Computer Science AS CIE
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data-representation as5 主题
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multimedia as3 主题
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compression as2 主题
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networks-and-the-internet as11 主题
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computers-and-components as5 主题
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logic-gates-and-logic-circuits as2 主题
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central-processing-unit-cpu-architecture as6 主题
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assembly-language- as4 主题
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bit-manipulation as1 主题
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operating-systems as3 主题
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language-translators as2 主题
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data-security as3 主题
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data-integrity as1 主题
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ethics-and-ownership as3 主题
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database-concepts as3 主题
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database-management-systems-dbms- as1 主题
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data-definition-language-ddl-and-data-manipulation-language-dml as1 主题
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computational-thinking-skills as1 主题
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algorithms as4 主题
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data-types-and-records as2 主题
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arrays as2 主题
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files as1 主题
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introduction-to-abstract-data-types-adt as1 主题
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programming-basics as1 主题
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constructs as2 主题
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structured-programming as1 主题
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program-development-life-cycle as1 主题
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program-design- as2 主题
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program-testing-and-maintenance as3 主题
vector-graphics- as
Exam code:9618
Vector graphics
What is a vector graphic?
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A vector graphic is created from mathematical equations and points
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Only the mathematics used to create the image are stored
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For example, to create a circle the data stored would be:
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Centre point (x, y coordinates)
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Radius
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Typical examples of vector images are logos and clipart

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Vector images are infinitely scalable
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Ideal for situations where the same image will be made bigger and smaller and a loss of quality is unacceptable
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For example, the same logo used on both a pencil and a billboard
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A vector graphic contains a drawing list (included in the file header)
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A typical drawing list will contain:
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Commands used to create each object in the image
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Attributes that define the properties of each object
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Relative position of each object
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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 |
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When choosing to use a bitmap or vector based image, the following should be considered:
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Does the image need to be resized?
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Does the image need to be drawn to scale?
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Does the image need to look real?
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Responses