ios - Non-scaling / absolute gradient for scatter plots in CorePlot? -

i've added gradient scatter plot in usual manner:

cptfill areagradientfill = [cptfill fillwithgradient:areagradient1]; boundlineplot.areafill = areagradientfill; boundlineplot.areabasevalue = 0; 

setting minimum gradient easy areabasevalue property. however, gradient stretch such entire range of color defined areagradient1 appears below line plot.

what i'd set absolute y-axis range (e.g., 0 100) , have gradient set range. if line @ y=50, bottom 50% of gradient rendered below line. thought setting boundlineplot.areabasevalue2 = 100; this, doesn't have effect.

does coreplot support this? if not, what's 'right' way go implementing it?

(this first question apologies if i'm not clear. gentle. :) )

while there's no direct way make happen use trick. make horizontal global range wider show , not make graph horizontally scrollable. add value graph in hidden area maximum value. filled full gradient. other parts partial gradient, depending on height.

i found trick accident while looking @ 1 of graphs. look:

the overview @ top shows big graph (the green limit band). compare part:

you can see tip of large value has different gradient value tip of smaller one.