1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /**
3 * @file
4 * Cairo surface that remembers its origin.
5 *//*
6 * Authors:
7 * Krzysztof Kosiński <tweenk.pl@gmail.com>
8 *
9 * Copyright (C) 2011 Authors
10 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
11 */
12
13 //#include <iostream>
14 #include "display/drawing-surface.h"
15 #include "display/drawing-context.h"
16 #include "display/cairo-utils.h"
17
18 namespace Inkscape {
19
20 using Geom::X;
21 using Geom::Y;
22
23
24 /**
25 * @class DrawingSurface
26 * Drawing surface that remembers its origin.
27 *
28 * This is a very minimalistic wrapper over cairo_surface_t. The main
29 * extra functionality provided by this class is that it automates
30 * the mapping from "logical space" (coordinates in the rendering)
31 * and the "physical space" (surface pixels). For example, patterns
32 * have to be rendered on tiles which have possibly non-integer
33 * widths and heights.
34 *
35 * This class has delayed allocation functionality - it creates
36 * the Cairo surface it wraps on the first call to createRawContext()
37 * of when a DrawingContext is constructed.
38 */
39
40 /**
41 * Creates a surface with the given physical extents.
42 * When a drawing context is created for this surface, its pixels
43 * will cover the area under the given rectangle.
44 */
DrawingSurface(Geom::IntRect const & area,int device_scale)45 DrawingSurface::DrawingSurface(Geom::IntRect const &area, int device_scale)
46 : _surface(nullptr)
47 , _origin(area.min())
48 , _scale(1, 1)
49 , _pixels(area.dimensions())
50 , _device_scale(device_scale)
51 {
52 assert(_device_scale > 0);
53 }
54
55 /**
56 * Creates a surface with the given logical and physical extents.
57 * When a drawing context is created for this surface, its pixels
58 * will cover the area under the given rectangle. IT will contain
59 * the number of pixels specified by the second argument.
60 * @param logbox Logical extents of the surface
61 * @param pixdims Pixel dimensions of the surface.
62 */
DrawingSurface(Geom::Rect const & logbox,Geom::IntPoint const & pixdims,int device_scale)63 DrawingSurface::DrawingSurface(Geom::Rect const &logbox, Geom::IntPoint const &pixdims, int device_scale)
64 : _surface(nullptr)
65 , _origin(logbox.min())
66 , _scale(pixdims[X] / logbox.width(), pixdims[Y] / logbox.height())
67 , _pixels(pixdims)
68 , _device_scale(device_scale)
69 {
70 assert(_device_scale > 0);
71 }
72
73 /**
74 * Wrap a cairo_surface_t.
75 * This constructor will take an extra reference on @a surface, which will
76 * be released on destruction.
77 */
DrawingSurface(cairo_surface_t * surface,Geom::Point const & origin)78 DrawingSurface::DrawingSurface(cairo_surface_t *surface, Geom::Point const &origin)
79 : _surface(surface)
80 , _origin(origin)
81 , _scale(1, 1)
82 {
83 cairo_surface_reference(surface);
84
85 double x_scale = 0;
86 double y_scale = 0;
87 cairo_surface_get_device_scale( surface, &x_scale, &y_scale);
88 if (x_scale != y_scale) {
89 std::cerr << "DrawingSurface::DrawingSurface: non-uniform device scale!" << std::endl;
90 }
91 _device_scale = x_scale;
92 assert(_device_scale > 0);
93
94 _pixels[X] = cairo_image_surface_get_width(surface)/_device_scale;
95 _pixels[Y] = cairo_image_surface_get_height(surface)/_device_scale;
96 }
97
~DrawingSurface()98 DrawingSurface::~DrawingSurface()
99 {
100 if (_surface)
101 cairo_surface_destroy(_surface);
102 }
103
104 /// Get the logical extents of the surface.
105 Geom::Rect
area() const106 DrawingSurface::area() const
107 {
108 Geom::Rect r = Geom::Rect::from_xywh(_origin, dimensions());
109 return r;
110 }
111
112 /// Get the pixel dimensions of the surface
113 Geom::IntPoint
pixels() const114 DrawingSurface::pixels() const
115 {
116 return _pixels;
117 }
118
119 /// Get the logical width and weight of the surface as a point.
120 Geom::Point
dimensions() const121 DrawingSurface::dimensions() const
122 {
123 Geom::Point logical_dims(_pixels[X] / _scale[X], _pixels[Y] / _scale[Y]);
124 return logical_dims;
125 }
126
127 Geom::Point
origin() const128 DrawingSurface::origin() const
129 {
130 return _origin;
131 }
132
133 Geom::Scale
scale() const134 DrawingSurface::scale() const
135 {
136 return _scale;
137 }
138
139 /// Device scale for HiDPI screens
140 int
device_scale() const141 DrawingSurface::device_scale() const
142 {
143 return _device_scale;
144 }
145
146 /// Get the transformation applied to the drawing context on construction.
147 Geom::Affine
drawingTransform() const148 DrawingSurface::drawingTransform() const
149 {
150 Geom::Affine ret = Geom::Translate(-_origin) * _scale;
151 return ret;
152 }
153
154 cairo_surface_type_t
type() const155 DrawingSurface::type() const
156 {
157 // currently hardcoded
158 return CAIRO_SURFACE_TYPE_IMAGE;
159 }
160
161 /// Drop contents of the surface and release the underlying Cairo object.
162 void
dropContents()163 DrawingSurface::dropContents()
164 {
165 if (_surface) {
166 cairo_surface_destroy(_surface);
167 _surface = nullptr;
168 }
169 }
170
171 /**
172 * Create a drawing context for this surface.
173 * It's better to use the surface constructor of DrawingContext.
174 */
175 cairo_t *
createRawContext()176 DrawingSurface::createRawContext()
177 {
178 // deferred allocation
179 if (!_surface) {
180 _surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
181 _pixels[X] * _device_scale,
182 _pixels[Y] * _device_scale);
183 cairo_surface_set_device_scale(_surface, _device_scale, _device_scale);
184 }
185 cairo_t *ct = cairo_create(_surface);
186 if (_scale != Geom::Scale::identity()) {
187 cairo_scale(ct, _scale[X], _scale[Y]);
188 }
189 cairo_translate(ct, -_origin[X], -_origin[Y]);
190 return ct;
191 }
192
193 Geom::IntRect
pixelArea() const194 DrawingSurface::pixelArea() const
195 {
196 Geom::IntRect ret = Geom::IntRect::from_xywh(_origin.round(), _pixels);
197 return ret;
198 }
199
200 //////////////////////////////////////////////////////////////////////////////
201
DrawingCache(Geom::IntRect const & area,int device_scale)202 DrawingCache::DrawingCache(Geom::IntRect const &area, int device_scale)
203 : DrawingSurface(area, device_scale)
204 , _clean_region(cairo_region_create())
205 , _pending_area(area)
206 {}
207
~DrawingCache()208 DrawingCache::~DrawingCache()
209 {
210 cairo_region_destroy(_clean_region);
211 }
212
213 void
markDirty(Geom::IntRect const & area)214 DrawingCache::markDirty(Geom::IntRect const &area)
215 {
216 cairo_rectangle_int_t dirty = _convertRect(area);
217 cairo_region_subtract_rectangle(_clean_region, &dirty);
218 }
219 void
markClean(Geom::IntRect const & area)220 DrawingCache::markClean(Geom::IntRect const &area)
221 {
222 Geom::OptIntRect r = Geom::intersect(area, pixelArea());
223 if (!r) return;
224 cairo_rectangle_int_t clean = _convertRect(*r);
225 cairo_region_union_rectangle(_clean_region, &clean);
226 }
227
228 /// Call this during the update phase to schedule a transformation of the cache.
229 void
scheduleTransform(Geom::IntRect const & new_area,Geom::Affine const & trans)230 DrawingCache::scheduleTransform(Geom::IntRect const &new_area, Geom::Affine const &trans)
231 {
232 _pending_area = new_area;
233 _pending_transform *= trans;
234 }
235
236 /// Transforms the cache according to the transform specified during the update phase.
237 /// Call this during render phase, before painting.
238 void
prepare()239 DrawingCache::prepare()
240 {
241 Geom::IntRect old_area = pixelArea();
242 bool is_identity = _pending_transform.isIdentity();
243 if (is_identity && _pending_area == old_area) return; // no change
244
245 bool is_integer_translation = is_identity;
246 if (!is_identity && _pending_transform.isTranslation()) {
247 Geom::IntPoint t = _pending_transform.translation().round();
248 if (Geom::are_near(Geom::Point(t), _pending_transform.translation())) {
249 is_integer_translation = true;
250 cairo_region_translate(_clean_region, t[X], t[Y]);
251 if (old_area + t == _pending_area) {
252 // if the areas match, the only thing to do
253 // is to ensure that the clean area is not too large
254 // we can exit early
255 cairo_rectangle_int_t limit = _convertRect(_pending_area);
256 cairo_region_intersect_rectangle(_clean_region, &limit);
257 _origin += t;
258 _pending_transform.setIdentity();
259 return;
260 }
261 }
262 }
263
264 // the area has changed, so the cache content needs to be copied
265 Geom::IntPoint old_origin = old_area.min();
266 cairo_surface_t *old_surface = _surface;
267 _surface = nullptr;
268 _pixels = _pending_area.dimensions();
269 _origin = _pending_area.min();
270
271 if (is_integer_translation) {
272 // transform the cache only for integer translations and identities
273 cairo_t *ct = createRawContext();
274 if (!is_identity) {
275 ink_cairo_transform(ct, _pending_transform);
276 }
277 cairo_set_source_surface(ct, old_surface, old_origin[X], old_origin[Y]);
278 cairo_set_operator(ct, CAIRO_OPERATOR_SOURCE);
279 cairo_pattern_set_filter(cairo_get_source(ct), CAIRO_FILTER_NEAREST);
280 cairo_paint(ct);
281 cairo_destroy(ct);
282
283 cairo_rectangle_int_t limit = _convertRect(_pending_area);
284 cairo_region_intersect_rectangle(_clean_region, &limit);
285 } else {
286 // dirty everything
287 cairo_region_destroy(_clean_region);
288 _clean_region = cairo_region_create();
289 }
290
291 //std::cout << _pending_transform << old_area << _pending_area << std::endl;
292 cairo_surface_destroy(old_surface);
293 _pending_transform.setIdentity();
294 }
295
296 /**
297 * Paints the clean area from cache and modifies the @a area
298 * parameter to the bounds of the region that must be repainted.
299 */
paintFromCache(DrawingContext & dc,Geom::OptIntRect & area,bool is_filter)300 void DrawingCache::paintFromCache(DrawingContext &dc, Geom::OptIntRect &area, bool is_filter)
301 {
302 if (!area) return;
303
304 // We subtract the clean region from the area, then get the bounds
305 // of the resulting region. This is the area that needs to be repainted
306 // by the item.
307 // Then we subtract the area that needs to be repainted from the
308 // original area and paint the resulting region from cache.
309 cairo_rectangle_int_t area_c = _convertRect(*area);
310 cairo_region_t *dirty_region = cairo_region_create_rectangle(&area_c);
311 cairo_region_t *cache_region = cairo_region_copy(dirty_region);
312 cairo_region_subtract(dirty_region, _clean_region);
313
314 if (is_filter && !cairo_region_is_empty(dirty_region)) { // To allow fast panning on high zoom on filters
315 return;
316 }
317 if (cairo_region_is_empty(dirty_region)) {
318 area = Geom::OptIntRect();
319 } else {
320 cairo_rectangle_int_t to_repaint;
321 cairo_region_get_extents(dirty_region, &to_repaint);
322 area = _convertRect(to_repaint);
323 markDirty(*area);
324 cairo_region_subtract_rectangle(cache_region, &to_repaint);
325 }
326 cairo_region_destroy(dirty_region);
327
328 if (!cairo_region_is_empty(cache_region)) {
329 int nr = cairo_region_num_rectangles(cache_region);
330 cairo_rectangle_int_t tmp;
331 for (int i = 0; i < nr; ++i) {
332 cairo_region_get_rectangle(cache_region, i, &tmp);
333 dc.rectangle(_convertRect(tmp));
334 }
335 dc.setSource(this);
336 dc.fill();
337 }
338 cairo_region_destroy(cache_region);
339 }
340
341 // debugging utility
342 void
_dumpCache(Geom::OptIntRect const & area)343 DrawingCache::_dumpCache(Geom::OptIntRect const &area)
344 {
345 static int dumpnr = 0;
346 cairo_surface_t *surface = ink_cairo_surface_copy(_surface);
347 DrawingContext dc(surface, _origin);
348 if (!cairo_region_is_empty(_clean_region)) {
349 Inkscape::DrawingContext::Save save(dc);
350 int nr = cairo_region_num_rectangles(_clean_region);
351 cairo_rectangle_int_t tmp;
352 for (int i = 0; i < nr; ++i) {
353 cairo_region_get_rectangle(_clean_region, i, &tmp);
354 dc.rectangle(_convertRect(tmp));
355 }
356 dc.setSource(0,1,0,0.1);
357 dc.fill();
358 }
359 dc.rectangle(*area);
360 dc.setSource(1,0,0,0.1);
361 dc.fill();
362 char *fn = g_strdup_printf("dump%d.png", dumpnr++);
363 cairo_surface_write_to_png(surface, fn);
364 cairo_surface_destroy(surface);
365 g_free(fn);
366 }
367
368 cairo_rectangle_int_t
_convertRect(Geom::IntRect const & area)369 DrawingCache::_convertRect(Geom::IntRect const &area)
370 {
371 cairo_rectangle_int_t ret;
372 ret.x = area.left();
373 ret.y = area.top();
374 ret.width = area.width();
375 ret.height = area.height();
376 return ret;
377 }
378
379 Geom::IntRect
_convertRect(cairo_rectangle_int_t const & r)380 DrawingCache::_convertRect(cairo_rectangle_int_t const &r)
381 {
382 Geom::IntRect ret = Geom::IntRect::from_xywh(
383 r.x, r.y,
384 r.width, r.height);
385 return ret;
386 }
387
388 } // end namespace Inkscape
389
390 /*
391 Local Variables:
392 mode:c++
393 c-file-style:"stroustrup"
394 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
395 indent-tabs-mode:nil
396 fill-column:99
397 End:
398 */
399 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :
400