From 87e98772b09b9b317dee020d22115517635a29c8 Mon Sep 17 00:00:00 2001 From: Henry Jameson Date: Wed, 10 Oct 2018 00:07:28 +0300 Subject: [PATCH] initial contrast display support --- .../contrast_ratio/contrast_ratio.vue | 64 +++++++++++++++++++ .../style_switcher/style_switcher.js | 37 +++++++++-- .../style_switcher/style_switcher.vue | 6 ++ src/services/color_convert/color_convert.js | 39 ++++++++++- 4 files changed, 141 insertions(+), 5 deletions(-) create mode 100644 src/components/contrast_ratio/contrast_ratio.vue diff --git a/src/components/contrast_ratio/contrast_ratio.vue b/src/components/contrast_ratio/contrast_ratio.vue new file mode 100644 index 00000000..6c4a59b6 --- /dev/null +++ b/src/components/contrast_ratio/contrast_ratio.vue @@ -0,0 +1,64 @@ + + + + + diff --git a/src/components/style_switcher/style_switcher.js b/src/components/style_switcher/style_switcher.js index c419a9ce..27efa230 100644 --- a/src/components/style_switcher/style_switcher.js +++ b/src/components/style_switcher/style_switcher.js @@ -1,5 +1,6 @@ -import { rgb2hex } from '../../services/color_convert/color_convert.js' +import { rgb2hex, hex2rgb, getContrastRatio } from '../../services/color_convert/color_convert.js' import ColorInput from '../color_input/color_input.vue' +import ContrastRatio from '../contrast_ratio/contrast_ratio.vue' import OpacityInput from '../opacity_input/opacity_input.vue' import StyleSetter from '../../services/style_setter/style_setter.js' @@ -127,7 +128,7 @@ export default { avatarAltRadius: this.avatarAltRadiusLocal, tooltipRadius: this.tooltipRadiusLocal, attachmentRadius: this.attachmentRadiusLocal - } + }, } }, preview () { @@ -143,9 +144,36 @@ export default { } }, previewTheme () { - if (!this.preview.theme) return { colors: {}, opacity: {}, radii: {} } + if (!this.preview.theme) return { colors: {}, opacity: {}, radii: {}, contrast: {} } return this.preview.theme }, + previewContrast () { + if (!this.previewTheme.colors) return {} + const colors = this.previewTheme.colors + const hints = (ratio) => ({ + text: ratio.toPrecision(3) + ':1', + // AA level, AAA level + aa: ratio >= 4.5, + aaa: ratio >= 7, + // same but for 18pt+ texts + laa: ratio >= 3, + laaa: ratio >= 4.5 + }) + + const ratios = { + bgText: getContrastRatio(hex2rgb(colors.bg), hex2rgb(colors.text)), + bgLink: getContrastRatio(hex2rgb(colors.bg), hex2rgb(colors.link)), + + panelText: getContrastRatio(hex2rgb(colors.panel), hex2rgb(colors.panelText)), + + btnText: getContrastRatio(hex2rgb(colors.btn), hex2rgb(colors.btnText)), + + topBarText: getContrastRatio(hex2rgb(colors.topBar), hex2rgb(colors.topBarText)), + topBarLink: getContrastRatio(hex2rgb(colors.topBar), hex2rgb(colors.topBarLink)), + } + + return Object.entries(ratios).reduce((acc, [k, v]) => { acc[k] = hints(v); return acc }, {}) + }, previewRules () { if (!this.preview.colorRules) return '' return [this.preview.colorRules, this.preview.radiiRules, 'color: var(--text)'].join(';') @@ -153,7 +181,8 @@ export default { }, components: { ColorInput, - OpacityInput + OpacityInput, + ContrastRatio }, methods: { exportCurrentTheme () { diff --git a/src/components/style_switcher/style_switcher.vue b/src/components/style_switcher/style_switcher.vue index 1b00603c..4235d65c 100644 --- a/src/components/style_switcher/style_switcher.vue +++ b/src/components/style_switcher/style_switcher.vue @@ -53,7 +53,9 @@ + +
@@ -81,13 +83,16 @@ +

Top bar

+ +

Inputs

@@ -100,6 +105,7 @@ +

Borders

diff --git a/src/services/color_convert/color_convert.js b/src/services/color_convert/color_convert.js index ae5d5a31..31ee3a6b 100644 --- a/src/services/color_convert/color_convert.js +++ b/src/services/color_convert/color_convert.js @@ -19,6 +19,42 @@ const rgb2hex = (r, g, b) => { return `#${((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1)}` } +// https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef +// https://www.w3.org/TR/2008/REC-WCAG20-20081211/relative-luminance.xml +// https://en.wikipedia.org/wiki/SRGB#The_reverse_transformation +const c2linear = (b) => { + // W3C gives 0.03928 while wikipedia states 0.04045 + // what those magical numbers mean - I don't know. + // something about gamma-correction, i suppose. + // Sticking with W3C example. + const c = b / 255 + if (c < 0.03928) { + return c / 12.92 + } else { + return Math.pow((c + 0.055) / 1.055, 2.4) + } +} + +const srgbToLinear = (srgb) => { + return 'rgb'.split('').reduce((acc, c) => { acc[c] = c2linear(srgb[c]); return acc }, {}) +} + +// https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef +// https://www.w3.org/TR/2008/REC-WCAG20-20081211/relative-luminance.xml +const relativeLuminance = (srgb) => { + const {r, g, b} = srgbToLinear(srgb) + return 0.2126 * r + 0.7152 * g + 0.0722 * b +} + +// https://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef +const getContrastRatio = (a, b) => { + const la = relativeLuminance(a) + const lb = relativeLuminance(b) + const [l1, l2] = la > lb ? [la, lb] : [lb, la] + + return (l1 + 0.05) / (l2 + 0.05) +} + const hex2rgb = (hex) => { const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex) return result ? { @@ -47,5 +83,6 @@ export { rgb2hex, hex2rgb, mixrgb, - rgbstr2hex + rgbstr2hex, + getContrastRatio }