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Diffstat (limited to 'src/display/drawing-surface.cpp')
| -rw-r--r-- | src/display/drawing-surface.cpp | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/src/display/drawing-surface.cpp b/src/display/drawing-surface.cpp new file mode 100644 index 0000000..9926134 --- /dev/null +++ b/src/display/drawing-surface.cpp @@ -0,0 +1,315 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/** + * @file + * Cairo surface that remembers its origin. + *//* + * Authors: + * Krzysztof Kosiński <tweenk.pl@gmail.com> + * + * Copyright (C) 2011 Authors + * Released under GNU GPL v2+, read the file 'COPYING' for more information. + */ + +#include "display/drawing-surface.h" +#include "display/drawing-context.h" +#include "display/cairo-utils.h" +#include "ui/util.h" + +namespace Inkscape { + +/** + * @class DrawingSurface + * Drawing surface that remembers its origin. + * + * This is a very minimalistic wrapper over cairo_surface_t. The main + * extra functionality provided by this class is that it automates + * the mapping from "logical space" (coordinates in the rendering) + * and the "physical space" (surface pixels). For example, patterns + * have to be rendered on tiles which have possibly non-integer + * widths and heights. + * + * This class has delayed allocation functionality - it creates + * the Cairo surface it wraps on the first call to createRawContext() + * of when a DrawingContext is constructed. + */ + +/** + * Creates a surface with the given physical extents. + * When a drawing context is created for this surface, its pixels + * will cover the area under the given rectangle. + */ +DrawingSurface::DrawingSurface(Geom::IntRect const &area, int device_scale) + : _surface(nullptr) + , _origin(area.min()) + , _scale(1, 1) + , _pixels(area.dimensions()) + , _device_scale(device_scale) +{ + assert(_device_scale > 0); +} + +/** + * Creates a surface with the given logical and physical extents. + * When a drawing context is created for this surface, its pixels + * will cover the area under the given rectangle. IT will contain + * the number of pixels specified by the second argument. + * @param logbox Logical extents of the surface + * @param pixdims Pixel dimensions of the surface. + */ +DrawingSurface::DrawingSurface(Geom::Rect const &logbox, Geom::IntPoint const &pixdims, int device_scale) + : _surface(nullptr) + , _origin(logbox.min()) + , _scale(pixdims / logbox.dimensions()) + , _pixels(pixdims) + , _device_scale(device_scale) +{ + assert(_device_scale > 0); +} + +/** + * Wrap a cairo_surface_t. + * This constructor will take an extra reference on @a surface, which will + * be released on destruction. + */ +DrawingSurface::DrawingSurface(cairo_surface_t *surface, Geom::Point const &origin) + : _surface(surface) + , _origin(origin) + , _scale(1, 1) +{ + cairo_surface_reference(surface); + + double x_scale = 0; + double y_scale = 0; + cairo_surface_get_device_scale( surface, &x_scale, &y_scale); + if (x_scale != y_scale) { + std::cerr << "DrawingSurface::DrawingSurface: non-uniform device scale!" << std::endl; + } + _device_scale = x_scale; + assert(_device_scale > 0); + + _pixels = Geom::IntPoint(cairo_image_surface_get_width(surface) / _device_scale, cairo_image_surface_get_height(surface) / _device_scale); +} + +DrawingSurface::~DrawingSurface() +{ + if (_surface) { + cairo_surface_destroy(_surface); + } +} + +/// Drop contents of the surface and release the underlying Cairo object. +void DrawingSurface::dropContents() +{ + if (_surface) { + cairo_surface_destroy(_surface); + _surface = nullptr; + } +} + +/** + * Create a drawing context for this surface. + * It's better to use the surface constructor of DrawingContext. + */ +cairo_t *DrawingSurface::createRawContext() +{ + // deferred allocation + if (!_surface) { + _surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, + _pixels.x() * _device_scale, + _pixels.y() * _device_scale); + cairo_surface_set_device_scale(_surface, _device_scale, _device_scale); + } + cairo_t *ct = cairo_create(_surface); + if (_scale != Geom::Scale::identity()) { + cairo_scale(ct, _scale.vector().x(), _scale.vector().y()); + } + cairo_translate(ct, -_origin.x(), -_origin.y()); + return ct; +} + +Geom::IntRect DrawingSurface::pixelArea() const +{ + return Geom::IntRect::from_xywh(_origin.round(), _pixels); +} + +////////////////////////////////////////////////////////////////////////////// + +DrawingCache::DrawingCache(Geom::IntRect const &area, int device_scale) + : DrawingSurface(area, device_scale) + , _clean_region(cairo_region_create()) + , _pending_area(area) +{ +} + +DrawingCache::~DrawingCache() +{ + cairo_region_destroy(_clean_region); +} + +void DrawingCache::markDirty(Geom::IntRect const &area) +{ + auto const dirty = geom_to_cairo(area); + cairo_region_subtract_rectangle(_clean_region, &dirty); +} + +void DrawingCache::markClean(Geom::IntRect const &area) +{ + auto const r = area & pixelArea(); + if (!r) return; + auto const clean = geom_to_cairo(*r); + cairo_region_union_rectangle(_clean_region, &clean); +} + +/// Call this during the update phase to schedule a transformation of the cache. +void DrawingCache::scheduleTransform(Geom::IntRect const &new_area, Geom::Affine const &trans) +{ + _pending_area = new_area; + _pending_transform *= trans; +} + +/// Transforms the cache according to the transform specified during the update phase. +/// Call this during render phase, before painting. +void DrawingCache::prepare() +{ + Geom::IntRect old_area = pixelArea(); + bool is_identity = _pending_transform.isIdentity(); + if (is_identity && _pending_area == old_area) return; // no change + + bool is_integer_translation = is_identity; + if (!is_identity && _pending_transform.isTranslation()) { + Geom::IntPoint t = _pending_transform.translation().round(); + if (Geom::are_near(Geom::Point(t), _pending_transform.translation())) { + is_integer_translation = true; + cairo_region_translate(_clean_region, t.x(), t.y()); + if (old_area + t == _pending_area) { + // if the areas match, the only thing to do + // is to ensure that the clean area is not too large + // we can exit early + auto const limit = geom_to_cairo(_pending_area); + cairo_region_intersect_rectangle(_clean_region, &limit); + _origin += t; + _pending_transform.setIdentity(); + return; + } + } + } + + // the area has changed, so the cache content needs to be copied + Geom::IntPoint old_origin = old_area.min(); + cairo_surface_t *old_surface = _surface; + _surface = nullptr; + _pixels = _pending_area.dimensions(); + _origin = _pending_area.min(); + + if (is_integer_translation) { + // transform the cache only for integer translations and identities + cairo_t *ct = createRawContext(); + if (!is_identity) { + ink_cairo_transform(ct, _pending_transform); + } + cairo_set_source_surface(ct, old_surface, old_origin.x(), old_origin.y()); + cairo_set_operator(ct, CAIRO_OPERATOR_SOURCE); + cairo_pattern_set_filter(cairo_get_source(ct), CAIRO_FILTER_NEAREST); + cairo_paint(ct); + cairo_destroy(ct); + + auto const limit = geom_to_cairo(_pending_area); + cairo_region_intersect_rectangle(_clean_region, &limit); + } else { + // dirty everything + cairo_region_destroy(_clean_region); + _clean_region = cairo_region_create(); + } + + //std::cout << _pending_transform << old_area << _pending_area << std::endl; + cairo_surface_destroy(old_surface); + _pending_transform.setIdentity(); +} + +/** + * Paints the clean area from cache and modifies the @a area + * parameter to the bounds of the region that must be repainted. + */ +void DrawingCache::paintFromCache(DrawingContext &dc, Geom::OptIntRect &area, bool is_filter) +{ + if (!area) return; + + // We subtract the clean region from the area, then get the bounds + // of the resulting region. This is the area that needs to be repainted + // by the item. + // Then we subtract the area that needs to be repainted from the + // original area and paint the resulting region from cache. + auto const area_c = geom_to_cairo(*area); + cairo_region_t *dirty_region = cairo_region_create_rectangle(&area_c); + cairo_region_t *cache_region = cairo_region_copy(dirty_region); + cairo_region_subtract(dirty_region, _clean_region); + + if (is_filter && !cairo_region_is_empty(dirty_region)) { // To allow fast panning on high zoom on filters + cairo_region_destroy(cache_region); + cairo_region_destroy(dirty_region); + cairo_region_destroy(_clean_region); + _clean_region = cairo_region_create(); + return; + } + + if (cairo_region_is_empty(dirty_region)) { + area = Geom::OptIntRect(); + } else { + cairo_rectangle_int_t to_repaint; + cairo_region_get_extents(dirty_region, &to_repaint); + area = cairo_to_geom(to_repaint); + cairo_region_subtract_rectangle(cache_region, &to_repaint); + } + cairo_region_destroy(dirty_region); + + if (!cairo_region_is_empty(cache_region)) { + int nr = cairo_region_num_rectangles(cache_region); + for (int i = 0; i < nr; ++i) { + cairo_rectangle_int_t tmp; + cairo_region_get_rectangle(cache_region, i, &tmp); + dc.rectangle(cairo_to_geom(tmp)); + } + dc.setSource(this); + dc.fill(); + } + cairo_region_destroy(cache_region); +} + +// debugging utility +void DrawingCache::_dumpCache(Geom::OptIntRect const &area) +{ + static int dumpnr = 0; + cairo_surface_t *surface = ink_cairo_surface_copy(_surface); + DrawingContext dc(surface, _origin); + if (!cairo_region_is_empty(_clean_region)) { + Inkscape::DrawingContext::Save save(dc); + int nr = cairo_region_num_rectangles(_clean_region); + cairo_rectangle_int_t tmp; + for (int i = 0; i < nr; ++i) { + cairo_region_get_rectangle(_clean_region, i, &tmp); + dc.rectangle(cairo_to_geom(tmp)); + } + dc.setSource(0,1,0,0.1); + dc.fill(); + } + dc.rectangle(*area); + dc.setSource(1,0,0,0.1); + dc.fill(); + char *fn = g_strdup_printf("dump%d.png", dumpnr++); + cairo_surface_write_to_png(surface, fn); + cairo_surface_destroy(surface); + g_free(fn); +} + +} // namespace Inkscape + +/* + Local Variables: + mode:c++ + c-file-style:"stroustrup" + c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) + indent-tabs-mode:nil + fill-column:99 + End: +*/ +// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 : |