.h"
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#include "gtkcssimagevalueprivate.h"
#include "gtkcssshadowsvalueprivate.h"
#include "gtkcsspositionvalueprivate.h"
#include "gtkcssrepeatvalueprivate.h"
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#include "gtkcsstypesprivate.h"
#include "gtkthemingengineprivate.h"
#include <math.h>
#include <gdk/gdk.h>
/* this is in case round() is not provided by the compiler,
* such as in the case of C89 compilers, like MSVC
*/
#include "fallback-c89.c"
static const GtkRoundedBox *
gtk_theming_background_get_box (GtkThemingBackground *bg,
GtkCssArea area)
{
switch (area)
{
case GTK_CSS_AREA_BORDER_BOX:
return &bg->border_box;
case GTK_CSS_AREA_PADDING_BOX:
return &bg->padding_box;
case GTK_CSS_AREA_CONTENT_BOX:
return &bg->content_box;
default:
g_return_val_if_reached (&bg->border_box);
}
}
static void
_gtk_theming_background_paint_color (GtkThemingBackground *bg,
cairo_t *cr,
GtkCssValue *background_image)
{
gint n_values = _gtk_css_array_value_get_n_values (background_image);
GtkCssArea clip = _gtk_css_area_value_get
(_gtk_css_array_value_get_nth
(_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP),
n_values - 1));
cairo_save (cr);
_gtk_rounded_box_path (gtk_theming_background_get_box (bg, clip), cr);
cairo_clip (cr);
gdk_cairo_set_source_rgba (cr, &bg->bg_color);
cairo_paint (cr);
cairo_restore (cr);
}
static void
_gtk_theming_background_paint_layer (GtkThemingBackground *bg,
guint idx,
cairo_t *cr)
{
GtkCssRepeatStyle hrepeat, vrepeat;
const GtkCssValue *pos, *repeat;
GtkCssImage *image;
const GtkRoundedBox *origin;
double image_width, image_height;
double width, height;
pos = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION), idx);
repeat = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_REPEAT), idx);
hrepeat = _gtk_css_background_repeat_value_get_x (repeat);
vrepeat = _gtk_css_background_repeat_value_get_y (repeat);
image = _gtk_css_image_value_get_image (
_gtk_css_array_value_get_nth (
_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE),
idx));
origin = gtk_theming_background_get_box (
bg,
_gtk_css_area_value_get (
_gtk_css_array_value_get_nth (
_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_ORIGIN),
idx)));
width = origin->box.width;
height = origin->box.height;
if (image == NULL || width <= 0 || height <= 0)
return;
_gtk_css_bg_size_value_compute_size (_gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_SIZE), idx),
image,
width,
height,
&image_width,
&image_height);
if (image_width <= 0 || image_height <= 0)
return;
/* optimization */
if (image_width == width)
hrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
if (image_height == height)
vrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
cairo_save (cr);
_gtk_rounded_box_path (
gtk_theming_background_get_box (
bg,
_gtk_css_area_value_get (
_gtk_css_array_value_get_nth (
_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP),
idx))),
cr);
cairo_clip (cr);
cairo_translate (cr, origin->box.x, origin->box.y);
if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT && vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
{
cairo_translate (cr,
_gtk_css_position_value_get_x (pos, width - image_width),
_gtk_css_position_value_get_y (pos, height - image_height));
/* shortcut for normal case */
_gtk_css_image_draw (image, cr, image_width, image_height);
}
else
{
int surface_width, surface_height;
cairo_rectangle_t fill_rect;
cairo_surface_t *surface;
cairo_t *cr2;
/* If background-repeat is round for one (or both) dimensions,
* there is a second step. The UA must scale the image in that
* dimension (or both dimensions) so that it fits a whole number of
* times in the background positioning area. In the case of the width
* (height is analogous):
*
* If X 0 is the width of the image after step one and W is the width
* of the background positioning area, then the rounded width
* X' = W / round(W / X) where round() is a function that returns the
* nearest natural number (integer greater than zero).
*
* If background-repeat is round for one dimension only and if
* background-size is auto for the other dimension, then there is
* a third step: that other dimension is scaled so that the original
* aspect ratio is restored.
*/
if (hrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
{
double n = round (width / image_width);
n = MAX (1, n);
if (vrepeat != GTK_CSS_REPEAT_STYLE_ROUND
/* && vsize == auto (it is by default) */)
image_height *= width / (image_width * n);
image_width = width / n;
}
if (vrepeat == GTK_CSS_REPEAT_STYLE_ROUND)
{
double n = round (height / image_height);
n = MAX (1, n);
if (hrepeat != GTK_CSS_REPEAT_STYLE_ROUND
/* && hsize == auto (it is by default) */)
image_width *= height / (image_height * n);
image_height = height / n;
}
/* if hrepeat or vrepeat is 'space', we create a somewhat larger surface
* to store the extra space. */
if (hrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
{
double n = floor (width / image_width);
surface_width = n ? round (width / n) : 0;
}
else
surface_width = round (image_width);
if (vrepeat == GTK_CSS_REPEAT_STYLE_SPACE)
{
double n = floor (height / image_height);
surface_height = n ? round (height / n) : 0;
}
else
surface_height = round (image_height);
surface = cairo_surface_create_similar (cairo_get_target (cr),
CAIRO_CONTENT_COLOR_ALPHA,
surface_width, surface_height);
cr2 = cairo_create (surface);
cairo_translate (cr2,
0.5 * (surface_width - image_width),
0.5 * (surface_height - image_height));
_gtk_css_image_draw (image, cr2, image_width, image_height);
cairo_destroy (cr2);
cairo_set_source_surface (cr, surface,
_gtk_css_position_value_get_x (pos, width - image_width),
_gtk_css_position_value_get_y (pos, height - image_height));
cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
cairo_surface_destroy (surface);
if (hrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
{
fill_rect.x = _gtk_css_position_value_get_x (pos, width - image_width);
fill_rect.width = image_width;
}
else
{
fill_rect.x = 0;
fill_rect.width = width;
}
if (vrepeat == GTK_CSS_REPEAT_STYLE_NO_REPEAT)
{
fill_rect.y = _gtk_css_position_value_get_y (pos, height - image_height);
fill_rect.height = image_height;
}
else
{
fill_rect.y = 0;
fill_rect.height = height;
}
cairo_rectangle (cr, fill_rect.x, fill_rect.y,
fill_rect.width, fill_rect.height);
cairo_fill (cr);
}
cairo_restore (cr);
}
static void
_gtk_theming_background_apply_shadow (GtkThemingBackground *bg,
cairo_t *cr)
{
_gtk_css_shadows_value_paint_box (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BOX_SHADOW),
cr,
&bg->padding_box);
}
static void
_gtk_theming_background_init_context (GtkThemingBackground *bg)
{
GtkStateFlags flags = gtk_style_context_get_state (bg->context);
GtkBorder border, padding;
gtk_style_context_get_border (bg->context, flags, &border);
gtk_style_context_get_padding (bg->context, flags, &padding);
gtk_style_context_get_background_color (bg->context, flags, &bg->bg_color);
/* In the CSS box model, by default the background positioning area is
* the padding-box, i.e. all the border-box minus the borders themselves,
* which determines also its default size, see
* http://dev.w3.org/csswg/css3-background/#background-origin
*
* In the future we might want to support different origins or clips, but
* right now we just shrink to the default.
*/
_gtk_rounded_box_init_rect (&bg->border_box, 0, 0, bg->paint_area.width, bg->paint_area.height);
_gtk_rounded_box_apply_border_radius_for_context (&bg->border_box, bg->context, bg->junction);
bg->padding_box = bg->border_box;
_gtk_rounded_box_shrink (&bg->padding_box,
border.top, border.right,
border.bottom, border.left);
bg->content_box = bg->padding_box;
_gtk_rounded_box_shrink (&bg->content_box,
padding.top, padding.right,
padding.bottom, padding.left);
}
void
_gtk_theming_background_init (GtkThemingBackground *bg,
GtkThemingEngine *engine,
gdouble x,
gdouble y,
gdouble width,
gdouble height,
GtkJunctionSides junction)
{
GtkStyleContext *context;
g_assert (bg != NULL);
context = _gtk_theming_engine_get_context (engine);
_gtk_theming_background_init_from_context (bg, context,
x, y, width, height,
junction);
}
void
_gtk_theming_background_init_from_context (GtkThemingBackground *bg,
GtkStyleContext *context,
gdouble x,
gdouble y,
gdouble width,
gdouble height,
GtkJunctionSides junction)
{
g_assert (bg != NULL);
bg->context = context;
bg->paint_area.x = x;
bg->paint_area.y = y;
bg->paint_area.width = width;
bg->paint_area.height = height;
bg->junction = junction;
_gtk_theming_background_init_context (bg);
}
void
_gtk_theming_background_render (GtkThemingBackground *bg,
cairo_t *cr)
{
gint idx;
GtkCssValue *background_image;
background_image = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
cairo_save (cr);
cairo_translate (cr, bg->paint_area.x, bg->paint_area.y);
_gtk_theming_background_paint_color (bg, cr, background_image);
for (idx = _gtk_css_array_value_get_n_values (background_image) - 1; idx >= 0; idx--)
{
_gtk_theming_background_paint_layer (bg, idx, cr);
}
_gtk_theming_background_apply_shadow (bg, cr);
cairo_restore (cr);
}
gboolean
_gtk_theming_background_has_background_image (GtkThemingBackground *bg)
{
GtkCssImage *image;
GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_IMAGE);
if (_gtk_css_array_value_get_n_values (value) == 0)
return FALSE;
image = _gtk_css_image_value_get_image (_gtk_css_array_value_get_nth (value, 0));
return (image != NULL);
}