1 /* GTK - The GIMP Toolkit
2 * Copyright (C) 2010 Carlos Garnacho <carlosg@gnome.org>
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
20 #define GDK_DISABLE_DEPRECATION_WARNINGS
22 #include "gtkgradientprivate.h"
24 #include "gtkcsscolorvalueprivate.h"
25 #include "gtkcssrgbavalueprivate.h"
26 #include "gtkstylecontextprivate.h"
27 #include "gtkstyleproperties.h"
28 #include "gtksymboliccolorprivate.h"
32 * @Short_description: Gradients
35 * GtkGradient is a boxed type that represents a gradient.
36 * It is the result of parsing a
37 * <link linkend="gtkcssprovider-gradients">gradient expression</link>.
38 * To obtain the gradient represented by a GtkGradient, it has to
39 * be resolved with gtk_gradient_resolve(), which replaces all
40 * symbolic color references by the colors they refer to (in a given
41 * context) and constructs a #cairo_pattern_t value.
43 * It is not normally necessary to deal directly with #GtkGradients,
44 * since they are mostly used behind the scenes by #GtkStyleContext and
48 G_DEFINE_BOXED_TYPE (GtkGradient, gtk_gradient,
49 gtk_gradient_ref, gtk_gradient_unref)
51 typedef struct ColorStop ColorStop;
56 GtkSymbolicColor *color;
74 * gtk_gradient_new_linear:
75 * @x0: X coordinate of the starting point
76 * @y0: Y coordinate of the starting point
77 * @x1: X coordinate of the end point
78 * @y1: Y coordinate of the end point
80 * Creates a new linear gradient along the line defined by (x0, y0) and (x1, y1). Before using the gradient
81 * a number of stop colors must be added through gtk_gradient_add_color_stop().
83 * Returns: A newly created #GtkGradient
88 gtk_gradient_new_linear (gdouble x0,
93 GtkGradient *gradient;
95 gradient = g_slice_new (GtkGradient);
96 gradient->stops = g_array_new (FALSE, FALSE, sizeof (ColorStop));
102 gradient->radius0 = 0;
103 gradient->radius1 = 0;
105 gradient->ref_count = 1;
111 * gtk_gradient_new_radial:
112 * @x0: X coordinate of the start circle
113 * @y0: Y coordinate of the start circle
114 * @radius0: radius of the start circle
115 * @x1: X coordinate of the end circle
116 * @y1: Y coordinate of the end circle
117 * @radius1: radius of the end circle
119 * Creates a new radial gradient along the two circles defined by (x0, y0, radius0) and
120 * (x1, y1, radius1). Before using the gradient a number of stop colors must be added
121 * through gtk_gradient_add_color_stop().
123 * Returns: A newly created #GtkGradient
128 gtk_gradient_new_radial (gdouble x0,
135 GtkGradient *gradient;
137 gradient = g_slice_new (GtkGradient);
138 gradient->stops = g_array_new (FALSE, FALSE, sizeof (ColorStop));
144 gradient->radius0 = radius0;
145 gradient->radius1 = radius1;
147 gradient->ref_count = 1;
153 * gtk_gradient_add_color_stop:
154 * @gradient: a #GtkGradient
155 * @offset: offset for the color stop
156 * @color: color to use
158 * Adds a stop color to @gradient.
163 gtk_gradient_add_color_stop (GtkGradient *gradient,
165 GtkSymbolicColor *color)
169 g_return_if_fail (gradient != NULL);
171 stop.offset = offset;
172 stop.color = gtk_symbolic_color_ref (color);
174 g_array_append_val (gradient->stops, stop);
179 * @gradient: a #GtkGradient
181 * Increases the reference count of @gradient.
183 * Returns: The same @gradient
188 gtk_gradient_ref (GtkGradient *gradient)
190 g_return_val_if_fail (gradient != NULL, NULL);
192 gradient->ref_count++;
198 * gtk_gradient_unref:
199 * @gradient: a #GtkGradient
201 * Decreases the reference count of @gradient, freeing its memory
202 * if the reference count reaches 0.
207 gtk_gradient_unref (GtkGradient *gradient)
209 g_return_if_fail (gradient != NULL);
211 gradient->ref_count--;
213 if (gradient->ref_count == 0)
217 for (i = 0; i < gradient->stops->len; i++)
221 stop = &g_array_index (gradient->stops, ColorStop, i);
222 gtk_symbolic_color_unref (stop->color);
225 g_array_free (gradient->stops, TRUE);
226 g_slice_free (GtkGradient, gradient);
231 * gtk_gradient_resolve:
232 * @gradient: a #GtkGradient
233 * @props: #GtkStyleProperties to use when resolving named colors
234 * @resolved_gradient: (out): return location for the resolved pattern
236 * If @gradient is resolvable, @resolved_gradient will be filled in
237 * with the resolved gradient as a cairo_pattern_t, and %TRUE will
238 * be returned. Generally, if @gradient can't be resolved, it is
239 * due to it being defined on top of a named color that doesn't
242 * Returns: %TRUE if the gradient has been resolved
247 gtk_gradient_resolve (GtkGradient *gradient,
248 GtkStyleProperties *props,
249 cairo_pattern_t **resolved_gradient)
251 cairo_pattern_t *pattern;
254 g_return_val_if_fail (gradient != NULL, FALSE);
255 g_return_val_if_fail (GTK_IS_STYLE_PROPERTIES (props), FALSE);
256 g_return_val_if_fail (resolved_gradient != NULL, FALSE);
258 if (gradient->radius0 == 0 && gradient->radius1 == 0)
259 pattern = cairo_pattern_create_linear (gradient->x0, gradient->y0,
260 gradient->x1, gradient->y1);
262 pattern = cairo_pattern_create_radial (gradient->x0, gradient->y0,
264 gradient->x1, gradient->y1,
267 for (i = 0; i < gradient->stops->len; i++)
272 stop = &g_array_index (gradient->stops, ColorStop, i);
274 if (!gtk_symbolic_color_resolve (stop->color, props, &color))
276 cairo_pattern_destroy (pattern);
280 cairo_pattern_add_color_stop_rgba (pattern, stop->offset,
281 color.red, color.green,
282 color.blue, color.alpha);
285 *resolved_gradient = pattern;
290 _gtk_gradient_resolve_full (GtkGradient *gradient,
291 GtkStyleProviderPrivate *provider,
292 GtkCssComputedValues *values,
293 GtkCssComputedValues *parent_values,
294 GtkCssDependencies *dependencies)
296 cairo_pattern_t *pattern;
299 g_return_val_if_fail (gradient != NULL, NULL);
300 g_return_val_if_fail (GTK_IS_STYLE_PROVIDER (provider), NULL);
301 g_return_val_if_fail (GTK_IS_CSS_COMPUTED_VALUES (values), NULL);
302 g_return_val_if_fail (parent_values == NULL || GTK_IS_CSS_COMPUTED_VALUES (parent_values), NULL);
303 g_return_val_if_fail (*dependencies == 0, NULL);
305 if (gradient->radius0 == 0 && gradient->radius1 == 0)
306 pattern = cairo_pattern_create_linear (gradient->x0, gradient->y0,
307 gradient->x1, gradient->y1);
309 pattern = cairo_pattern_create_radial (gradient->x0, gradient->y0,
311 gradient->x1, gradient->y1,
314 for (i = 0; i < gradient->stops->len; i++)
319 GtkCssDependencies stop_deps;
321 stop = &g_array_index (gradient->stops, ColorStop, i);
323 /* if color resolving fails, assume transparency */
324 val = _gtk_css_color_value_resolve (_gtk_symbolic_color_get_css_value (stop->color),
326 _gtk_css_computed_values_get_value (values, GTK_CSS_PROPERTY_COLOR),
327 GTK_CSS_DEPENDS_ON_COLOR,
331 rgba = *_gtk_css_rgba_value_get_rgba (val);
332 *dependencies = _gtk_css_dependencies_union (*dependencies, stop_deps);
333 _gtk_css_value_unref (val);
337 rgba.red = rgba.green = rgba.blue = rgba.alpha = 0.0;
340 cairo_pattern_add_color_stop_rgba (pattern, stop->offset,
341 rgba.red, rgba.green,
342 rgba.blue, rgba.alpha);
349 append_number (GString *str,
355 if (zero && d == 0.0)
356 g_string_append (str, zero);
357 else if (half && d == 0.5)
358 g_string_append (str, half);
359 else if (one && d == 1.0)
360 g_string_append (str, one);
363 char buf[G_ASCII_DTOSTR_BUF_SIZE];
365 g_ascii_dtostr (buf, sizeof (buf), d);
366 g_string_append (str, buf);
371 * gtk_gradient_to_string:
372 * @gradient: the gradient to print
374 * Creates a string representation for @gradient that is suitable
375 * for using in GTK CSS files.
377 * Returns: A string representation for @gradient
380 gtk_gradient_to_string (GtkGradient *gradient)
385 g_return_val_if_fail (gradient != NULL, NULL);
387 str = g_string_new ("-gtk-gradient (");
389 if (gradient->radius0 == 0 && gradient->radius1 == 0)
391 g_string_append (str, "linear, ");
392 append_number (str, gradient->x0, "left", "center", "right");
393 g_string_append_c (str, ' ');
394 append_number (str, gradient->y0, "top", "center", "bottom");
395 g_string_append (str, ", ");
396 append_number (str, gradient->x1, "left", "center", "right");
397 g_string_append_c (str, ' ');
398 append_number (str, gradient->y1, "top", "center", "bottom");
402 g_string_append (str, "radial, ");
403 append_number (str, gradient->x0, "left", "center", "right");
404 g_string_append_c (str, ' ');
405 append_number (str, gradient->y0, "top", "center", "bottom");
406 g_string_append (str, ", ");
407 append_number (str, gradient->radius0, NULL, NULL, NULL);
408 g_string_append (str, ", ");
409 append_number (str, gradient->x1, "left", "center", "right");
410 g_string_append_c (str, ' ');
411 append_number (str, gradient->y1, "top", "center", "bottom");
412 g_string_append (str, ", ");
413 append_number (str, gradient->radius1, NULL, NULL, NULL);
416 for (i = 0; i < gradient->stops->len; i++)
421 stop = &g_array_index (gradient->stops, ColorStop, i);
423 g_string_append (str, ", ");
425 if (stop->offset == 0.0)
426 g_string_append (str, "from (");
427 else if (stop->offset == 1.0)
428 g_string_append (str, "to (");
431 g_string_append (str, "color-stop (");
432 append_number (str, stop->offset, NULL, NULL, NULL);
433 g_string_append (str, ", ");
436 s = gtk_symbolic_color_to_string (stop->color);
437 g_string_append (str, s);
440 g_string_append (str, ")");
443 g_string_append (str, ")");
445 return g_string_free (str, FALSE);
449 gtk_gradient_fade (GtkGradient *gradient,
455 faded = g_slice_new (GtkGradient);
456 faded->stops = g_array_new (FALSE, FALSE, sizeof (ColorStop));
458 faded->x0 = gradient->x0;
459 faded->y0 = gradient->y0;
460 faded->x1 = gradient->x1;
461 faded->y1 = gradient->y1;
462 faded->radius0 = gradient->radius0;
463 faded->radius1 = gradient->radius1;
465 faded->ref_count = 1;
467 for (i = 0; i < gradient->stops->len; i++)
469 GtkSymbolicColor *color;
472 stop = &g_array_index (gradient->stops, ColorStop, i);
473 color = gtk_symbolic_color_new_alpha (stop->color, opacity);
474 gtk_gradient_add_color_stop (faded, stop->offset, color);
475 gtk_symbolic_color_unref (color);
482 _gtk_gradient_transition (GtkGradient *start,
487 GtkGradient *gradient;
490 g_return_val_if_fail (start != NULL, NULL);
493 return gtk_gradient_fade (start, 1.0 - CLAMP (progress, 0.0, 1.0));
495 if (start->stops->len != end->stops->len)
498 /* check both are radial/linear */
499 if ((start->radius0 == 0 && start->radius1 == 0) != (end->radius0 == 0 && end->radius1 == 0))
502 gradient = g_slice_new (GtkGradient);
503 gradient->stops = g_array_new (FALSE, FALSE, sizeof (ColorStop));
505 gradient->x0 = (1 - progress) * start->x0 + progress * end->x0;
506 gradient->y0 = (1 - progress) * start->y0 + progress * end->y0;
507 gradient->x1 = (1 - progress) * start->x1 + progress * end->x1;
508 gradient->y1 = (1 - progress) * start->y1 + progress * end->y1;
509 gradient->radius0 = (1 - progress) * start->radius0 + progress * end->radius0;
510 gradient->radius1 = (1 - progress) * start->radius1 + progress * end->radius1;
512 gradient->ref_count = 1;
514 for (i = 0; i < start->stops->len; i++)
516 ColorStop *start_stop, *end_stop;
517 GtkSymbolicColor *color;
520 start_stop = &g_array_index (start->stops, ColorStop, i);
521 end_stop = &g_array_index (end->stops, ColorStop, i);
523 offset = (1 - progress) * start_stop->offset + progress * end_stop->offset;
524 color = gtk_symbolic_color_new_mix (start_stop->color,
527 gtk_gradient_add_color_stop (gradient, offset, color);
528 gtk_symbolic_color_unref (color);