LINE
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The LINE statement is used in graphic SCREEN modes to create lines or boxes.
Syntax
- LINE [STEP] [(column1, row1)]-[STEP] (column2, row2), color[, [{B|BF}], style%]
- The STEP keyword make column and row coordinates relative to the previously coordinates set by any graphic statement.
- The optional parameters (column1, row1) set the line's starting point.
- The dash and second coordinate parameters (column2, row2) must be designated to complete the line or box.
- The INTEGER color attribute or LONG _RGB32 32 bit color value sets the drawing color. If omitted, the current destination page's _DEFAULTCOLOR is used.
- Optional B keyword creates a rectangle (box) using the start and end coordinates as diagonal corners. BF creates a box filled.
- The style% signed INTEGER value sets a dotted pattern to draw the line or rectangle outline.
Description
- Creates a colored line between the given coordinates. Can be drawn partially off screen.
- B creates a box outline with each side parallel to the program screen sides. BF creates a filled box.
- style% can be used to create a dotted pattern to draw the line.
- B can be used with a style% to draw the rectangle outline using the desired pattern.
- BF ignores the style% parameter. See examples 2, 3 and 4 below.
- The graphic cursor is set to the center of the program window on program start. Using the STEP keyword makes the coordinates relative to the current graphic cursor.
- LINE can be used in any graphic screen mode, but cannot be used in the default screen mode 0 as it is text only.
Examples
Example 1: Following one line with another by omitting the second line's first coordinate parameter bracket entirely:
SCREEN 12 LINE (100, 100)-(200, 200), 10 'creates a line LINE -(400, 200), 12 'creates a second line from end of first END |
- Explanation: The full equivalent LINE statement would be: LINE(200, 200)-(400, 200), 12
Example 2: Creating styled lines and boxes with the LINE statement. Different style values create different dashed line spacing.
SCREEN 12 LINE (100, 100)-(300, 300), 10, , 63 'creates a styled line LINE (100, 100)-(300, 300), 12, B, 255 'creates styled box shape END |
- Explanation: The first diagonal dashed green line bisects the red dashed square from Top Left to Bottom Right Corners.
Example 3: The style value sets each 16 pixel line section as the value's bits are set on or off:
SCREEN 13 _FULLSCREEN 'required in QB64 only _DELAY 5 FOR i% = 1 TO 2 ^ 15 'use exponential value instead of -32768 COLOR 15:LOCATE 10, 5: PRINT i%; LINE (10, 60)-(300, 60), 0 'erase previous lines LINE (10, 60)-(300, 60), 12, , i% tmp$ = "" FOR b% = 15 TO 0 STEP -1 'create binary text value showing bits on as █, off as space IF i% AND 2 ^ b% THEN tmp$ = tmp$ + CHR$(219) ELSE tmp$ = tmp$ + SPACE$(1) NEXT COLOR 12:LOCATE 10, 20: PRINT tmp$; IF INKEY$ <> "" THEN EXIT FOR 'any key exit _DELAY .001 'set delay time as required NEXT |
- Explanation: The style value's Most Significant Bit (MSB) is set to the left with LSB on right as 16 text blocks are set on or off.
Example 4: Using binary code to design a style pattern:
SCREEN 12 LINE (100, 100)-(300, 100), 10, , &B0000111100001111 '16-bits LINE (100, 110)-(300, 110), 11, , &B0011001100110011 LINE (100, 120)-(300, 120), 12, , &B0101010101010101 LINE (100, 130)-(300, 130), 13, , &B1000100010001000 |
- Explanation: The binary pattern created with 0s and 1s using the &B number prefix define the pattern to draw the colored lines.
See also