nextcloud/core/js/placeholder.js

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JavaScript
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/**
* ownCloud
*
* @author John Molakvoæ
* @copyright 2016-2018 John Molakvoæ <skjnldsv@protonmail.com>
* @author Morris Jobke
* @copyright 2013 Morris Jobke <morris.jobke@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
* License as published by the Free Software Foundation; either
* version 3 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*/
/*
* Adds a background color to the element called on and adds the first character
* of the passed in string. This string is also the seed for the generation of
* the background color.
*
* You have following HTML:
*
* <div id="albumart"></div>
*
* And call this from Javascript:
*
* $('#albumart').imageplaceholder('The Album Title');
*
* Which will result in:
*
* <div id="albumart" style="background-color: rgb(121, 90, 171); ... ">T</div>
*
* You may also call it like this, to have a different background, than the seed:
*
* $('#albumart').imageplaceholder('The Album Title', 'Album Title');
*
* Resulting in:
*
* <div id="albumart" style="background-color: rgb(121, 90, 171); ... ">A</div>
*
*/
/*
* Alternatively, you can use the prototype function to convert your string to rgb colors:
*
* "a6741a86aded5611a8e46ce16f2ad646".toRgb()
*
* Will return the rgb parameters within the following object:
*
* Color {r: 208, g: 158, b: 109}
*
*/
(function ($) {
String.prototype.toRgb = function() {
var hash = this.toLowerCase().replace(/[^0-9a-f]+/g, '');
// Already a md5 hash?
if( !hash.match(/^[0-9a-f]{32}$/g) ) {
hash = md5(hash);
}
function Color(r,g,b) {
this.r = r;
this.g = g;
this.b = b;
}
function stepCalc(steps, ends) {
var step = new Array(3);
step[0] = (ends[1].r - ends[0].r) / steps;
step[1] = (ends[1].g - ends[0].g) / steps;
step[2] = (ends[1].b - ends[0].b) / steps;
return step;
}
function mixPalette(steps, color1, color2) {
var count = steps + 1;
var palette = new Array();
palette.push(color1);
var step = stepCalc(steps, [color1, color2])
for (i = 1; i < steps; i++) {
var r = parseInt(color1.r + (step[0] * i));
var g = parseInt(color1.g + (step[1] * i));
var b = parseInt(color1.b + (step[2] * i));
palette.push(new Color(r,g,b));
}
return palette;
}
var red = new Color(182, 70, 157);
var yellow = new Color(221, 203, 85);
var blue = new Color(0, 130, 201); // Nextcloud blue
// Number of steps to go from a color to another
// 3 colors * 6 will result in 18 generated colors
var steps = 6;
var palette1 = mixPalette(steps, red, yellow);
var palette2 = mixPalette(steps, yellow, blue);
var palette3 = mixPalette(steps, blue, red);
var finalPalette = palette1.concat(palette2).concat(palette3);
// Convert a string to an integer evenly
function hashToInt(hash, maximum) {
var finalInt = 0;
var result = Array();
// Splitting evenly the string
for (var i in hash) {
// chars in md5 goes up to f, hex:16
result.push(parseInt(hash.charAt(i), 16) % 16);
}
// Adds up all results
for (var j in result) {
finalInt += result[j];
}
// chars in md5 goes up to f, hex:16
// make sure we're always using int in our operation
return parseInt(parseInt(finalInt) % maximum);
}
return finalPalette[hashToInt(hash, steps * 3 )];
};
$.fn.imageplaceholder = function(seed, text, size) {
text = text || seed;
// Compute the hash
var rgb = seed.toRgb();
this.css('background-color', 'rgb('+rgb.r+', '+rgb.g+', '+rgb.b+')');
// Placeholders are square
var height = this.height() || size || 32;
this.height(height);
this.width(height);
// CSS rules
this.css('color', '#fff');
this.css('font-weight', 'normal');
this.css('text-align', 'center');
// calculate the height
this.css('line-height', height + 'px');
this.css('font-size', (height * 0.55) + 'px');
if(seed !== null && seed.length) {
this.html(text[0].toUpperCase());
}
};
$.fn.clearimageplaceholder = function() {
this.css('background-color', '');
this.css('color', '');
this.css('font-weight', '');
this.css('text-align', '');
this.css('line-height', '');
this.css('font-size', '');
this.html('');
this.removeClass('icon-loading');
};
}(jQuery));