1 #define __SP_FILTER_CHEMISTRY_C__
3 /*
4 * Various utility methods for filters
5 *
6 * Authors:
7 * Hugo Rodrigues
8 * bulia byak
9 * Niko Kiirala
10 *
11 * Copyright (C) 2006,2007 authors
12 *
13 * Released under GNU GPL, read the file 'COPYING' for more information
14 */
17 #include "style.h"
18 #include "document-private.h"
19 #include "desktop-style.h"
21 #include "sp-filter.h"
22 #include "sp-gaussian-blur.h"
23 #include "svg/css-ostringstream.h"
25 #include "xml/repr.h"
27 /**
28 * Count how many times the filter is used by the styles of o and its
29 * descendants
30 */
31 static guint
32 count_filter_hrefs(SPObject *o, SPFilter *filter)
33 {
34 if (!o)
35 return 1;
37 guint i = 0;
39 SPStyle *style = SP_OBJECT_STYLE(o);
40 if (style
41 && style->filter.set
42 && style->filter.filter == filter)
43 {
44 i ++;
45 }
47 for (SPObject *child = sp_object_first_child(o);
48 child != NULL; child = SP_OBJECT_NEXT(child)) {
49 i += count_filter_hrefs(child, filter);
50 }
52 return i;
53 }
55 /**
56 * Sets a suitable filter effects area according to given blur radius,
57 * expansion and object size.
58 */
59 static void set_filter_area(Inkscape::XML::Node *repr, gdouble radius,
60 double expansion, double expansionX,
61 double expansionY, double width, double height)
62 {
63 // TODO: make this more generic, now assumed, that only the blur
64 // being added can affect the required filter area
66 double rx = radius * (expansionY != 0 ? (expansion / expansionY) : 1);
67 double ry = radius * (expansionX != 0 ? (expansion / expansionX) : 1);
69 if (width != 0 && height != 0 && (2.4 * rx > width * 0.1 || 2.4 * ry > height * 0.1)) {
70 // If not within the default 10% margin (see
71 // http://www.w3.org/TR/SVG11/filters.html#FilterEffectsRegion), specify margins
72 // The 2.4 is an empirical coefficient: at that distance the cutoff is practically invisible
73 // (the opacity at 2.4*radius is about 3e-3)
74 double xmargin = 2.4 * (rx) / width;
75 double ymargin = 2.4 * (ry) / height;
77 // TODO: set it in UserSpaceOnUse instead?
78 sp_repr_set_svg_double(repr, "x", -xmargin);
79 sp_repr_set_svg_double(repr, "width", 1 + 2 * xmargin);
80 sp_repr_set_svg_double(repr, "y", -ymargin);
81 sp_repr_set_svg_double(repr, "height", 1 + 2 * ymargin);
82 }
83 }
85 /**
86 * Creates a filter with blur primitive of specified radius for an item with the given matrix expansion, width and height
87 */
88 SPFilter *
89 new_filter_gaussian_blur (SPDocument *document, gdouble radius, double expansion, double expansionX, double expansionY, double width, double height)
90 {
91 g_return_val_if_fail(document != NULL, NULL);
93 SPDefs *defs = (SPDefs *) SP_DOCUMENT_DEFS(document);
95 Inkscape::XML::Document *xml_doc = sp_document_repr_doc(document);
97 // create a new filter
98 Inkscape::XML::Node *repr;
99 repr = xml_doc->createElement("svg:filter");
100 //repr->setAttribute("inkscape:collect", "always");
102 set_filter_area(repr, radius, expansion, expansionX, expansionY,
103 width, height);
105 //create feGaussianBlur node
106 Inkscape::XML::Node *b_repr;
107 b_repr = xml_doc->createElement("svg:feGaussianBlur");
108 //b_repr->setAttribute("inkscape:collect", "always");
110 double stdDeviation = radius;
111 if (expansion != 0)
112 stdDeviation /= expansion;
114 //set stdDeviation attribute
115 sp_repr_set_svg_double(b_repr, "stdDeviation", stdDeviation);
117 //set feGaussianBlur as child of filter node
118 repr->appendChild(b_repr);
119 Inkscape::GC::release(b_repr);
121 // Append the new filter node to defs
122 SP_OBJECT_REPR(defs)->appendChild(repr);
123 Inkscape::GC::release(repr);
125 // get corresponding object
126 SPFilter *f = SP_FILTER( document->getObjectByRepr(repr) );
127 SPGaussianBlur *b = SP_GAUSSIANBLUR( document->getObjectByRepr(b_repr) );
129 g_assert(f != NULL);
130 g_assert(SP_IS_FILTER(f));
131 g_assert(b != NULL);
132 g_assert(SP_IS_GAUSSIANBLUR(b));
134 return f;
135 }
137 /**
138 * Creates a filter with blur primitive of specified radius for the given item
139 */
140 SPFilter *
141 new_filter_gaussian_blur_from_item (SPDocument *document, SPItem *item, gdouble radius)
142 {
143 NR::Maybe<NR::Rect> const r = sp_item_bbox_desktop(item);
145 double width;
146 double height;
147 if (r) {
148 width = r->extent(NR::X);
149 height= r->extent(NR::Y);
150 } else {
151 width = height = 0;
152 }
154 NR::Matrix i2d = sp_item_i2d_affine (item);
156 return (new_filter_gaussian_blur (document, radius, i2d.expansion(), i2d.expansionX(), i2d.expansionY(), width, height));
157 }
159 /**
160 * Modifies the gaussian blur applied to the item.
161 * If no filters are applied to given item, creates a new blur filter.
162 * If a filter is applied and it contains a blur, modify that blur.
163 * If the filter doesn't contain blur, a blur is added to the filter.
164 * Should there be more references to modified filter, that filter is
165 * duplicated, so that other elements referring that filter are not modified.
166 */
167 /* TODO: this should be made more generic, not just for blurs */
168 SPFilter *
169 modify_filter_gaussian_blur_from_item(SPDocument *document, SPItem *item,
170 gdouble radius)
171 {
172 if (!item->style || !item->style->filter.set) {
173 return new_filter_gaussian_blur_from_item(document, item, radius);
174 }
176 SPFilter *filter = SP_FILTER(item->style->filter.filter);
177 Inkscape::XML::Document *xml_doc = sp_document_repr_doc(document);
179 // If there are more users for this filter, duplicate it
180 if (SP_OBJECT_HREFCOUNT(filter) > count_filter_hrefs(item, filter)) {
181 Inkscape::XML::Node *repr;
182 repr = SP_OBJECT_REPR(item)->duplicate(xml_doc);
183 SPDefs *defs = (SPDefs *) SP_DOCUMENT_DEFS(document);
184 SP_OBJECT_REPR(defs)->appendChild(repr);
186 filter = SP_FILTER( document->getObjectByRepr(repr) );
187 Inkscape::GC::release(repr);
188 }
190 // Determine the required standard deviation value
191 NR::Matrix i2d = sp_item_i2d_affine (item);
192 double expansion = i2d.expansion();
193 double stdDeviation = radius;
194 if (expansion != 0)
195 stdDeviation /= expansion;
197 // Get the object size
198 NR::Maybe<NR::Rect> const r = sp_item_bbox_desktop(item);
199 double width;
200 double height;
201 if (r) {
202 width = r->extent(NR::X);
203 height= r->extent(NR::Y);
204 } else {
205 width = height = 0;
206 }
208 // Set the filter effects area
209 Inkscape::XML::Node *repr = SP_OBJECT_REPR(item->style->filter.filter);
210 set_filter_area(repr, radius, expansion, i2d.expansionX(),
211 i2d.expansionY(), width, height);
213 // Search for gaussian blur primitives. If found, set the stdDeviation
214 // of the first one and return.
215 Inkscape::XML::Node *primitive = repr->firstChild();
216 while (primitive) {
217 if (strcmp("svg:feGaussianBlur", primitive->name()) == 0) {
218 sp_repr_set_svg_double(primitive, "stdDeviation",
219 stdDeviation);
220 return filter;
221 }
222 primitive = primitive->next();
223 }
225 // If there were no gaussian blur primitives, create a new one
227 //create feGaussianBlur node
228 Inkscape::XML::Node *b_repr;
229 b_repr = xml_doc->createElement("svg:feGaussianBlur");
230 //b_repr->setAttribute("inkscape:collect", "always");
232 //set stdDeviation attribute
233 sp_repr_set_svg_double(b_repr, "stdDeviation", stdDeviation);
235 //set feGaussianBlur as child of filter node
236 SP_OBJECT_REPR(filter)->appendChild(b_repr);
237 Inkscape::GC::release(b_repr);
239 return filter;
240 }
242 void remove_filter (SPObject *item, bool recursive)
243 {
244 SPCSSAttr *css = sp_repr_css_attr_new ();
245 sp_repr_css_unset_property (css, "filter");
246 if (recursive)
247 sp_repr_css_change_recursive(SP_OBJECT_REPR(item), css, "style");
248 else
249 sp_repr_css_change (SP_OBJECT_REPR(item), css, "style");
250 sp_repr_css_attr_unref (css);
251 }
253 /**
254 * Removes the first feGaussianBlur from the filter attached to given item.
255 * Should this leave us with an empty filter, remove that filter.
256 */
257 /* TODO: the removed filter primitive may had had a named result image, so
258 * after removing, the filter may be in erroneous state, this situation should
259 * be handled gracefully */
260 void remove_filter_gaussian_blur (SPObject *item)
261 {
262 if (item->style && item->style->filter.set && item->style->filter.filter) {
263 // Search for the first blur primitive and remove it. (if found)
264 Inkscape::XML::Node *repr = SP_OBJECT_REPR(item->style->filter.filter);
265 Inkscape::XML::Node *primitive = repr->firstChild();
266 while (primitive) {
267 if (strcmp("svg:feGaussianBlur", primitive->name()) == 0) {
268 sp_repr_unparent(primitive);
269 break;
270 }
271 primitive = primitive->next();
272 }
274 // If there are no more primitives left in this filter, discard it.
275 if (repr->childCount() == 0) {
276 remove_filter(item, false);
277 }
278 }
279 }
281 /*
282 Local Variables:
283 mode:c++
284 c-file-style:"stroustrup"
285 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
286 indent-tabs-mode:nil
287 fill-column:99
288 End:
289 */
290 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :