There are two different ways to
make a picture on a computer screen, you can either use a bitmap,
pixel-based PAINTING software or a vector, object-based vector DRAWING software,
and people are often not sure of the difference between these two types of
Art Package.
Pixel Base Bitmap DrawingMany Art software packages are pixel-based and the images they produce are
called ‘bitmaps’. Common image files produced in this way are jpg’s, png’s
bmp’s and many more. A pixel is the tiniest dot that can be displayed on the
computer screen and the whole screen is divided up into rows and columns of
them.
A bitmap image is made by arranging this single layer of pixels with
different colours and shades of light to form the painting, just as a
newspaper photo is made from many dots. Have you ever looked at a pictue in
a newspaper using a magnifying glass?
A bitmap painting has only one layer of pixels, which means that if you
paint over part of the picture, the part that was obscured is irretrievable.
The whole picture has to be regarded as a single object because the computer
has no means of identifying or distinguishing between the different elements
that make it up.
Object based Vector DrawingA vector drawing is constructed from geometric shapes, circles, squares and
lines, and these shapes are called objects. These discreet shapes or
objects, once drawn, can be moved around the screen in any arrangement and
can fully or partly obscure one another. Objects in the drawing can be
edited individually at any time. Objects can also be placed in front of
other objects in ’layers’; and a vector drawing can have many layers.
If you want to change the picture you can select an object and move it,
change its shape, size or colour, copy it or transform it in various other
ways.
Both types of software, Bitmap Painting and Vector Drawing, have their uses
and advantages. The two main advantages of Vector Drawing are:
• Vector images retain their quality at all times, even when the image is
‘zoomed in’ close, whereas Bitmap images become distorted or pixellated.
• Vector images are made from layers of individual objects, each of which
can be manipulated and edited. You cannot edit a bitmap image like this.
Primary schools need a vector drawing software so pupils can learn to
manipulate images, move, copy, rotate and colour them, in accordance with
the ICT curriculum (ICT QCA5)
AspexDraw is a Vector Drawing Software specifically made for pupils in the
primary or secondary classroom.
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