SC ICT CertificationLevel 1

SC ICT CertificationLevel 1

12 Graphics

By Ross Parker

Graphics

• Computer graphics utilise a computer’s ability to display a bitmap in order to create an image:

Source: Wikimedia Commons

Bitmap vs. Vector

Source: Wikimedia Commons

• Bitmap is the default• When should we use vector?

File Types

• Bitmap– .tif – uncompressed (or not), pages, layers– .bmp – uncompressed– .png – compressed, lossless– .jpg – highly compressed, lossy– .gif – highly compressed, lossy, indexed– .xcf – GIMP’s format– .psd – Abode Photoshop’s format

• Vector– .svg – open standard– .ai – Adobe Illustrator’s format

USING THE GIMPBasic & Intermediate

The GIMP

• The GIMP is F/OSS for creating and editing bitmap images.

• www.gimp.org/downloads/

Source: Wikimedia Commons

Image Size

• Generally rectangular• Image size is expressed in pixels (px):• To resize: Image > Scale Image

113 px

150 px

Crop• Change size of image whilst...

– Maintaining size of contents• To crop: Image > Canvas Size

75 px

75 px

Layers• Images can contain layers• To see Layers: Windows > Layers

• Try the “Opacity” setting.

5-layer example

Colors

• RGB model represents colour as mix of:– Red– Green– Blue

• Each colour ranges from 0 (off) to 255 (on)• HTML notation uses hexidecimal

Toolbox

Select by colorSelectLassoMove

Paint fillGradient fill

Colour pickerRotateTextPen

Foreground color Background color

Tool options

USING THE GIMPAdvanced Focus (optional, not assessed)

Advanced Features

• Colour Curves & Balance• Filters• Select by colour• Mask• Clone Tool• Healing Tool

Licensing• All original work used here is licensed under the Creative Commons Attribution-Share

Alike 3.0 Unported license. For more details please look at http://creativecommons.org/licenses/by-sa/3.0/.

• This license has been chosen to permit a high degree of sharing, whilst protecting the author’s control as to how the content is used.

• Please respect this license and use accordingly!• Recycled and borrowed works from other sources are used under appropriate

licenses, which are not affected by this license. The original source is always given. • All original work created by Ross Parker (Sha Tin College, English Schools

Foundation, Hong Kong), except where specified.