CODE EXAMPLE FOR JAVASCRIPT

download canvas to png

var canvas =temp1
// Convert the canvas to data
var image = canvas.toDataURL();
// Create a link
var aDownloadLink = document.createElement('a');
// Add the name of the file to the link
aDownloadLink.download = 'canvas_image.png';
// Attach the data to the link
aDownloadLink.href = image;
// Get the code to click the download link
aDownloadLink.click();