Blank screen when changing concrete5 5.7 presets
A little workaround if you're hitting a blank page when changing your theme presets and customizations in concrete5 5.7
concrete5 5.7 has some fantastic theme customization options which allow theme developers to bundle specific 'preset' color schemes each of which can be further customized to achieve the look you want.
To achieve this, concrete5 makes use of LESS which is compiled to static CSS when you change the preset or make additional customizations. However this compile process is fairly memory intensive and in some themes depending on the amount of options in the LESS preset files you may find that PHP does not have sufficient memory to complete this task. Typically the screen will go completely blank after a preset or customization change.
In testing we were amazed to find the maximum memory requirement reach over 200Mb for this process on one of our themes! This is not a bug in concrete5 nor a problem with the theme it's just the way it is - the price of such terrific flexibility.
Obviously a blank screen is not ideal, so here is a work around. If you have access to php.ini, you can increase the maximum memory available to PHP, or alternatively add a single line to to your theme package which increases it for the duration of the running script i.e your website page render.
Both approaches are shown below, in examples which set the memory limit for PHP to 256MB. Go higher if you need to.
memory_limit = 256M
In the theme
in the theme packages controller.php, add the following on_start method.
public function on_start()