IT152_Lecture_08_Graphics_2013a Flashcards
Why do we use Graphics…?
- Photos
- Diagrams / Illustrations
- Text Created in paint packages
- Interface
- Animation Sequence
- Interactive
Photos…?
Scanned, Digital Cameras, Video, Library (CD), WWW Stock Photos area available to purchase a license to use.
Diagrams/ Illustrations…?
Information, Vector Drawing, Converted to Bitmap?, Drawn in paint package, Other (word, powerpoint, Internal Drawing Editor)
Text Created in paint packages…?
‘Typed in’ using internal editor, Imported from file.
Interface…?
Backgrounds, Buttons, Display Areas, Title Bars, Menus.
Animation Sequence…?
Vector/Bitmap
Interactive…?
Up / Down states, Rollovers Enabled/ Disabled states, Games/ Virtual Environments.
What are the Sources of Digital Images…?
- Scanned Images
- Still Images (digital camera)
- Video Images
- Photo CD
- Stock Photography
- Clip Art
- Original Artwork
- Copyright Laws
Scanners digitize already developed images, including…?
photographs and drawings.
Slide scanners are also available for…?
converting a slide or a negative to a digital image.
Digital cameras capture…?
images in a digital format.
Digital video cameras can also be used to…?
capture frames of video or still images.
Enables photos taken with a film camera to be viewed in a…?
digital format - hi resolution digital cameras taken over from film
Stock Photography: Photographs available on…?
CD or on Web sites, like www.iStockphoto.com
A collection of member-generated royalty-free images, that you have to pay for.
Clip Art is a collection of drawings or illustrations, generally organized by…?
category.
Public Domain refers to…?
Clip art images available free of charge for what ever use.
Licensed material may have some license restrictions such as…?
not allowed for commercial use.
Artwork that is created using an original drawing created by…?
hand or one of many graphics programs.
Advantages include not having to worry about licensing agreements or copyright laws.
Copyright laws are designed to protect intellectual property rights and…?
provide potential monetary rewards for inventiveness and hard work.
The 1994 Copyright Act and recent 2011 amendments applies to graphics.
Image types:
Line art…?
Term used to describe drawings that contain flat colors without tonal variations.
Image types:
Continuous-tone images…?
graphics that have tonal variations, such as color photographs.
Image types:
Grayscale images…?
Continuous-tone image consisting of black, white, and gray data only.
Image types:
Images can also be classified as…?
two-dimensional (2-D) or, by adding depth to them, they become three-dimensional (3-D)
Layering…?
- Process that keeps elements of an image separate and editable from the rest of an image
- Can overlap
- Particular elements can be selected and edited without affection the rest of the image
Transparency…?
Defines a colour as a transparency index, so the background shows through
(Namely GIF and PNG – support transparency. In addition, most image editing programs support transparency, but only when the image is saved in the software program’s native format.
Rendering…?
Process of capturing a view of a 3-D scene and saving it as a 2D image
“Lossless” and “lossy” compression…?
Lossless and lossy compression describe whether or not, in the compression of a file, all original data can be recovered when the file is uncompressed.
Lossless compression…?
None of data actually lost during compression
Lossy compression…?
Some data is lost during compression
- Lossy compression is generally used for video and sound, where a certain amount of information loss will not be detected by most users.
Interpolation…?
changing the size of the image using resizing tool.
Scaling…?
Dragging the edges of the image.
Resolution…?
- measurement of the output quality of an image, usually in terms of samples, pixels, dots, or lines per inch.
- Pixel Dimensions: The Number of pixels in total image
- Output devices display images as groups of pixels.
When you reduce the side of a bitmap image through your software’s resample or resize command, you must…?
throw away pixels.
When you increase the side of a bitmap image through your software’s resample or resize command, the software has to…?
create new pixels.
(When creating pixels, the software must estimate the colour values of the new pixels based on the surrounding pixels. This process is called interpolation zooming in and out, or dragging the edges of your images in a page layout program to resize it. This type of resizing is more accurately called scaling.
Changing screen resolution changes…?
size of pixels and size of bitmap image on screen. (Vector no change).
Online image ( WWW, CDROM), your maximum size is determined by …?
the lowest pixel dimension on screen.
Image resolution refers to the amount of…?
information stored for each image.
Image resolution is measured in…?
pixels per inch (PPI)
Web graphics can be set to…?
72 PPI because most computer monitors cannot display more than 72 PPI.
Image resolution…?
the number of pixels per unit.
- length normally pixels per inch =ppi
- Which determines the file size72 ppi (72 x 72 pixels = 5184 pixels in one square inch)300 ppi (300 x 300 pixels 90000 pixels in one square inch)
Precision to which a pixel can…?
specify colour is its colour depth
File size formula…?
Width x Height x bit depth in bytes 185 x 276 pixels.
at 8 bit colour depth…?
= 185 x 276 x 1
= 51, 060 bytes
Device resolution
Scanner…?
- Scanning at 600dpi
- 32 bit colour resolution.
Device resolution
Screen…?
- number of pixels the screen is divided into 640x480, 800x600, 1024x768, 1280x1024
- Dot pitch is the distance between the pixels
. - 28mm - Display adapter – 72dpi
- Web graphics can be set to 72dpi as most monitors cannot display more than that
- colour resolution of 256 colours
Device Resolution
Printer…?
600 dpi
Vectors:
Consist of lines and curves defined by…?
mathematical objects called vectors.
Vectors describe graphics according to…?
their geometric characterisitics
Vector graphics are made up of…?
many individual objects
Vectors:
Each of these objects can be defined by….?
mathematical statements and has individual properties assigned to it such as colour, fill, and outline.
Vectors:
They are resolution independent because they can…?
be output to the highest quality at any scale.
Vectors:
They are not restricted to…?
a rectangular shape like bitmaps.