add tips

.gitignore

@@ -4,3 +4,4 @@
 Manifest.toml
 /docs/Manifest.toml
 /docs/build/
+/docs/.CondaPkg/

docs/src/clip.md

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+# Important tips
+
+The relaxationColorMap() function selects the appropriate color-map (in this case, Lipari for T1) and applies logarithm-processing on that color map. The resulting colormap is returned.
+The "imclip" image should retain the distinction between the "invalid" value of 0 (which is to be displayed as black) and "valid" values that are below loLev (these should be shown in a dark shade of blue). Depending on the calibration of your screen, you may or may not see that distinction.
+
+A simplified processing can be done by
+
+```julia
+using qMRIColors
+cmap = relaxationColorMap("T1")
+VIEW(x,c=cmap) # Do not use range limits here! 
+```
+Again, "VIEW" refers to your favorite viewing software.
+
+If the simplified processing is invoked WITH use of range limits, then the 
+distinction is lost between invalid values and low-but-valid values. See second image in the 
+example below: it represents a circular object with a T1 value that is gradually increasing
+from top to bottom, but only valid within a circular "object", the outside thereof representing 
+unknown T1 values.
+
+Let's build an example to see the effect.
+
+## Create a Synthetic phantom
+
+```@example clip
+using qMRIColors
+using CairoMakie
+
+# -----  Make test object: gradually increasing T1, but invalid outside a circle
+size = 256; center = size÷2+1; radius = 100; origin = CartesianIndex(center,center)
+d(x::CartesianIndex, y::CartesianIndex) = √( (x[1]-y[1])^2 + (x[2]-y[2])^2 )
+row = [10*i for i in 1:size]
+testT1= zeros(size,size)
+testT1 .= row
+
+# Set invalid values to 0
+allidx = CartesianIndices(testT1)
+invalid = allidx[ d.(origin, allidx) .> radius];
+testT1[invalid] .= 0
+nothing
+```
+## Display the example in 3 ways
+
+```@example clip
+# -------------------- Display test object the correct and the wrong way
+loLev = 700
+upLev = 2000
+begin
+  f=CairoMakie.Figure()
+  ax=Axis(f[1,1],aspect = DataAspect(),title = "Using imClip")
+  cmap,imClip = relaxationColorMap("T1",testT1,loLev,upLev)
+  h=heatmap!(ax,rotr90(imClip),colormap=cmap,colorrange=(loLev,upLev))
+  Colorbar(f[1,2],h)
+  hidedecorations!(ax)
+
+  ax=Axis(f[2,1],aspect = DataAspect(),title = "wrong: simplified, \n with range")
+  cmap = relaxationColorMap("T1")
+  h=heatmap!(ax,rotr90(testT1),colormap=cmap,colorrange=(loLev,upLev))
+  Colorbar(f[2,2],h)
+  hidedecorations!(ax)
+
+  ax=Axis(f[3,1],aspect = DataAspect(),title = "OK: simplified, \n no range")
+  cmap = relaxationColorMap("T1")
+  h=heatmap!(ax,rotr90(testT1),colormap=cmap)
+  Colorbar(f[3,2],h)
+  hidedecorations!(ax)
+
+  # clean up plot
+  colsize!(f.layout, 1, Aspect(1,1))
+  resize_to_layout!(f)
+  f
+end
+```
+
+## Conclusion
+
+
+Use the clip version of the images + colormap + the color range
+
+```julia
+ cmap,imClip = relaxationColorMap("T1",testT1,loLev,upLev)
+heatmap(rotr90(imClip),colormap=cmap,colorrange=(loLev,upLev))
+```

docs/src/colormaps.md

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+
+# Colormaps available
+
+```@example 1
+using qMRIColors
+using CairoMakie
+```
+
+## Lipari
+
+This colormap is used for :
+- T1
+
+```@example 1
+cmap = relaxationColorMap("T1")
+cgrad(cmap)
+```
+
+## Navia
+
+This colormap is used for :
+- T2
+- T2*
+- T1rho
+- T1ρ
+
+```@example 1
+cmap = relaxationColorMap("T2")
+cgrad(cmap)
+```
+
+## Reverse lipari
+
+This colormap is used for :
+- R1
+
+```@example 1
+cmap = relaxationColorMap("R1")
+cgrad(cmap)
+```
+
+
+## Reverse navia
+
+This colormap is used for :
+- R2
+- R2*
+- R1rho
+- R1ρ
+- 
+```@example 1
+cmap = relaxationColorMap("R2")
+cgrad(cmap)
+```