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diff --git a/image/image_cache.h b/image/image_cache.h
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+/*
+ * Copyright 2011 John-Mark Bell <jmb@netsurf-browser.org>
+ *
+ * This file is part of NetSurf, http://www.netsurf-browser.org/
+ *
+ * NetSurf is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * NetSurf is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** \file
+ * The image content handler intermediate image cache.
+ *
+ * This cache allows netsurf to use a generic intermediate bitmap
+ * format without keeping the
+ * intermediate representation in memory.
+ *
+ * The bitmap structure is opaque to the rest of netsurf and is
+ * controlled by the platform-specific code (see image/bitmap.h for
+ * detials). All image content handlers convert into this format and
+ * pass it to the plot functions for display,
+ * 
+ * This cache maintains a link between the underlying original content
+ * and the intermediate representation. It is intended to be flexable
+ * and either manage the bitmap plotting completely or give the image
+ * content handler complete control.
+ */
+
+#ifndef NETSURF_IMAGE_IMAGE_CACHE_H_
+#define NETSURF_IMAGE_IMAGE_CACHE_H_
+
+#include "utils/errors.h"
+#include "desktop/plotters.h"
+#include "image/bitmap.h"
+
+typedef struct bitmap * (image_cache_convert_fn) (struct content *content);
+
+/** Initialise the image cache */
+nserror image_cache_init(void);
+nserror image_cache_fini(void);
+
+/** adds an image content to be cached. 
+ * 
+ * @param content The content handle used as a key
+ * @param bitmap A bitmap representing the already converted content or NULL.
+ * @param convert A function pointer to convert the content into a bitmap or NULL.
+ * @return A netsurf error code.
+ */
+nserror image_cache_add(struct content *content, 
+			struct bitmap *bitmap, 
+			image_cache_convert_fn *convert);
+
+nserror image_cache_remove(struct content *content);
+
+
+/** Obtain a bitmap from a content converting from source if neccessary. */
+struct bitmap *image_cache_get_bitmap(struct content *c);
+
+/** Obtain a bitmap from a content with no conversion */
+struct bitmap *image_cache_find_bitmap(struct content *c);
+
+/** Decide if a content should be speculatively converted.
+ *
+ * This allows for image content handlers to ask the cache if a bitmap
+ * should be generated before it is added to the cache. This is the
+ * same decision logic used to decide to perform an immediate
+ * conversion when a content is initially added to the cache. 
+ *
+ * @param c The content to be considered.
+ * @return true if a speculative conversion is desired false otehrwise.
+ */
+bool image_cache_speculate(struct content *c);
+
+/* Image content handler generic cache callbacks */
+
+/** Generic content redraw callback
+ *
+ * May be used by image content handlers as their redraw
+ * callback. Performs all neccissary cache lookups and conversions and
+ * calls the bitmap plot function in the redraw context.
+ */
+bool image_cache_redraw(struct content *c, 
+			struct content_redraw_data *data,
+			const struct rect *clip, 
+			const struct redraw_context *ctx);
+
+void image_cache_destroy(struct content *c);
+
+void *image_cache_get_internal(const struct content *c, void *context);
+
+content_type image_cache_content_type(void);
+
+#endif