Merge https://gitlab.com/inkscape/inkscape into selectable-knots

2 files changed, 72 insertions, 16 deletions

diff --git a/src/display/sp-canvas.cpp b/src/display/sp-canvas.cpp
index d04c81ecb..8857b8c68 100644
--- a/src/display/sp-canvas.cpp
+++ b/src/display/sp-canvas.cpp
@@ -966,6 +966,9 @@ static void sp_canvas_init(SPCanvas *canvas)
     canvas->_drawing_disabled = false;
 
     canvas->_backing_store = NULL;
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
+    canvas->_surface_for_similar = NULL;
+#endif
     canvas->_clean_region = cairo_region_create();
     canvas->_background = cairo_pattern_create_rgb(1, 1, 1);
     canvas->_background_is_checkerboard = false;
@@ -1003,6 +1006,12 @@ void SPCanvas::dispose(GObject *object)
         cairo_surface_destroy(canvas->_backing_store);
         canvas->_backing_store = NULL;
     }
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
+    if (canvas->_surface_for_similar) {
+        cairo_surface_destroy(canvas->_surface_for_similar);
+        canvas->_surface_for_similar = NULL;
+    }
+#endif
     if (canvas->_clean_region) {
         cairo_region_destroy(canvas->_clean_region);
         canvas->_clean_region = NULL;
@@ -1125,8 +1134,14 @@ void SPCanvas::handle_size_allocate(GtkWidget *widget, GtkAllocation *allocation
         allocation->width, allocation->height);
 
     // resize backing store
-    cairo_surface_t *new_backing_store = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
-        allocation->width, allocation->height);
+    cairo_surface_t *new_backing_store = NULL;
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
+    if (canvas->_surface_for_similar != NULL)
+        new_backing_store = cairo_surface_create_similar_image(canvas->_surface_for_similar,
+                CAIRO_FORMAT_ARGB32, allocation->width, allocation->height);
+#endif
+    if (new_backing_store == NULL)
+        new_backing_store = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, allocation->width, allocation->height);
     if (canvas->_backing_store) {
         cairo_t *cr = cairo_create(new_backing_store);
         cairo_translate(cr, -canvas->_x0, -canvas->_y0);
@@ -1510,8 +1525,23 @@ void SPCanvas::paintSingleBuffer(Geom::IntRect const &paint_rect, Geom::IntRect
     buf.canvas_rect = canvas_rect;
     buf.is_empty = true;
 
-    // create temporary surface
-    cairo_surface_t *imgs = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, paint_rect.width(), paint_rect.height());
+    // Make sure the following code does not go outside of _backing_store's data
+    assert(cairo_image_surface_get_format(_backing_store) == CAIRO_FORMAT_ARGB32);
+    assert(paint_rect.left() - _x0 >= 0);
+    assert(paint_rect.top() - _y0 >= 0);
+    assert(paint_rect.right() - _x0 <= cairo_image_surface_get_width(_backing_store));
+    assert(paint_rect.bottom() - _y0 <= cairo_image_surface_get_height(_backing_store));
+
+    // Create a temporary surface that draws directly to _backing_store
+    cairo_surface_flush(_backing_store);
+    unsigned char *data = cairo_image_surface_get_data(_backing_store);
+    int stride = cairo_image_surface_get_stride(_backing_store);
+    // Move to the right row
+    data += stride * (paint_rect.top() - _y0);
+    // Move to the right pixel inside of that row
+    data += 4 * (paint_rect.left() - _x0);
+    cairo_surface_t *imgs = cairo_image_surface_create_for_data(data, CAIRO_FORMAT_ARGB32,
+            paint_rect.width(), paint_rect.height(), stride);
     buf.ct = cairo_create(imgs);
 
     cairo_save(buf.ct);
@@ -1552,16 +1582,7 @@ void SPCanvas::paintSingleBuffer(Geom::IntRect const &paint_rect, Geom::IntRect
     }
 #endif // defined(HAVE_LIBLCMS1) || defined(HAVE_LIBLCMS2)
 
-    //cairo_t *xct = gdk_cairo_create(gtk_widget_get_window (widget));
-    cairo_t *xct = cairo_create(_backing_store);
-    cairo_translate(xct, paint_rect.left() - _x0, paint_rect.top() - _y0);
-    cairo_rectangle(xct, 0, 0, paint_rect.width(), paint_rect.height());
-    cairo_clip(xct);
-    cairo_set_source_surface(xct, imgs, 0, 0);
-    cairo_set_operator(xct, CAIRO_OPERATOR_SOURCE);
-    cairo_paint(xct);
-    cairo_destroy(xct);
-    cairo_surface_destroy(imgs);
+    cairo_surface_mark_dirty(_backing_store);
 
     // Mark the painted rectangle clean
     markRect(paint_rect, 0);
@@ -1764,6 +1785,28 @@ void SPCanvas::endForcedFullRedraws()
 gboolean SPCanvas::handle_draw(GtkWidget *widget, cairo_t *cr) {
     SPCanvas *canvas = SP_CANVAS(widget);
 
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
+    if (canvas->_surface_for_similar == NULL && canvas->_backing_store != NULL) {
+        canvas->_surface_for_similar = cairo_surface_create_similar(
+                cairo_get_target(cr), CAIRO_CONTENT_COLOR_ALPHA, 1, 1);
+
+        // Reallocate backing store so that cairo can use shared memory
+        cairo_surface_t *new_backing_store = cairo_surface_create_similar_image(
+                canvas->_surface_for_similar, CAIRO_FORMAT_ARGB32,
+                cairo_image_surface_get_width(canvas->_backing_store),
+                cairo_image_surface_get_height(canvas->_backing_store));
+
+        // Copy the old backing store contents
+        cairo_t *cr = cairo_create(new_backing_store);
+        cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
+        cairo_set_source_surface(cr, canvas->_backing_store, 0, 0);
+        cairo_paint(cr);
+        cairo_destroy(cr);
+        cairo_surface_destroy(canvas->_backing_store);
+        canvas->_backing_store = new_backing_store;
+    }
+#endif
+
     // Blit from the backing store, without regard for the clean region.
     // This is necessary because GTK clears the widget for us, which causes
     // severe flicker while drawing if we don't blit the old contents.
@@ -1853,6 +1896,7 @@ int SPCanvas::paint()
         cairo_region_get_rectangle(to_draw, i, &crect);
         if (!paintRect(crect.x, crect.y, crect.x + crect.width, crect.y + crect.height)) {
             // Aborted
+            cairo_region_destroy(to_draw);
             return FALSE;
         };
     }
@@ -1862,6 +1906,8 @@ int SPCanvas::paint()
         _forced_redraw_count = 0;
     }
 
+    cairo_region_destroy(to_draw);
+
     return TRUE;
 }
 
@@ -1946,8 +1992,14 @@ void SPCanvas::scrollTo( Geom::Point const &c, unsigned int clear, bool is_scrol
 
     // adjust backing store contents
     assert(_backing_store);
-    cairo_surface_t *new_backing_store = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
-        allocation.width, allocation.height);
+    cairo_surface_t *new_backing_store = NULL;
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
+    if (_surface_for_similar != NULL)
+        new_backing_store = cairo_surface_create_similar_image(
+                _surface_for_similar, CAIRO_FORMAT_ARGB32, allocation.width, allocation.height);
+#endif
+    if (new_backing_store == NULL)
+        new_backing_store = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, allocation.width, allocation.height);
     cairo_t *cr = cairo_create(new_backing_store);
     cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
     // Paint the background
diff --git a/src/display/sp-canvas.h b/src/display/sp-canvas.h
index a2cbe0b27..92a50da11 100644
--- a/src/display/sp-canvas.h
+++ b/src/display/sp-canvas.h
@@ -179,6 +179,10 @@ public:
 
     /// Image surface storing the contents of the widget
     cairo_surface_t *_backing_store;
+#if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1, 12, 0)
+    /// This should be e.g. a cairo-xlib surface that is used to allocate _backing_store; might be NULL.
+    cairo_surface_t *_surface_for_similar;
+#endif
     /// Area of the widget that has up-to-date content
     cairo_region_t *_clean_region;
     /// Widget background, defaults to white