If the Horizon Administrator configures a remote desktop with the correct amount of video RAM, the Web client can resize a remote desktop to match the size of the browser window. The default configuration is 36MB of video RAM, which is comfortably more than minimum requirement of 16MB if you are not using 3D applications.
If you use a browser or Chrome device that has a high pixel density resolution, such as a Macbook with Retina Display or a Google Chromebook Pixel, you can set the remote desktop or application to use that resolution. Turn on the High Resolution Mode option in the Settings window, which is available from the sidebar. (This option only appears in the Settings window if you are using a high-resolution display or a normal display that uses a scale that is greater than 100 percent.)