Due to performance concerns the data size of the Description field is limited. Since the content of the Description may be loaded whenever a user opens an item structure, a description of a single item or issue could increase the loading time for users who don't even intent to read the specific description. The size of single description may seem irrelevant, but since descriptions account for a big portion of the data size of a item, the reduction of the loading time can be substantial especially for large structures.
Note: The loading of descriptions is actually not done until requested by a user, such as when selecting an item when the Overview view is selected or when searching in Descriptions. The problem of data size is generic and something you should keep in mind if an item's Description will be frequently read by users. If you include pictures with excessive resolution in web sites or MS Word files, users will also suffer from the excessive size of the files when they open or load the content.
The descriptions in SystemWeaver are compressed using compression algorithms that are effective for text. Text in a description may contain around 300,000 characters, or 100 pages. Pictures, however, need specific compression algorithms which are built into the picture formats themselves. If you get the "Excessive data size" message, you need to limit the size of the Description content. Often, this is due to large bitmap pictures.
Inserting a Picture
The first option is the Edit/Paste Special... option in the Description editor. In addition to the default Bitmap picture format, you may get the Metafile picture alternative, which is usually preferable.
Note that the Metafile picture format is especially efficient for drawings copied from PowerPoint or Visio applications.
The second option is to insert the picture from a file, using the Insert/Picture... option. This alternative is effective for pictures with lots of details, shapes, colors and gradients. If the picture is not already in a file, you will need to store the picture in a temporary file. When you store a picture to a file, use a compressed format like PNG, rather than a bitmap.
Decreasing the Size of a Picture
Should you need to reduce the data size of a picture even further, try one of these simple alternatives:
- Make sure the file format is of a compressed format. You can even use MS Paint to save a picture in a compressed format:
- PNG is the preferred alternative for drawings and screenshots. The format is lossless.
- JPEG is the preferred alternative for photographs and pictures with lots of details.
- Resample the picture in a picture editing tool. Adapt the resolution to the used size of the picture. MS Paint can be used here as well by using the Resize option. Note that resizing a picture in an editor like the Description editor or in MS Word does not affect the data size!
- Reduce the color resolution in a picture editing tool, e.g., decreasing the color resolution from full 32 bit color to 256 colors.
The examples below are used for illustration of different options. These examples are quite small so scaling to larger examples may yield larger differences.
The picture below in 133 x 160 bitmap with 24 bit colors is 64 kB in size (and requires 45 kB* when stored in SystemWeaver).
The same picture, in 8 bit color PNG format is 16 kB in size (and requires 14 kB when stored in SystemWeaver). Can you see the difference?
For pictures with no or little details or gradients, the difference is greater.
The following 24 bit color, 252 by 252 bitmap picture is 187 kB in raw size, and requires 16 kB** when stored in SystemWeaver:
The same picture in 8 bit color PNG format is 16 KB in raw size, and requires around 10 KB when stored in SystemWeaver:
Using the Built-in Image Editor
With SystemWeaver version R33 or later, the Description editor offers an image editor tool which enables you to resize images. See Using the Image Editor for more information.
* SystemWeaver is not able to compress a PNG file further from the original format so the reduction indicated is likely due to measurement errors.
** Bitmap pictures with few details and colors can be compressed efficiently with text compression algorithms such as the one used for text in SystemWeaver. Formats like PNG are optimized for many details and colors and are not solely intended for pictures with few details.