Adding upstream version 43.9.upstream/43.9upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 196 insertions, 0 deletions

diff --git a/src/st/st-scrollable.c b/src/st/st-scrollable.c
new file mode 100644
index 0000000..3a77052
--- /dev/null
+++ b/src/st/st-scrollable.c
@@ -0,0 +1,196 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/*
+ * st-scrollable.c: Scrollable interface
+ *
+ * Copyright 2008 OpenedHand
+ * Copyright 2009 Intel Corporation.
+ * Copyright 2010 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU Lesser General Public License,
+ * version 2.1, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "st-private.h"
+#include "st-scrollable.h"
+
+G_DEFINE_INTERFACE (StScrollable, st_scrollable, G_TYPE_OBJECT)
+
+/**
+ * SECTION:st-scrollable
+ * @short_description: A #ClutterActor that can be scrolled
+ *
+ * The #StScrollable interface is exposed by actors that support scrolling.
+ *
+ * The interface contains methods for getting and setting the adjustments
+ * for scrolling; these adjustments will be used to hook the scrolled
+ * position up to scrollbars or other external controls. When a #StScrollable
+ * is added to a parent container, the parent container is responsible
+ * for setting the adjustments. The parent container then sets the adjustments
+ * back to %NULL when the scrollable is removed.
+ *
+ * For #StScrollable supporting height-for-width size negotiation, size
+ * negotiation works as follows:
+ *
+ * In response to get_preferred_width(), the scrollable should report
+ * the minimum width at which horizontal scrolling is needed for the
+ * preferred width, and natural width of the actor when not
+ * horizontally scrolled as the natural width.
+ *
+ * The for_width passed into get_preferred_height() is the width at which
+ * the scrollable will be allocated; this will be smaller than the minimum
+ * width when scrolling horizontally, so the scrollable may want to adjust
+ * it up to the minimum width before computing a preferred height. (Other
+ * scrollables may want to fit as much content into the allocated area
+ * as possible and only scroll what absolutely needs to scroll - consider,
+ * for example, the line-wrapping behavior of a text editor where there
+ * is a long line without any spaces.) As for width, get_preferred_height()
+ * should return the minimum size at which no scrolling is needed for the
+ * minimum height, and the natural size of the actor when not vertically scrolled
+ * as the natural height.
+ *
+ * In allocate() the allocation box passed in will be actual allocated
+ * size of the actor so will be smaller than the reported minimum
+ * width and/or height when scrolling is present. Any scrollable actor
+ * must support being allocated at any size down to 0x0 without
+ * crashing, however if the actor has content around the scrolled area
+ * and has an absolute minimum size that's bigger than 0x0 its
+ * acceptable for it to misdraw between 0x0 and the absolute minimum
+ * size. It's up to the application author to avoid letting the user
+ * resize the scroll view small enough so that the scrolled area
+ * vanishes.
+ *
+ * In response to allocate, in addition to normal handling, the
+ * scrollable should also set the limits of the the horizontal and
+ * vertical adjustments that were set on it earlier. The standard
+ * settings are:
+ *
+ *  lower: 0
+ *  page_size: allocated size (width or height)
+ *  upper: MAX (total size of the scrolled area,allocated_size)
+ *  step_increment: natural row/column height or a fixed fraction of the page size
+ *  page_increment: page_size - step_increment
+ */
+static void
+st_scrollable_default_init (StScrollableInterface *g_iface)
+{
+  static gboolean initialized = FALSE;
+
+  if (!initialized)
+    {
+      /**
+       * StScrollable:hadjustment:
+       *
+       * The horizontal #StAdjustment used by the #StScrollable.
+       *
+       * Implementations should override this property to provide read-write
+       * access to the #StAdjustment.
+       *
+       * JavaScript code may override this as demonstrated below:
+       *
+       * |[<!-- language="JavaScript" -->
+       * var MyScrollable = GObject.registerClass({
+       *     Properties: {
+       *         'hadjustment': GObject.ParamSpec.override(
+       *             'hadjustment',
+       *             St.Scrollable
+       *         )
+       *     }
+       * }, class MyScrollable extends St.Scrollable {
+       *
+       *     get hadjustment() {
+       *         return this._hadjustment || null;
+       *     }
+       *
+       *     set hadjustment(adjustment) {
+       *         if (this.hadjustment === adjustment)
+       *             return;
+       *
+       *         this._hadjustment = adjustment;
+       *         this.notify('hadjustment');
+       *     }
+       * });
+       * ]|
+       */
+      g_object_interface_install_property (g_iface,
+                                           g_param_spec_object ("hadjustment",
+                                                                "StAdjustment",
+                                                                "Horizontal adjustment",
+                                                                ST_TYPE_ADJUSTMENT,
+                                                                ST_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY));
+
+      /**
+       * StScrollable:vadjustment:
+       *
+       * The vertical #StAdjustment used by the #StScrollable.
+       *
+       * Implementations should override this property to provide read-write
+       * access to the #StAdjustment.
+       *
+       * See #StScrollable:hadjustment for an example of how to override this
+       * property in JavaScript code.
+       */
+      g_object_interface_install_property (g_iface,
+                                           g_param_spec_object ("vadjustment",
+                                                                "StAdjustment",
+                                                                "Vertical adjustment",
+                                                                ST_TYPE_ADJUSTMENT,
+                                                                ST_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY));
+
+      initialized = TRUE;
+    }
+}
+
+/**
+ * st_scrollable_set_adjustments:
+ * @scrollable: a #StScrollable
+ * @hadjustment: the horizontal #StAdjustment
+ * @vadjustment: the vertical #StAdjustment
+ *
+ * This method should be implemented by classes implementing the #StScrollable
+ * interface.
+ *
+ * JavaScript code should do this by overriding the `vfunc_set_adjustments()`
+ * method.
+ */
+void
+st_scrollable_set_adjustments (StScrollable *scrollable,
+                               StAdjustment *hadjustment,
+                               StAdjustment *vadjustment)
+{
+  ST_SCROLLABLE_GET_IFACE (scrollable)->set_adjustments (scrollable,
+                                                         hadjustment,
+                                                         vadjustment);
+}
+
+/**
+ * st_scroll_bar_get_adjustments:
+ * @hadjustment: (transfer none) (out) (optional): location to store the horizontal adjustment, or %NULL
+ * @vadjustment: (transfer none) (out) (optional): location to store the vertical adjustment, or %NULL
+ *
+ * Gets the adjustment objects that store the offsets of the scrollable widget
+ * into its possible scrolling area.
+ *
+ * This method should be implemented by classes implementing the #StScrollable
+ * interface.
+ *
+ * JavaScript code should do this by overriding the `vfunc_get_adjustments()`
+ * method.
+ */
+void
+st_scrollable_get_adjustments (StScrollable  *scrollable,
+                               StAdjustment **hadjustment,
+                               StAdjustment **vadjustment)
+{
+  ST_SCROLLABLE_GET_IFACE (scrollable)->get_adjustments (scrollable,
+                                                         hadjustment,
+                                                         vadjustment);
+}