Rockwell Automation 9301 Series RSView32 Users Guide - Manual (Page 403)

11–110

RSView32 User’s Guide
Using bitmaps
Bitmaps consume Windows resources, so when using bitmaps follow
these guidelines:
Use device–dependent bitmaps
Device–dependent bitmaps (.bmp files) display faster than display–
independent bitmaps (.dib files) because the RSView32 Graphic
Display editor is optimized for device–dependent bitmaps. Also,
you can in–place edit device–dependent bitmaps using the
Microsoft Paint program.
Avoid unnecessary color depth
Create bitmaps in the lowest color depth possible. The more colors
you use, the more memory that is consumed:
16–color bitmaps consume 4 bits per pixel (1/2 byte per pixel)
256–color bitmaps consume 8 bits per pixel (1 byte per pixel)
24–bit bitmaps consume 24 bits per pixel (3 bytes per pixel)
If possible, use 16–color bitmaps. To change a higher–resolution
bitmap to 16–colors, open the bitmap in the Microsoft Paint
program and save the bitmap as a 16–color bitmap.
In 256–color systems, match palettes
In a 256–color system, if bitmaps use two different color palettes,
Windows must recalculate and redraw all bitmaps when window
focus changes. Redrawing the bitmaps causes delays and can make
a scanned image or photograph ‘sparkle’ or appear as a negative.
To match palettes, use a bitmap–oriented graphical tool that lets
you match palettes.
Palette matching is an issue only for 256–color video adapters. 24–
bit color systems do not match palettes and 16–color systems