static void
gtk_css_image_linear_snapshot (GtkCssImage *image,
GtkSnapshot *snapshot,
double width,
double height)
{
GtkCssImageLinear *linear = GTK_CSS_IMAGE_LINEAR (image);
GskColorStop *stops;
GskRenderNode *node;
double off_x, off_y; /* snapshot offset */
double angle; /* actual angle of the gradiant line in degrees */
double x, y; /* coordinates of start point */
double length; /* distance in pixels for 100% */
double start, end; /* position of first/last point on gradient line - with gradient line being [0, 1] */
double offset;
int i, last;
char *name;
if (linear->side)
{
/* special casing the regular cases here so we don't get rounding errors */
switch (linear->side)
{
case 1 << GTK_CSS_RIGHT:
angle = 90;
break;
case 1 << GTK_CSS_LEFT:
angle = 270;
break;
case 1 << GTK_CSS_TOP:
angle = 0;
break;
case 1 << GTK_CSS_BOTTOM:
angle = 180;
break;
default:
angle = atan2 (linear->side & 1 << GTK_CSS_TOP ? -width : width,
linear->side & 1 << GTK_CSS_LEFT ? -height : height);
angle = 180 * angle / G_PI + 90;
break;
}
}
else
{
angle = _gtk_css_number_value_get (linear->angle, 100);
}
gtk_css_image_linear_compute_start_point (angle,
width, height,
&x, &y);
length = sqrt (x * x + y * y);
gtk_css_image_linear_get_start_end (linear, length, &start, &end);
if (start == end)
{
/* repeating gradients with all color stops sharing the same offset
* get the color of the last color stop */
GtkCssImageLinearColorStop *stop = &g_array_index (linear->stops, GtkCssImageLinearColorStop, linear->stops->len - 1);
gtk_snapshot_append_color_node (snapshot,
_gtk_css_rgba_value_get_rgba (stop->color),
&GRAPHENE_RECT_INIT (0, 0, width, height),
"RepeatingLinearGradient<degenerate>");
return;
}
offset = start;
last = -1;
stops = g_newa (GskColorStop, linear->stops->len);
for (i = 0; i < linear->stops->len; i++)
{
GtkCssImageLinearColorStop *stop;
double pos, step;
stop = &g_array_index (linear->stops, GtkCssImageLinearColorStop, i);
if (stop->offset == NULL)
{
if (i == 0)
pos = 0.0;
else if (i + 1 == linear->stops->len)
pos = 1.0;
else
continue;
}
else
pos = _gtk_css_number_value_get (stop->offset, length) / length;
pos = MAX (pos, offset);
step = (pos - offset) / (i - last);
for (last = last + 1; last <= i; last++)
{
stop = &g_array_index (linear->stops, GtkCssImageLinearColorStop, last);
offset += step;
stops[last].offset = (offset - start) / (end - start);
stops[last].color = *_gtk_css_rgba_value_get_rgba (stop->color);
}
offset = pos;
last = i;
}
gtk_snapshot_get_offset (snapshot, &off_x, &off_y);
if (linear->repeating)
{
node = gsk_repeating_linear_gradient_node_new (
&GRAPHENE_RECT_INIT (off_x, off_y, width, height),
&GRAPHENE_POINT_INIT (off_x + width / 2 + x * (start - 0.5), off_y + height / 2 + y * (start - 0.5)),
&GRAPHENE_POINT_INIT (off_x + width / 2 + x * (end - 0.5), off_y + height / 2 + y * (end - 0.5)),
stops,
linear->stops->len);
}
else
{
node = gsk_linear_gradient_node_new (
&GRAPHENE_RECT_INIT (off_x, off_y, width, height),
&GRAPHENE_POINT_INIT (off_x + width / 2 + x * (start - 0.5), off_y + height / 2 + y * (start - 0.5)),
&GRAPHENE_POINT_INIT (off_x + width / 2 + x * (end - 0.5), off_y + height / 2 + y * (end - 0.5)),
stops,
linear->stops->len);
}
name = g_strdup_printf ("%sLinearGradient<%ustops>", linear->repeating ? "Repeating" : "", linear->stops->len);
gsk_render_node_set_name (node, name);
g_free (name);
gtk_snapshot_append_node (snapshot, node);
gsk_render_node_unref (node);
}
static void
gtk_css_image_linear_draw (GtkCssImage *image,
cairo_t *cr,
double width,
double height)
{
GtkCssImageLinear *linear = GTK_CSS_IMAGE_LINEAR (image);
cairo_pattern_t *pattern;
double angle; /* actual angle of the gradiant line in degrees */
double x, y; /* coordinates of start point */
double length; /* distance in pixels for 100% */
double start, end; /* position of first/last point on gradient line - with gradient line being [0, 1] */
double offset;
int i, last;
if (linear->side)
{
/* special casing the regular cases here so we don't get rounding errors */
switch (linear->side)
{
case 1 << GTK_CSS_RIGHT:
angle = 90;
break;
case 1 << GTK_CSS_LEFT:
angle = 270;
break;
case 1 << GTK_CSS_TOP:
angle = 0;
break;
case 1 << GTK_CSS_BOTTOM:
angle = 180;
break;
default:
angle = atan2 (linear->side & 1 << GTK_CSS_TOP ? -width : width,
linear->side & 1 << GTK_CSS_LEFT ? -height : height);
angle = 180 * angle / G_PI + 90;
break;
}
}
else
{
angle = _gtk_css_number_value_get (linear->angle, 100);
}
gtk_css_image_linear_compute_start_point (angle,
width, height,
&x, &y);
length = sqrt (x * x + y * y);
gtk_css_image_linear_get_start_end (linear, length, &start, &end);
pattern = cairo_pattern_create_linear (x * (start - 0.5), y * (start - 0.5),
x * (end - 0.5), y * (end - 0.5));
if (linear->repeating)
cairo_pattern_set_extend (pattern, CAIRO_EXTEND_REPEAT);
else
cairo_pattern_set_extend (pattern, CAIRO_EXTEND_PAD);
offset = start;
last = -1;
for (i = 0; i < linear->stops->len; i++)
{
GtkCssImageLinearColorStop *stop;
double pos, step;
stop = &g_array_index (linear->stops, GtkCssImageLinearColorStop, i);
if (stop->offset == NULL)
{
if (i == 0)
pos = 0.0;
else if (i + 1 == linear->stops->len)
pos = 1.0;
else
continue;
}
else
pos = _gtk_css_number_value_get (stop->offset, length) / length;
pos = MAX (pos, offset);
step = (pos - offset) / (i - last);
for (last = last + 1; last <= i; last++)
{
const GdkRGBA *rgba;
stop = &g_array_index (linear->stops, GtkCssImageLinearColorStop, last);
rgba = _gtk_css_rgba_value_get_rgba (stop->color);
offset += step;
cairo_pattern_add_color_stop_rgba (pattern,
(offset - start) / (end - start),
rgba->red,
rgba->green,
rgba->blue,
rgba->alpha);
}
offset = pos;
last = i;
}
cairo_rectangle (cr, 0, 0, width, height);
cairo_translate (cr, width / 2, height / 2);
cairo_set_source (cr, pattern);
cairo_fill (cr);
cairo_pattern_destroy (pattern);
}
