setViewportSettings method
Configures the zoom and translate.
viewportScale
is the zoom factor to use, likely >= 1.0 where 1.0 maps
the complete data extents to the output range, and 2.0 only maps half the
data to the output range.
viewportTranslatePx
is the translate/pan to use in pixel units,
likely <= 0 which shifts the start of the data before the edge of the
chart giving us a pan.
Implementation
@override
void setViewportSettings(double viewportScale, double viewportTranslatePx) {
_viewportSettings
..scalingFactor = viewportScale
..translatePx = viewportTranslatePx
..domainExtent = null;
_scaleReady = false;
}