[gnome-shell] st-image-content: Wrap ClutterImage with explicit preferred size

[Jonas Ådahl <jadahl src gnome org>]

commit 0464361ca5470645995e3aeb9a113ac1d50e4b9f
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Wed Feb 27 00:23:40 2019 +0100

    st-image-content: Wrap ClutterImage with explicit preferred size
    
    Create StImageContent as a simple ClutterImage with preferred width/height
    properties in order to be able to use explicit sizing when creating clutter
    contents that will be applied to actors whose size depends on the content itself.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/5

 src/st/meson.build        |   2 +
 src/st/st-image-content.c | 191 ++++++++++++++++++++++++++++++++++++++++++++++
 src/st/st-image-content.h |  33 ++++++++
 3 files changed, 226 insertions(+)
---
diff --git a/src/st/meson.build b/src/st/meson.build
index 21756eb07..118d0fda0 100644
--- a/src/st/meson.build
+++ b/src/st/meson.build
@@ -12,6 +12,7 @@ st_headers = [
   'st-generic-accessible.h',
   'st-icon.h',
   'st-icon-colors.h',
+  'st-image-content.h',
   'st-label.h',
   'st-private.h',
   'st-scrollable.h',
@@ -66,6 +67,7 @@ st_sources = [
   'st-generic-accessible.c',
   'st-icon.c',
   'st-icon-colors.c',
+  'st-image-content.c',
   'st-label.c',
   'st-private.c',
   'st-scrollable.c',
diff --git a/src/st/st-image-content.c b/src/st/st-image-content.c
new file mode 100644
index 000000000..6195fdc8f
--- /dev/null
+++ b/src/st/st-image-content.c
@@ -0,0 +1,191 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/*
+ * st-image-content.h: A content image with scaling support
+ *
+ * Copyright 2019 Canonical, Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation, either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * 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-image-content.h"
+
+struct _StImageContent
+{
+  /*< private >*/
+  ClutterImage parent_instance;
+};
+
+typedef struct _StImageContentPrivate StImageContentPrivate;
+struct _StImageContentPrivate
+{
+  int width;
+  int height;
+};
+
+enum
+{
+  PROP_0,
+  PROP_PREFERRED_WIDTH,
+  PROP_PREFERRED_HEIGHT,
+};
+
+static void clutter_content_interface_init (ClutterContentInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (StImageContent, st_image_content, CLUTTER_TYPE_IMAGE,
+                         G_ADD_PRIVATE (StImageContent)
+                         G_IMPLEMENT_INTERFACE (CLUTTER_TYPE_CONTENT,
+                                                clutter_content_interface_init))
+
+static void
+st_image_content_init (StImageContent *self)
+{
+}
+
+static void
+st_image_content_constructed (GObject *object)
+{
+  StImageContent *self = ST_IMAGE_CONTENT (object);
+  StImageContentPrivate *priv = st_image_content_get_instance_private (self);
+
+  if (priv->width < 0 || priv->height < 0)
+    g_warning ("StImageContent initialized with invalid preferred size: %dx%d\n",
+               priv->width, priv->height);
+}
+
+static void
+st_image_content_get_property (GObject    *object,
+                               guint       prop_id,
+                               GValue     *value,
+                               GParamSpec *pspec)
+{
+  StImageContent *self = ST_IMAGE_CONTENT (object);
+  StImageContentPrivate *priv = st_image_content_get_instance_private (self);
+
+  switch (prop_id)
+    {
+    case PROP_PREFERRED_WIDTH:
+      g_value_set_int (value, priv->width);
+      break;
+
+    case PROP_PREFERRED_HEIGHT:
+      g_value_set_int (value, priv->height);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+st_image_content_set_property (GObject      *object,
+                               guint         prop_id,
+                               const GValue *value,
+                               GParamSpec   *pspec)
+{
+  StImageContent *self = ST_IMAGE_CONTENT (object);
+  StImageContentPrivate *priv = st_image_content_get_instance_private (self);
+
+  switch (prop_id)
+    {
+    case PROP_PREFERRED_WIDTH:
+      priv->width = g_value_get_int (value);
+      break;
+
+    case PROP_PREFERRED_HEIGHT:
+      priv->height = g_value_get_int (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+st_image_content_class_init (StImageContentClass *klass)
+{
+  GParamSpec *pspec;
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->constructed = st_image_content_constructed;
+  object_class->get_property = st_image_content_get_property;
+  object_class->set_property = st_image_content_set_property;
+
+  pspec = g_param_spec_int ("preferred-width",
+                            "Preferred Width",
+                            "Preferred Width of the Content when painted",
+                             -1, G_MAXINT, -1,
+                             G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
+  g_object_class_install_property (object_class, PROP_PREFERRED_WIDTH, pspec);
+
+  pspec = g_param_spec_int ("preferred-height",
+                            "Preferred Height",
+                            "Preferred Height of the Content when painted",
+                             -1, G_MAXINT, -1,
+                             G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
+  g_object_class_install_property (object_class, PROP_PREFERRED_HEIGHT, pspec);
+}
+
+static gboolean
+st_image_content_get_preferred_size (ClutterContent *content,
+                                     float          *width,
+                                     float          *height)
+{
+  StImageContent *self = ST_IMAGE_CONTENT (content);
+  StImageContentPrivate *priv = st_image_content_get_instance_private (self);
+  ClutterTexture *texture;
+
+  texture = clutter_image_get_texture (CLUTTER_IMAGE (content));
+
+  if (texture == NULL)
+    return FALSE;
+
+  g_assert_cmpint (priv->width, >, -1);
+  g_assert_cmpint (priv->height, >, -1);
+
+  if (width != NULL)
+    *width = (float) priv->width;
+
+  if (height != NULL)
+    *height = (float) priv->height;
+
+  return TRUE;
+}
+
+static void
+clutter_content_interface_init (ClutterContentInterface *iface)
+{
+  iface->get_preferred_size = st_image_content_get_preferred_size;
+}
+
+/**
+ * st_image_content_new_with_preferred_size:
+ * @width: The preferred width to be used when drawing the content
+ * @height: The preferred width to be used when drawing the content
+ *
+ * Creates a new #StImageContent, a simple content for sized images.
+ *
+ * Return value: (transfer full): the newly created #StImageContent content
+ *   Use g_object_unref() when done.
+ */
+ClutterContent *
+st_image_content_new_with_preferred_size (int width,
+                                          int height)
+{
+  return g_object_new (ST_TYPE_IMAGE_CONTENT,
+                       "preferred-width", width,
+                       "preferred-height", height,
+                       NULL);
+}
diff --git a/src/st/st-image-content.h b/src/st/st-image-content.h
new file mode 100644
index 000000000..0ebb0b74f
--- /dev/null
+++ b/src/st/st-image-content.h
@@ -0,0 +1,33 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/*
+ * st-image-content.h: A content image with scaling support
+ *
+ * Copyright 2019 Canonical, Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation, either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * 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/>.
+ */
+
+#ifndef __ST_IMAGE_CONTENT_H__
+#define __ST_IMAGE_CONTENT_H__
+
+#include <clutter/clutter.h>
+
+#define ST_TYPE_IMAGE_CONTENT (st_image_content_get_type ())
+G_DECLARE_FINAL_TYPE (StImageContent, st_image_content,
+                      ST, IMAGE_CONTENT, ClutterImage)
+
+ClutterContent *st_image_content_new_with_preferred_size (int width,
+                                                          int height);
+
+#endif /* __ST_IMAGE_CONTENT_H__ */