An image region can support 2, 16 and 256 color bitmaps (.bmp) at compile time. At run time, an image region can read in the following file formats:

 

•Standard Bitmap (include 24 bit color format).bmp

•Joint Picture Expert Group .jpg

•Graphics Interchange Format .gif

•Windows Icon .ico

•Tagged Image Format .tif

 

These files can be created in the following ways:

 

For an image to be used at compile time, use a graphics package, such as Microsoft Paint, and save the file created as a monochrome, 16 color, or 256 color bitmap .BMP file. By default, compiled bitmap images are cached within the ESL application, however, if the image region is resized, the bitmap file will be re-read from disk. To allow for the resizing of image regions, compiled bitmap files must be distributed with the ESL application, using the same directory structure as at time of compilation.

We recommend that ESL applications do not display multiple windows that use different 256-color tables, as this will degrade the performance of your applications. The reason for this lies in the way that Windows manages color palettes. Because Windows has only one system palette, it must load a new logical palette each time your application displays a new window. This does not cause any degradation when using 16-color palettes, as they are all the same. 256-color palettes, however, may contain any of a near-infinite combination of shades. Therefore, Windows must reload the appropriate palette each time the application changes windows. You can use 16-color palettes in multiple windows simultaneously, or a single 256-color palette in combination with 16-color palettes, but do not use multiple 256-color palettes.

Note that once bitmap files are compiled, they should not be changed, or reading them will cause I/O buffer errors because the size of the bitmap file is different from its original size.

 

Due to the limited range of supported file formats that can be used at time of compilation, it is recommended that images are loaded into an image region at runtime. The runtime read file into statement supports the commonly used graphical file formats, and can be created using the majority of photographic packages available for Windows. In addition to read file into statement, it is possible to use the add to statement to insert a string that contains a hexadecimal representation of one of the supported image file formats. This add to facility removes the need to create a file.