DynaPDF Manual - Page 777

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Function Reference

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Return values:

If the function succeeds the return value is 1. If the function fails the return value is 0.

SetLineDashPattern2

Syntax:

LBOOL pdfSetLineDashPattern2(

const PPDF* IPDF,

// Instance pointer

const float* Dash, // Dash array defined

UI32 NumValues,

// Number of values in the dash array

float Phase)

// The pattern's phase

The line dash pattern controls the pattern of dashes and gaps used to stroke paths. It is specified by

a dash array and a dash phase. The dash array’s elements are numbers that specify the lengths of

alternating dashes and gaps; the dash phase specifies the distance into the dash pattern at which to

start the dash. The elements of both the dash array and the dash phase are expressed in user space

units. Before beginning to stroke a path, the dash array is cycled through, adding up the lengths of

dashes and gaps. When the accumulated length equals the value specified by the dash phase,

stroking of the path begins, using the dash array cyclically from that point onward. The table shows

examples of line dash patterns. As can be seen from the table, an empty dash array and zero phase

can be used to restore the dash pattern to a solid line (you can also use ResetLineDashPattern()).

Dash & Phase Appearance

Description

(NULL, 0)

No dash; solid, unbroken lines

("3", 0)

3 units on, 3 units off…

("2", 1)

1 on, 2 off, 2 on, 2 off, …

("2 1", 0)

2 on, 1 off, 2 on, 1 off, …

("3 5", 6)

2 off, 3 on, 5 off, 3 on, 5 off, ...

("2 3", 11)

1 on, 3 off, 2 on, 3 off, 2 on, ...

Dashed lines wrap around curves and corners just as solid stroked lines do. The ends of each dash

are treated with the current line cap style, and corners within dashes are treated with the current

line join style. A stroking operation takes no measures to coordinate the dash pattern with features

of the path; it simply dispenses dashes and gaps along the path in the pattern defined by the dash

array. When a path consisting of several sub paths is stroked, each sub path is treated independently

- that is, the dash pattern is restarted and the dash phase is reapplied to it at the beginning of each

sub path.

How to create a dotted line?

As described above, a line dash pattern is drawn by applying the current line cap style and join

style. A round cap is painted as semicircular arc with a diameter equal to the line width. If we set

Previous topic: SetLineCapStyle, SetLineDashPattern (obsolete)

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