gensvg generates SVG to an io.Writer

gensvg: A Go library for SVG generation

The library generates SVG as defined by the Scalable Vector Graphics 1.1 Specification (http://www.w3.org/TR/SVG11/). Output goes to the specified io.Writer.

Supported SVG elements and functions

Shapes, lines, text

circle, ellipse, polygon, polyline, rect (including roundrects), line, text, tspan

Paths

general, arc, cubic and quadratic bezier paths,

Image and Gradients

image, linearGradient, radialGradient,

Transforms

translate, rotate, scale, skewX, skewY

Animation

animate, animateMotion, animateTranslate, animateRotate, animateScale, animateSkewX, animateSkewY

Filter Effects

filter, feBlend, feColorMatrix, feColorMatrix, feComponentTransfer, feComposite, feConvolveMatrix, feDiffuseLighting, feDisplacementMap, feDistantLight, feFlood, feGaussianBlur, feImage, feMerge, feMorphology, feOffset, fePointLight, feSpecularLighting, feSpotLight,feTile, feTurbulence

Metadata elements

desc, defs, g (style, transform, id), marker, mask, pattern, title, (a)ddress, link, script, use

Building and Usage

See svgdef.[svg|png|pdf] for a graphical view of the function calls

Usage: (assuming GOPATH is set)

go get github.com/ajstarks/gensvg

a minimal program, to generate SVG to standard output.

package main

import (
	"github.com/ajstarks/gensvg"
	"os"
)

func main() {
	width := 500
	height := 500
	canvas := gensvg.New(os.Stdout)
	canvas.Start(width, height)
	canvas.Circle(width/2, height/2, 100)
	canvas.Text(width/2, height/2, "Hello, SVG", "text-anchor:middle;font-size:30px;fill:white")
	canvas.End()
}

Drawing in a web server: (http://localhost:2003/circle)

package main

import (
	"log"
	"github.com/ajstarks/gensvg"
	"net/http"
)

func main() {
	http.Handle("/circle", http.HandlerFunc(circle))
	err := http.ListenAndServe(":2003", nil)
	if err != nil {
		log.Fatal("ListenAndServe:", err)
	}
}

func circle(w http.ResponseWriter, req *http.Request) {
  w.Header().Set("Content-Type", "image/svg+xml")
  s := gensvg.New(w)
  s.Start(500, 500)
  s.Circle(250, 250, 125, "fill:none;stroke:black")
  s.End()
}

You may view the SVG output with a browser that supports SVG (tested on Chrome, Opera, Firefox and Safari), or any other SVG user-agent such as Batik Squiggle.

Graphics Sketching with gensvg and svgplay

Combined with the svgplay command, gensvg can be used to "sketch" with code in a browser.

To use svgplay and gensvg, first go to a directory with your code, and run:

$ svgplay
2014/06/25 22:05:28 ☠ ☠ ☠ Warning: this server allows a client connecting to 127.0.0.1:1999 to execute code on this computer ☠ ☠ ☠	

Next open your browser to the svgplay server you just started. svgplay only listens on localhost, and uses port 1999 (guess which year SVG was first introduced) by default

http://localhost:1999/

Enter your code in the textarea, and when you are ready to run press Shift--Enter. The code will be compiled, with the results on the right. To update, change the code and repeat. Note that compilation errors are shown in red under the code. In order for svgplay/gensvg to work, make sure that the io.Writer specified with the New function is os.Stdout.

If you want to sketch with an existing file, enter its URL:

http://localhost:1999/foo.go

SVGplay

Papers and presentations

Package contents

  • *.go: Library
  • svgdef: Creates a SVG representation of the API
  • am: Animate motion demo
  • amt: Animate transformation demo
  • android: The Android logo
  • animate: Animation demo
  • benchviz: visualize benchmarks
  • bubtrail: Bubble trails
  • bulletgraph: Bullet Graphs (via Stephen Few)
  • cascade: animation on curves
  • codepic: show code and pictures together
  • colortab: Display SVG named colors with RGB values
  • compx: Component diagrams
  • cube: random cubes
  • f50: Get 50 photos from Flickr based on a query
  • fe: Filter effects
  • flower: Random "flowers"
  • fontcompare: Compare two fonts
  • funnel: Funnel from transparent circles
  • gradient: Linear and radial gradients
  • html5logo: HTML5 logo with draggable elements
  • imfade: Show image fading
  • lewitt: Version of Sol Lewitt's Wall Drawing 91
  • ltr: Layer Tennis Remixes
  • marker: Test markers
  • paths: Demonstrate SVG paths
  • pattern: Test patterns
  • planets: Show the scale of the Solar system
  • pmap: Proportion maps
  • randcomp: Compare random number generators
  • richter: Gerhard Richter's 256 colors
  • rl: Random lines (port of a Processing demo)
  • rpd: read/parse/draw
  • rr: radial graphs
  • skewabc: Skew ABC
  • span: Text span
  • stockproduct: Visualize product and stock prices
  • svgdef: gensvg placemat
  • svgopher: gensvg Mascot
  • svgplay: gensvg sketching server
  • svgplot: Plot data
  • svgrid: Compose SVG files in a grid
  • tsg: Twitter Search Grid
  • tumblrgrid: Tumblr picture grid
  • turbulence: Turbulence filter effect
  • vismem: Visualize data from files
  • webfonts: "Hello, World" with Google Web Fonts
  • websvg: Generate SVG as a web server

Functions and types

Many functions use x, y to specify an object's location, and w, h to specify the object's width and height. Where applicable, a final optional argument specifies the style to be applied to the object. The style strings follow the SVG standard; name:value pairs delimited by semicolons, or a series of name="value" pairs. For example: "fill:none; opacity:0.3" or fill="none" opacity="0.3" (see: http://www.w3.org/TR/SVG11/styling.html)

The SVG type:

type SVG struct {
    Writer   io.Writer
}

Most operations are methods on this type, specifying the destination io.Writer.

The Offcolor type:

type Offcolor struct {
	Offset  uint8
	Color   string
	Opacity float64
}

is used to specify the offset, color, and opacity of stop colors in linear and radial gradients

The Filterspec type:

type Filterspec struct {
	In string
	In2 string
	Result string
}

is used to specify inputs and results for filter effects

Structure, Scripting, Metadata, Transformation and Links

New(w io.Writer) *SVG

Constructor, Specify the output destination.

Start(w int, h int, attributes ...string)

begin the SVG document with the width w and height h. Optionally add additional elements (such as additional namespaces or scripting events) http://www.w3.org/TR/SVG11/struct.html#SVGElement

Startview(w, h, minx, miny, vw, vh int)

begin the SVG document with the width w, height h, with a viewBox at minx, miny, vw, vh. http://www.w3.org/TR/SVG11/struct.html#SVGElement

Startunit(w int, h int, unit string, ns ...string)

begin the SVG document, with width and height in the specified units. Optionally add additional elements (such as additional namespaces or scripting events) http://www.w3.org/TR/SVG11/struct.html#SVGElement

Startpercent(w int, h int, ns ...string)

begin the SVG document, with width and height in percent. Optionally add additional elements (such as additional namespaces or scripting events) http://www.w3.org/TR/SVG11/struct.html#SVGElement

StartviewUnit(w, h int, unit string, minx, miny, vw, vh int)

begin the SVG document with the width w, height h, in the specified unit, with a viewBox at minx, miny, vw, vh. http://www.w3.org/TR/SVG11/struct.html#SVGElement

End()

end the SVG document

Script(scriptype string, data ...string)

Script defines a script with a specified type, (for example "application/javascript"). if the first variadic argument is a link, use only the link reference. Otherwise, treat variadic arguments as the text of the script (marked up as CDATA). if no data is specified, simply close the script element. http://www.w3.org/TR/SVG/script.html

Style(scriptype string, data ...string)

Style defines a script with a specified type, (for example "text/css"). if the first variadic argument is a link, use only the link reference. Otherwise, treat variadic arguments as the text of the script (marked up as CDATA). if no data is specified, simply close the style element. https://www.w3.org/TR/SVG/styling.html#StyleElement

Group(s ...string)

begin a group, with arbitrary attributes http://www.w3.org/TR/SVG11/struct.html#GElement

Gstyle(s string)

begin a group, with the specified style. http://www.w3.org/TR/SVG11/struct.html#GElement

Gid(s string)

begin a group, with the specified id.

Gtransform(s string)

begin a group, with the specified transform, end with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

Translate(x, y int)

begins coordinate translation to (x,y), end with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

Scale(n float64)

scales the coordinate system by n, end with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

ScaleXY(x, y float64)

scales the coordinate system by x, y. End with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

SkewX(a float64)

SkewX skews the x coordinate system by angle a, end with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

SkewY(a float64)

SkewY skews the y coordinate system by angle a, end with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

SkewXY(ax, ay float64)

SkewXY skews x and y coordinate systems by ax, ay respectively, end with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

Rotate(r float64)

rotates the coordinate system by r degrees, end with Gend(). http://www.w3.org/TR/SVG11/coords.html#TransformAttribute

TranslateRotate(x, y int, r float64)

translates the coordinate system to (x,y), then rotates to r degrees, end with Gend().

RotateTranslate(x, y int, r float64)

rotates the coordinate system r degrees, then translates to (x,y), end with Gend().

Gend()

end the group (must be paired with Gstyle, Gtransform, Gid).

ClipPath(s ...string)

Begin a ClipPath http://www.w3.org/TR/SVG/masking.html#ClippingPaths

ClipEnd()

End a ClipPath http://www.w3.org/TR/SVG/masking.html#ClippingPaths

Def()

begin a definition block. http://www.w3.org/TR/SVG11/struct.html#DefsElement

DefEnd()

end a definition block.

Marker(id string, x, y, w, h int, s ...string)

define a marker http://www.w3.org/TR/SVG11/painting.html#MarkerElement

MarkerEnd()

end a marker

Mask(id string, x int, y int, w int, h int, s ...string)

creates a mask with a specified id, dimension, and optional style. http://www.w3.org/TR/SVG/masking.html

MaskEnd()

ends the Mask element.

Pattern(id string, x, y, width, height int, putype string, s ...string)

define a Pattern with the specified dimensions, the putype can be either "user" or "obj", which sets the patternUnits attribute to be either userSpaceOnUse or objectBoundingBox. http://www.w3.org/TR/SVG11/pservers.html#Patterns

Desc(s string)

specify the text of the description. http://www.w3.org/TR/SVG11/struct.html#DescElement

Title(s string)

specify the text of the title. http://www.w3.org/TR/SVG11/struct.html#TitleElement

Link(href string, title string)

begin a link named "href", with the specified title. http://www.w3.org/TR/SVG11/linking.html#Links

LinkEnd()

end the link.

Use(x int, y int, link string, s ...string)

place the object referenced at link at the location x, y. http://www.w3.org/TR/SVG11/struct.html#UseElement

Shapes

Circle(x int, y int, r int, s ...string)

draw a circle, centered at x,y with radius r. http://www.w3.org/TR/SVG11/shapes.html#CircleElement

Circle

Ellipse(x int, y int, w int, h int, s ...string)

draw an ellipse, centered at x,y with radii w, and h. http://www.w3.org/TR/SVG11/shapes.html#EllipseElement

Ellipse

Polygon(x []int, y []int, s ...string)

draw a series of line segments using an array of x, y coordinates. http://www.w3.org/TR/SVG11/shapes.html#PolygonElement

Polygon

Rect(x int, y int, w int, h int, s ...string)

draw a rectangle with upper left-hand corner at x,y, with width w, and height h. http://www.w3.org/TR/SVG11/shapes.html#RectElement

Rect

CenterRect(x int, y int, w int, h int, s ...string)

draw a rectangle with its center at x,y, with width w, and height h.

Roundrect(x int, y int, w int, h int, rx int, ry int, s ...string)

draw a rounded rectangle with upper the left-hand corner at x,y, with width w, and height h. The radii for the rounded portion is specified by rx (width), and ry (height).

Roundrect

Square(x int, y int, s int, style ...string)

draw a square with upper left corner at x,y with sides of length s.

Square

Paths

Path(p string, s ...style)

draw the arbitrary path as specified in p, according to the style specified in s. http://www.w3.org/TR/SVG11/paths.html

Arc(sx int, sy int, ax int, ay int, r int, large bool, sweep bool, ex int, ey int, s ...string)

draw an elliptical arc beginning coordinate at sx,sy, ending coordinate at ex, ey width and height of the arc are specified by ax, ay, the x axis rotation is r

if sweep is true, then the arc will be drawn in a "positive-angle" direction (clockwise), if false, the arc is drawn counterclockwise.

if large is true, the arc sweep angle is greater than or equal to 180 degrees, otherwise the arc sweep is less than 180 degrees. http://www.w3.org/TR/SVG11/paths.html#PathDataEllipticalArcCommands

Arc

Bezier(sx int, sy int, cx int, cy int, px int, py int, ex int, ey int, s ...string)

draw a cubic bezier curve, beginning at sx,sy, ending at ex,ey with control points at cx,cy and px,py. http://www.w3.org/TR/SVG11/paths.html#PathDataCubicBezierCommands

Bezier

Qbezier(sx int, sy int, cx int, cy int, ex int, ey int, tx int, ty int, s ...string)

draw a quadratic bezier curve, beginning at sx, sy, ending at tx,ty with control points are at cx,cy, ex,ey. http://www.w3.org/TR/SVG11/paths.html#PathDataQuadraticBezierCommands

Qbezier

Qbez(sx int, sy int, cx int, cy int, ex int, ey int, s...string)

draws a quadratic bezier curver, with optional style beginning at sx,sy, ending at ex, sy with the control point at cx, cy. http://www.w3.org/TR/SVG11/paths.html#PathDataQuadraticBezierCommands

Qbez

Lines

Line(x1 int, y1 int, x2 int, y2 int, s ...string)

draw a line segment between x1,y1 and x2,y2. http://www.w3.org/TR/SVG11/shapes.html#LineElement

Line

Polyline(x []int, y []int, s ...string)

draw a polygon using coordinates specified in x,y arrays. http://www.w3.org/TR/SVG11/shapes.html#PolylineElement

Polyline

Image and Text

Image(x int, y int, w int, h int, link string, s ...string)

place at x,y (upper left hand corner), the image with width w, and height h, referenced at link. http://www.w3.org/TR/SVG11/struct.html#ImageElement

Image

Text(x int, y int, t string, s ...string)

Place the specified text, t at x,y according to the optional style specified in s. http://www.w3.org/TR/SVG11/text.html#TextElement

Textspan(x int, y int, t string, s ...string)

Place specified text, t at x,y according to the optional style specified in s. https://www.w3.org/TR/SVG11/text.html#TSpanElement Use this method with Span(...). End with TextEnd()

Span(t string, s ...string)

Create a text span t, using optional style s

TextEnd()

End a text span

Textlines(x, y int, s []string, size, spacing int, fill, align string)

Places lines of text in s, starting at x,y, at the specified size, fill, and alignment, and spacing.

Textpath(t string, pathid string, s ...string)

places optionally styled text along a previously defined path. http://www.w3.org/TR/SVG11/text.html#TextPathElement Image

Color

RGB(r int, g int, b int) string

creates a style string for the fill color designated by the (r)ed, g(reen), (b)lue components. http://www.w3.org/TR/css3-color/

RGBA(r int, g int, b int, a float64) string

as above, but includes the color's opacity as a value between 0.0 (fully transparent) and 1.0 (opaque).

Gradients

LinearGradient(id string, x1, y1, x2, y2 uint8, sc []Offcolor)

constructs a linear color gradient identified by id, along the vector defined by (x1,y1), and (x2,y2). The stop color sequence defined in sc. Coordinates are expressed as percentages. http://www.w3.org/TR/SVG11/pservers.html#LinearGradients LinearGradient

RadialGradient(id string, cx, cy, r, fx, fy uint8, sc []Offcolor)

constructs a radial color gradient identified by id, centered at (cx,cy), with a radius of r. (fx, fy) define the location of the focal point of the light source. The stop color sequence defined in sc. Coordinates are expressed as percentages. http://www.w3.org/TR/SVG11/pservers.html#RadialGradients

RadialGradient

Animation

Animate(link, attr string, from, to int, duration float64, repeat int, s ...string)

Animate animates the item referenced by the link, using the specified attribute The animation starts at coordinate from, terminates at to, and repeats as specified. Addtional attributes may be added as needed. https://www.w3.org/TR/SVG11/animate.html#AnimateElement

AnimateMotion(link, path string, duration float64, repeat int, s ...string) 

AnimateMotion animates the referenced object link along the specified path https://www.w3.org/TR/SVG11/animate.html#AnimateMotionElement

AnimateTranslate(link string, fx, fy, tx, ty int, duration float64, repeat int, s ...string)

AnimateTranslate animates the translation transformation (link refers to the object to animate, fx, fy are from coordinates, tx, ty are the to coordinates) https://www.w3.org/TR/SVG11/animate.html#AnimateTransformElement

AnimateRotate(link string, fs, fc, fe, ts, tc, te int, duration float64, repeat int, s ...string)

AnimateRotate animates the rotation transformation (link refers to the object to animate, f[s,c,e] are the from start, center, and end angles, t[s,c,e] are the start, center, and end angles) https://www.w3.org/TR/SVG11/animate.html#AnimateTransformElement

AnimateScale(link string, from, to, duration float64, repeat int, s ...string)

AnimateScale animates the scale transformation (link refers to the object to animate, from and to specify the scaling factor) https://www.w3.org/TR/SVG11/animate.html#AnimateTransformElement

AnimateSkewX(link string, from, to, duration float64, repeat int, s ...string)

AnimateSkewX animates the skewX transformation ((link refers to the object to animate, from and to specify the skew angle) https://www.w3.org/TR/SVG11/animate.html#AnimateTransformElement

AnimateSkewY(link string, from, to, duration float64, repeat int, s ...string)

AnimateSkewY animates the skewY transformation (link refers to the object to animate, and from and to specify the skew angle) https://www.w3.org/TR/SVG11/animate.html#AnimateTransformElement

Filter Effects

Filter(id string, s ...string)

Filter begins a filter set Standard reference: http://www.w3.org/TR/SVG11/filters.html#FilterElement

Fend() 

Fend ends a filter set Standard reference: http://www.w3.org/TR/SVG11/filters.html#FilterElement

FeBlend(fs Filterspec, mode string, s ...string) 

FeBlend specifies a Blend filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feBlendElement

FeColorMatrix(fs Filterspec, values [20]float64, s ...string)	

FeColorMatrix specifies a color matrix filter primitive, with matrix values Standard reference: http://www.w3.org/TR/SVG11/filters.html#feColorMatrixElement

FeColorMatrixHue(fs Filterspec, value float64, s ...string)  	

FeColorMatrix specifies a color matrix filter primitive, with hue values Standard reference: http://www.w3.org/TR/SVG11/filters.html#feColorMatrixElement

FeColorMatrixSaturate(fs Filterspec, value float64, s ...string) 

FeColorMatrix specifies a color matrix filter primitive, with saturation values Standard reference: http://www.w3.org/TR/SVG11/filters.html#feColorMatrixElement

FeColorMatrixLuminence(fs Filterspec, s ...string) 

FeColorMatrix specifies a color matrix filter primitive, with luminence values Standard reference: http://www.w3.org/TR/SVG11/filters.html#feColorMatrixElement

FeComponentTransfer()  	

FeComponentTransfer begins a feComponent filter Element> Standard reference: http://www.w3.org/TR/SVG11/filters.html#feComponentTransferElement

FeCompEnd()

FeCompEnd ends a feComponent filter Element>

FeComposite(fs Filterspec, operator string, k1, k2, k3, k4 int, s ...string)

FeComposite specifies a feComposite filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feCompositeElement

FeConvolveMatrix(fs Filterspec, matrix [9]int, s ...string)

FeConvolveMatrix specifies a feConvolveMatrix filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feConvolveMatrixElement

 FeDiffuseLighting(fs Filterspec, scale, constant float64, s ...string) 

FeDiffuseLighting specifies a diffuse lighting filter primitive, a container for light source Element>s, end with DiffuseEnd()

 FeDiffEnd()

FeDiffuseEnd ends a diffuse lighting filter primitive container Standard reference: http://www.w3.org/TR/SVG11/filters.html#feDiffuseLightingElement

 FeDisplacementMap(fs Filterspec, scale float64, xchannel, ychannel string, s ...string)

FeDisplacementMap specifies a feDisplacementMap filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feDisplacementMapElement

 FeDistantLight(fs Filterspec, azimuth, elevation float64, s ...string)

FeDistantLight specifies a feDistantLight filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feDistantLightElement

 FeFlood(fs Filterspec, color string, opacity float64, s ...string)

FeFlood specifies a flood filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feFloodElement

FeFuncLinear(channel string, slope, intercept float64)

FeFuncLinear is the linear form of feFunc Standard reference: http://www.w3.org/TR/SVG11/filters.html#feComponentTransferElement

 FeFuncGamma(channel, amplitude, exponent, offset float64)

FeFuncGamma is the gamma curve form of feFunc Standard reference: http://www.w3.org/TR/SVG11/filters.html#feComponentTransferElement

FeFuncTable(channel string, tv []float64)

FeFuncGamma is the form of feFunc using a table of values Standard reference: http://www.w3.org/TR/SVG11/filters.html#feComponentTransferElement

FeFuncDiscrete(channel string, tv []float64)

FeFuncGamma is the form of feFunc using discrete values Standard reference: http://www.w3.org/TR/SVG11/filters.html#feComponentTransferElement

 FeGaussianBlur(fs Filterspec, stdx, stdy float64, s ...string)

FeGaussianBlur specifies a Gaussian Blur filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feGaussianBlurElement

 FeImage(href string, result string, s ...string)

FeImage specifies a feImage filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feImageElement

 FeMerge(nodes []string, s ...string)

FeMerge specifies a feMerge filter primitive, containing feMerge Element>s Standard reference: http://www.w3.org/TR/SVG11/filters.html#feMergeElement

 FeMorphology(fs Filterspec, operator string, xradius, yradius float64, s ...string)

FeMorphologyLight specifies a feMorphologyLight filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feMorphologyElement

 FeOffset(fs Filterspec, dx, dy int, s ...string)

FeOffset specifies the feOffset filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feOffsetElement

 FePointLight(x, y, z float64, s ...string)

FePointLight specifies a fePpointLight filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#fePointLightElement

 FeSpecularLighting(fs Filterspec, scale, constant float64, exponent int, color string, s ...string)

FeSpecularLighting specifies a specular lighting filter primitive, a container for light source elements, end with SpecularEnd()

 FeSpecEnd()

FeSpecularEnd ends a specular lighting filter primitive container Standard reference: http://www.w3.org/TR/SVG11/filters.html#feSpecularLightingElement

 FeSpotLight(fs Filterspec, x, y, z, px, py, pz float64, s ...string)

FeSpotLight specifies a feSpotLight filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feSpotLightElement

 FeTile(fs Filterspec, in string, s ...string)

FeTile specifies the tile utility filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feTileElement

 FeTurbulence(fs Filterspec, ftype string, bfx, bfy float64, octaves int, seed int64, stitch bool, s ...string)

FeTurbulence specifies a turbulence filter primitive Standard reference: http://www.w3.org/TR/SVG11/filters.html#feTurbulenceElement

Filter convenience functions (modeled on CSS filter effects)

Blur(p float64)

Blur function by standard deviation

Brightness(p float64)

Brightness function (0-100)

Grayscale()

Apply a grayscale filter to the image

HueRotate(a float64)

Rotate Hues (0-360 degrees)

Invert()

Invert the image's colors

Saturate(p float64)

Percent saturation, 0 is grayscale

Sepia()

Apply sepia tone

Utility

Grid(x int, y int, w int, h int, n int, s ...string)

draws a grid of straight lines starting at x,y, with a width w, and height h, and a size of n.

Grid

Credits

Thanks to Jonathan Wright for the io.Writer update.

Owner
Anthony Starks
Human Being
Anthony Starks
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Rotating File writer An io.writer & io.Closer compliant file writer that will always write to the path that you give it, even if somebody deletes/rena

Jul 12, 2021

Optimized bit-level Reader and Writer for Go.

bitio Package bitio provides an optimized bit-level Reader and Writer for Go. You can use Reader.ReadBits() to read arbitrary number of bits from an i

Dec 1, 2022

A minimalist Go PDF writer in 1982 lines. Draws text, images and shapes. Helps understand the PDF format. Used in production for reports.

A minimalist Go PDF writer in 1982 lines. Draws text, images and shapes. Helps understand the PDF format. Used in production for reports.

one-file-pdf - A minimalist PDF generator in 2K lines and 1 file The main idea behind this project was: "How small can I make a PDF generator for it

Dec 11, 2022

go-colorable - Colorable writer for Windows

go-colorable - Colorable writer for Windows

go-colorable Colorable writer for windows. For example, most of logger packages doesn't show colors on windows. (I know we can do it with ansicon. But

Dec 21, 2022

Golang io.Reader and io.Writer but with limits

LimitIO io.Reader and io.Writer with limit.

Dec 14, 2022

csv reader/writer.

IO csv reader sample version 0.0.1-SNAPSHOT Goals: main: read huge file, hex substring, write to new file. cmd/v2 version can read and write use ony o

Nov 4, 2021

csv reader/writer and csv generator.

IO csv reader sample version 0.0.1-SNAPSHOT Goals: main: read huge file, hex substring, write to new file. repo has 2 version. v1 can read a file and

Nov 4, 2021

Simple binary reader and writer

Simple binary reader and writer

Simple Binary Stream Reader/Writer This package contains a set of simple utility reader and writer that can be used to efficiently read/write binary i

Oct 30, 2022

A drop-in replacement to any Writer type, which also calculates a hash using the provided hash type.

writehasher A drop-in replacement to any Writer type, which also calculates a hash using the provided hash type. Example package main import ( "fmt"

Jan 10, 2022

Cheap/fast/simple XLSX file writer for textual data

xlsxwriter Cheap/fast/simple XLSX file writer for textual data -- no fancy formatting or graphs go get github.com/mzimmerman/xlsxwriter data := [][]s

Feb 8, 2022

2D rendering for different output (raster, pdf, svg)

2D rendering for different output (raster, pdf, svg)

draw2d Package draw2d is a go 2D vector graphics library with support for multiple outputs such as images (draw2d), pdf documents (draw2dpdf), opengl

Dec 25, 2022

Rasterx is an SVG 2.0 path compliant rasterizer that can use either the golang vector or a derivative of the freetype anti-aliaser.

Rasterx is an SVG 2.0 path compliant rasterizer that can use either the golang vector or a derivative of the freetype anti-aliaser.

rasterx Rasterx is a golang rasterizer that implements path stroking functions capable of SVG 2.0 compliant 'arc' joins and explicit loop closing. Pat

Nov 1, 2022

Go Language Library for SVG generation

Go Language Library for SVG generation

SVGo: A Go library for SVG generation The library generates SVG as defined by the Scalable Vector Graphics 1.1 Specification (http://www.w3.org/TR/SVG

Jan 6, 2023

Cairo in Go: vector to SVG, PDF, EPS, raster, HTML Canvas, etc.

Cairo in Go: vector to SVG, PDF, EPS, raster, HTML Canvas, etc.

Canvas is a common vector drawing target that can output SVG, PDF, EPS, raster images (PNG, JPG, GIF, ...), HTML Canvas through WASM, and OpenGL. It h

Dec 25, 2022

A simple API written in Go that creates badges in SVG format, based on the requested route.

A simple API written in Go that creates badges in SVG format, based on the requested route. Those graphics can be used to style README.md files, or to add tags to webpages.

Jul 2, 2021

Quick and dirty Minecraft player head to SVG converter

Head SVG Quick and dirty Minecraft player head to SVG converter. Can be used to generate player head icons. Usage usage: Head SVG [-h|--help] -n|--nam

May 29, 2022
Related tags
Rasterx is an SVG 2.0 path compliant rasterizer that can use either the golang vector or a derivative of the freetype anti-aliaser.
Rasterx is an SVG 2.0 path compliant rasterizer that can use either the golang vector or a derivative of the freetype anti-aliaser.

rasterx Rasterx is a golang rasterizer that implements path stroking functions capable of SVG 2.0 compliant 'arc' joins and explicit loop closing. Pat

Nov 1, 2022
Go Language Library for SVG generation
Go Language Library for SVG generation

SVGo: A Go library for SVG generation The library generates SVG as defined by the Scalable Vector Graphics 1.1 Specification (http://www.w3.org/TR/SVG

Jan 6, 2023
Cairo in Go: vector to SVG, PDF, EPS, raster, HTML Canvas, etc.
Cairo in Go: vector to SVG, PDF, EPS, raster, HTML Canvas, etc.

Canvas is a common vector drawing target that can output SVG, PDF, EPS, raster images (PNG, JPG, GIF, ...), HTML Canvas through WASM, and OpenGL. It h

Dec 25, 2022
A simple API written in Go that creates badges in SVG format, based on the requested route.

A simple API written in Go that creates badges in SVG format, based on the requested route. Those graphics can be used to style README.md files, or to add tags to webpages.

Jul 2, 2021
Very simple SVG to PNG converter library using the Inkscape.

svg2png Description Very simple SVG to PNG converter library using the Inkscape.

Jan 11, 2022
Snippit - Creates syntax-highlighted code snippets in png or svg format
Snippit - Creates syntax-highlighted code snippets in png or svg format

snippit creates syntax-highlighted code snippets in png or svg format. Installat

Oct 10, 2022
Go-binsize-treemap - Go binary size SVG treemap

?? Go binary size SVG treemap Make treemap breakdown of Go executable binary $ g

Dec 21, 2022
Cryptseaside generates seaside images using Unix nanoseconds as the seed value.
Cryptseaside generates seaside images using Unix nanoseconds as the seed value.

Cryptseaside Welcome to the Cryptseaside project. Cryptseaside generates seaside images using Unix nanoseconds as the seed value.

Nov 12, 2021
A sample FaaS function that gets a stock quote and 30 day history by symbol and returns a HTML page with a generates SVG sparkline.

faas stonks This uses serverless technology to get a stock quote and 30 day sparkline from Yahoo Finance. Deployment Nimbella account Namespace with o

Sep 23, 2021
go-colorable - Colorable writer for windows.
go-colorable - Colorable writer for windows.

go-colorable Colorable writer for windows. For example, most of logger packages doesn't show colors on windows. (I know we can do it with ansicon. But

Dec 30, 2022