ChiGui is an application running on iOS devices, providing a platform of drawing geometry graphs with straight lines and circles, a.k.a. Compass-and-straightedge construction (or ruler-and-compass construction or classical construction), is the construction of lengths, angles, and other geometric figures using only an idealized ruler and compass.
The "compass" and "straightedge" of compass and straightedge constructions are idealizations of rulers and compasses in the real world. The classical definition of the two tools is as following.
(1) The compass can be opened arbitrarily wide, but (unlike some real compasses) it has no markings on it. Circles can only be drawn starting from two given points: the centre and a point on the circle. The compass may or may not collapse when it's not drawing a circle.
(2) The straightedge is infinitely long, but it has no markings on it and has only one straight edge, unlike ordinary rulers. It can only be used to draw a line segment between two points or to extend an existing line.
However, even though there is a rule about "the compass may or may not collapse when it's not drawing a circle", the function of transfering distance could be realized using a multi-step procedure, a distance can be transferred even with collapsing compass, see compass equivalence theorem.
The app contains only two parts of its main view, a drawing board above and a tool box below. Drawing board is for drawing and tool box provides a number of buttons to execute certain functions.
Use pinch gesture to scale the drawing. However, it would only change the scale to make it easier to tell two near components out.
There are four groups of buttons in the tool box, from left to right are drawing group, editing group, information group, and finally workspace group.
Drawing Group contains:
Free
Stop current drawing and make the temporary points free.
Select
With this switcher on, ChiGui would show you all possible known points, and make it only possible to select point form the choices. (It is useful when you want to do with the point which is the intersection of any line and circle without worrying about mistouch on any area nearby). Otherwise, if it is not turned on, by default, you can select any point on the drawing board. The two way would be generally named "select a point" for short. You can tap this button to switch the two method at any time.
Point
Tap this button, and select a point on the board, you can mark a point as key point, and a cross sign would be centered on the point.
Line
Tap this button and select two points, a infinite line would be drawn through the two points.
Segment
Tap this button and select two points, a segment would be drawn through the two points.
CP Circle
Tap this button, select a point as center and select a point again on circle edge, then a circle would be drawn.
CR Circle
Tap this button, select a point as center, select two points whose distance would be the radius of the circle, then a circle would be drawn.
There are two buttons, Undo and Pressing. Undo function is to earse the last element. And the Pressing Switch controls the Pressing-Select feature.
After you select a point by touch on the draw board, the action of leaving the screen would cause the change of position. If the Pressing is on, you can select a point by hold on the point for about five seconds, then the point would be selected no matter where your touch finally ends. The view around the touch point would be shown in a mirror on top corner.
There are two methods to process the drawing. One is Camera, and the other is Progress.
Camera
Take the snapshot of the current drawing and save it to album, then show the tool box with several methods to share the drawing. If you choose to share with mail, the body text would be the process of drawing it.
Progress
Open the progress page to show the whole history. You can set some elements to be hidden (such as Auxiliary Line or Auxiliary Circle), just tap the elements to fade the checkmark. If you want set it visible again, tap again to recover the checkmark.
In workspace group, you can save the current drawing, open stored drawing to edit, or reset the drawing to be brand new. The final function is what you opened, showing this introduction.
ChiGui is provided by Everstray Jun Sinri Edogawa since 2015. All rights reserved.
Personal Site: http://www.everstray.com Contact: sinri@everstray.com