qt5base-lts/util/gradientgen/gradientgen.js
Tor Arne Vestbø c4a21708ed Provide presets for QGradient
Similar to Qt::GlobalColor, the presets allow the user to create
brushes based on predefined gradients, quickly getting pretty pixels
on screen.

The presets are based on the linear gradients from WebGradients, a
free collection of gradients, hosted at https://webgradients.com/.
The few radial and blended gradient presets have been excluded.

Change-Id: I1ce8f2210a6045c9edb8829ab3eddcc313549127
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
2018-05-31 15:50:50 +00:00

124 lines
4.0 KiB
JavaScript
Executable File

#! /usr/bin/env node
/****************************************************************************
**
** Copyright (C) 2018 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the utils of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
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****************************************************************************/
const _ = require('lodash');
const fs = require('fs');
const postcss = require('postcss');
const minifyGradients = require('postcss-minify-gradients');
const valueParser = require('postcss-value-parser');
const parseColor = require('parse-color');
const math = require('mathjs');
const argc = process.argv.length;
if (argc < 3) {
console.log("usage: gradientgen [mode] <filename>");
process.exit(1);
}
const filename = process.argv[argc - 1];
const mode = argc > 3 ? process.argv[argc - 2] : '';
fs.readFile(filename, (err, css) => {
postcss([minifyGradients]).process(css)
.then(result => {
let enums = [];
let gradients = [];
result.root.walkRules(rule => {
gradients.push(null); // Placeholder
const name = _.startCase(rule.selector).replace(/\s/g, '');
if (enums.indexOf(name) >= 0)
return; // Duplicate entry
// We can only support single gradient declarations
if (rule.nodes.length > 1)
return;
valueParser(rule.nodes[0].value).walk(node => {
if (node.type !== 'function')
return;
if (node.value !== 'linear-gradient')
return;
const args = node.nodes.reduce((args, arg) => {
if (arg.type === 'div')
args.push([]);
else if (arg.type !== 'space')
args[args.length - 1].push(arg.value);
return args;
}, [[]]);
let angle = valueParser.unit(args[0][0]);
if (angle.unit !== 'deg')
return;
angle = parseInt(angle.number);
if (angle < 0)
angle += 360;
// Angle is in degrees, but we need radians
const radians = angle * math.pi / 180;
const gradientLine = (math.abs(math.sin(radians)) + math.abs(math.cos(radians)));
const cathetus = fn => math.round(fn(radians - math.pi / 2) * gradientLine / 2, 10);
const x = cathetus(math.cos);
const y = cathetus(math.sin);
const start = { x: 0.5 - x, y: 0.5 - y };
const end = { x: 0.5 + x, y: 0.5 + y };
let stops = []
args.slice(1).forEach((arg, index) => {
let [color, stop = !index ? '0%' : '100%'] = arg;
stop = parseInt(stop) / 100;
color = parseColor(color).hex;
color = parseInt(color.slice(1), 16)
stops.push({ color, stop })
});
gradients[gradients.length - 1] = { start, end, stops };
});
enums.push(name);
if (mode == 'enums')
console.log(`${name} = ${gradients.length},`)
});
// Done walking declarations
if (mode != 'enums')
console.log(JSON.stringify(gradients, undefined, 4));
});
});