CRISTAL Draw: Draw consists of drawing and painting functions that can be implemented for image processing and graphic design. Draw provides access to the following commands: Dot, Line, Circle, Rectangle, Arc, Spline, Polygon, Text, and Erase. Options controls settings for Weight of line, Line style, and Fill type. After activating the desired Draw command, user interaction with the graphics screen is through a two-button mouse. The left button activates and controls each Draw procedure, and the right button terminates the procedure. Draw Dot: Dot places a single dot or a series of dots on the graphics screen. A single dot is generated by pressing the left mouse button once, and a continuous stream of dots is produced by holding the left button down as the mouse is moved. Press the right mouse button to leave the Dot function and return to the Graphic menu in the worksheet. Draw Line: Line places a line on the graphics screen. The placement is determined by using the mouse to position the cursor at the starting point of the line. Press the left mouse button to mark the beginning of the line. Use the mouse to move the cursor to the desired end location of the line, and press the left button again to set the end point. Lines will be continuously linked until the right mouse button is pressed to break the sequence. A beginning point for a new line segment can then be located by positioning the cursor at the desired location and pressing the left button. Repeat the process as desired. To leave the Line function and return to the Graphic menu in the worksheet, press the right mouse button twice. For adjustments to Line style and Weight of line, see the Options section of the Draw menu. Draw Circle: Circle generates a circle of user specified size to the graphics screen. Placement is determined by using the mouse to position the cursor at the desired focal point, and pressing the left mouse button to set the center of the circle. The circle is sized by moving the mouse to establish the desired diameter. Press the left mouse button to set the circle on the screen. Adjust the Line style, Weight of line, and Fill type at the Options section of the Draw menu. The circle function remains active until the right mouse button is pressed. Draw Rectangle: Rectangle allows the placement of rectangles on the graphics screen. The placement is determined by using the mouse to position the cursor at the starting corner of the rectangle. Press the left mouse button to mark the corner. Use the mouse to establish the desired dimensions and orientation of the rectangle. Press the left button again to set the rectangle in place on the graphics screen. Repeat the procedure as desired, or press the right mouse button to terminate the function and return to the Graphic menu in the worksheet. Adjust the Line style, Weight of line, and Fill type at the Options section of the Draw menu. Draw Text: Text controls the placement of text of different size, style, and color on the graphics screen. Text size is initially set to a default size of (50 X 50) screen units. Size can be adjusted with the "Set Text Size" option. Text style is specified from a list of ten alternatives. Text color is changed in the graphics screen by using the color palette option that can be activated at the bottom of the screen. The Text Style is selected from a list of 10 built-in style options: Roman, Italic Roman, Light Euro., Old English, Script, Helvetica, Universe, Claredon, and Greek & Math. Adjust Line style, Weight of line, or Fill style for Text at the Options menu. Text color is changed by moving the cursor to the bottom of the graphics screen to activate the display of the color palette. When the color palette appears, position the cursor on the desired color selection and press the left mouse button to set the active color. Colors may also be selected from the displayed image in the graphics screen. The default color is set in the Graphic Options menu. Text size allows the text to be set to the default size (50 X 50 screen units), or to be dynamically sized using the "Set Text Size" option. A [YES] response to the text size query displays the sample letter "A" on the graphics screen at the default size setting. Press the left mouse button and move the mouse to size the sample character. Set the text size at the desired dimension by pressing the left mouse button. Type the text on the Message Line of the worksheet and press [E] [Enter]. A rectangle representing the text string appears on the graphics screen as the text is typed on the Message Line. Use the mouse to position the rectangle on the screen at the desired location. Press the left mouse button to set the text on the graphics screen. Repeat the procedure, or press the right mouse button to return to the Graphics menu in the worksheet. Draw Spline: Spline draws a spline curve between two points on the graphics screen. Use the mouse to position the cursor at the beginning point of the spline curve. Press the left mouse button to set the beginning point. Move the cursor to the desired ending point of the spline. Press the left button to set the ending point. A straight line is then displayed on the graphics screen between the two end points of the spline. Move the mouse to adjust the apex of the curve to the desired dimension. Press the left mouse button a third time to set the arc on the screen. Repeat the procedure as desired, or press the right mouse button to return to the Graphics menu in the worksheet. Draw Polygon: Polygon places a figure that has a specified number of equal sides (1-20) on the graphics screen. The number of sides in the polygon is specified by the user at the query on the Message Line. The mouse is used to size and place the polygon on the screen. Move the cursor to the desired focal point of the polygon and press the left mouse button to set the point. Adjust the size and rotation of the polygon by moving the mouse. Placement is set by pressing the left mouse button. Repeat the procedure as desired, or press the right mouse button to return to the Graphics menu in the worksheet. Adjust Line style, Weight of line, and Fill type at the Options menu. Draw Arc: Arc allows a smooth curve to be drawn relative to two end points and a radius specification. After activating the Arc command, use the mouse to position the cursor at the beginning point of the arc. Press the left mouse button to set the beginning point. Position the cursor at the ending point. Press the left mouse button to set the ending point. Use the mouse to adjust the arc to the desired radius and press the left mouse button to set the arc. Repeat the procedure, or press the right mouse button to return to the Graphics menu in the worksheet. Adjust the Line style and Weight of line at the Options section of the Draw menu. Erase: Erase allows a portion of the screen to be deleted. The portion of the screen to be erased is determined by the size of the "eraser." The eraser box is sized by pressing the left button of the mouse to set a corner, then moving the mouse to establish the desired dimensions. Press the left button again to set the size. Place the eraser over the section of the graphics screen to be eliminated. Press the left mouse button to delete the area framed by the eraser. Press the right button to quit the erase procedure and return to the Graphic menu in the worksheet. Draw Options: Options control the characteristics of the graphics that are drawn to the screen. The settings at this submenu level apply only to drawing functions, and not to the Graph or Image functions. The default settings are controlled at the Graphic Options menu. Weight of line influences all Draw functions including Text. There are four line weights that can be selected: 1,2,4, and 8 screen units. Line style provides control over the Line type for Draw functions. Line style can be set at one of three alternatives: [Continuous, Segment, Dot]. Fill style provides control over the fill options for Draw functions. Fill style can be set at one of four alternatives: [No fill, Dithered, Grid, Solid fill]. The Fill option can be used with the Circle, Rectangle, Polygon, and Text functions. Appendix Two: CRISTAL Graphics and Image Processing