QB64-PE/internal/help/LINE.txt

The [[LINE]] statement is used in graphic [[SCREEN (statement)|SCREEN]] modes to create lines or boxes.


{{PageSyntax}}
: [[LINE]] [STEP] ['''('''''column1''''',''' ''row1''''')''']'''-'''[STEP] '''('''''column2'', ''row2'''''),''' ''color''[, [{B|BF}], {{Parameter|style%}}]


{{Parameters}}
* 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 [[_DEST|destination]] page's [[_DEFAULTCOLOR]] is used.
* Optional '''B''' keyword creates a rectangle ('''b'''ox) using the start and end coordinates as diagonal corners. '''BF''' creates a '''b'''ox '''f'''illed. 
* The ''style%'' signed [[INTEGER]] value sets a dotted pattern to draw the line or rectangle outline.


{{PageDescription}}
* 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.
* {{Parameter|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 {{Parameter|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.''' 


{{PageExamples}}
''Example 1:'' Following one line with another by omitting the second line's first coordinate parameter bracket entirely:
{{CodeStart}}{{Cl|SCREEN}} 12

{{Cl|LINE}} (100, 100)-(200, 200), 10    'creates a line
{{Cl|LINE}} -(400, 200), 12              'creates a second line from end of first

{{Cl|END}} '' ''
{{CodeEnd}}
:''Explanation:'' The full equivalent LINE statement would be: '''{{text|LINE(200, 200)-(400, 200), 12|green}}'''


''Example 2:'' Creating styled lines and boxes with the LINE statement. Different style values create different dashed line spacing.
{{CodeStart}}{{Cl|SCREEN}} 12

{{Cl|LINE}} (100, 100)-(300, 300), 10, , 63    'creates a styled line
{{Cl|LINE}} (100, 100)-(300, 300), 12, B, 255  'creates styled box shape

{{Cl|END}} '' ''
{{CodeEnd}}
:''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:
{{CodeStart}}{{Cl|SCREEN}} 13
{{Cl|_FULLSCREEN}} 'required in QB64 only
{{Cl|_DELAY}} 5
{{Cl|FOR...NEXT|FOR}} i% = 1 {{Cl|TO}} 2 ^ 15 'use exponential value instead of -32768
    {{Cl|COLOR}} 15:{{Cl|LOCATE}} 10, 5: {{Cl|PRINT}} i%;
    {{Cl|LINE}} (10, 60)-(300, 60), 0 'erase previous lines
    {{Cl|LINE}} (10, 60)-(300, 60), 12, , i%
    tmp$ = ""
    {{Cl|FOR...NEXT|FOR}} b% = 15 {{Cl|TO}} 0 {{Cl|STEP}} -1 'create binary text value showing bits on as {{text|█|red}}, off as space
        {{Cl|IF...THEN|IF}} i% {{Cl|AND}} 2 ^ b% {{Cl|THEN}} tmp$ = tmp$ + {{Cl|CHR$}}(219) {{Cl|ELSE}} tmp$ = tmp$ + {{Cl|SPACE$}}(1)
    {{Cl|NEXT}}
    {{Cl|COLOR}} 12:{{Cl|LOCATE}} 10, 20: {{Cl|PRINT}} tmp$;
    {{Cl|IF...THEN|IF}} {{Cl|INKEY$}} <> "" {{Cl|THEN}} {{Cl|EXIT}} {{Cl|FOR...NEXT|FOR}} 'any key exit
    {{Cl|_DELAY}} .001 'set delay time as required
{{Cl|NEXT}} '' ''
{{CodeEnd}}
: ''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 [[&B|binary code]] to design a style pattern:
{{CodeStart}}{{Cl|SCREEN}} 12

{{Cl|LINE}} (100, 100)-(300, 100), 10, , &B0000111100001111 '16-bits
{{Cl|LINE}} (100, 110)-(300, 110), 11, , &B0011001100110011
{{Cl|LINE}} (100, 120)-(300, 120), 12, , &B0101010101010101
{{Cl|LINE}} (100, 130)-(300, 130), 13, , &B1000100010001000
{{CodeEnd}}
:''Explanation:'' The binary pattern created with 0s and 1s using the [[&B]] number prefix define the pattern to draw the colored lines.


{{PageSeeAlso}}
* [[SCREEN (statement)|SCREEN]], [[COLOR]] 
* [[DRAW]], [[CIRCLE]], [[STEP]]
* [[PSET]], [[PRESET]]
* [[AND]], [[OR]] {{text|(logical operators)}}


{{PageNavigation}}
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