9618 · 1.2.1
Multimedia - Graphics flashcards
Revision flashcards for Cambridge 9618 Multimedia - Graphics (syllabus 1.2.1). Flip, recall, then mark a real past-paper question.
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What is a bitmap image?
An image stored as a grid of individual picture elements (pixels), where each pixel has a specific colour value. Also known as a raster image.
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What is a vector image?
An image stored as a set of mathematical objects (lines, curves, shapes) and their properties (e.g., colour, fill). It is defined by equations rather than pixels.
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Define 'pixel'.
Short for 'picture element', it is the smallest addressable element in a bitmap image. It is a single coloured dot in the image grid.
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What is 'image resolution'?
The dimensions of a bitmap image, expressed as the number of pixels in width and height (e.g., 1920 x 1080 pixels).
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What is 'colour depth' (or bit depth)?
The number of bits used to represent the colour of a single pixel. A higher colour depth allows for a greater number of distinct colours.
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How many colours can be represented by a colour depth of 8 bits?
$2^8 = 256$ colours.
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What is the main advantage of vector graphics over bitmap graphics?
Scalability. Vector graphics can be resized to any dimension without any loss of quality or sharpness, as they are recalculated from mathematical formulae.
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What is a major disadvantage of bitmap graphics?
They suffer from pixelation (appearing blocky or jagged) when scaled up beyond their original resolution.
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What is 'metadata' in an image file?
Data about the data. It includes information like image dimensions, colour depth, creation date, camera settings (for photos), and compression type, but not the pixel data itself.
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When would you use a bitmap image instead of a vector image?
For complex, photorealistic images with continuous tones and subtle colour variations, such as photographs. Editing individual pixels is also straightforward.
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When would you use a vector image instead of a bitmap image?
For logos, icons, illustrations, and diagrams that need to be scaled to various sizes (e.g., for websites, print, and billboards) while maintaining crisp edges.
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How do you calculate the file size of an uncompressed bitmap image in bits?
File Size (bits) = Image Width (pixels) × Image Height (pixels) × Colour Depth (bits).