Package 'skiagd'

Add circles

Description

Add circles

Usage

add_circle(img, center, radius, props = paint())

Arguments

img	A raw vector of picture.
center	A double matrix where each row is circle center.
radius	Numerics of circle radius.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Add difference rectangles

Description

Add difference rectangles

Usage

add_diff_rect(img, outer, outer_radii, inner, inner_radii, props = paint())

Arguments

img	A raw vector of picture.
outer	A double matrix where each row is an outer rectangle XYWH (left, top, right, bottom).
outer_radii	A double matrix where each row is a pair of axis lengths on X-axis and Y-axis of outer oval describing rounded corners.
inner	A double matrix where each row is an inner rectangle XYWH (left, top, right, bottom).
inner_radii	A double matrix where each row is a pair of axis lengths on X-axis and Y-axis of inner oval describing rounded corners.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Add lines

Description

Add lines

Usage

add_line(img, from, to, props = paint())

Arguments

img	A raw vector of picture.
from	A double matrix where each row is a start point.
to	A double matrix where each row is an end point.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Add paths

Description

Add paths

Usage

add_path(img, path, transform = c(1, 0, 0, 0, 1, 0, 0, 0, 1), props = paint())

Arguments

img	A raw vector of picture.
path	Characters of SVG notations like "M10 10 H 90 V 90 H 10 L 10 10".
transform	Numerics of length 9 to apply affine transformations to the path themselves. See transform-matrix for affine transformations.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Add PNG image to canvas

Description

Add PNG image to canvas

Usage

add_png(img, png, left = 0, top = 0, props = paint())

Arguments

img	A raw vector of picture.
png	A raw vector of PNG data.
left	Left offset for drawing PNG image.
top	Top offset for drawing PNG image.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Add points

Description

Add points

Usage

add_point(img, point, props = paint())

Arguments

img	A raw vector of picture.
point	A double matrix where each row is a point.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Add rectangles

Description

Add rectangles

Usage

add_rect(img, rect, props = paint())

Arguments

img	A raw vector of picture.
rect	A double matrix where each row is a rectangle XYWH (left, top, right, bottom).
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Add rounded rectangles

Description

Add rounded rectangles

Usage

add_rounded_rect(img, rect, radii, props = paint())

Arguments

img	A raw vector of picture.
rect	A double matrix where each row is a rectangle XYWH (left, top, right, bottom).
radii	A double matrix where each row is a pair of axis lengths on X-axis and Y-axis of oval describing rounded corners.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Convert picture into PNG data

Description

Convert picture into PNG data

Usage

as_png(img, props = paint())

Arguments

img	A raw vector of picture.
props	A paint properties out of paint().

Value

A raw vector of PNG data.

---

Convert a picture into a recorded plot

Description

This is mainly for testing purposes.

Usage

as_recordedplot(img, props = paint())

Arguments

img	A raw vector of picture.
props	A paint properties out of paint().

Value

A recordedplot object. See grDevices::recordPlot() for details.

---

BlendMode (0-28)

Description

BlendMode determines how source and destination colors are combined.

Usage

BlendMode

Format

An object of class BlendMode__bundle (inherits from savvy_skiagd__sealed) of length 29.

Details

The following blend modes are available in Skia:

1. Clear

2. Src

3. Dst

4. SrcOver

5. DstOver

6. SrcIn

7. DstIn

8. SrcOut

9. DstOut

10. SrcATop

11. DstATop

12. Xor

13. Plus

14. Modulate

15. Screen

16. Overlay

17. Darken

18. Lighten

19. ColorDodge

20. ColorBurn

21. HardLight

22. SoftLight

23. Difference

24. Exclusion

25. Multiply

26. Hue

27. Saturation

28. Color

29. Luminosity

See Also

BlendMode in skia_safe - Rust

Other paint-attributes: Cap, FillType, Join, PathEffect, PointMode, Shader, Style

---

Create a canvas

Description

Creates a new canvas filled with specified color.

Usage

canvas(fill = "transparent", size = paint()[["canvas_size"]])

Arguments

fill	RGBA representation of a color. This can be specified using named colors or hexadecimal color codes, which are converted internally using grDevices::col2rgb().
size	Integers of length 2; canvas size.

Value

A raw vector of picture.

---

Cap (0-2)

Description

Cap determines the stroke cap (the geometry drawn at the beginning and end of strokes).

Usage

Cap

Format

An object of class Cap__bundle (inherits from savvy_skiagd__sealed) of length 3.

Details

The following caps are available:

• Butt: Butt cap.

• Round: Round cap.

• Square: Square cap.

See Also

Cap in skia_safe::paint - Rust

Other paint-attributes: BlendMode, FillType, Join, PathEffect, PointMode, Shader, Style

---

Color to RGBA

Description

A wrapper of grDevices::col2rgb().

Usage

col2rgba(color)

Arguments

color

col for grDevices::col2rgb().

Value

An integer vector.

---

Device size

Description

Just returns the size of the current device as an integer (not a numeric).

Usage

dev_size(units = "px")

Arguments

units

units for grDevices::dev.size().

Value

An integer vector.

---

Plot picture as PNG image

Description

Plot picture as PNG image

Usage

draw_img(img, props = paint())

Arguments

img	A raw vector of picture.
props	A paint properties out of paint().

Value

img is returned invisibly.

---

FillType (0-3)

Description

FillType determines how paths are drawn. This is for add_path() only. Not used in other functions.

Usage

FillType

Format

An object of class FillType__bundle (inherits from savvy_skiagd__sealed) of length 4.

Details

The following FillType are available:

• Winding

• EvenOdd

• InverseWinding

• InverseEvenOdd

See Also

FillType in skia_safe::path - Rust

Other paint-attributes: BlendMode, Cap, Join, PathEffect, PointMode, Shader, Style

---

Freeze a picture

Description

as_png(img) and then adds it to a new canvas.

Usage

freeze(img, fill = "transparent", props = paint())

Arguments

img	A raw vector of picture.
fill	A string scalar; named colors or hexadecimal color codes.
props	A paint properties out of paint().

Value

A raw vector of picture.

---

Join (0-2)

Description

Join determines the stroke join (the geometry drawn at the corners of strokes) for shapes.

Usage

Join

Format

An object of class Join__bundle (inherits from savvy_skiagd__sealed) of length 3.

Details

The following joins are available:

• Miter: Miter join.

• Round: Round join.

• Bevel: Bevel join.

See Also

Join in skia_safe::paint - Rust

Other paint-attributes: BlendMode, Cap, FillType, PathEffect, PointMode, Shader, Style

---

Define painting attributes

Description

The paint() function allows users to specify various painting attributes for drawing shapes on the canvas, such as color, stroke width, and transformations.

Usage

paint(...)

Arguments

...	<dynamic-dots> Named arguments specifying painting attributes. See details.

Details

The following painting attributes can be specified:

• canvas_size: Integers of length 2 (width, height).

• color: RGBA representation of a color. This can be specified using named colors or hexadecimal color codes, which are converted internally using grDevices::col2rgb().

• style: The paint style. See Style.

• join: Stroke join. See Join.

• cap: Stroke cap. See Cap.

• width: A numeric scalar (stroke width).

• miter: A numeric scalar (stroke miter).

• blend_mode: See BlendMode.

• path_effect: See PathEffect.

• shader: See Shader.

• point_mode: PointMode for add_point().

• fill_type: FillType for add_path().

• transform: Numerics of length 9. See transform-matrix for affine transformations.

Value

A list containing the specified painting attributes, merged with default values.

---

PathEffect

Description

PathEffect is a struct that offers a reference to skia_safe::PathEffect. You can apply a path effect to shapes via paint(). Currently only single PathEffect can be specified; multiple effects are not supported.

Arguments

start	A numeric scalar in the range ⁠[0, 1]⁠.
end	A numeric scalar in the range ⁠[0, 1]⁠.
length	A numeric scalar; length of the subsegments.
deviation	A numeric scalar; limit of the movement of the endpoints.
seed	An integer scalar; random seed.
intervals	A numeric vector; even number of entries with even indices specifying the length of the "on" intervals, and the odd index specifying the length of "off".
phase	A numeric scalar; offset into the intervals array (for dash()), or distance (mod advance) along the path for its initial position (for path_1d()).
radius	A numeric scalar; radius of the rounded corners.
path	A string scalar of SVG notation to replicate.
advance	A numeric scalar; space between instances of path.
style	A string scalar; how to transform path at each point. Can be "translate", "rotate", or "morph".
transform	Numerics of length 9; transformation matrix.
width	A numeric scalar; width of the path to be stamped.

Details

The following effects are available:

• no_effect(): does not apply any path effect. This is the default effect for paint().

• trim(start, end): trims the start and end of the path. Note that you can't trim nothing at all, i.e., setting start = 0 and end = 1 arises an error.

• discrete(lentgh, deviation, seed): applies discrete path effect.

• dash(intervals, phase): applies dash path effect.

• corner(radius): applies corner path effect.

• path_1d(path, advance, phase, style): applies 1D path effect.

• path_2d(path, transform): applies 2D path effect.

• line_2d(width, transform): applies 2D line path effect.

Value

A PathEffect object.

See Also

Path Effects | React Native Skia

Other paint-attributes: BlendMode, Cap, FillType, Join, PointMode, Shader, Style

---

PointMode (0-2)

Description

PointMode determines how points are drawn. This is for add_point() only. Not used in other functions.

Usage

PointMode

Format

An object of class PointMode__bundle (inherits from savvy_skiagd__sealed) of length 3.

Details

The following PointMode are available:

• Points: Draws each point as a point. The shape of point drawn depends on props.

• Lines: Each pair of point draws a line segment. One line is drawn for every two points; each point is used once. If count is odd, the final point is ignored.

• Polygon: Each adjacent pair of point draws a line segment. count minus one lines are drawn; the first and last point are used once.

See Also

PointMode in skia_safe::canvas - Rust

Other paint-attributes: BlendMode, Cap, FillType, Join, PathEffect, Shader, Style

---

Shader

Description

Shader is a struct that offers a reference to skia_safe::Shader. You can apply a shader to shapes via paint().

Note that concatenating shaders with c() is equivalent to blend them all into a single shader using Shader$blend() with the default BlendMode. You can pass mode explicitly for c() to change the blend mode.

Arguments

img	A raw vector of picture.
mode	For blend(), BlendMode. For others, TileMode.
tile_size	Numerics of length 2; tile size (width, height).
transform	Numerics of length 9; transformation matrix.
png_bytes	A raw vector of PNG data.
rgba	Integers of length 4 in range ⁠[0, 255]⁠ representing RGBA.
dst	A Shader object; destination shader.
src	A Shader object; source shader.
freq	Numerics of length 2; frequencies.
octaves	A numeric scalar; number of octaves.
seed	Integer scalar; random seed.
start	Numerics of length 2; starting point (x, y).
end	Numerics of length 2; ending point (x, y).
from	Integers of lenth 4 in range ⁠[0, 255]⁠; starting color.
to	Integers of length 4 in range ⁠[0, 255]⁠; ending color.
flags	A logical scalar; typically, you can leave this as FALSE. See here for details.
radii	Numerics of length 2; radii of start and end circles.
center	Numerics of length 2; center of the gradient.
start_angle	A numeric scalar in range ⁠[0, 360]⁠; starting angle. For default, set 0.
end_angle	A numeric scalar in range ⁠[0, 360]⁠; ending angle. For default, set 360.

Details

The following shaders are available:

• no_shader(): does not apply any shader. This is the default shader for paint().

• from_picture(img, mode, tile_size, transform): takes a picture and returns an image shader.

• from_png(png_bytes, mode, transform): takes a PNG image and returns an image shader.

• color(rgba): takess a color and returns a color shader.

• blend(mode, dst, src): returns a shader that combines the given shaders with a BlendMode.

• fractal_noise(freq, octaves, seed, tile_size): fractal perlin noise shader.

• turbulence(freq, octaves, seed, tile_size): turbulence noise shader.

• linear_gradient(start, end, from, to, mode, flags, transform): linear gradient shader.

• radial_gradient(center, radius, from, to, mode, flags, transform): radial gradient shader.

• conical_gradient(start, end, radii, from, to, mode, flags, transform): conical gradient shader.

• sweep_gradient(center, start_angle, end_angle, from, to, mode, flags, transform): sweep gradient shader.

Value

A Shader object.

See Also

• Image Shaders | React Native Skia

• Gradients | React Native Skia

• Perlin Noise Shaders | React Native Skia

• Blending and Colors | React Native Skia

Other paint-attributes: BlendMode, Cap, FillType, Join, PathEffect, PointMode, Style

---

Style (0-2)

Description

Style determines the stroke style of shapes.

Usage

Style

Format

An object of class Style__bundle (inherits from savvy_skiagd__sealed) of length 3.

Details

The following styles are available:

• StrokeAndFill: Stroke and fill.

• Stroke: Stroke only.

• Fill: Fill only.

See Also

Style in skia_safe::paint - Rust

Other paint-attributes: BlendMode, Cap, FillType, Join, PathEffect, PointMode, Shader

---

TileMode (0-3)

Description

TileMode determines how the source is tiled for shaders. This is not a paint attribute. To specify TileMode, directly pass these pointers to shader functions.

Usage

TileMode

Format

An object of class TileMode__bundle (inherits from savvy_skiagd__sealed) of length 4.

Details

The following TileMode are available:

• Clamp

• Repeat

• Mirror

• Decal

See Also

TileMode in skia_safe - Rust

---

Applying affine transformations to a picture

Description

When loading a picture into a canvas, you can apply an affine transformation by providing a numeric vector of length 9 to paint() as transform.

Details

This vector defines a transformation matrix that modifies a picture before rendering it onto the canvas.

The transform vector represents a 3x3 matrix used for affine transformations, following the format:

$\begin{bmatrix} \text{scale}_x & \text{skew}_y & \text{pers}_0 \\ \text{skew}_x & \text{scale}_y & \text{pers}_1 \\ \text{trans}_x & \text{trans}_y & \text{pers}_2 \end{bmatrix}$

The first two columns define standard affine transformations, including scaling, skewing, and translation. The third column (pers_0, pers_1, and pers_2) is typically used for perspective transformations, though in most affine transformations, it remains as c(0, 0, 1).

See Also

• Matrix in skia_safe::matrix - Rust

---