Files
barter-app/components/vue-canvas-poster/gradient.js

103 lines
3.7 KiB
JavaScript

/* eslint-disable */
export const api = {
isGradient: function(bg) {
if (bg && (bg.startsWith('linear') || bg.startsWith('radial'))) {
return true
}
return false
},
doGradient: function(bg, width, height, ctx) {
if (bg.startsWith('linear')) {
linearEffect(width, height, bg, ctx)
} else if (bg.startsWith('radial')) {
radialEffect(width, height, bg, ctx)
}
}
}
function analizeGrad(string) {
const colorPercents = string.substring(0, string.length - 1).split('%,')
const colors = []
const percents = []
for (let colorPercent of colorPercents) {
colors.push(colorPercent.substring(0, colorPercent.lastIndexOf(' ')).trim())
percents.push(colorPercent.substring(colorPercent.lastIndexOf(' '), colorPercent.length) / 100)
}
return { colors: colors, percents: percents }
}
function radialEffect(width, height, bg, ctx) {
const colorPer = analizeGrad(bg.match(/radial-gradient\((.+)\)/)[1])
const grd = ctx.createRadialGradient(0, 0, 0, 0, 0, width < height ? height / 2 : width / 2)
for (let i = 0; i < colorPer.colors.length; i++) {
grd.addColorStop(colorPer.percents[i], colorPer.colors[i])
}
ctx.fillStyle = grd
//ctx.fillRect(-(width / 2), -(height / 2), width, height);
}
function analizeLinear(bg, width, height) {
const direction = bg.match(/([-]?\d{1,3})deg/)
const dir = direction && direction[1] ? parseFloat(direction[1]) : 0
let coordinate
switch (dir) {
case 0:
coordinate = [0, -height / 2, 0, height / 2]
break
case 90:
coordinate = [width / 2, 0, -width / 2, 0]
break
case -90:
coordinate = [-width / 2, 0, width / 2, 0]
break
case 180:
coordinate = [0, height / 2, 0, -height / 2]
break
case -180:
coordinate = [0, -height / 2, 0, height / 2]
break
default:
let x1 = 0
let y1 = 0
let x2 = 0
let y2 = 0
if (direction[1] > 0 && direction[1] < 90) {
x1 = width / 2 - (((width / 2) * Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) - height / 2) * Math.sin((2 * (90 - direction[1]) * Math.PI * 2) / 360)) / 2
y2 = Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) * x1
x2 = -x1
y1 = -y2
} else if (direction[1] > -180 && direction[1] < -90) {
x1 = -(width / 2) + (((width / 2) * Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) - height / 2) * Math.sin((2 * (90 - direction[1]) * Math.PI * 2) / 360)) / 2
y2 = Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) * x1
x2 = -x1
y1 = -y2
} else if (direction[1] > 90 && direction[1] < 180) {
x1 = width / 2 + ((-(width / 2) * Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) - height / 2) * Math.sin((2 * (90 - direction[1]) * Math.PI * 2) / 360)) / 2
y2 = Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) * x1
x2 = -x1
y1 = -y2
} else {
x1 = -(width / 2) - ((-(width / 2) * Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) - height / 2) * Math.sin((2 * (90 - direction[1]) * Math.PI * 2) / 360)) / 2
y2 = Math.tan(((90 - direction[1]) * Math.PI * 2) / 360) * x1
x2 = -x1
y1 = -y2
}
coordinate = [x1, y1, x2, y2]
break
}
return coordinate
}
function linearEffect(width, height, bg, ctx) {
const param = analizeLinear(bg, width, height)
const grd = ctx.createLinearGradient(param[0], param[1], param[2], param[3])
const content = bg.match(/linear-gradient\((.+)\)/)[1]
const colorPer = analizeGrad(content.substring(content.indexOf(',') + 1))
for (let i = 0; i < colorPer.colors.length; i++) {
grd.addColorStop(colorPer.percents[i], colorPer.colors[i])
}
ctx.fillStyle = grd
//ctx.fillRect(-(width / 2), -(height / 2), width, height);
}