giocanvas

package module
v0.0.0-...-919e581 Latest Latest
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 Go to latest Published: Jul 29, 2020 License: MIT, Unlicense Imports: 19 Imported by: 0

README

giocanvas -- a canvas API built on top of gio

(Note: this code is under development and the API may change)

canvas API

Documentation

Overview

Package giocanvas is a 2D canvas API built on gio

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func ColorLookup 

func ColorLookup(s string) color.RGBA

ColorLookup returns a color.RGBA corresponding to the named color or "rgb(r)", "rgb(r,b)", "rgb(r,g,b), "rgb(r,g,b,a)" string. On error, return black.

func EndTransform 

func EndTransform(stack op.StackOp)

EndTransform ends a transformation

func MapRange 

func MapRange(value, low1, high1, low2, high2 float64) float64

MapRange maps a value between low1 and high1, return the corresponding value between low2 and high2

Types

type Canvas 

type Canvas struct {
	Width, Height float32
	TextColor     color.RGBA
	Context       layout.Context
}

Canvas defines the Gio canvas

func NewCanvas 

func NewCanvas(width, height float32, e system.FrameEvent) *Canvas

NewCanvas initializes a Canvas

func (*Canvas) AbsArc 

func (c *Canvas) AbsArc(x, y, radius float32, start, end float64, fillcolor color.RGBA)

AbsArc makes circulr arc centered at (x, y), through angles start and end; the angles are measured in radians and increase clockwise N.B: derived from the clipLoader function in widget/material/loader.go

func (*Canvas) AbsCenterImage 

func (c *Canvas) AbsCenterImage(name string, x, y float32, w, h int, scale float32)

AbsCenterImage places a named image centered at (x, y) using the specified dimensions (w, h), and hen scaled

func (*Canvas) AbsCenterRect 

func (c *Canvas) AbsCenterRect(x, y, w, h float32, fillcolor color.RGBA)

AbsCenterRect makes a filled rectangle centered at (x, y), with dimensions (w,h)

func (*Canvas) AbsCircle 

func (c *Canvas) AbsCircle(x, y, radius float32, fillcolor color.RGBA)

AbsCircle makes a circle centered at (x, y), radius r

func (*Canvas) AbsCubicBezier 

func (c *Canvas) AbsCubicBezier(x, y, cx1, cy1, cx2, cy2, ex, ey, size float32, fillcolor color.RGBA)

AbsCubicBezier makes a cubic bezier curve

func (*Canvas) AbsEllipse 

func (c *Canvas) AbsEllipse(x, y, w, h float32, fillcolor color.RGBA)

AbsEllipse makes a ellipse centered at (x, y) radii (w, h)

func (*Canvas) AbsGrid 

func (c *Canvas) AbsGrid(width, height, size, interval float32, fillcolor color.RGBA)

AbsGrid uses horizontal and vertical lines to make a grid

func (*Canvas) AbsHLine 

func (c *Canvas) AbsHLine(x, y, w, h float32, fillcolor color.RGBA)

AbsHLine makes a horizontal line starting at (x, y), with dimensions (w, h)

func (*Canvas) AbsImg 

func (c *Canvas) AbsImg(im image.Image, x, y float32, w, h int, scale float32)

AbsImg places a image.Image centered at (x, y) using the specified dimensions (w, h), and then scaled

func (*Canvas) AbsLine 

func (c *Canvas) AbsLine(x0, y0, x1, y1, size float32, fillcolor color.RGBA)

AbsLine makes a line from (x0,y0) to (x1, y1) using absolute coordinates

func (*Canvas) AbsPolygon 

func (c *Canvas) AbsPolygon(x, y []float32, fillcolor color.RGBA)

AbsPolygon makes a closed, filled polygon with vertices in x and y

func (*Canvas) AbsQuadBezier 

func (c *Canvas) AbsQuadBezier(x, y, cx, cy, ex, ey, size float32, fillcolor color.RGBA)

AbsQuadBezier makes a quadratic curve starting at (x, y), control point at (cx, cy), end point (ex, ey)

func (*Canvas) AbsRect 

func (c *Canvas) AbsRect(x, y, w, h float32, fillcolor color.RGBA)

AbsRect makes a filled Rectangle; left corner at (x, y), with dimensions (w,h)

func (*Canvas) AbsRotate 

func (c *Canvas) AbsRotate(x, y, angle float32) op.StackOp

AbsRotate rotates around (x,y) using angle (radians)

func (*Canvas) AbsScale 

func (c *Canvas) AbsScale(x, y, factor float32) op.StackOp

AbsScale scales by factor at (x,y)

func (*Canvas) AbsShear 

func (c *Canvas) AbsShear(x, y, ax, ay float32) op.StackOp

AbsShear shears at (x,y) using angle ax and ay

func (*Canvas) AbsText 

func (c *Canvas) AbsText(x, y, size float32, s string, fillcolor color.RGBA)

AbsText places text at (x,y)

func (*Canvas) AbsTextEnd 

func (c *Canvas) AbsTextEnd(x, y, size float32, s string, fillcolor color.RGBA)

AbsTextEnd places text aligned to the end

func (*Canvas) AbsTextMid 

func (c *Canvas) AbsTextMid(x, y, size float32, s string, fillcolor color.RGBA)

AbsTextMid places text centered at (x,y)

func (*Canvas) AbsTextWrap 

func (c *Canvas) AbsTextWrap(x, y, size, width float32, s string, fillcolor color.RGBA)

AbsTextWrap places and wraps text at (x, y), wrapped at width

func (*Canvas) AbsTranslate 

func (c *Canvas) AbsTranslate(x, y float32) op.StackOp

AbsTranslate moves current location by (x,y)

func (*Canvas) AbsVLine 

func (c *Canvas) AbsVLine(x, y, w, h float32, fillcolor color.RGBA)

AbsVLine makes a vertical line beginning at (x,y) with dimension (w, h)

func (*Canvas) Arc 

func (c *Canvas) Arc(x, y, r float32, a1, a2 float64, fillcolor color.RGBA)

Arc makes a filled arc, using percentage-based measures center is (x, y) the arc begins at angle a1, and ends at a2, with radius r. The arc is filled with the specified color.

func (*Canvas) ArcLine 

func (c *Canvas) ArcLine(x, y, r float32, a1, a2 float64, size float32, fillcolor color.RGBA)

ArcLine makes a stroked arc, using percentage-based measures center is (x, y), the arc begins at angle a1, and ends at a2, with radius r. The arc is stroked with the specified stroke size and color

func (*Canvas) Background 

func (c *Canvas) Background(fillcolor color.RGBA)

Background makes a filled rectangle covering the whole canvas

func (*Canvas) CText 

func (c *Canvas) CText(x, y, size float32, s string, fillcolor color.RGBA)

CText - alternative name for TextMid

func (*Canvas) CenterImage 

func (c *Canvas) CenterImage(name string, x, y float32, w, h int, scale float32)

CenterImage places a scaled image centered at (x,y), using percentage coordinates and scales

func (*Canvas) CenterRect 

func (c *Canvas) CenterRect(x, y, w, h float32, fillcolor color.RGBA)

CenterRect makes a rectangle using percentage-based measures with center at (x,y), sized at (w,h)

func (*Canvas) Circle 

func (c *Canvas) Circle(x, y, r float32, fillcolor color.RGBA)

Circle makes a filled circle, using percentage-based measures center is (x,y), radius r

func (*Canvas) Coord 

func (c *Canvas) Coord(x, y, size float32, s string, fillcolor color.RGBA)

Coord shows the specified coordinate, using percentage-based coordinates the (x, y) label is above the point, with a label below

func (*Canvas) CornerRect 

func (c *Canvas) CornerRect(x, y, w, h float32, fillcolor color.RGBA)

CornerRect makes a rectangle using percentage-based measures upper left corner at (x,y), with sized at (w,h)

func (*Canvas) CubeCurve 

func (c *Canvas) CubeCurve(x, y, cx1, cy1, cx2, cy2, ex, ey float32, fillcolor color.RGBA)

CubeCurve makes a cubic Bezier curve, using percentage-based measures starting at (x, y), control points at (cx1, cy1), (cx2, cy2), end point (ex, ey)

func (*Canvas) Curve 

func (c *Canvas) Curve(x, y, cx, cy, ex, ey float32, fillcolor color.RGBA)

Curve makes a quadric Bezier curve, using percentage-based measures starting at (x, y), control point at (cx, cy), end point (ex, ey)

func (*Canvas) EText 

func (c *Canvas) EText(x, y, size float32, s string, fillcolor color.RGBA)

EText - alternative name for TextEnd

func (*Canvas) Ellipse 

func (c *Canvas) Ellipse(x, y, w, h float32, fillcolor color.RGBA)

Ellipse makes a filled circle, using percentage-based measures center is (x,y), radii (w, h)

func (*Canvas) Grid 

func (c *Canvas) Grid(x, y, w, h, size, interval float32, linecolor color.RGBA)

Grid makes vertical and horizontal grid lines, percentage-based coordinates

func (*Canvas) HLine 

func (c *Canvas) HLine(x, y, linewidth, size float32, linecolor color.RGBA)

HLine makes a horizontal line starting at (x, y), with dimensions (w, h) the line begin at (x,y) and extends to the left by linewidth

func (*Canvas) Image 

func (c *Canvas) Image(name string, x, y float32, w, h int, scale float32)

Image places a scaled image centered at (x,y), reading from a named file, using percetage coordinates and scales

func (*Canvas) Img 

func (c *Canvas) Img(im image.Image, x, y float32, w, h int, scale float32)

Img places a scaled image centered at (x, y), data from image.Image using percentage coordinates and scales

func (*Canvas) Line 

func (c *Canvas) Line(x0, y0, x1, y1, size float32, strokecolor color.RGBA)

Line makes a stroked line using percentage-based measures from (x0, y0) to (x1, y1), stroke width size

func (*Canvas) Polar 

func (c *Canvas) Polar(cx, cy, r, theta float32) (float32, float32)

Polar returns the Cartesian coordinates (x, y) from polar coordinates with compensation for canvas aspect ratio center at (cx, cy), radius r, and angle theta (radians)

func (*Canvas) PolarDegrees 

func (c *Canvas) PolarDegrees(cx, cy, r, theta float32) (float32, float32)

PolarDegrees returns the Cartesian coordinates (x, y) from polar coordinates with compensation for canvas aspect ratio center at (cx, cy), radius r, and angle theta (degrees)

func (*Canvas) Polygon 

func (c *Canvas) Polygon(x, y []float32, fillcolor color.RGBA)

Polygon makes a filled polygon using percentage-based measures vertices in x and y,

func (*Canvas) QuadCurve 

func (c *Canvas) QuadCurve(x, y, cx, cy, ex, ey float32, fillcolor color.RGBA)

QuadCurve makes a quadric Bezier curve, using percentage-based measures starting at (x, y), control point at (cx, cy), end point (ex, ey)

func (*Canvas) Rect 

func (c *Canvas) Rect(x, y, w, h float32, fillcolor color.RGBA)

Rect makes a rectangle using percentage-based measures upper left corner at (x,y), with size at (w,h)

func (*Canvas) Rotate 

func (c *Canvas) Rotate(x, y, angle float32) op.StackOp

Rotate around (x,y) by angle (radians) using percentage-based measures

func (*Canvas) Scale 

func (c *Canvas) Scale(x, y, factor float32) op.StackOp

Scale centered at (x,y) by factor using percentage-based measures

func (*Canvas) Shear 

func (c *Canvas) Shear(x, y, ax, ay float32) op.StackOp

Shear the object centered at (x,y) using x-angle and y-angle (radians) using percentage-based measures

func (*Canvas) Square 

func (c *Canvas) Square(x, y, w float32, fillcolor color.RGBA)

Square makes a square shape, using percentage based measures centered at (x, y), sides are w. Accounts for screen aspect

func (*Canvas) Text 

func (c *Canvas) Text(x, y, size float32, s string, fillcolor color.RGBA)

Text places text using percentage-based measures left at x, baseline at y, at the specified size and color

func (*Canvas) TextEnd 

func (c *Canvas) TextEnd(x, y, size float32, s string, fillcolor color.RGBA)

TextEnd places text using percentage-based measures x is the end of the string, baseline at y, using specified size and color

func (*Canvas) TextMid 

func (c *Canvas) TextMid(x, y, size float32, s string, fillcolor color.RGBA)

TextMid places text using percentage-based measures text is centered at x, baseline y, using specied size and color

func (*Canvas) TextWrap 

func (c *Canvas) TextWrap(x, y, size, width float32, s string, fillcolor color.RGBA)

TextWrap places and wraps text using percentage-based measures text begins at (x,y), baseline y, and wraps at width, using specied size and color

func (*Canvas) Translate 

func (c *Canvas) Translate(x, y float32) op.StackOp

Translate moves current location by (x,y) using percentage-based measures

func (*Canvas) VLine 

func (c *Canvas) VLine(x, y, lineheight, size float32, linecolor color.RGBA)

VLine makes a vertical line beginning at (x,y) with dimension (w, h) the line begins at (x,y) and moves upward by linewidth

Source Files

View all Source files

Directories

Path Synopsis
confetti -- random shapes
 confetti -- random shapes
Package chart makes charts using the gio canvas
 Package chart makes charts using the gio canvas
gchart
gchart -- command line chart using giocanvas chart package
 gchart -- command line chart using giocanvas chart package
concentric circles
 concentric circles
confetti -- random shapes
 confetti -- random shapes
eclipse illustrates the eclipse
 eclipse illustrates the eclipse
flowers demonstrated transforms with "flowers"
 flowers demonstrated transforms with "flowers"
hello is the giocanvas hello, world
 hello is the giocanvas hello, world
lines tests line drawing
 lines tests line drawing
mondrian makes Composition II with Red Blue and Yellow by Piet Mondrian
 mondrian makes Composition II with Red Blue and Yellow by Piet Mondrian
play demos the giocanvas API
 play demos the giocanvas API
rl makes random lines
 rl makes random lines
tile makes a tiling visual
 tile makes a tiling visual
transform tests affine transforms
 transform tests affine transforms

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