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04/02/2005 09:34:06 PM · #1 |
Ayone care to give me a simple explanation of the uses and definitions of these?
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04/02/2005 09:53:58 PM · #2 |
| vector image do not lose quality as they are enlarged. They can be enlarged by the program and not be pixellated because they are based on a mathematical formula. Raster images will get pixellated as enlarged. |
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04/02/2005 10:02:04 PM · #3 |
Originally posted by petrakka:
vector image do not lose quality as they are enlarged. They can be enlarged by the program and not be pixellated because they are based on a mathematical formula. Raster images will get pixellated as enlarged. |
Can you tell me how this translates into what I see each day on my PC? What I am working with when I might being using one of these two kinds?
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04/02/2005 10:06:16 PM · #4 |
Vector images are created by programs like Illustrator or CorelDraw, and create shapes by drawing lines with various tools (those curves are what's described by a "mathematical formula") and then filling them with color. These are usually found in the form of an EPS (Encapsulated PostScript) file.
A raster image (e.g. TIFF, JPEG) describes the color of each pixel individually (although the data can be stored in a compressed form). |
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04/02/2005 10:06:59 PM · #5 |
A raster image is an image made up of a grid of dots, or pixels. For any given image, there are only so many pixels, so scaling it up will produce progressively blockier, fuzzier results.
A vector image is made up of drawn shapes. Text in Photoshop is drawn as vector shapes. As you scale up a vector image, the edges remain smooth and sharp, since the shapes can be scaled up with perfect accuracy.
Vector images can be easily converted to raster, but not vice versa.
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04/02/2005 10:16:29 PM · #6 |
Thank you all so much. Please forgive my ignorance. You always come through on this site.
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04/03/2005 12:18:06 AM · #7 |
Let me add that, from a "computer"'s point of view, this is the difference:
Speaking of B/W here, for simplicity's case (a high-contrast image of only black or white), when I "draw a line" with a tool in a raster (bitmap) mode, I am telling the computer to fill with black every pixel that the line crosses. If the screen is composed of only 100 pixels (10x10) then the ACTUAL NUMBER OF PIXELS COLORED is much lower than if I drew the same line on a screen composed of 1000 pixels total, or a million pixels, total. So, as pointed out above, when i try to scale this up I am scaling up this same actual number of pixels, and if the line is anything but at right angles to the pixel grid, it will become progressively more jagged.
When I draw the line with a vector tool, as in CorelDraw, I am actually telling the computer "generate a line that begins HERE and ends HERE, witht he following characteristics", and this is resolution-independent. When I scale up such a drawing, what I am actually scaling up is the locations of the starting and ending points, making them further apart, and the same formula is embedded and instructs the computer how the two points are to be connected.
Maybe this doesn't add anything to anyone's understanding, but this is how I have explained it in the past when I have taught the subject.
Robt.
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