FS#6321: Universal Image Viewer

This unifies jpeg viewer, png viewer, and bmp viewer to one plugin, image viewer, so that you can navigate through different image formats.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28626 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/imageviewer/image_decoder.c

@@ -0,0 +1,130 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * load image decoder.
+ *
+ * This program 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; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include "plugin.h"
+#include "imageviewer.h"
+#include "image_decoder.h"
+
+static const char *decoder_names[MAX_IMAGE_TYPES] = {
+    "bmp",
+    "jpeg",
+    "png",
+};
+
+/* check file type by extention */
+enum image_type get_image_type(const char *name)
+{
+    static const struct {
+        char *ext;
+        enum image_type type;
+    } ext_list[] = {
+        { ".bmp",   IMAGE_BMP  },
+        { ".jpg",   IMAGE_JPEG },
+        { ".jpe",   IMAGE_JPEG },
+        { ".jpeg",  IMAGE_JPEG },
+        { ".png",   IMAGE_PNG  },
+    };
+
+    const char *ext = rb->strrchr(name, '.');
+    int i;
+    if (!ext)
+        return IMAGE_UNKNOWN;
+
+    for (i = 0; i < (int)ARRAYLEN(ext_list); i++)
+    {
+        if (!rb->strcasecmp(ext, ext_list[i].ext))
+            return ext_list[i].type;
+    }
+    return IMAGE_UNKNOWN;
+}
+
+static void *decoder_handle = NULL;
+const struct image_decoder *load_decoder(struct loader_info *loader_info)
+{
+    const char *name;
+    char filename[MAX_PATH];
+    struct imgdec_header *hdr;
+    struct lc_header     *lc_hdr;
+
+    if (loader_info->type < 0 || loader_info->type >= MAX_IMAGE_TYPES)
+    {
+        rb->splashf(2*HZ, "Unknown type: %d", loader_info->type);
+        goto error;
+    }
+
+    release_decoder();
+
+    name = decoder_names[loader_info->type];
+    rb->snprintf(filename, MAX_PATH, VIEWERS_DIR "/%s.ovl", name);
+
+    /* load decoder to the buffer. */
+    decoder_handle = rb->lc_open(filename, loader_info->buffer, loader_info->size);
+    if (!decoder_handle)
+    {
+        rb->splashf(2*HZ, "Can't open %s", filename);
+        goto error;
+    }
+
+    hdr = rb->lc_get_header(decoder_handle);
+    if (!hdr)
+    {
+        rb->splash(2*HZ, "Can't get header");
+        goto error_close;
+    }
+    lc_hdr = &hdr->lc_hdr;
+
+    if (lc_hdr->magic != PLUGIN_MAGIC || lc_hdr->target_id != TARGET_ID)
+    {
+        rb->splashf(2*HZ, "%s decoder: Incompatible model.", name);
+        goto error_close;
+    }
+
+    if (lc_hdr->api_version != IMGDEC_API_VERSION)
+    {
+        rb->splashf(2*HZ, "%s decoder: Incompatible version.", name);
+        goto error_close;
+    }
+
+    *(hdr->api) = rb;
+    *(hdr->img_api) = loader_info->iv;
+
+    /* set remaining buffer size to loader_info. decoder will
+     * be loaded to the end of the buffer, so fix size only. */
+#if (CONFIG_PLATFORM & PLATFORM_NATIVE)
+    loader_info->size = lc_hdr->load_addr - loader_info->buffer;
+#endif
+
+    return hdr->decoder;
+
+error_close:
+    release_decoder();
+error:
+    return NULL;
+}
+
+void release_decoder(void)
+{
+    if (decoder_handle != NULL)
+    {
+        rb->lc_close(decoder_handle);
+        decoder_handle = NULL;
+    }
+}