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Device-Independent Bitmap Sizing

IP.com Disclosure Number: IPCOM000099985D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Franklin, SM: AUTHOR [+2]

Abstract

This article describes a method for using bitmaps to create icons of the same size on different display devices. Bitmaps are a very efficient method for describing the graphical appearance of a picture. A bitmap actually describes the state of each screen pixel in the picture. This type of graphical description is called a "raster" image. While this method allows for fast display of pictures, it is very device dependent, since different devices have pixels of different sizes as well as different support for color. A bitmap appears to have shrunk in size when displayed on a high resolution display, since the pixels on a high resolution display are often smaller. The initial solution for this problem is to describe graphical pictures in real units, such as millimeters or inches, using vector graphics.

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Device-Independent Bitmap Sizing

       This article describes a method for using bitmaps to
create icons of the same size on different display devices. Bitmaps
are a very efficient method for describing the graphical appearance
of a picture. A bitmap actually describes the state of each screen
pixel in the picture. This type of graphical description is called a
"raster" image.  While this method allows for fast display of
pictures, it is very device dependent, since different devices have
pixels of different sizes as well as different support for color.  A
bitmap appears to have shrunk in size when displayed on a high
resolution display, since the pixels on a high resolution display are
often smaller.  The initial solution for this problem is to describe
graphical pictures in real units, such as millimeters or inches,
using vector graphics.  However, implementation of vector graphics is
a more difficult solution and often results in poorer performance by
the system.

      Device-independent bitmap sizing provides a solution to this
problem by determining the desired size of an object in real units
and defining a minimum standard screen resolution.  At execution
time, the screen device type is queried and the real object size is
translated to pixel units for the specified device.  If this device
is of the minimum standard resolution, then the application-supplied
bitmap can be used as is.  However, if the device is of a greater
resolution, then the applicat...