Bitmaps: Basic Editing Concepts

ClarisDraw is unlike MacDraw Pro in that it has the capability to edit bitmap, or "paint," images. This article should help answer some basic questions about bitmaps.

This information was provided by Claris Corporation on 16 March 1998, and incorporated into Apple Computer's Tech Info Library.

What is a Bitmap Image?

An image consisting of colored dots. Typical examples are scans (which can be saved as TIFF or PICT files) and paint documents (which are created by applications such as MacPaint or Brushstrokes). ClarisDraw works only with bitmap frames - in other words, bitmap images are only contained within a frame in the document. ClarisDraw cannot save out as a "pure" bitmap file like a paint application can.

Any bitmapped image is probably going to require that additional RAM be allocated to the application; in fact, the larger the image, or the more colors it contains, the more RAM will be required to even open the file, much less edit it. Sometimes the additional amount of RAM needed can be substantial - many megabytes. Additionally, bitmap images can require substantial amounts of disk space to store, again, depending on the number of colors in the file and the image's resolution (expressed in dpi, or dots per inch).

How To Edit a Bitmap Image in ClarisDraw

- Create a new document
- Place the bitmap in the document

- Alternatively, simply open the bitmap file
- Click the bitmap image to it is selected
- Choose "Ungroup Picture" from the ARRANGE menu
- The image is now ready for editing. Click again to activate the paint tools

You can also cut/copy/paste a paint image into a ClarisDraw paint frame. However, the "Ungroup Picture" method is superior because (1) it's easier, and (2) it retains the original bitmap's resolution. Copy/paste reduces the images resolution to 72 dpi. This may look okay on screen (which can display only 72 dpi at 100 percent magnification) but you will certainly see the difference when printing to any high resolution printer (laser or inkjet printer).

Side Issue:

Choosing "Ungroup Picture" also changes white pixels to transparent. Try this example:

- Create a simple MacPaint image; save it
- Create a new ClarisDraw document
- Draw an object
- Place the MacPaint image in the file; move it over the other object you've drawn. Notice how you cannot see what's underneath the MacPaint image
- Now click the MacPaint image and choose "Ungroup Picture" from the ARRANGE menu

- Notice that you can now see beneath the MacPaint image. The white pixels have become transparent.

Published Date: Feb 18, 2012