2D sketcher: move a selection

Move a selection

After you have made a selection of entities, it is possible to displace it graphically by clicking over then while maintaining the click to move the mouse.

During the displacement, without depressing the click of the mouse, the user can visualize the displacement that he is going to perform.

The selection of displacement requires introducing several constraining rules concerning the arcs.

It exists keyboard shortcuts to move a selection:
  • Accurate movement (equivalent to the dimension of a subdivision of a grid cell) : Ctrl + Arrows (keyboard)
  • Very accurate movement (equivalent to the distance between the magnetization points of the grid : Shift + Ctrl + Arrows (keyboard)

Move an Arc 2 points with center

Here are the rules of displacement of the entities of an isolated arc 2 points with center.

Type of move Arc 2 points with center (alone)
Move an extremity point
  • The center point of the arc remains fixed
  • The radius is modified
  • The 2 nd point extremity is moved on the same axis to respect the radius
  • The angle is modified
Move the center point
  • The assembly of the arc is moved (the line + the three points)
  • The radius and the angle remain unchanged
Move the arc

Move an Arc 2 points without center

Here are the rules of displacement of the entities of an isolated arc 2 points without center .

Type of move Arc 2 points without center (alone)
Move an extremity point
  • The center point of the arc remains fixed
  • The radius is modified
  • The 2 nd point extremity is moved along the same axis to respect the radius
  • The angle is modified
Move the arc
  • The assembly of the arc is moved (the line + the 2 points)
  • The radius and the angle remain unchanged

Move an Arc 3 points

Here are the rules of displacement of the entities of an isolated arc 3 points.

Type of move Arc 3 points (alone)
Displacement of the 1 st point extremity
  • The two other points remain fixed
  • The angle, the radius and the centre point get adapted
Displacement of a point extremity
Displacement of the 2nd point extremity
Displacement of the arc
  • The assembly of the arc is displaced (the line + the three points)
  • The radius and the angle remain unchanged

Arc movement: conflicts

These rules are discussed again due to interdependences between the arcs resulting in complexity increasing rapidly.

Choices of priorities are implemented for the case with several interdependences. For example, the point center of an arc can be the point extremity of another one. In this case, the rule of the point center becomes prevalent over that of point extremity.

The configurations with too much interdependency are not displaceable. In this case, during the displacement the cursor becomes the following symbol

Detection direction lines

During the movement of a selection, a point of the selection must detect direction lines (graphic help, horizontal and vertical lines detected…). This point is called “ grip point ”. It is identifiable by a red highlight and is randomly chosen.

The user can change the movement grip point by using the arrow keys (keyboard) .