This page is to help draw and manipulate parallelograms to teach resolution of 2D vectors.
Hover the mouse over a vector for guidance. Right click anywhere for a new vector.
Or left click the button, bottom right, for moments, and simple line drawing. Also freehand drawing, in case there is use for a tablet pen.
See below the panel to select a background diagram. Single left click to put the diagram in the frame, then click and drag.
Not tablet- or phone-friendly, as yet.
load a saved work file or a background image file:
Left click the buttons below to put diagrams into the frame.
There are no double clicks. All click and drag is left mouse button. All single clicks are right button in the frame; but single clicks are left button out of the frame (for all of the buttons, where right wasn't feasible, sorry about that).
The right-clicks for the magnitude and angle labels toggle as follows:
Magnitude (or moment or line) label: first click, get default expression; second click, open menu; third click, close menu.
Angle: first click, get default expression; second click open menu; third click, close menu, keep new expression and lock angle (shows arc); fourth click, lose expression and keep arc; fifth click lose all.
For subscripts, type an underscore '_' before the character; for superscripts, a hat '^' before the character.
For Greek letters, type a '`' (far left key on the number row) before an approximate English correlate.
For the degree circle '°', type '@'.
For the root sign '√', type back slash '\'.
For fractions '¼', '½' and '¾', type shift-1, shift-2 and shift-3.
Hover near the top end of a vector (or moment or other) and type ctrl-c to copy the shape, then ctrl-v to paste at a new mouse position.
With ctrl key down, left click on whitespace and drag to enclose multiple shapes in a box to copy (ctrl-c while dragging when box ready) or drag (ctrl-d while dragging when box ready, then mouse up then click in box and drag).
In Chrome and Firefox but not IE: the very first ctrl-v (in a refreshed page) will paste any image currently in the main operating system's clipboard. E.g. a screenshot.
Or you can load a background image (as well as saved work) using the load button.
Either way, the background image will not be included in a work file that you save. (But can of course be reloaded along with the work file.)
'Print' exports a snapshot (including background, but minus buttons) as a png file.
There are also two blank sheets with just a centimetre corner poking out (when you hover) top-left and top-right, which can be dragged over unwanted parts of a background image.
There is some undo and re-do function (ctrl-z and ctrl-y).
ctrl-left-arrow will hide shapes one by one. ctrl-right-arrow will un-hide one by one (including those hidden by ctrl-h). (Excluding freehand marks.)
This allows you to present a ready-made picture step-by-step, powerpoint-style. While presenting you can also modify any (unhidden) shape in the sequence, and insert or remove from the sequence.
Notice also you can unhide a shape, then subsequently unhide its various labels.
Really grateful for any contributions in the form of worked examples to add to the wall, above. (Email the work file and the background image file if any.)
All feedback welcome, including improvements to the amateur coding, and reports of unfriendly behaviour.
Latest update 10/12/18. Tweaked print.