javascript6_examples/examples/16.04.scale.js at master · repos-javascript/javascript6_examples

Repository navigation

// Scale the text size of element e by the specified factor

function scale(e, factor) {

// Use the computed style to query the current size of the text

var size = parseInt(window.getComputedStyle(e,"").fontSize);

// And use the inline style to enlarge that size

e.style.fontSize = factor*size + "px";

}

// Alter the background color of element e by the specified amount.

// Factors > 1 lighten the color and factors < 1 darken it.

function scaleColor(e, factor) {

var color = window.getComputedStyle(e, "").backgroundColor; // Query

var components = color.match(/[\d\.]+/g); // Parse r,g,b, and a components

for(var i = 0; i < 3; i++) { // Loop through r, g and b

var x = Number(components[i]) * factor; // Scale each one

x = Math.round(Math.min(Math.max(x, 0), 255)); // Round and set bounds

components[i] = String(x);

}

if (components.length == 3) // A rgb() color

e.style.backgroundColor = "rgb(" + components.join() + ")";

else // A rgba() color

e.style.backgroundColor = "rgba(" + components.join() + ")";

}