Example: Create a Line using the Record Panel

 

Example: Create a Line using the Record Panel

In this example we create a line in a drawing using the Coordinates tab of the Record panel in the Contents pane.  

 

We begin with a new, blank drawing.  We  right-click into the Project pane and choose New Drawing and then we double-click on that new drawing to open it in a window.

 

il_create_line_command.png

 

As described in the Editing Drawings topic, we choose Create Line for the mode button in the main toolbar.

 

eg_newob02_01.png

 

In the drawing we click three times to mark three vertices for the drawing.    To see the coordinates, click on the Coordinates tab in the Record panel in the Contents pane.  

 

eg_newob02_02.png

 

The coordinates of the vertices appear in the Coordinates tab.   The coordinates are shown in blue preview color since the line has not yet been committed.  Even though the line is still in the process of being created, we can click on one of the coordinates rows to edit the location of a vertex that has already been clicked.   We click on the row handle for the second row.

 

eg_newob02_03.png

 

That moves the row cursor onto that row.

 

eg_newob02_04.png

 

In the drawing, the corresponding vertex is marked as selected for editing.

 

eg_newob02_05.png

 

Back in the Coordinates tab, we can Double-click onto one of the coordinates to edit that coordinate.

 

eg_newob02_06.png

 

We will change the Y coordinate for that vertex from 8 to 70.    Press Enter.

 

eg_newob02_07.png

 

Right away, in the drawing the vertex moves upwards from the position using a Y coordinate of 8 to the position using a Y coordinate of 70.  

 

If we like, we can use the Coordinates tab to add a new vertex immediately after the selected vertex.  On the keyboard, we press the Insert key.

 

eg_newob02_08.png

 

A new insert row appears below the previously selected row.  

 

eg_newob02_09.png

 

If we move the mouse over the drawing, the drawing lines now follow the mouse cursor to allow us to click to insert a new vertex.   We click at the indicated position to insert a new vertex.

 

eg_newob02_10.png

 

Back in the Coordinates tab a new vertex row has appeared and the insert row has moved down one position.

 

eg_newob02_11.png

 

In the drawing we can click at the indicated position to insert another new vertex.

 

eg_newob02_12.png

 

The drawing line segments will "rubber band" to follow the mouse cursor.   Instead of clicking we will now click the Add Record button in the Coordinates tab.

 

eg_newob02_13.png

 

Clicking the Add Record button has the same effect as right-clicking in the drawing: it commits the creation of the new line, which up to now has simply been previewed in blue preview color.    If we want to abandon the creation of the new line, we can press the Esc key.

 

eg_newob02_14.png

 

That creates a new line.

Editing a Line

We can continue this example by editing the line we just created.

 

eg_newob02_15.png

 

We begin by clicking the default mouse mode to get out of line creation mode.

 

eg_newob02_16.png

 

Next, to select the line for editing we Shift-Alt-click it.    A Shift-Alt-click chooses the line and immediately opens the Coordinates tab of the Record panel.

 

eg_newob02_17.png

 

The line appears in blue provisional color, marked with larger boxes at the vertices, with a large, enabled-for-editing box marking the first vertex.

 

eg_newob02_18.png

 

The Record panel automatically opens to the Coordinates tab.   By default, the row cursor is on the first vertex row, corresponding to the first vertex in the line that is marked with a large, enabled-for-editing box.

 

eg_newob02_19.png

 

We Click on the row handle for the third vertex.  That moves the row cursor to that vertex row.

 

eg_newob02_20.png

 

In the drawing the third vertex is now marked with the larger, enabled-for-editing box.   We can click and drag that vertex to a different position.

 

eg_newob02_21.png

 

As we drag the vertex to a new location the blue preview lines showing the proposed new shape of the line will rubber-band to follow the moved vertex.  Current line segments remain shown in black.

 

eg_newob02_22.png

 

Releasing the click and drag motion, the vertex appears in the new location in blue preview color.

 

eg_newob02_23.png

 

The new coordinates of the vertex are shown in the Coordinates tab in blue preview color.   To commit the change, we can press the Update Record button or right click in the drawing and choose Save Changes.

 

eg_newob02_24.png

 

The line appears in the new configuration, still chosen for use in the Record panel.   To exit the selection of the line we can Alt-click anywhere outside the line.

 

eg_newob02_25.png

 

That shows the line in final, edited appearance.

 

Notes

Zillions of digits after the decimal point - Why are the coordinate numbers in some illustrations relatively short numbers like 199.5 or 177.5 but sometimes when we try to repeat this example the numbers have many digits after the decimal point as in the illustration above?   That depends upon the zoom level we use in the drawing.

 

If we create a new. blank drawing in the Project pane, open it and without zooming in or out begin adding new lines we are working at the default zoom level of a drawing when it opens.   At the default zoom level, every pixel on the screen occupies a more or less round number of units of measure in whatever coordinate system the drawing utilizes, so no matter where we click we click on a pixel at some reasonably round number of units of measure.     We might click at a coordinate location with numbers such as 199.5 or 177.5 but because we cannot click into a fraction of a pixel we cannot click at a location that has numbers such as 15.921622760800847 or -52.834836670179136.

 

In contrast, when we zoom in or out, especially if we use Zoom Box where Manifold will zoom not to some quantized zoom level but to whatever zoom we command with exact mathematical accuracy, the coordinate numbers that each pixel represents could easily be some fraction that could extend with many digits past the decimal point.   

 

In fact, Manifold uses full accuracy at all times but the system truncates endless strings of zeros so instead of showing numbers like 199.500000000000000 the dialogs simply show 199.5.  

 

How do we constrain our creation of objects so that we always click onto coordinates that are reasonably round numbers?   By always editing using default zoom levels.    If we want to go beyond that and to use whatever zoom we like while constraining new coordinates to reasonably round values, when features such as  snap to grid become available we could use those.

 

See Also

Drawings

 

Coordinates

 

Contents Pane

 

Contents - Record

 

Example: Create a Line using Curved Segments - Creating a line made up from curvilinear geometry using the New Object Dialog.

 

Example: Create an Area with a Hole - Using the New Object Dialog, create an area in a drawing where the area includes one or more holes.  This is similar to how we create areas that have islands as part of the area.   

 

Example: Create an Area with Holes and Islands - Using the New Object Dialog, create an area in a drawing where the area includes holes and also islands.

 

Example: Create a Multipoint - How to create multipoints using the New Object Dialog.  This topic provides two examples:  First we create a multipoint and then next we create a multipoint having two branches.  The purpose of this topic is to help teach the implementation of geometry in Manifold and other typical spatial packages using a somewhat unusual and rarely met object type, the multipoint, which combines what appear to be many separate points into a single multipoint object.

 

Example: Edit Coordinates While Creating an Object - When creating an object in a map using a tool such as Create Area, right in the middle of the process we can edit coordinates in the Contents - Record panel's Coordinates tab.   This example shows the step by step process.

 

Example: Edit Attributes and Move a Point - We look at the attributes for a point in a drawing layer and edit one of the attributes using a more expanded Edit dialog.  We then move the point to a new location. Easy!

 

Example: Edit Attributes, Larger Text, IME for Asian Languages - A tour showing how to edit attributes in a drawing using the Record panel Values tab and the expanded Edit dialog, including advanced Unicode facilities and use of the built in Input Method Editor (IME) to input text in Japanese language.