1 files changed, 173 insertions, 0 deletions
diff --git a/src/ui/cache/svg_preview_cache.cpp b/src/ui/cache/svg_preview_cache.cpp
new file mode 100644
index 0000000..10bf3cf
--- /dev/null
+++ b/src/ui/cache/svg_preview_cache.cpp
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/** \file
+ * SVGPreview: Preview cache
+ */
+/*
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   Bryce Harrington <brycehar@bryceharrington.org>
+ *   bulia byak <buliabyak@users.sf.net>
+ *
+ * Copyright (C) 2001-2005 authors
+ * Copyright (C) 2001 Ximian, Inc.
+ * Copyright (C) 2004 John Cliff
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ *
+ */
+
+#include <gtk/gtk.h>
+
+#include <2geom/transforms.h>
+
+#include "selection.h"
+#include "inkscape.h"
+
+#include "display/cairo-utils.h"
+#include "display/drawing-context.h"
+#include "display/drawing-item.h"
+#include "display/drawing.h"
+
+
+#include "ui/cache/svg_preview_cache.h"
+
+cairo_surface_t* render_surface(Inkscape::Drawing &drawing, double scale_factor, Geom::Rect const &dbox,
+    Geom::IntPoint pixsize, double device_scale, const guint32* checkerboard_color, bool no_clip)
+{
+    scale_factor *= device_scale;
+    pixsize.x() *= device_scale;
+    pixsize.y() *= device_scale;
+
+    Geom::IntRect ibox = (dbox * Geom::Scale(scale_factor)).roundOutwards();
+
+    if (no_clip) {
+        // check if object fits in the surface
+        if (ibox.width() > pixsize.x() || ibox.height() > pixsize.y()) {
+            auto sx = static_cast<double>(ibox.width()) / pixsize.x();
+            auto sy = static_cast<double>(ibox.height()) / pixsize.y();
+            // reduce scale
+            scale_factor /= std::max(sx, sy);
+            ibox = (dbox * Geom::Scale(scale_factor)).roundOutwards();
+        }
+    }
+
+    drawing.root()->setTransform(Geom::Scale(scale_factor));
+
+    drawing.update(ibox);
+
+    /* Find visible area */
+    int width = ibox.width();
+    int height = ibox.height();
+    int dx = pixsize.x();
+    int dy = pixsize.y();
+    dx = (dx - width)/2; // watch out for size, since 'unsigned'-'signed' can cause problems if the result is negative
+    dy = (dy - height)/2;
+
+    Geom::IntRect area = Geom::IntRect::from_xywh(ibox.min() - Geom::IntPoint(dx, dy), pixsize);
+
+    /* Render */
+    cairo_surface_t *s = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, pixsize.x(), pixsize.y());
+    Inkscape::DrawingContext dc(s, area.min());
+
+    if (checkerboard_color) {
+        guint rgba = *checkerboard_color;
+        auto pattern = ink_cairo_pattern_create_checkerboard(rgba);
+        dc.save();
+        dc.transform(Geom::Scale(device_scale));
+        dc.setOperator(CAIRO_OPERATOR_SOURCE);
+        dc.setSource(pattern);
+        dc.paint();
+        dc.restore();
+        cairo_pattern_destroy(pattern);
+    }
+
+    drawing.render(dc, area, Inkscape::DrawingItem::RENDER_BYPASS_CACHE);
+    cairo_surface_flush(s);
+
+    return s;
+}
+
+GdkPixbuf* render_pixbuf(Inkscape::Drawing &drawing, double scale_factor, Geom::Rect const &dbox, unsigned psize) {
+    auto s = render_surface(drawing, scale_factor, dbox, Geom::IntPoint(psize, psize), 1, nullptr, true);
+    GdkPixbuf* pixbuf = ink_pixbuf_create_from_cairo_surface(s);
+    return pixbuf;
+}
+
+namespace Inkscape {
+namespace UI {
+namespace Cache {
+
+SvgPreview::SvgPreview()
+= default;
+
+SvgPreview::~SvgPreview()
+{
+    for (auto & i : _pixmap_cache)
+    {
+        g_object_unref(i.second);
+        i.second = NULL;
+    }
+}
+
+Glib::ustring SvgPreview::cache_key(gchar const *uri, gchar const *name, unsigned psize) const {
+    Glib::ustring key;
+    key += (uri!=nullptr)  ? uri  : "";
+    key += ":";
+    key += (name!=nullptr) ? name : "unknown";
+    key += ":";
+    key += psize;
+    return key;
+}
+
+GdkPixbuf* SvgPreview::get_preview_from_cache(const Glib::ustring& key) {
+    std::map<Glib::ustring, GdkPixbuf *>::iterator found = _pixmap_cache.find(key);
+    if ( found != _pixmap_cache.end() ) {
+        return found->second;
+    }
+    return nullptr;
+}
+
+void SvgPreview::set_preview_in_cache(const Glib::ustring& key, GdkPixbuf* px) {
+    g_object_ref(px);
+    _pixmap_cache[key] = px;
+}
+
+GdkPixbuf* SvgPreview::get_preview(const gchar* uri, const gchar* id, Inkscape::DrawingItem */*root*/,
+                                   double /*scale_factor*/, unsigned int psize) {
+    // First try looking up the cached preview in the cache map
+    Glib::ustring key = cache_key(uri, id, psize);
+    GdkPixbuf* px = get_preview_from_cache(key);
+
+    if (px == nullptr) {
+        /*
+            px = render_pixbuf(root, scale_factor, dbox, psize);
+            set_preview_in_cache(key, px);
+        */
+    }
+    return px;
+}
+
+void SvgPreview::remove_preview_from_cache(const Glib::ustring& key) {
+    std::map<Glib::ustring, GdkPixbuf *>::iterator found = _pixmap_cache.find(key);
+    if ( found != _pixmap_cache.end() ) {
+        g_object_unref(found->second);
+        found->second = NULL;
+        _pixmap_cache.erase(key);
+    }
+}
+
+
+}
+}
+}
+
+/*
+  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 :