1Prima::Drawable::GradieUnste(r3)Contributed Perl DocumenPtraitmiao:n:Drawable::Gradient(3)
2
3
4

NAME

6       Prima::Drawable::Gradient - gradient fills for primitives
7

DESCRIPTION

9       Prima offers primitive gradient services to draw gradually changing
10       colors.  A gradient is requested by setting of at least two colors and
11       optionally a set of quadratic spline points that, when, projected,
12       generate the transition curve between the colors.
13
14       The module augments the "Prima::Drawable" drawing functionality by
15       adding "new_gradient" function.
16

SYNOPSIS

18               $canvas-> new_gradient(
19                       palette => [ cl::White, cl::Blue, cl::White ],
20               )-> sector(50,50,100,100,0,360);
21

API

23   Methods
24       new $CANVAS, %OPTIONS
25           Here are %OPTIONS understood in the gradient request:
26
27           clone %OPTIONS
28               Creates a new gradient object with %OPTIONS replaced.
29
30           widgetClass INTEGER
31               Points to a widget class to resolve generic colors like
32               "cl::Back", that may differ from widget class to widget class.
33
34           palette @COLORS
35               Each color is a "cl::" value. The gradient is calculated as
36               polyline where each its vertex corresponds to a certain blend
37               between two neighbouring colors in the palette. F.ex. the
38               simplest palette going from "cl::White" to "cl::Black" over a
39               polyline 0..1 (default), produces pure white color at the start
40               and pure black color at the end, filling all available shades
41               of gray in between, and changing monotonically.
42
43           poly @VERTICES
44               Set of 2-integer polyline vertexes where the first integer is a
45               coordinate (x, y, or whatever required by the drawing
46               primitive) between 0 and 1, and the second is the color blend
47               value between 0 and 1.
48
49               Default: ((0,0),(1,1))
50
51           spline \@VERTICES, %OPTIONS
52               Serving same purpose as "poly" but vertexes are projected first
53               to a B-spline curve using render_spline and %OPTIONS. The
54               resulting polyline is treated as "poly".
55
56           vertical BOOLEAN
57               Only used in bar, to set gradient direction.
58
59           See also: bar, stripes .
60
61       bar X1, Y1, X2, Y2, VERTICAL = 0
62           Draws a filled rectangle within (X1,Y1) - (X2,Y2) extents
63
64           Context used: fillPattern, rop, rop2
65
66       colors BREADTH
67           Returns a list of gradient colors for each step from 1 to BREADTH.
68
69       ellipse X, Y, DIAM_X, DIAM_Y
70           Draws a filled ellipse with center in (X,Y) and diameters
71           (DIAM_X,DIAM_Y)
72
73           Context used: fillPattern, rop, rop2
74
75       sector X, Y, DIAM_X, DIAM_Y, START_ANGLE, END_ANGLE
76           Draws a filled sector with center in (X,Y) and diameters
77           (DIAM_X,DIAM_Y) from START_ANGLE to END_ANGLE
78
79           Context used: fillPattern, rop, rop2
80
81       stripes BREADTH
82           Returns an array consisting of integer pairs, where the first one
83           is a color value, and the second is the breadth of the color strip.
84           bar uses this information to draw a gradient fill, where each color
85           strip is drawn with its own color. Can be used for implementing
86           other gradient-aware primitives (see examples/f_fill.pl )
87

AUTHOR

89       Dmitry Karasik, <dmitry@karasik.eu.org>.
90

SEE ALSO

92       Prima::Drawable, examples/f_fill.pl, examples/gradient.pl
93
94
95
96perl v5.36.0                      2023-03-20      Prima::Drawable::Gradient(3)
Impressum