About image update tolerance

The image update tolerance defines how much of the resizing the Fred can apply on dummy images, or images to be updated, if their dimensions are different of the dimensions of dummy or existing updated image.

This is per-user setting.

The procedure of setting the image update tolerance is explained in Set the tolerance for image replacement.

About isotropic resizing

If you opt for an isotropic resizing, be aware that such updating may result in changing of the size of images on the page.

For example, if the difference of heights between dummy and real image was 3%, while the difference of the widths was 5% (still within tolerance) Fred4 will scale the image box for the updated image, so it may get out from the grid where it was before updating.

If you opt for not isotropic resizing, the image will always keep its outer dimensions, but it will be distorted as needed to achieve it.

About manual images update from the menu

The Update Selected Image command on the Images menu calls the Fred4 system script ImgUpdateCropIsoKeep. It contains the command Fred4.ImgUpdate 0,true, true. The parameters mean 0% of tolerance, isotropic resizing turned on, referred to image size = true. Please note that the values of the preferences, specified in Tolerance under Automatic refresh (on the Edit > Preferences) may be different, but these are ignored as the used values are hard-coded in the script.

Should you want to specify some tolerance, and/or exclude isotropic, create an overrides script in CustomPage.vb that will call the same command Page.ImgUpdate but with different parameters, e.g. Page.ImgUpdate 10,false, that applies 10% of tolerance and non-isotropic resizing.

See also

Enabling images refresh on page loading or refresh