MonoGRAF basic terms
Drawing
A drawing is a geometric model of a real object, a product, a schematic diagram, a chart, etc.
It consists of graphic entities, which have certain attributes and are interrelated in a certain way.
The drawing may be displayed, plotted and edited.
Graphic entities
The following elements of the drawing are called graphic entities:
- line;
- circle;
- arc;
- text;
- hatch of a closed area.
Entity parameters
The parameters of the graphic entities determine the value of some of their characteristics, such as the circle radius, the height of the text, the distance between the hatch lines, etc.
Entity attributes
The attributes determine the non-geometrical characteristics of the graphic entities. They don't influence the form and the size, they only set the outer appearance of the entity. The graphic entities have the following attributes in MonoGRAF:
- entity color;
- line type;
- level of detail.
All graphic entities can be drawn in any one of the MonoGRAF line types.
The level of detail determines which entities will be visible. There are 8 levels of detail in MonoGRAF (from 0 to 7). The default level of detail is zero. When you create graphic objects, you can determine their level of detail in an appropriate way. For example, the contour lines of a machine part may have level of detail zero, the holes - one, the dimension lines and dimension texts - two and so on. By setting the current level of detail to two, you will see only the contour lines and the holes on your display, but not the dimension lines and dimension texts.
Points
The position of the graphic entities in the drawing area is determined by one or several points. A single point can determine the origin of several entities.
Coordinate system. Point coordinates.
Each point is defined in the plane by the two coordinates x, y. The coordinates are in the orthogonal coordinate system and denote, respectively, the distance between the projection of the point on the axes Ox and Oy and the origin of the coordinate system. The origin of the coordinate system has coordinates (0,0) and usually represents the lower left angle of the drawing. You can determine a local coordinate system, which has another origin and is rotated around it. MonoGRAF provides the possibility of entering points by its local coordinates.
Orthogonal coordinate system
Groups
A group is a names set of graphic entities, which is treated as a new complex entity. A new group can contain other groups as well. A group may be inserted in the drawing area with a specified scale factor and rotated at a given angle. The group can be saved on disk. The name of the file coincides with the name of the group and has extension GRP.
Graphic objects
A "graphic object" in MonoGRAF can be any set of entities, groups, or the entire drawing. It can be named for convenient selection.
Associated data
You may wish to associate some non-graphic data records with graphic objects. The layout of the data record is specified in a data dictionary with the dBASE system. The record may contain characters, numbers and dates. The number of associated graphic objects and data records within a drawing is unlimited.
Layers
You may organize your drawing in an unlimited number of transparent overlays called layers. Each layer has the same drawing limits as the drawing. Any number of layers can be displayed simultaneously, but you may insert graphic objects and edit only the current layer.
Relations
MonoGRAF supports special relations between graphic objects. They can represent semantic or purely geometrical relationships. The relations between graphic objects are created either implicitly or explicitly. The relations can be essential in preserving the integrity of your drawing. For example, when you hatch a closed contour, you create the implicit relation between the entities comprising the contour and the hatch lines. If you change the contour, the hatching will be changed automatically thanks to the implicit relation. You may create explicit relations between objects for your own purposes.
Drawing area
The drawing area is a rectangular area in the real two-dimensional space. It is defined at the beginning of a new drawing, but you can change it later by the "drawing limits" function. The drawing area is defined by the coordinates at the lower left and the upper right part of the drawing. The coordinates of the points, which determine the graphic elements on the drawing, are in real units. Thus, the real measures of the object are saved in the model and all calculations and dimensions have real values. When we visualize on the screen of the display or when we draw on paper of the plotters, the system automatically transforms the real coordinates into coordinates of the graphic device, saving the interrelations between the drawing space and the plane of the device.
Drawing area
Window
This is a rectangular part of the drawing area, which is displayed at a given moment on the screen of the graphic display.
Views
Views are named windows, which can be displayed on the screen of the graphic display.
Zoom
Zoom - the process of magnifying or shrinking the visible image of the drawing. Usually we create a window by indicating the coordinates of a rectangular area on the screen or a new scale for visualization of some area of the drawing.
Pan
Pan - the process of viewing different potion of the drawing without changing the magnification.
Resolution
The physical resolution refers to the amount of detail which can be represented and depends on the graphic device. The resolution of the digitizer and plotter is measured by the number of dots per cm, and for the graphic display - by the number of dots on the axes x and y on the screen. The resolution of the digitizer determines the precision by which we can point to the nearest point. The resolution of the plotter and display determines the quality of the drawing on the respective device. The physical resolution is applicable only to a particular device, but it doesn't influence the precision of the internal model of the drawing.
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