Define a gradient (left to right) as the fill style for the rectangle:
<!DOCTYPE html> <html> <body> <canvas id="myCanvas" width="300" height="180" style="border:1px solid #d3d3d3;"> Your browser does not support the HTML5 canvas tag.</canvas> <script> var c = document.getElementById("myCanvas"); var ctx = c.getContext("2d"); var my_gradient = ctx.createLinearGradient(0, 0, 170, 0); my_gradient.addColorStop(0, "black"); my_gradient.addColorStop(1, "white"); ctx.fillStyle = my_gradient;//from ww w . j a v a 2 s. co m ctx.fillRect(20, 20, 150, 100); </script> </body> </html>