fabricjs - how can I unlock the aspect ratio
Just press the Shift key while scaling.
OR
You can adding this code:
canvas.uniScaleTransform = true;
EDIT:
the property is now called as of Fabric.js 4.0
canvas.uniformScaling = false;
By default, corner controls only resize and maintain aspect ratio.
You can turn off corner controls using setControlsVisibility, like this:
object.setControlsVisibility({
tl: false, //top left
tr: false, //top right
bl: false, //bottom left
br: false //bottom right
});
See this fiddle: http://jsfiddle.net/da7L0n1e/1/