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Ballistic Calculator 2

User guide — a free, open-source ballistic calculator for Windows, Linux and macOS

Reticle elements

Goal of this article: build a reticle out of the six element types, and control what covers what.

A reticle is a list of elements drawn in order. The middle section of the right-hand panel is that list, each entry spelled out as text — Line(s=(-5mil:0mil),e=(5mil:0mil),w=0.01mil,c=black) — and the bottom section is what you do to it.

Every position and size below is an angular measurement relative to the zero point, X positive right and Y positive up, as the previous article describes.

The operations

Button What it does
New Adds an element of the type chosen in the dropdown, opening its dialog empty
Edit Opens the selected element’s dialog
Duplicate Appends an exact copy of the selected element
Delete Removes the selected element
Up / Down Moves the selected element earlier or later in the list

All but New need a selection. The status bar reports what happened after each one — including Edit cancelled, so you can tell a cancelled dialog from one that did nothing.

Duplicate lands exactly on top of the original. It is an exact copy appended at the end of the list, so you will not see anything change; the copy is selected, so Edit it straight away and move it. That is the normal way to build a row of identical marks: duplicate, edit the Y, repeat.

Draw order is list order

Elements are drawn in the order they appear, so later elements cover earlier ones. That makes Up and Down more than tidying:

The five drawing types

Line

Field Notes
Start Point X / Y, End Point X / Y Both ends, in reticle coordinates
Line Width Angular, like everything else. In the shipped Mil-Dot, 0.01 mrad is the hairline crosshair and 0.2 mrad the heavy outer bars
Style Solid, Dashed or Dotted
Color 28 named colours, from black and white through gray, red, darkblue, gold and the rest

The workhorse. Crosshairs, tick marks, ladders, posts.

Circle

Centre X / Y, Radius, line width, style, colour, and a Fill checkbox. Filled circles make dots — the “dot” in Mil-Dot — and unfilled ones make rings, which are useful as range or reference circles.

Rectangle

Position X / Y (its top-left corner), Size width × height, line width, style, colour, Fill. Used for boxes, blocks, and as filled backdrops.

Text

Field Notes
Position X / Y Where the text sits
Text What it says
Text Height Angular — the text is measured in the reticle’s own units, so it scales with everything else
Anchor Left, Center or Right — which end of the string sits at the position
Color As above

Anchor is what makes a column of numbers line up: right-anchored labels to the left of a vertical ladder, left-anchored to the right of it.

Path

Anything with a corner or a curve that is not a circle: chevrons, horseshoes, tapered posts. It has enough in it to deserve its own article.

BDC points are not drawings

The sixth type, BDC Point, is different in kind. It does not draw a shape — it marks a position the calculator will label with a distance.

Field Notes
Position X / Y Where the mark is
Text Height The angular height of the label the calculator will draw
Text Offset How far to the side of the position that label sits

In the editor’s preview, each BDC point shows as a dark blue circle with its own Y coordinate as the label — the editor has no trajectory, so the only number it can show you is where the point is.

In the calculator, the same point gets labelled with the range at which your current load’s drop lands there, which is what the reticle view’s Far and Near BDC overlays are made of. So BDC points are anchors: you put them on the marks your reticle really has, and the solver names them for the load you are shooting.

They live in the same list as the drawing elements and take the same Duplicate / Delete / Up / Down operations.

Seeing what you have selected

View → Highlight Current Item redraws the selected element in blue, on top of everything. On a busy reticle it is the only quick way to tell which of many similar lines is selected.

It is a copy of the element with the colour changed, so a filled shape highlights as a filled blue shape — which can hide what is underneath it while the highlight is on. Turn it off when you want to judge the finished drawing.

Next

Reticle paths — the one element type with its own editor inside the editor.


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