ESPTerm web interface submodule, separated to make testing and development easier
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espterm-front-end/js/term/font_cache.js

202 lines
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7 years ago
module.exports = class GLFontCache {
constructor (gl) {
this.gl = gl
// cache: string => WebGLTexture
this.cache = new Map()
this.dp = 1
this.cellSize = { width: 0, height: 0 }
this.canvas = document.createElement('canvas')
this.ctx = this.canvas.getContext('2d')
}
clearCache () {
for (let texture of this.cache.values()) this.gl.deleteTexture(texture)
this.cache = new Map()
}
getChar (font, character) {
let name = `${font}@${this.dp}x:${character}`
if (!this.cache.has(name)) {
this.cache.set(name, this.render(font, character))
}
return this.cache.get(name)
}
render (font, character) {
const { gl, ctx, dp, cellSize } = this
let width = dp * cellSize.width * 3
let height = dp * cellSize.height * 3
if (this.canvas.width !== width) this.canvas.width = width
if (this.canvas.height !== height) this.canvas.height = height
ctx.setTransform(1, 0, 0, 1, 0, 0)
ctx.clearRect(0, 0, width, height)
ctx.scale(dp, dp)
if (ctx.font !== font) ctx.font = font
ctx.textAlign = 'center'
ctx.textBaseline = 'middle'
ctx.fillStyle = 'white'
this.drawCharacter(character)
7 years ago
let imageData = ctx.getImageData(0, 0, width, height)
let texture = gl.createTexture()
gl.bindTexture(gl.TEXTURE_2D, texture)
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, imageData)
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
return texture
}
drawCharacter (character) {
const { ctx, cellSize } = this
let screenX = cellSize.width
let screenY = cellSize.height
let codePoint = character.codePointAt(0)
if (codePoint >= 0x2580 && codePoint <= 0x259F) {
// block elements
ctx.beginPath()
const left = screenX
const top = screenY
const cw = cellSize.width
const ch = cellSize.height
const c2w = cellSize.width / 2
const c2h = cellSize.height / 2
// http://www.fileformat.info/info/unicode/block/block_elements/utf8test.htm
// 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F
// 0x2580 ▀ ▁ ▂ ▃ ▄ ▅ ▆ ▇ █ ▉ ▊ ▋ ▌ ▍ ▎ ▏
// 0x2590 ▐ ░ ▒ ▓ ▔ ▕ ▖ ▗ ▘ ▙ ▚ ▛ ▜ ▝ ▞ ▟
if (codePoint === 0x2580) {
// upper half block >▀<
ctx.rect(left, top, cw, c2h)
} else if (codePoint <= 0x2588) {
// lower n eighth block (increasing) >▁< to >█<
let offset = (1 - (codePoint - 0x2580) / 8) * ch
ctx.rect(left, top + offset, cw, ch - offset)
} else if (codePoint <= 0x258F) {
// left n eighth block (decreasing) >▉< to >▏<
let offset = (codePoint - 0x2588) / 8 * cw
ctx.rect(left, top, cw - offset, ch)
} else if (codePoint === 0x2590) {
// right half block >▐<
ctx.rect(left + c2w, top, c2w, ch)
} else if (codePoint <= 0x2593) {
// shading >░< >▒< >▓<
// dot spacing by dividing cell size by a constant. This could be
// reworked to always return a whole number, but that would require
// prime factorization, and doing that without a loop would let you
// take over the world, which is not within the scope of this project.
let dotSpacingX, dotSpacingY, dotSize
if (codePoint === 0x2591) {
dotSpacingX = cw / 4
dotSpacingY = ch / 10
dotSize = 1
} else if (codePoint === 0x2592) {
dotSpacingX = cw / 6
dotSpacingY = cw / 10
dotSize = 1
} else if (codePoint === 0x2593) {
dotSpacingX = cw / 4
dotSpacingY = cw / 7
dotSize = 2
}
let alignRight = false
for (let dy = 0; dy < ch; dy += dotSpacingY) {
for (let dx = 0; dx < cw; dx += dotSpacingX) {
// prevent overflow
let dotSizeY = Math.min(dotSize, ch - dy)
ctx.rect(left + (alignRight ? cw - dx - dotSize : dx), top + dy, dotSize, dotSizeY)
}
alignRight = !alignRight
}
} else if (codePoint === 0x2594) {
// upper one eighth block >▔<
ctx.rect(left, top, cw, ch / 8)
} else if (codePoint === 0x2595) {
// right one eighth block >▕<
ctx.rect(left + (7 / 8) * cw, top, cw / 8, ch)
} else if (codePoint === 0x2596) {
// left bottom quadrant >▖<
ctx.rect(left, top + c2h, c2w, c2h)
} else if (codePoint === 0x2597) {
// right bottom quadrant >▗<
ctx.rect(left + c2w, top + c2h, c2w, c2h)
} else if (codePoint === 0x2598) {
// left top quadrant >▘<
ctx.rect(left, top, c2w, c2h)
} else if (codePoint === 0x2599) {
// left chair >▙<
ctx.rect(left, top, c2w, ch)
ctx.rect(left + c2w, top + c2h, c2w, c2h)
} else if (codePoint === 0x259A) {
// quadrants lt rb >▚<
ctx.rect(left, top, c2w, c2h)
ctx.rect(left + c2w, top + c2h, c2w, c2h)
} else if (codePoint === 0x259B) {
// left chair upside down >▛<
ctx.rect(left, top, c2w, ch)
ctx.rect(left + c2w, top, c2w, c2h)
} else if (codePoint === 0x259C) {
// right chair upside down >▜<
ctx.rect(left, top, cw, c2h)
ctx.rect(left + c2w, top + c2h, c2w, c2h)
} else if (codePoint === 0x259D) {
// right top quadrant >▝<
ctx.rect(left + c2w, top, c2w, c2h)
} else if (codePoint === 0x259E) {
// quadrants lb rt >▞<
ctx.rect(left, top + c2h, c2w, c2h)
ctx.rect(left + c2w, top, c2w, c2h)
} else if (codePoint === 0x259F) {
// right chair upside down >▟<
ctx.rect(left, top + c2h, c2w, c2h)
ctx.rect(left + c2w, top, c2w, ch)
}
ctx.fill()
} else if (codePoint >= 0xE0B0 && codePoint <= 0xE0B3) {
// powerline symbols, except branch, line, and lock. Basically, just the triangles
ctx.beginPath()
if (codePoint === 0xE0B0 || codePoint === 0xE0B1) {
// right-pointing triangle
ctx.moveTo(screenX, screenY)
ctx.lineTo(screenX + cellSize.width, screenY + cellSize.height / 2)
ctx.lineTo(screenX, screenY + cellSize.height)
} else if (codePoint === 0xE0B2 || codePoint === 0xE0B3) {
// left-pointing triangle
ctx.moveTo(screenX + cellSize.width, screenY)
ctx.lineTo(screenX, screenY + cellSize.height / 2)
ctx.lineTo(screenX + cellSize.width, screenY + cellSize.height)
}
if (codePoint % 2 === 0) {
// triangle
ctx.fill()
} else {
// chevron
ctx.strokeStyle = ctx.fillStyle
ctx.stroke()
}
} else {
// Draw other characters using the text renderer
ctx.fillText(character, cellSize.width * 1.5, cellSize.height * 1.5)
}
}
7 years ago
}