Page caching
Once accessed all pages are kept in a RAM cache up to the maximum allowed cache size depending on the actual
platform’s available RAM. This allows a much faster access since cached pages, once reloaded, only need to re-paint their
content without reloading all page resources.
Image DB
Image DB is a technique used to track the usage of image files and reduce the cost of image loading by caching most
frequently used images (example, Push Button images, Gauge needles, Slider thumbs and so on). The same image used in
many different places is therefore loaded just once.
The image DB function will preload the top most used images at startup until memory limit is reached. This would further
improve the individual page loading times.
The file imagecachelist.xml is created in project/opt folder, containing relevant information:
l Fill color (in case of SVG images)
l Size of SVG image
l Number of times an image is used in the project
l Number of different sizes for the same image
Tips for using the Image DB function
1. Use uniform size of buttons, gauges and other widgets wherever possible.
2. Use same color themes among widgets of the same kind.
Precaching
The Precache attribute of pages can be used to notify HMI Runtime to preload some pages in RAM at boot time for quicker
access. Precaching is useful for complex pages having many dynamic widgets.
When this function is enabled on a page, access to the page is faster, however it also slows down boot-time since the
system is not ready until all pages to be precached are not saved into the RAM.
Tips to precaching
1. Enable the precache function just for few pages having many dynamic widgets or for pages frequently used by
users.
2. Do not enable the precache function for all the pages in the project since you would hìruno out of memory and have
no benefit at all.
3. Disable static optimization for pages where the precache function is enabled to reduce memory used.
FAQ on precaching
Page limit for precaching
Based on the size and complexity of a page, the space required for precaching can be from 1,5Mb to 3Mb.
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HMWIN Studio |User Manual|v206 (2017-06-30) |EN|© 2014-2017 Panasonic Electric Works Europe AG
Page caching
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