Add as_image_save_filename()

2 files changed, 109 insertions, 0 deletions

diff --git a/libappstream-glib/as-image.c b/libappstream-glib/as-image.c
index 3642e8f..4ddcdbd 100644
--- a/libappstream-glib/as-image.c
+++ b/libappstream-glib/as-image.c
@@ -372,6 +372,93 @@ as_image_node_parse (AsImage *image, GNode *node, GError **error)
 }
 
 /**
+ * as_image_save_filename:
+ * @image: a #AsImage instance.
+ * @filename: filename to write to
+ * @width: target width, or 0 for default
+ * @height: target height, or 0 for default
+ * @flags: some #AsImageSaveFlags values, e.g. %AS_IMAGE_SAVE_FLAG_PAD_16_9
+ * @error: A #GError or %NULL.
+ *
+ * Saves a pixbuf to a file.
+ *
+ * Returns: %TRUE for success
+ *
+ * Since: 0.1.6
+ **/
+gboolean
+as_image_save_filename (AsImage *image,
+		        const gchar *filename,
+		        guint width,
+		        guint height,
+		        AsImageSaveFlags flags,
+		        GError **error)
+{
+	AsImagePrivate *priv = GET_PRIVATE (image);
+	GdkPixbuf *pixbuf = NULL;
+	GdkPixbuf *pixbuf_tmp = NULL;
+	gboolean ret;
+	guint tmp_height;
+	guint tmp_width;
+	guint pixbuf_height;
+	guint pixbuf_width;
+
+	/* 0 means 'default' */
+	if (width == 0)
+		width = gdk_pixbuf_get_width (priv->pixbuf);
+	if (height == 0)
+		height = gdk_pixbuf_get_height (priv->pixbuf);
+
+	/* is the aspect ratio of the source perfectly 16:9 */
+	pixbuf_width = gdk_pixbuf_get_width (priv->pixbuf);
+	pixbuf_height = gdk_pixbuf_get_height (priv->pixbuf);
+	if (flags == AS_IMAGE_SAVE_FLAG_NONE ||
+	    (pixbuf_width / 16) * 9 == pixbuf_height) {
+		pixbuf = gdk_pixbuf_scale_simple (priv->pixbuf,
+						  width, height,
+						  GDK_INTERP_BILINEAR);
+	} else {
+		/* create new 16:9 pixbuf with alpha padding */
+		pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB,
+					 TRUE, 8,
+					 width,
+					 height);
+		gdk_pixbuf_fill (pixbuf, 0x00000000);
+		if ((pixbuf_width / 16) * 9 > pixbuf_height) {
+			tmp_width = width;
+			tmp_height = width * pixbuf_height / pixbuf_width;
+		} else {
+			tmp_width = height * pixbuf_width / pixbuf_height;
+			tmp_height = height;
+		}
+		pixbuf_tmp = gdk_pixbuf_scale_simple (priv->pixbuf,
+						      tmp_width, tmp_height,
+						      GDK_INTERP_BILINEAR);
+		gdk_pixbuf_copy_area (pixbuf_tmp,
+				      0, 0, /* of src */
+				      tmp_width, tmp_height,
+				      pixbuf,
+				      (width - tmp_width) / 2,
+				      (height - tmp_height) / 2);
+	}
+
+	/* save source file */
+	ret = gdk_pixbuf_save (pixbuf,
+			       filename,
+			       "png",
+			       error,
+			       NULL);
+	if (!ret)
+		goto out;
+out:
+	if (pixbuf != NULL)
+		g_object_unref (pixbuf);
+	if (pixbuf_tmp != NULL)
+		g_object_unref (pixbuf_tmp);
+	return ret;
+}
+
+/**
  * as_image_new:
  *
  * Creates a new #AsImage.
diff --git a/libappstream-glib/as-image.h b/libappstream-glib/as-image.h
index 4d82f87..ecca9f3 100644
--- a/libappstream-glib/as-image.h
+++ b/libappstream-glib/as-image.h
@@ -76,6 +76,20 @@ typedef enum {
 	AS_IMAGE_KIND_LAST
 } AsImageKind;
 
+/**
+ * AsImageSaveFlag:
+ * @AS_IMAGE_SAVE_FLAG_NONE:		No special flags set
+ * @AS_IMAGE_SAVE_FLAG_PAD_16_9:	Pad with alpha to 16:9 aspect
+ *
+ * The flags used for saving images.
+ **/
+typedef enum {
+	AS_IMAGE_SAVE_FLAG_NONE		= 0,	/* Since: 0.1.6 */
+	AS_IMAGE_SAVE_FLAG_PAD_16_9	= 1,	/* Since: 0.1.6 */
+	/*< private >*/
+	AS_IMAGE_SAVE_FLAG_LAST
+} AsImageSaveFlags;
+
 GType		 as_image_get_type		(void);
 AsImage		*as_image_new			(void);
 
@@ -103,6 +117,14 @@ void		 as_image_set_kind		(AsImage	*image,
 void		 as_image_set_pixbuf		(AsImage	*image,
 						 GdkPixbuf	*pixbuf);
 
+/* object methods */
+gboolean	 as_image_save_filename		(AsImage	*image,
+						 const gchar	*filename,
+						 guint		 width,
+						 guint		 height,
+						 AsImageSaveFlags flags,
+						 GError		**error);
+
 G_END_DECLS
 
 #endif /* __AS_IMAGE_H */