1. Bitmap and Vector Graphics Bitmap Graphics Pictures are made up of little dots called pixels The colour of each dot is saved –Examples: Binary code representing Vector Graphics Pictures are made up of lines, shapes and objects Attributes of each object are saved –Example – a line: Line start x,y Line finish x,y Line thickness in points Line colour –Different objects have different attributes

2. Editing Bitmap Graphics Allows editing of individual pixels Can’t change objects once drawn –Have to draw over them Vector Graphics Can not edit individual pixels Can subsequently change attributes of an object –eg: line thickness Both types of graphics usually include a wide range of tools to help you draw, but …

3. Translating Bitmap Graphics Moving part of the image reveals a set of blank pixels underneath Vector Graphics Objects can be separated freely Moving an object about an image highlights another difference between the two types:

4. Rotating Bitmap Graphics A rotated pixel may lie across more than one actual pixel Have to approximate resulting colours of pixels Vector Graphics Objects can be rotated freely Mathematical formula used to recalculate attributes Turning an object shows also the difference between the two types:

5. Scaling Bitmap Graphics Increasing the size of an object can cause aliasing Vector Graphics Lines stay smooth as the object is scaled Changing the size of an object shows the difference between the two types:

6. Storage Requirements Bitmap Graphics Storage requirements relate to the number of pixels and colours Storage requirements constant, no matter complexity of picture Vector Graphics Each object and its attributes have to be saved The more objects you add, the more has to be saved The two types have different storage requirements

7. All graphics are displayed and printed in bitmap form!

8. Resolution dependence Bitmap Graphics The print / display resolution may not match the bitmap resolution The bitmap will have to be scaled to match Vector Graphics Attributes are printed / displayed –Some printers support vector based page description languages The picture is scaled as vector to match before conversion Resolution independent