Cascade Historian™ : Version 6.4
	Dynamic Library Functions

`hist_scale_buffer`

hist_scale_buffer — performs offset and scaling operations.

Syntax

hist_scale_buffer (buffer, xscale, xoffset, yscale, yoffset)

Parameters

buffer

A binary buffer of X-Y pairs of doubles, created by a call to hist_buffer_id_read.

xscale, xoffset

The X value of the data pairs is transformed as follows:

x' = x * xscale + xoffset

yscale, yoffset

The Y value of the data pairs is transformed as follows:

y' = y * yscale + yoffset

Returns

t (true) if the transformation was performed with no errors, otherwise nil.

Description

This function performs an offset and scaling transformation on a binary buffer of X-Y data pairs. The buffer is modified in place (i.e., a new buffer is not created, and the old values cannot be recovered). This function can be used to adjust data for graphing.

This function corresponds to the Cogent C API function HI_ScaleBuffer.

Example

// To shift the Y data by 100 units:
hist_scale_buffer (data, 1, 0, 1, 100);


hist_register		hist_stat_buffer