Sams Teach Yourself StarOffice® 5 for Linux in 24 Hours |
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Hour 6: Creating Graphics with StarDraw |
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In this hour, you learn how to create vector-based graphics using the StarDraw tools in StarOffice. The drawing and editing tools of StarDraw are explained, as are adding text and modifying colors in the graphic images that you create.
The first thing that needs to be explained before using StarDraw to create a graphic is the difference between a vector-based graphic image and a raster-based (also called bitmapped) graphic image.
Most of the images you've seen, such as computerized photos and graphics on the Web in GIF for JPEG format, are raster graphics. These can be created in raster, or bitmap, drawing programs such as Adobe PhotoShop, PaintShop PRO, CorelPAINT, or the Image Editor in StarOffice (see Hour 11, "Adding Graphics to Documents").
If you have created graphics using programs such as CorelDRAW, the GIMP, or Adobe Illustrator, you've used vector drawing programs.
What's the difference? A file containing a bitmapped graphic image contains a piece of information for each pixel (bit) in the image. Every line, or raster, in the image must be described in this way, with color, brightness, and other information stored for each pixel.
Of course, the information stored for all those bits can be compressed. Using fewer colors requires less space to describe each bit, and areas that are the same color can be compressed using file formats such as GIF and PCX. But the information for each pixel is still extracted when the image is displayed.
Raster graphics are best for photos, scanning the Web, and very small images such as icons. Raster graphics are easier to work with and display in a computer than vector-based images are.
Vector-based images describe how to draw an image on a blank page. So instead of a set of color information for every dot on the screen, a vector image might have the following instructions:
1. Draw a circle with a center at point 100,150 and with a radius of 50 pixels, and fill it with color number 12.
2. Draw a line from point 25,25 to point 100,25. Make it black, and 5 pixels wide.
These examples of drawing commands can be stored in a vector drawing program using very little space. Using vector drawing commands also means that the image can be scaled to any size without seeing the stairstep or pixelation that comes from resizing bitmapped images.
Of course, it isn't easy to describe a photograph of a castle using drawing commands like these--but the commands get a lot more complicated than you might think. Bitmapped images are the best choice for some things, but for many business graphics applications, vector graphics are the right choice.
StarDraw is a vector-based drawing program. You can use the Image Editor in StarOffice if you need to create bitmapped images. The advantages of using StarDraw for a graphics project include
Graphics files are smaller than equivalent bitmapped images, unless you're creating a very complicated image.
Graphics can be resized for display on different screens or printed formats.
Objects within StarDraw images (objects are described later in this hour) can be individually modified.
Vector images are useful for flyers, business graphics such as boxes and brochures that have a lot of text, and page layout tasks such as newsletters.
The following section shows you how to create a new StarDraw image and start working with the drawing tools that StarDraw provides.
Sams Teach Yourself StarOffice® 5 for Linux in 24 Hours |
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Hour 6: Creating Graphics with StarDraw |
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