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 QuickSCREEN Details Example Contents Index |
| ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ |
| LINE Statement Details |
|
| Syntax |
| LINE [[STEP] (x1,y1)]-[STEP] (x2,y2) [,[color][,[B[F]][,style]]] |
| |
| The coordinates (x1,y1) and (x2,y2) specify the endpoints of the line; |
| note that the order in which these endpoints appear is unimportant, |
| since a line from (10,20) to (120,130) is the same as a line from |
| (120,130) to (10,20). |
| |
| The STEP option makes the specified coordinates relative to the most recent |
| point, instead of absolute, mapped coordinates. For example, if the most |
| recent point referred to by the program is (10,10), then |
| |
| LINE -STEP (10,5) |
| |
| draws a line from (10,10) to the point with x coordinate equal to |
| 10 + 10 and y coordinate equal to 10 + 5, or (20,15). |
| |
| You may establish a new most recent point by initializing the screen |
| with the CLS and SCREEN statements. Using the PSET, PRESET, CIRCLE, |
| and DRAW statements will also establish a new most recent point. |
| |
| Variations of the STEP argument are shown below. For the following |
| examples, assume that the last point plotted was (10,10): |
| |
| Statement Description |
| |
| LINE -(50,50) Draws from (10,10) to (50,50) |
| |
| LINE -STEP(50,50) Draws from (10,10) to (60,60); that |
| is, to 10 plus offset 50 |
| |
| LINE (25,25)-STEP(50,50) Draws from (25,25) to (75,75); that |
| is, to 25 plus offset 50 |
| |
| LINE STEP(25,25)-STEP(50,50) Draws from (35,35) to (85,85); that |
| is, from 10 plus offset 25 to that |
| point plus offset 50 |
| |
| LINE STEP(25,25)-(50,50) Draws from (35,35) to (50,50); that |
| is, from 10 plus offset 25 to |
| absolute 50 |
| |
| The color is the number of the color in which the line is drawn. |
| (If the B or BF options are used, the box is drawn in this color.) |
| See the COLOR statement details and the SCREEN statement details for |
| information about how to specify a color number in different screen |
| modes. |
| |
| The B option draws a box with the points (x1,y1) and (x2,y2) specifying |
| diagonally opposite corners. |
| |
| The BF option draws a filled box. This option is similar to the B option; |
| BF also paints the interior of the box with the selected color. |
| |
| The style is a 16-bit integer mask used to put pixels on the screen. Using |
| the style argument is called "line styling." With line styling, LINE reads |
| the bits in style from left to right. If a bit is 0, then no point is |
| plotted; if the bit is 1, a point is plotted. After plotting a point, LINE |
| selects the next bit position in style. |
| |
| Because a 0 bit in style does not change the point on the screen, you may |
| want to draw a background line before using styling so you can have a known |
| background. Style is used for normal lines and boxes, but has no effect on |
| filled boxes. |
| |
| When coordinates specify a point that is not in the current viewport, the |
| line segment is clipped to the viewport. |
