Computer-science_A-level_Cie
-
computers-and-components6 主题
-
logic-gates-and-logic-circuits2 主题
-
central-processing-unit-cpu-architecture6 主题
-
assembly-language-4 主题
-
bit-manipulation1 主题
-
operating-systems3 主题
-
language-translators2 主题
-
data-security3 主题
-
data-integrity1 主题
-
ethics-and-ownership3 主题
-
database-concepts3 主题
-
database-management-systems-dbms-1 主题
-
data-definition-language-ddl-and-data-manipulation-language-dml1 主题
-
computational-thinking-skills1 主题
-
algorithms14 主题
-
data-types-and-records2 主题
-
arrays2 主题
-
files1 主题
-
introduction-to-abstract-data-types-adt1 主题
-
programming-basics1 主题
-
constructs2 主题
-
structured-programming1 主题
-
program-development-life-cycle2 主题
-
program-design-2 主题
-
program-testing-and-maintenance3 主题
-
user-defined-data-types1 主题
-
file-organisation-and-access-3 主题
-
floating-point-numbers-representation-and-manipulation3 主题
-
protocols2 主题
-
circuit-switching-packet-switching1 主题
-
processors-parallel-processing-and-virtual-machines5 主题
-
boolean-algebra-and-logic-circuits4 主题
-
purposes-of-an-operating-system-os3 主题
-
translation-software3 主题
-
encryption-encryption-protocols-and-digital-certificates3 主题
-
artificial-intelligence-ai4 主题
-
recursion1 主题
-
programming-paradigms4 主题
-
object-oriented-programming7 主题
-
file-processing-and-exception-handling2 主题
-
data-representation5 主题
-
multimedia3 主题
-
compression2 主题
-
networks-and-the-internet11 主题
vector-graphics
Vector graphics
What is a vector graphic?
-
A vector graphic is created from mathematical equations and points
-
Only the mathematics used to create the image are stored
-
For example, to create a circle the data stored would be:
-
Centre point (x, y coordinates)
-
Radius
-
-
Typical examples of vector images are logos and clipart

-
Vector images are infinitely scalable
-
Ideal for situations where the same image will be made bigger and smaller and a loss of quality is unacceptable
-
For example, the same logo used on both a pencil and a billboard
-
-
A vector graphic contains a drawing list (included in the file header)
-
A typical drawing list will contain:
-
Commands used to create each object in the image
-
Attributes that define the properties of each object
-
Relative position of each object
-
-
Dimensions of the image are not defined, meaning scaling up does not result in a loss of quality
Bitmap vs vector
|
Feature |
Bitmap Images |
Vector Images |
|---|---|---|
|
Made from |
Pixels (tiny coloured squares) |
Shapes and lines using maths (vectors) |
|
File size |
Larger (depends on resolution) |
Smaller (uses formulas, not pixels) |
|
Scalability |
Loses quality when resized (pixelates) |
Can be resized without losing quality |
|
Best for |
Photographs, detailed images |
Logos, icons, text graphics |
|
Editable with |
Paint software (e.g. Photoshop, GIMP) |
Drawing software (e.g. Illustrator, Inkscape) |
|
Common file types |
.jpg, .png, .bmp, .gif |
.svg, .ai, .eps |
-
When choosing to use a bitmap or vector based image, the following should be considered:
-
Does the image need to be resized?
-
Does the image need to be drawn to scale?
-
Does the image need to look real?
-
Responses