qtvcp -docs: update qt_vismach for HideCollection function

Author: c-morley

docs/src/gui/qtvcp-vismach.adoc

@@ -172,6 +172,9 @@ It is much easier to move while building if the origin of the model is at a rota
 
 Alternatively parts can be _created inside the model script from a range of shape primitives_.
 
+*`assembly = collction([part1,part2,part3])`*::
+ Collection is a general container of related parts
+
 Many shapes are _created at the origin_ and need to be _moved to the required location_ after creation.
 
 *`cylinder = CylinderX(x1, r1, x2, r2)`*::
@@ -210,9 +213,6 @@ part4 = Collection([part1, part2])
 Parts may need to be moved in the Vismach space to assemble the model.
 The origin does not move - Translate() and Rotate() move the Collection as you add parts, relative to a stationary origin.
 
-//FIXME unclear
-They may also need to be moved to create the animation as the animation rotation axis is created at the origin (but moves with the Part).
-
 [[sub:qtvcp:vismach:translate]]
 === Translating Model parts
 
@@ -227,7 +227,6 @@ They may also need to be moved to create the animation as the animation rotation
 [[sec:qtvcp:vismach:animate]]
 == Animating Parts
 
-//FIXME 2 or 3 functions ? HalToolCylinder not documented here ?
 To *animate the model controlled by the values of HAL pins* there are four functions:
 `HalTranslate`, `HalRotate`, `HalToolCylinder` and `HalToolTriangle`.
 
@@ -305,7 +304,7 @@ toolshape = Color([1, 1, 0, 1],[HalToolTriangle()])
 ----
 
 === HAL Adjustable Primitives
-All primitives can have HAL pin names substituted for coordinates. +
+All shape primitives can have HAL pin names substituted for coordinates. +
 Either by adding the component object as the first variable and substituting the pinname string for a coordinate, or +
 by substituting the full component/pinname string for a coordinate. +
 
@@ -396,17 +395,17 @@ Sets the _display color of the part_. +
 *`part = Color([_colorspec_], [_part_])`*::
 
   Note that unlike the other functions, the part definition comes second in this case. +
-  `_colorspec_`;; Three RGB values and opacity. +
-  For example [1,0,0,0.5] for a 50% opacity red.
+  `_colorspec_`;; Three (0-1.0) RGB values and opacity. [R,G,B,A] +
+  For example [1.0,0,0,0.5] for a 50% opacity red.
 
 === HALColorFlip
 Sets the _display color of the part based on a designated HAL bit pin state_. +
 
 *`part = HALColorFlip([_colorspec_], [_colorspec_], [_part_], hal_comp, hal_pin)`*::
 
   Note that unlike the other functions, the part definition comes second in this case. +
-  `_colorspec_`;; Three RGB values and opacity. +
-  For example [1,0,0,0.5] for a 50% opacity red.
+  `_colorspec_`;; Three (0-1.0) RGB values and opacity. +
+  For example [1.0,0,0,0.5] for a 50% opacity red.
   `hal_comp`;; The _HAL component Object_ or None. +
     In QtVCP if you are reading _system pins_ directly, then the component argument is set to `None`. +
   `hal_pin`;; The _name of the BIT HAL IN pin_ that will change the color. +
@@ -462,6 +461,20 @@ Some of the available HalHUD function: +
 * add_pin(text, format, pinname)
 * set_text_color(red, green, blue)
 
+=== HideCollection
+
+ HideCollection is a container that uses a HAL pin to control display of the contained parts. +
+ A logic high on the HAL pin will hide the contained parts.
+
+[source,python]
+----
+comp.newpin("hide-chuck", hal.HAL_BIT, hal.HAL_IN)
+# <snip make a machine with an A axis chuck assembly>
+chuckassembly = HideCollection([chuckassembly],comp,'hide-chuck')
+# also can be used like this
+chuckassembly = HideCollection([chuckassembly],None,'myvismach.hide-chuck') 
+----
+
 === Capture
 This sets the current position in the model.