gtk2/gtk/gtkthemingbackground.c
Cosimo Cecchi 65166c36b9 themingbackground: fix drawing for repeating positioned images
When we determine the fill rectangle for an image layer, and the image
is not repeating, we should also position the rectangle according to the
values of background-position, or we will always fill a tiny slice at
the top/left of the clip box.

https://bugzilla.gnome.org/show_bug.cgi?id=677109
2012-05-30 12:16:11 -04:00

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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
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "gtkthemingbackgroundprivate.h"
#include "gtkcssarrayvalueprivate.h"
#include "gtkcssbgsizevalueprivate.h"
#include "gtkcssenumvalueprivate.h"
#include "gtkcssimagevalueprivate.h"
#include "gtkcssshadowsvalueprivate.h"
#include "gtkcsspositionvalueprivate.h"
#include "gtkcssrepeatvalueprivate.h"
#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"
typedef struct {
cairo_rectangle_t image_rect;
GtkCssImage *image;
GtkRoundedBox clip_box;
gint idx;
} GtkThemingBackgroundLayer;
static void
_gtk_theming_background_layer_apply_origin (GtkThemingBackground *bg,
GtkThemingBackgroundLayer *layer)
{
cairo_rectangle_t image_rect;
GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_ORIGIN);
GtkCssArea origin = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, layer->idx));
/* The default size of the background image depends on the
background-origin value as this affects the top left
and the bottom right corners. */
switch (origin) {
case GTK_CSS_AREA_BORDER_BOX:
image_rect.x = 0;
image_rect.y = 0;
image_rect.width = bg->paint_area.width;
image_rect.height = bg->paint_area.height;
break;
case GTK_CSS_AREA_CONTENT_BOX:
image_rect.x = bg->border.left + bg->padding.left;
image_rect.y = bg->border.top + bg->padding.top;
image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right - bg->padding.left - bg->padding.right;
image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom - bg->padding.top - bg->padding.bottom;
break;
case GTK_CSS_AREA_PADDING_BOX:
default:
image_rect.x = bg->border.left;
image_rect.y = bg->border.top;
image_rect.width = bg->paint_area.width - bg->border.left - bg->border.right;
image_rect.height = bg->paint_area.height - bg->border.top - bg->border.bottom;
break;
}
/* XXX: image_rect might have negative width/height here.
* Do we need to do something about it? */
layer->image_rect = image_rect;
}
static void
_gtk_theming_background_apply_clip (GtkThemingBackground *bg,
GtkRoundedBox *box,
GtkCssArea clip)
{
if (clip == GTK_CSS_AREA_PADDING_BOX)
{
_gtk_rounded_box_shrink (box,
bg->border.top, bg->border.right,
bg->border.bottom, bg->border.left);
}
else if (clip == GTK_CSS_AREA_CONTENT_BOX)
{
_gtk_rounded_box_shrink (box,
bg->border.top + bg->padding.top,
bg->border.right + bg->padding.right,
bg->border.bottom + bg->padding.bottom,
bg->border.left + bg->padding.left);
}
}
static void
_gtk_theming_background_layer_apply_clip (GtkThemingBackground *bg,
GtkThemingBackgroundLayer *layer)
{
GtkCssValue *value = _gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_CLIP);
GtkCssArea clip = _gtk_css_area_value_get (_gtk_css_array_value_get_nth (value, layer->idx));
_gtk_theming_background_apply_clip (bg, &layer->clip_box, clip);
}
static void
_gtk_theming_background_paint_color (GtkThemingBackground *bg,
cairo_t *cr,
GtkCssValue *background_image)
{
GtkRoundedBox clip_box;
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));
clip_box = bg->border_box;
_gtk_theming_background_apply_clip (bg, &clip_box, clip);
cairo_save (cr);
_gtk_rounded_box_path (&clip_box, 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,
GtkThemingBackgroundLayer *layer,
cairo_t *cr)
{
cairo_save (cr);
_gtk_rounded_box_path (&layer->clip_box, cr);
cairo_clip (cr);
if (layer->image
&& layer->image_rect.width > 0
&& layer->image_rect.height > 0)
{
const GtkCssValue *pos, *repeat;
double image_width, image_height;
double width, height;
GtkCssRepeatStyle hrepeat, vrepeat;
pos = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_POSITION), layer->idx);
repeat = _gtk_css_array_value_get_nth (_gtk_style_context_peek_property (bg->context, GTK_CSS_PROPERTY_BACKGROUND_REPEAT), layer->idx);
hrepeat = _gtk_css_background_repeat_value_get_x (repeat);
vrepeat = _gtk_css_background_repeat_value_get_y (repeat);
width = layer->image_rect.width;
height = layer->image_rect.height;
_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), layer->idx),
layer->image,
width,
height,
&image_width,
&image_height);
/* optimization */
if (image_width == width)
hrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
if (image_height == height)
vrepeat = GTK_CSS_REPEAT_STYLE_NO_REPEAT;
cairo_translate (cr, layer->image_rect.x, layer->image_rect.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 (layer->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 (layer->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_layer (GtkThemingBackground *bg,
GtkThemingBackgroundLayer *layer,
GtkCssValue *background_image,
gint idx)
{
layer->idx = idx;
layer->clip_box = bg->border_box;
_gtk_theming_background_layer_apply_clip (bg, layer);
_gtk_theming_background_layer_apply_origin (bg, layer);
layer->image = _gtk_css_image_value_get_image (_gtk_css_array_value_get_nth (background_image, layer->idx));
}
static void
_gtk_theming_background_init_context (GtkThemingBackground *bg)
{
bg->flags = gtk_style_context_get_state (bg->context);
gtk_style_context_get_border (bg->context, bg->flags, &bg->border);
gtk_style_context_get_padding (bg->context, bg->flags, &bg->padding);
gtk_style_context_get_background_color (bg->context, bg->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,
bg->border.top, bg->border.right,
bg->border.bottom, bg->border.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;
GtkThemingBackgroundLayer layer;
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_init_layer (bg, &layer, background_image, idx);
_gtk_theming_background_paint_layer (bg, &layer, 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);
}