| Prima::Drawable::Gradient(3) | User Contributed Perl Documentation | Prima::Drawable::Gradient(3) |
NAME¶
Prima::Drawable::Gradient - gradient fills for primitives
DESCRIPTION¶
Prima offers primitive gradient services to draw gradually changing colors. A gradient is requested by setting of at least two colors and optionally a set of quadratic spline points that, when, projected, generate the transition curve between the colors.
The module augments the "Prima::Drawable" drawing functionality by adding "new_gradient" function.
SYNOPSIS¶
$canvas-> new_gradient(
palette => [ cl::White, cl::Blue, cl::White ],
)-> sector(50,50,100,100,0,360);
API¶
Methods¶
- new $CANVAS, %OPTIONS
- Here are %OPTIONS understood in the gradient request:
- clone %OPTIONS
- Creates a new gradient object with %OPTIONS replaced.
- widgetClass INTEGER
- Points to a widget class to resolve generic colors like "cl::Back", that may differ from widget class to widget class.
- palette @COLORS
- Each color is a "cl::" value. The gradient is calculated as polyline where each its vertex corresponds to a certain blend between two neighbouring colors in the palette. F.ex. the simplest palette going from "cl::White" to "cl::Black" over a polyline 0..1 (default), produces pure white color at the start and pure black color at the end, filling all available shades of gray in between, and changing monotonically.
- poly @VERTICES
- Set of 2-integer polyline vertexes where the first integer is a coordinate
(x, y, or whatever required by the drawing primitive) between 0 and 1, and
the second is the color blend value between 0 and 1.
Default: ((0,0),(1,1))
- spline \@VERTICES, %OPTIONS
- Serving same purpose as "poly" but vertexes are projected first to a B-spline curve using render_spline and %OPTIONS. The resulting polyline is treated as "poly".
- vertical BOOLEAN
- Only used in bar, to set gradient direction.
See also: bar, stripes .
- bar X1, Y1, X2, Y2, VERTICAL = 0
- Draws a filled rectangle within (X1,Y1) - (X2,Y2) extents
Context used: fillPattern, rop, rop2
- colors BREADTH
- Returns a list of gradient colors for each step from 1 to BREADTH.
- ellipse X, Y, DIAM_X, DIAM_Y
- Draws a filled ellipse with center in (X,Y) and diameters (DIAM_X,DIAM_Y)
Context used: fillPattern, rop, rop2
- sector X, Y, DIAM_X, DIAM_Y, START_ANGLE, END_ANGLE
- Draws a filled sector with center in (X,Y) and diameters (DIAM_X,DIAM_Y)
from START_ANGLE to END_ANGLE
Context used: fillPattern, rop, rop2
- stripes BREADTH
- Returns an array consisting of integer pairs, where the first one is a color value, and the second is the breadth of the color strip. bar uses this information to draw a gradient fill, where each color strip is drawn with its own color. Can be used for implementing other gradient-aware primitives (see examples/f_fill.pl )
AUTHOR¶
Dmitry Karasik, <dmitry@karasik.eu.org>.
SEE ALSO¶
Prima::Drawable, examples/f_fill.pl, examples/gradient.pl
| 2023-09-05 | perl v5.26.1 |