12. Ответьте на вопросы:

1. What is rendering useful for?

2. What new capabilities do rendering programs provide?

3. How can users create realistic images?

4. Where can CAD drawing be imported?

13. Прочтите и переведите текст.

TEXT C

CREATIVE PAINT AND DRAW PROGRAMS

A number of different types of graphics programs are used to create free-form drawings. These programs provide the user with tools that can be used to create lines, patterns, and designs.

Creative graphics programs generally are categorized as falling into one of two types. Both types of programs provide op­tions that allow the artist or designer to create sophisticated freehand drawings, but they do it in very different ways. In order to understand the difference be­tween these two types of graphics pro­grams, it is necessary to understand something about bit-mapped (paint) and vector (draw) images.

Paint Programs. When an image (such as a circle or a rectangle) is created in a bit-mapped graphics program (generally referred to as a paint program), it loses its identity as a whole object. The object is created as a pattern of pixels. This means that the characteristics of the rectangle, such as its overall size, or its line thickness, cannot be changed; instead, the image is changed by erasing or adding individual pixels. Information about the image is stored in the computer’s memory as a series of bits.

In monochrome paint programs (usually displayed as black images on a white background), one pixel corresponds to one bit in memory. Color graphics programs assign more bits to display the color of each pixel. The smaller and closer together the pixels are, the better the image will be. The number of pixels is determined by the resolution of the screen. High-resolution monitors can use 1.024 by 1.024 pixels.

Paint programs provide a set of software drawing tools that can be manipulated using a pointing device such as a mouse. These tools mimic the drawing characteristics of a real-world drawing tool such as a pencil or a paint­brush. These tools can be used to turn the pixels on the screen from white to black or from black to white or in patterns of black and white pixels. An “erasing” tool is used to turn pixels back to the standard white.

Paint programs generally include an option that lets the user “zoom in” or mag­nify any area of the screen. This gives the user a way to make detailed corrections to the image.

These programs also include a palette of textures or patterns that can be used to “fill” shapes and objects with the selected pattern. Today, paint programs provide users access to full color as well as a great variety of drawing tools and other options for modifying an image.

These programs offer the artist/designer a way to create very sophisticated drawings. In addition, a wide variety of clip art (art on disk) is available for those who are less adept at creating their own images.

Draw or Vector Programs. When an object such as a rectangle is created in a vector graphics (or draw) program, the program uses a set of mathematical instructions that describe all of the rectangle’s characteristics. The object is treated as a whole entity. This means that the characteristics of a drawn rectangle can be changed. The object, once drawn, can be resized or reshaped as a whole. Its line thickness can be changed and the object can be filled with a pattern. The objects created with a draw program of this type can be resized without being distorted (not true for paint graphics images).

As with paint graphics, a special drawing device such as a mouse, lightpen, or digitizing (or graphics) tablet is used and the programs provide a set of software tools to create the images.

Because draw programs usually are used to create more precise drawings than can be created using paint programs, many draw programs have rulers and grids that allow the user to place objects precisely on the screen.